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  • Digitale Medien  (1.738)
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  • 1
    Digitale Medien
    Digitale Medien
    Springer
    Diseases of the colon & rectum 40 (1997), S. 939-945 
    ISSN: 1530-0358
    Schlagwort(e): Laparoscopy ; Port site implants ; Colectomy ; Complications ; Pneumoperitoneum
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Abstract BACKGROUND: An increased risk of laparoscopic port wound tumor implantation in the presence of overt or covert abdominal malignancy has been identified. PURPOSE: A porcine laparoscopic colectomy model has been used to quantify the influence surgical practices may have on tumor cell implantation. METHODS:51Cr-labeled, fixed HeLa cells were injected intraperitoneally before surgery. Tumor cell contamination of instruments, ports, security threads, and excised wound margins was assessed by gamma counting. RESULTS: Greatest contamination occurred in ports used by the operating surgeon under pneumoperitoneum (64 percent of all port wound tumor cells) and mechanical elevation (76 percent). Gasless surgery in patients in the head-down position increased the rostral accumulation of tumor cells in the abdomen and right upper quadrant port wound by 330 and 176 percent, respectively. Under pneumoperitoneum, port movement was the major contributor to port leakage and wound contamination (21 percent of total recovered wound tumor cells per port). Tumor cells were not carried in aerosol form. Instrument passage and the withdrawal of security threads through the abdominal wall increased port wound contamination 430 and 263 percent, respectively, over pneumoperitoneum control ports. Preoperative lavage reduced by 61 percent, but did not eliminate, wound contamination. CONCLUSION: This porcine model may be used to evaluate surgical factors for the impact on port wound contamination.
    Materialart: Digitale Medien
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  • 2
    Digitale Medien
    Digitale Medien
    Springer
    Diseases of the colon & rectum 40 (1997), S. 1009-1013 
    ISSN: 1530-0358
    Schlagwort(e): Abscess ; Computed tomography-guided drainage ; Complications ; Anastomotic leak
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Abstract PURPOSE: This study was designed to assess the efficacy of computed tomography-guided percutaneous abscess drainage in intestinal disease. METHODS: Retrospective chart review of patients who underwent percutaneous abscess drainage for complications of intestinal disease with or without surgery between 1990 and 1994. RESULTS: Eighty-two patients with 111 abscesses were identified. Causes of abscess included anastomotic leaks (35 percent), postoperative complications without leak (30 percent), and diverticular disease (23 percent). Complete success (no surgery necessary) was achieved in 53 of 82 patients (65 percent). Nine patients (11 percent) who underwent interval surgery were classified as having partial successes. Twenty-six of 26 (100 percent) well-defined unilocular collections containing pus were successfully drained. Complex abscesses (loculated, poorly defined, multiple, associated with fistula, draining feces) were successfully drained in 35 of 55 patients (63 percent). Success rates varied inversely with the number of complicating factors present. Apache II scores of 15 or higher were associated with decreased success rates. CONCLUSION: Percutaneous abscess drainage is a highly successful technique for treatment of patients with intra-abdominal infection related to intestinal disease. Although several factors are associated with decreased success rates and multiple complicating factors combine to reduce success rates, no identifiable factor or combination of factors preclude the possibility of a successful outcome.
    Materialart: Digitale Medien
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  • 3
    Digitale Medien
    Digitale Medien
    Springer
    Diseases of the colon & rectum 40 (1997), S. 257-262 
    ISSN: 1530-0358
    Schlagwort(e): Heal pouch-anal anastomosis ; Ulcerative colitis ; Crohn's disease ; Familial adenomatous polyposis ; Complications
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Abstract PURPOSE: This study was designed to identify factors associated with pelvic pouch failure. METHOD: A retrospective review of patients undergoing the pelvic pouch procedure with a minimum of 30 months follow-up was conducted. RESULTS: A total of 551 patients had pelvic pouch procedures from 1981 to 1992. Forty-nine patients (8.8 percent) have undergone pouch excision, and 9 (1.6 percent) have been defunctioned, for 58 (10.5 percent) patients with pouch failure. Cause of failure was leakage from the ileoanal anastomosis (IAA) in 21 (39 percent) patients, poor functional results in 13 (23 percent), pouchitis in 7 (12 percent), pouch leakage in 7 (12 percent), perianal disease in 7 (12 percent), and miscellaneous in 3 (5.2 percent). Nine of 22 patients (41 percent) had pouch failure during the first two years, with 2 of 147 patients (1 percent) having failure during the last two years of the study. The 58 patients whose pouches failed (Group 1) were compared with the 493 patients whose pouches did not fail (Group 2). Handsewn IAA (P 〈0.001), tension on the IAA (P 〈0.001), use of a defunctioning ileostomy (P 〈0.01), a diagnosis of Crohn's disease (P 〈0.001), and a leak from the pouch (P 〈0.001) or the IAA (P 〈0.001) were associated with pouch failure. Pouchitis was not a risk factor. CONCLUSION: The majority of pouch failures were caused by leaks at the IAA. Although the leak rate remained stable, leaks following a stapled anastomosis seemed to have a better prognosis than leaks following a handsewn anastomosis. Experience with the pouch procedure and the management of complications likely plays an important role in decreasing the risk of pouch failure.
    Materialart: Digitale Medien
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  • 4
    Digitale Medien
    Digitale Medien
    Springer
    Diseases of the colon & rectum 40 (1997), S. 112-115 
    ISSN: 1530-0358
    Schlagwort(e): Stoma ; Laparoscopy ; Closed technique ; Complications ; Surgical technique
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Abstract Stoma creation often involves a separate laparotomy incision. Recently, laparoscopy was suggested to minimize the morbidity associated with conventional open stomal techniques. We describe and evaluate a technique of stoma creation done directly through the stoma site, avoiding both laparotomy and laparoscopy. METHODS: Charts of 36 patients who underwent attempted stoma creation using this closed technique were retrospectively reviewed. RESULTS: A total of 32 patients had stomas successfully created in this fashion (closed group); although four patients failed and required laparotomy (open group), there was an overall success rate of 89 percent. Blood loss (17±5 vs. 350±130 ml; P 〈.001), operative time (52±8 vs. 169±35 minutes; P 〈0.001), and complications (3/32 vs. 4/4;P 〈0.001) favored the closed group. No factors, including diagnosis, obesity, or previous abdominal surgery were identified that contraindicated use of the closed technique. CONCLUSIONS: Stomas can be safely made in a high proportion of patients without the need for laparotomy or laparoscopy. Failure of the closed technique identifies a group of patients who have a high associated operative time, blood loss, and morbidity when laparotomy is used for stoma creation and in whom laparoscopic procedures may improve results.
    Materialart: Digitale Medien
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  • 5
    Digitale Medien
    Digitale Medien
    Springer
    Annals of surgical oncology 4 (1997), S. 349-354 
    ISSN: 1534-4681
    Schlagwort(e): Epithelial ovarian cancer ; Second-look laparotomy ; Complications ; Secondary cytoreduction ; Survival
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Abstract Background: The routine inclusion of second-look laparotomy in the management of patients with epithelial ovarian cancer is controversial. At issue is the justification of morbidity incumbent upon surgery and the possible survival benefit of secondary cytoreduction. Methods: The rate of major complications of surgery was assessed among 100 consecutive patients with FIGO stage III or IV epithelial ovarian cancer who underwent second-look laparotomy. All patients demonstrated a complete clinical and biochemical (CA125 〈35 U/ml) response to first-line therapy. Patients were stratified based on findings at surgery. Patients in group 1 (n=37) had a negative second-look laparotomy. Patients in group 2 (n=35) had only microscopically appreciable disease. Patients in group 3 (n=28) had macroscopic disease. Cytoreductive efforts aimed at resection of all macroscopic disease were carried out for patients in group 3. Results: Thirteen patients (13%) had 15 major complications at surgery. Comparison of the complication rates for patients in groups 1, 2, and 3, of 10%, 8.5%, and 21.4%, respectively, did not achieve statistical significance (p=0.228). The estimated 5-year survival for patients in groups 1, 2, and 3 of 63.9%, 39.8%, and 14.2%, did differ significantly (p〈0.0001). Cytoreductive efforts resulted in the resection of all macroscopic disease in 18 of 28 patients (64.2%) in group 3. The median survival for this group of 18 patients was 33 months, and estimated 5-year survival was 20%. These values do not differ significantly from those observed for patients in group 2. Conclusion: The major complication rate associated with second-look laparotomy is not prohibitive Secondary cytoreductive efforts may result in improved survival for patients with epithelial ovarian cancer.
    Materialart: Digitale Medien
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  • 6
    ISSN: 1438-8359
    Schlagwort(e): Double-lumen tube ; Complications ; Tube troubles ; Airway obstruction ; One-lung ventilation
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Abstract Purpose Several case reports indicate critical respiratory complications in relation to the double-lumen endobronchial tube (DLT). A prospective survey for the airway problems in using the DLT is presented. Methods One hundred adult patients undergoing thoracotomy for lung cancer were investigated. Tube malposition and airway obstruction were searched using a fiber-optic scope. The endobronchial cuff was positioned just below the trachcal carina while the trachea was intubated with a DLT (Rüsch). The distances of displacement, from the tracheal carina to the bronchial cuff, were measured during anesthesia using an epidural catheter, which had marks every 5 mm. The distances for correcting the tube position were measured at both the bronchial cuff and the level of the teethPaO2,PaCO2 andSPO2 were also measured. Results Malposition (displacement over 5 mm from the correct position) was found in 42 patients, and 40 of them were in a withdrawal direction, occurring at the postural change and during one-lung ventilation, especially during manipulation of the lung hilum. Correcting distances at the level of the teeth were 15.3–3-times longer than those at the bronchial cuff. Airway deformities and gradual withdrawal of the bronchial cuff were found in association with surgical manipulation. Obstruction occurred at the tips of the tracheal tube in four patients and the bronchial tube in six patients, and at the tip of both in two patients. Hypoxemia (PaO2〈60 mmHg) occurred in four patients and hypercapnea (PaCO2〉60 mm Hg) in two patients. Conclusion Most of the DLT obstructions were associated with withdrawal malposition. Great attention to DLT displacement and airway deformity is advised.
    Materialart: Digitale Medien
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  • 7
    Digitale Medien
    Digitale Medien
    Springer
    Gefässchirurgie 2 (1997), S. 144-149 
    ISSN: 1434-3932
    Schlagwort(e): Schlüsselwörter Shunt ; Dialyse ; Offenheitsrate ; Komplikation ; Key words Fistula ; Hemodialysis ; Patency rate ; Complications
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Beschreibung / Inhaltsverzeichnis: Abstract This paper reports our experience in surgery for hemodialysis access. In the period from 1983 to 1995, 728 operative procedures for hemodialysis access shunts were carried out. These were performed in 391 patients. A total of 599 shunts were placed as the primary form of access, including 423 autologous fistulas in the forearm and 144 in the upper arm. Additionally, 30 PTFE grafts were placed. As proposed, we have seen good functional results of the Brescia-Cimino-fistula in the forearm. Shunts in the upper arm show similar results but a higher rate of complications. PTFE grafts are associated with multiple complications and show a significantly lower rate of patency.
    Notizen: Zusammenfassung Ziel der Arbeit ist die Darstellung eigener Erfahrungen als gefäßchirurgisches Zentrum mit der Dialyseshuntchirurgie. Im Zeitraum von 1983–1995 erfolgten in unserer Klinik insgesamt 728 shuntchirurgische Eingriffe an 391 Patienten; 599 Eingriffe waren Neuanlagen von Dialyseshunts. Als autologe Dialysefisteln wurden 423 am Unterarm und 144 am Oberarm angelegt. Bei 30 Dialyseshunts erfolgte die Anlage unter Verwendung von Gefäßprothesen. Erwartungsgemäß fanden sich gute Ergebnisse für die Brescia-Cimino-Fistel am Unterarm. Oberarmfisteln wiesen bei höherer Komplikationsrate gleich gute funktionelle Ergebnisse auf. Prothesenshunts waren komplikationsträchtig und zeigten signifikant schlechtere Funktionszeiten.
    Materialart: Digitale Medien
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  • 8
    Digitale Medien
    Digitale Medien
    Springer
    Gefässchirurgie 2 (1997), S. 65-68 
    ISSN: 1434-3932
    Schlagwort(e): Schlüsselwörter Glutealnekrose ; Aortoiliakale Chirurgie ; Komplikationen ; Key words Gluteal necrosis ; Aorto-iliac surgery ; Complications
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Beschreibung / Inhaltsverzeichnis: Abstract Chronic hypoperfusion of the hypogastric arteries due to aortoiliac surgery leads to a complex of symptoms well known as Lerich's syndome. In contrast, acute ischemia of the pelvic arterial tree leads to lethal complications [2, 4, 5, 9, 10, 12, 13]. Acute interruption of the hypogastric perfusion mainly occurs after aortoiliac surgery or after selective transcatheter embolisation of the internal iliac artery for control of pelvic bleeding [1, 8]. Several complications may occur after total occlusion: urinary bladder necrosis [6], left colon ischemia, spinal cord ischemia [10], nerve palsy, necrosis of the rectum and gluteal musculature [2, 11–13]. Despite adequate therapy, mortality is over 70% [2]. We report the case of a 66-year-old patient who survived after acute occlusion of the iliac arteries with gluteal necrosis following replacement of the infrarenal aorta with an aortobiiliacal graft.
    Notizen: Zusammenfassung Die chronische Minderperfusion im aortoiliakalen Stromgebiet führt zu einem Symptomenkomplex, der als Leriche-Syndrom bekannt ist. Im Gegensatz dazu drohen bei akuter Ischämie nach Verschluß der Beckenarterien schwere Komplikationen mit teilweise letalem Ausgang [2, 4, 5, 9, 10, 12, 13]. Die akute Unterbrechung der aortoiliakalen Perfusion wird überwiegend nach Eingiffen an der Aorta und den Beckenarterien, oder auch nach selektiver kathetergesteuerter Embolisation der Iliakalarterien zur Beherrschung von Blutungen im Beckenbereich beobachtet [1, 8]. Die verschiedenen Komplikationen verteilen sich auf Blasennekrosen [6], linksseitige Kolonischämien und Spinalarterienischämien [10], Nervenausfälle sowie Nekrosen des Rektums und der Glutealmuskulatur [2, 11–13]. Trotz adäquater Therapie beträgt die Letalität über 70% [2]. Wir berichten über einen 66jährigen Patienten, bei dem nach Ausschaltung eines rechtsseitig gedeckt rupturierten Iliakalaneurysmas durch eine Y-Prothese aufgrund eines beidseitigen Verschlusses der Aa. iliacae internae eine bilaterale Glutealnekrose auftrat, der aber dennoch diese meist letale Komplikation überlebte.
    Materialart: Digitale Medien
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  • 9
    Digitale Medien
    Digitale Medien
    Springer
    Der Chirurg 68 (1997), S. 395-402 
    ISSN: 1433-0385
    Schlagwort(e): Key words: Laparoscopic cholecystectomy ; Complications ; Legal consequences. ; Schlüsselwörter: Laparoskopische Cholecystektomie ; Komplikationen ; forensische Konsequenzen.
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Beschreibung / Inhaltsverzeichnis: Zusammenfassung. Mit zunehmender Etablierung der laparoskopischen Cholecystektomie treten seit einigen Jahren juristische Aspekte in den Vordergrund. Zur Klärung der Frage, welche Folgen eine kompliziert oder auch fehlerhaft verlaufene laparoskopische Cholecystektomie in juristischer Hinsicht nach sich zieht, wurden die erreichbaren Entscheidungen der Schlichtungsstellen der Ärztekammern sowie der Gerichte aufgearbeitet. Von 40 ausgewerteten Fällen von Behandlungsfehlervorwürfen wurden 16 als Behandlungsfehler anerkannt, 24 mal wurden die Vorwürfe zurückgewiesen. Der häufigste Vorwurf betraf mit 26 Fällen die Gallenwegverletzung. Von diesen 26 Verletzungen wurden 7 als Behandlungsfehler anerkannt, davon 2 als schwere Behandlungsfehler. Als Gründe für anerkannte Behandlungsfehler wurden in den Urteilen im wesentlichen ein verzögertes Umsteigen auf die konventionelle Operation, eine verzögerte Revision, die laparoskopische Durchführung einer Revisionsoperation und das fehlende Umsteigen bei unübersichtlichem Situs genannt.
    Notizen: Summary. As laparoscopic cholecystectomy becomes more established, interest in legal aspects increases. The legal cases dealt with in Germany since the introduction of this laparoscopic method in 1989 were studied to determine the legal consequences of complications. Of 40 cases, 16 were judged to be cases of malpractice, whereas 24 were not. The most common cause was injury of the common bile duct (26 cases). Seven of these 26 cases were judged to be cases of malpractice, 2 of these as grave errors. The main reasons for the acceptance of a case as malpractice were delay in changing to conventional cholecystectomy, delayed revision, laparoscopic revisions and not reverting to conventional cholecystectomy in unclear situations.
    Materialart: Digitale Medien
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  • 10
    ISSN: 1279-8509
    Schlagwort(e): Hemophilia ; Complications ; Africa
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Abstract In order to describe the presenting features at diagnosis and complications of hemophilia in Dakar, we conducted a study of hospital records between October 1991 and January 1993. Twenty-five cases of hemophilia were identified. We found that only 4% of our patients were diagnosed in the first 6 months of life whereas 64% of patients were diagnosed between 6 months and 5 years of age, 32% were detected between 5 years and 14 years of age. The presenting feature at diagnosis was external bleeding in 60% of cases and internal bleeding in 40%. 92% of cases were hemophilia type A and only 8% hemophilia type B. 56% of patients had mild hemophilia, 40% moderate and only 4% severe disease. Hemophiliac arthropathy was present on radiography in 76%. Complications were dominated by repeated joint bleeding, which was present in 92% of patients, and repeated hematomas (80% of patients). A functional handicap was present in 60% of cases. 12% of transfused hemophiliacs developed an inhibitor and 4% of patients were HIV positive. Greater awareness of hemophilia amongst the medical community as well as continued efforts to improve care for hemophiliacs in Senegal are necessary.
    Materialart: Digitale Medien
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  • 11
    ISSN: 1438-1435
    Schlagwort(e): Pancreatitis ; Pleural effusions ; Complications
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Abstract Recognition of pleural effusions in acute pancreatitis is important since it carries prognostic implications. This study evaluates the incidence and characteristics of pleural effusions on computed tomography (CT) of patients with mainly an alcohol ingestion etiology of acute pancreatitis. A review of medical records and abdominal CT scans in 50 patients with clinical and laboratory evidence of acute pancreatitis was carried out. All patients were referred for abdominal CT scanning based on an initial clinical presentation consistent with acute pancreatitis and had confirmatory elevation of the corresponding serum enzyme levels. The presence, laterality, and size of any pleural effusions were recorded from the initial sections through the lung bases. Based on a review of medical records, 36 patients (72%) had an alcohol-related etiology of acute pancreatitis. Overall, 10 patients (20%) with acute pancreatitis had pleural effusions on abdominal CT imaging. Five of the effusions were bilateral, three were unilateral right sided, and two were unilateral left sided. Nine of the effusions were small (〈1 cm in maximal height) or medium (1–2 cm) in size. Small and medium-sized pleural effusions are not uncommon in acute pancreatitis. The higher incidence in this study compared to that in earlier reports likely represents the increased sensitivity of cross-sectional imaging for small amounts of pleural fluid. The absence of left-sided effusion predominance in our study group is contrary to much of the earlier literature and may reflect demographic factors, such as etiology and previous history of pancreatitis, although statistical variability must also be considered.
    Materialart: Digitale Medien
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  • 12
    ISSN: 1433-044X
    Schlagwort(e): Schlüsselwörter Acetabulum ; Fraktur ; Operative Behandlung ; Komplikationen ; Ergebnisse ; Key words Acetabulum ; Fractures ; Operative treatment ; Complications ; Results
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Beschreibung / Inhaltsverzeichnis: Between December 1986 and November 1995, 222 patients with 225 acetabular fractures were treated operatively by three surgeons in the Department of Traumatology and Emergency Surgery of the University Hospitals of the Catholic University of Leuven. Indications for surgery were unstable fracture, displaced fracture through the acetabular dome and fracture with intra-acetabular fracture fragments. There were 37.3% A-fractures, 49.7% B-fractures, and 13% C fractures according to the AO Classification. In 16.4% of fractures there were primary neurological deficits. Patients were treated operatively after an average of 5.0 days. The Kocher-Langenbeck approach was used in 56.9% of cases, the ilio-inguinal approach in 27.1% and the extended iliofemoral approach in 4%. In 7.1% of patients, a primary total hip endoprosthesis was implanted. There was no intra- oder perioperative mortality. The average hospital stay was 26.1 days. In 7.1% of patients, we noted secondary neurological problems. Deep infections were present in 1.3%. In 11.1% of patients a second operative procedure was necessary. We were able to review 175 patients after an average of 2 years. Signs of arthrosis and periarticular ossification were noted on the x-rays: walking distance, hip mobility and pain intensity were asked about and recorded after the clinical examination. In 76% of patients an excellent or good result on the Merle-d'Aubigne scale was obtained. T-fractures and posterior wall fractures were followed by the worst results. During this 9-year period, changes have been made to the preoperative radiological examination carried out, the choice of operative approach and our policy on prevention of thrombosis prophylaxis and postoperative ossification. After thorough preoperative diagnosis and with a meticulous operative technique, it is possible to stabilise the vast majority of acetabular fractures through the three classical approaches. Because the fractures are relatively rare, their diagnosis complex and their surgical treatment difficult, specific training is essential for every acetabular surgeon.
    Notizen: In der Zeit zwischen Dezember 1986 und November 1995 wurden in der Klinik für Unfall- und Notfallchirurgie der Universitätskliniken der Katholischen Universität Leuven 222 Patienten mit 225 Acetabulumfrakturen von drei Chirurgen operativ versorgt. Operationsindikationen bestanden bei instabilen Frakturen, verschobenen Frakturen durch das Acetabulumdach und Frakturen mit intraartikulären Frakturfragmenten. Es lagen in 37,3% A-Frakturen, in 49,7% B-Frakturen und in 13% C-Frakturen der AO-Klassifikation vor. Bei 16,4% der Frakturen waren präoperativ neurologische Ausfälle vorhanden. Die Patienten wurden durchschnittlich nach 5,0 Tagen operativ versorgt. Der Kocher-Langenbeck-Zugang wurde in 56,9% verwendet, der ilioinguinale Zugang in 27,1% und der erweiterte iliofemorale Zugang in 4%. Bei 7,1% der Patienten wurde primär eine Totalendoprothese implantiert. Es gab keine intra- oder perioperative Mortalität. Der durchschnittliche Krankenhausaufenthalt betrug 26,1 Tage. Bei 7,1% der Patienten bestanden sekundäre neurologische Probleme, Infektprobleme kamen in 1,3% vor, Sekundäreingriffe waren in 11,1% notwendig. 175 Patienten wurden nach einem durchschnittlichen Zeitraum von 2 Jahren nachuntersucht. Arthrosezeichen und periartikuläre Ossifikationen wurden röntgenologisch, Gehstrecke, Hüftmobilität und Schmerzintensität klinisch ausgewertet; 76% dieser Patienten erhielten ein sehr gutes bis gutes Ergebnis nach der Merle-D'Aubigne-Skala. Die schlechtesten Ergebnisse erhielten die T-Frakturen und die Hinterwandfrakturen. Im Laufe des Neunjahreszeitraums der Studie haben sich präoperative Röntgendiagnostik, die Wahl des operativen Zugangs und die postoperative Versorgung in Bezug auf Thromboseprophylaxe und Prävention von periartikulären Ossifikationen eingehend geändert. Nach ausführlicher präoperativer Diagnostik und mit sorgfältiger Operationstechnik ist es möglich, die Mehrheit der Acetabulumfrakturen durch die drei klassischen Zugänge zu operieren. Weil diese Frakturen eher selten sind, die Diagnostik mühsam und die chirurgische Technik sich schwierig gestaltet, ist eine spezifische Schulung für jeden Acetabulumchirurgen unerläßlich.
    Materialart: Digitale Medien
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  • 13
    Digitale Medien
    Digitale Medien
    Springer
    Monatsschrift Kinderheilkunde 145 (1997), S. 1286-1288 
    ISSN: 1433-0474
    Schlagwort(e): Schlüsselwörter Septumsabszeß ; Diagnose ; Komplikationen ; Kasuistik ; Key words Septal abscess ; Diagnosis ; Complications ; Case report
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Beschreibung / Inhaltsverzeichnis: Summary Nasal abscesses are uncommon and therefore have been given little attention in the medical literatur. So there are possible diagnostical problems, especially in children. Immediate therapy is indicated to avoid cosmetic deformity or intracranial infections. Treatment entailsm surgical drainage, reconstruction of the septum, and adequate antibiotic backup. Discussion: Nasal septal abscesses should be considered whenever obstructions in nasal breathing with concomitant raised body temperature and swelling occur after trauma.
    Notizen: Zusammenfassung Ein Nasenseptumhämatom bzw. -abszeß ist ein seltenes Krankheitsbild und wird in der medizinischen Fachliteratur nur wenig berücksichtigt. Das führt dazu, daß bei der Diagnose Schwierigkeiten bestehen, was v.a. bei Kindern der Fall zu sein scheint. Eine unmittelbare Therapie zur Vermeidung von kosmetischen Problemen bzw. intrakraniallen Komplikationen ist erforderlich. Diese besteht in einer Drainierung, Rekonstruktion des Septums bzw. antibiotischen Abschirmung. Diskussion: Bei einer nach Trauma auftretenden Behinderung der Nasenatmung mit Fieber und Schwellung ist an einen Septumabszeß zu denken.
    Materialart: Digitale Medien
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  • 14
    Digitale Medien
    Digitale Medien
    Springer
    Der Chirurg 68 (1997), S. 613-617 
    ISSN: 1433-0385
    Schlagwort(e): Key words: Outpatient laparoscopic cholecystectomy ; Outpatient clinic ; Prospective study ; Complications ; Costs ; Cost effective. ; Schlüsselwörter: Ambulante laparoskopische Cholecystektomie ; niedergelassene Operationseinrichtung ; prospektive Studie ; Komplikationen ; Kosten.
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Beschreibung / Inhaltsverzeichnis: Zusammenfassung. In einer prospektiven Beobachtungsstudie wurden 140 Patienten erfaßt, die rein ambulant laparoskopisch cholecystektomiert wurden. Das Patientengut entspricht im wesentlichen den Veröffentlichungen stationär operierter Patienten. Es gab keine relevanten intra- und postoperativen Komplikationen. Postoperativ brauchten die Patienten weniger Schmerzmittel, erholten sich schneller und waren schneller wieder arbeitsfähig als Patienten in vergleichbaren Veröffentlichungen stationär operierter Patienten. Die ambulante laparoskopische Cholecystektomie ist eine gute Alternative für Patienten mit geringem oder mittlerem Risiko. Selbst bei verbesserter Ertragssituation für die Operationseinrichtung eröffnet sie außerdem Einsparpotentiale im Gesundheitssystem.
    Notizen: Summary. A total of 140 patients underwent outpatient laparoscopic cholecystectomy in an outpatient clinic. Evaluation and follow-up of the patients were done prospectively. Population and preoperative data were comparable to published studies of patients operated on in hospitals. There were no serious intra- or postoperative complications. Postoperatively, patients needed less pain medication, were less tired and returned to work earlier than patients after clinical laparoscopic cholecystectomies. Outpatient laparoscopic cholecystectomy offers a good alternative to patients with moderate operative risks (ASA 1–3). It could reduce costs in the German health system and would be therefore highly cost effective.
    Materialart: Digitale Medien
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  • 15
    ISSN: 1433-0423
    Schlagwort(e): Key words Cytomegalovirus retinitis ; Intraocular sustained release device ; Complications ; Ablatio retinae ; CMV resistance ; Schlüsselwörter CMV-Retinitis ; Ganciclovir-Medikamententräger ; Pars-plana-Implantation ; Komplikationen ; Begleittherapie
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Beschreibung / Inhaltsverzeichnis: Zusammenfassung Die Zytomegalievirus-(CMV)-Retinitis als häufigste opportunistische Infektion bei Patienten mit Aids wurde erstmals 1992 mit einem intraokular implantierten Medikamententräger therapiert. Im Jahr 1995 wurden die ersten Medikamententräger in Deutschland implantiert und im Rahmen einer offenen Studie der postoperative Verlauf, die Komplikationen und die Wirkdauer überprüft. Patienten und Methode: 20 Patienten wurden in die Studie eingeschlossen und insgesamt 32 Augen mit einem Ganciclovir-Medikamententräger (Vitrasert™, Fa. Chiron-Adatomed, München) versehen. Alle Patienten bekamen zusätzlich eine orale Ganciclovir- oder adjuvante i. v.-Therapie. Der Medikamententräger besteht aus Ethylenvinylazetat und enthält 4,5 mg Ganciclovir mit einer Freisetzungsrate von 1 μg/h Ganciclovir in den Glaskörper über eine prognostizierte Wirkdauer von 6–8 Monaten. Ergebnisse: Die schwerwiegendste Komplikation war die Ablatio retinae bei 5 Patienten (5 Augen), diese Inzidenz entspricht der Ablationshäufigkeit unserer konservativ (d. h. i. v. oder oral) behandelten Patienten. Resistenz gegen Ganciclovir und andere Nukleosidanaloga war die Ursache für die Progredienz der Retinitis nach Implantation bei 2 Patienten mit nachfolgender Erblindung. In keinem Fall wurde eine CMV-Neuinfektion der nicht betroffenen Augen gesehen, es wurden keine extraokularen CMV-Manifestationen unter systemischer antiviraler Begleittherapie festgestellt. Innerhalb des Untersuchungszeitraums von 12 Monaten trat kein Rezidiv auf. Schlußfolgerung: Die Implantation eines Ganciclovir-Medikamententrägers erlaubt eine zielgerichtete antivirale Therapie der CMV-Retinitis mit dem deutlichen Vorteil der wesentlich selteneren Rezidivhäufigkeit. Extraokulare und Zweitaugen-CMV-Infektionen können durch tolerable systemische Therapieschemata verhindert werden.
    Notizen: Summary We performed an open clinical trial to assess the safety and efficacy of a 1 μg/h ganciclovir implant for the treatment of newly and pretreated cytomegalovirus (CMV) retinitis in patients with the acquired immunodeficiency syndrome (AIDS). Patients and methods: Thirty-two eyes (20 patients) received the ganciclovir intraocular device and were prospectively followed up from 30 to 365 days. We used a modified technique for fixation of the device in half of the patients. The modification improved the fixation of the implant with a two-hole technique in the strut. Results: Thirty eyes showed stabilization of the retinitis over the time, but in two patients resistance against ganciclovir and other nucleosid analogue compounds developed. Postoperative complications included vitreous hemorrhage (n = 1), cataract (n = 1), and uveitis anterior (n = 1). Late retinal detachment was seen in five eyes (25 %) at 30 to 60 days after implantation. Followup until 1 year after implantation did not show progression of CMV retinitis in 18 of 20 patients. All received antiviral CMV therapy to protect noninfected eyes and intestinum against CMV infection. Conclusions: The ganciclovir intraocular device seemed to be effective in most cases of CMV retinitis and offers a promising alternative for cytomegalovirus retinitis. Patients pretreated longer than 6 months with i. v. ganciclovir have to be carefully selected for implantation, because resistance against ganciclovir could be three times more likely than in i. v.-therapy naive patients.
    Materialart: Digitale Medien
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  • 16
    Digitale Medien
    Digitale Medien
    Springer
    Der Ophthalmologe 94 (1997), S. 50-52 
    ISSN: 1433-0423
    Schlagwort(e): Key words rTPA ; Fibrin ; Eye ; Anterior segment ; Complications ; Schlüsselwörter rTPA ; Fibrin ; Auge ; Vorderabschnitt ; Komplikationen
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Beschreibung / Inhaltsverzeichnis: Seit einigen Jahren wird Gewebeplasminogenaktivator (rTPA) intraokular zur Behandlung persistierender Fibrinmembranen eingesetzt, ohne daß bisher nennenswerte Komplikationen beschrieben wurden. Wir berichten über unsere eigenen Erfahrungen beim Einsatz von rTPA im vorderen Augenabschnitt bei 25 Patienten. Über eine Parazentese wurden komplikationslos jeweils 25 µg rTPA (Actilyse, Dr. Karl Thomae GmbH) in die Vorderkammer gespritzt. Ein Rückgang des Fibrins war – wenn auch bei einigen Augen nur allmählich – in 21 Fällen zu verzeichnen. Als postoperative Komplikationen traten 2mal eine (beherrschbare) Nachblutung und 2mal eine irreversible oberflächliche Hornhauttrübung auf. Die Behandlung einer Fibrinmembran des vorderen Augenabschnitts mit rTPA stellt in vielen Fällen eine sinnvolle Ergänzung der lokalen Steroidgabe dar. Beunruhigend ist für uns jedoch das Auftreten von irreversiblen Hornhautkomplikationen, deren Pathogenese wir uns derzeit noch nicht erklären können. Aufgrund des eindeutigen zeitlichen Zusammenhangs müssen wir jedoch von einer kausalen bzw. toxischen Wirkung des rTPA selbst oder einer der Lösungskomponenten ausgehen.
    Notizen: Recombinant tissue plasminogen activator (rTPA) is commonly used in patients with myocardial infarction. Recently, it has also been applied intraocularly to dissolve post-operative fibrin with no serious complications being reported so far. In this study we describe our own experience with rTPA in 25 patients with persisting fibrinous membranes in the anterior segment. rTPA (Actilyse, Dr. Karl Thomae GmbH) was given in a single dose of 25 µg and injected into the anterior chamber via a paracentesis. We did not encounter any complications during the injection of rTPA. In 21 eyes fibrin could be reduced significantly, albeit sometimes only slowly. In 13 patients, the membrane had dissolved almost completely by the following day. In contrast, no success was observed after glaucoma surgery (2 eyes) and in chronic iritis (1 eye), or when fibrin mixed with blood was treated (1 eye). There were two (controllable) post-operative hemorrhages (rTPA after vitrectomy, and for fibrin/blood after cataract surgery). In addition, we noted 2 cases of irreversible superficial corneal clouding (rTPA after cataract surgery). We conclude that injection of rTPA can be a useful addition to steroid treatment in selective cases of persisting fibrin in the anterior segment. Long-standing membranes, however, are unlikely to be dissolved. Care should also be taken and rTPA be avoided when there is evidence of recent bleeding. Most worrying to us were the corneal complications that we cannot explain to date. With regard to the definite time correlation we feel that rTPA or one of the solution components might be the cause of this unusual feature.
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  • 17
    Digitale Medien
    Digitale Medien
    Springer
    Der Orthopäde 26 (1997), S. 67-74 
    ISSN: 1433-0431
    Schlagwort(e): Schlüsselwörter Kongenitale Hüftluxation ; Offene Reposition ; Zugangswege ; Operationstechnik ; Komplikationen ; Femurkopfnekrose ; Reluxation ; Key words Congenital dislocation of the hip ; CDH ; DDH ; Open reduction ; Surgical approach ; Surgical technique ; Complications ; avascular necrosis ; Recurrent dislocation
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Beschreibung / Inhaltsverzeichnis: Summary Closed reduction of a hip dislocation will prove even more difficult if the dislocation has existed over a longer period of time. The indication is based on several principles: An open reduction may be carried out only after an unsuccessful attempt to perform a closed reduction or at a fixed age limit (12 or 24 months) or based upon arthrographic findings. In our department, for babies up to the age of 12 months, we always try to perform a closed reduction. Between 12 to 24 months, arthrographic findings will determine the choice of method. After the age of two, as a rule, we use an open reduction. The preliminary treatment consists of longitudinal traction. Current methods of approach to the hip joint are the medial approach according to Ludloff or the frontal approach by means of an inguinal incision. With the medial approach, there is greater risk of damaging the circumflex artery; also, a higher rate of avascular necrosis of the femoral head has been observed. Therefore, we only practice the ventral approach. Mainly for cosmetic reasons, however, instead of using the Smith-Petersen procedure, we apply a pure inguinal incision proximal to the inguinal ligament. The approach is found by detaching the muscle tissue at the anterior and interior iliac spine. Medially and laterally of the pelvic ridge, though, the tissue may be left. The joint capsule may be opened in the shape of a T or a V. A t-shape incision offers a better survey, wherby the risk of damaging a vessel is somewhat higher. In addition to resection of the teres ligament, it is necessary to indent the transverse acetabular ligament. Often, aponeurotic recession of the psoas tendon must be performed as well and the labrum indented and pushed outwards before reduction. The risk of insufficient development of the acetabulum can be minimized only if the femoral head is optimally centered. If the femoral head is in a high position (i. e., if the upper ridge of the femoral metaphysis lies higher than the triradiate cartilage), a shortening osteotomy of the femur should always be performed. This is the only possibility of repositioning the femoral head without exercizing exaggerated pressure. On the other hand, we are rather reticent to perform a pelvic osteotomy at the time of repositioning. For children unter 2 years of age, we recommend to that the acetabulum be allowed to develop and that a pelvic osteotomy be performed at a lager period if necessary. Postoperative treatment is given for a period of 12 weeks in a hip-leg cast in the Fettweis position, followed by another 3 months in a splint. Possible complications are redislocations, avascular necrosis of the femoral head and persistent acetabular dysplasia. An optimal technique will considerably reduce the risks of such complications.
    Notizen: Zusammenfassung Je länger eine Hüftgelenkluxation besteht, desto schwieriger wird es, sie geschlossen zu reponieren. Für die Indikation der offenen Reposition kann nach verschiedenen Prinzipien vorgegangen werden. Sie kann entweder nur nach mißlungenem geschlossenem Repositionsversuch durchgeführt werden oder aufgrund einer starren Altersgrenze (12 oder 24 Monate) oder auf der Basis von arthrographischen Befunden. An unserer Klinik versuchen wir bis zum Alter von 12 Monaten stets primär geschlossen zu reponieren, zwischen 12 und 24 Monaten richten wir uns nach dem arthrographischen Befund, jenseits des 2. Lebensjahres reponieren wir stets von Anfang an offen. Als Vorbehandlung führen wir eine Extension durch. Als Zugänge zum Hüftgelenk sind der mediale Zugang nach Ludloff sowie der vordere Zugang durch Leistenschnitt gebräuchlich. Die Gefahr der Verletzung der A. circumflexa femoris ist beim medialen Zugang größer, es wurde auch eine höhere Rate von Femurkopfnekrosen beobachtet. Wir benutzen deshalb nur den ventralen Zugang. Die Gelenkkapsel kann T- oder V-förmig eröffnet werden. Die T-förmige Eröffnung erlaubt eine bessere Übersicht, die Gefahr der Gefäßverletzung ist aber etwas größer. Nur wenn es gelingt, den Femurkopf optimal zu zentrieren, kann das Risiko der ungenügenden Pfannenentwicklung minimiert werden. Bei hochstehendem Femurkopf (Oberrand der Femurmetaphyse höher als die Y-Fuge) sollte immer eine Verkürzungsosteotomie des Femurs durchgeführt werden. Nur so kann ohne ungebührlichen Druck der Femurkopf stabil reponiert werden. Hingegen sind wir mit pfannendachplastischen Eingriffen zum Zeitpunkt der Reposition eher zurückhaltend. Bei Kindern unter 2 Jahren lohnt es sich, die Pfannenentwicklung vorerst abzuwarten und allenfalls später einen pfannendachplastischen Eingriff durchzuführen. Die Nachbehandlung erfolgt während 12 Wochen in einem Becken-Bein-Gips in Fettweis-Stellung, anschließend während weiteren 3 Monaten in einer Schiene. Als Komplikationen treten Reluxationen, Femurkopfnekrosen und persistierende Dysplasien der Gelenkpfanne auf.
    Materialart: Digitale Medien
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  • 18
    Digitale Medien
    Digitale Medien
    Springer
    Monatsschrift Kinderheilkunde 145 (1997), S. 729-733 
    ISSN: 1433-0474
    Schlagwort(e): Schlüsselwörter Otitis media acuta ; Komplikationen ; Akute Mastoiditis ; Chronische Mastoiditis ; Mastoidektomie ; Therapie ; Key words Otitis media ; Complications ; Acute mastoiditis ; Chronic mastoiditis ; Masked mastoiditis ; Mastoidectomy
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Beschreibung / Inhaltsverzeichnis: Summary Antibiotics have led to a substantial decrease in the number of infants developing acute mastoiditis from middle ear infection. However, subacute or chronic mastoiditis can still often be observed, causing a variety of intracranial and extracranial life threating complications. The clinical course, the causative organism, risc factors and the role of surgical therapy were studied in 59 patients with mastoiditis. Masked forms of mastoiditis outnumbered the acute disease 2 to 1. 15% had developed complications, 5% life threatening intracranial complications (Abb. 3). Mastoid surgery was employed in all cases. 7 (12%) children needed repeated surgery because of delayed healing or clinical deterioration. The previous surgery in those cases was found to be inappropriate. Nevertheless, children recovered without any additional morbidity from surgery. Diagnostic and therapeutic strategies are discussed to cope with the difficult problem of chronic mastoiditis, taking into account bacteriologic findings, risk factors and important diagnostic information.
    Notizen: Zusammenfassung Die häufigste Komplikation der Otitis media ist die Mastoiditis. Trotz der Antibiotika entwickelt eine nicht zu vernachlässigende Anzahl von Kindern eine subakute, chronische Form der Mastoiditis, die mit den gleichen intra- und extrakranialen Komplikationen einhergehen kann. Es wird über 59 Kinder mit Mastoiditis berichtet, die klinischen Symptome, Keimspektrum, Antibiotikasensibilität und die aufgetretenen Komplikationen werden dargelegt. Bei allen Kindern wurde eine Mastoidektomie durchgeführt. Die diagnostischen und therapeutischen Probleme der chronischen Mastoiditis werden unter Einbeziehung der Risikofaktoren diskutiert.
    Materialart: Digitale Medien
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  • 19
    Digitale Medien
    Digitale Medien
    Springer
    Der Orthopäde 26 (1997), S. 327-335 
    ISSN: 1433-0431
    Schlagwort(e): Key words Acetabulum ; Radiographic assessment ; Indications for surgery ; Surgical technique ; Complications ; Schlüsselwörter Acetabulum ; Diagnostik ; Operationsindikation ; Operationstechnik ; Komplikationen
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Beschreibung / Inhaltsverzeichnis: Zusammenfassung Acetabulumfrakturen sind fast zur Hälfte mit einem Polytrauma vergesellschaftet und in über 80 % der Fälle findet man zusätzliche Verletzungen. Das Operationsziel besteht in der anatomischen Wiederherstellung der Hüftpfanne und Stabilisierung der Fraktur durch Osteosynthese, so daß postoperativ auf jegliche zusätzliche äußere Fixation verzichtet werden kann. Eine penible klinische und radiologische Abklärung ist notwendig, um eine erfolgversprechende Operationsplanung durchführen zu können. In jedem Fall gehören zum Röntgenstandard neben der Beckenübersicht die Zielaufnahme der verletzten Hüfte sowie das Ala- und Obturatorbild. Mit diesen Aufnahmen läßt sich u. a. auch das zentrale Acetabulumsegment („Domfragment“) gut beurteilen. Von besonderer Wichtigkeit ist, die primäre traumabedingte Ischiadicusverletzung genau zu dokumentieren. Auf die Repositionsqualität hat der Operationszeitpunkt ganz erheblichen Einfluß. Die Operation sollte zum frühest möglichen Zeitpunkt durchgeführt und das taktische Vorgehen genau geplant werden. Dabei sind besonders bei komplexen Frakturen und für die Wahl des Zugangs 3D-Rekonstruktionen sehr hilfreich. Ohne Repositionshilfen ist das Operationsziel in vielen Fällen nicht zu erreichen. Als Implantate kommen die vorgebogenen Rekonstruktionsplatten der AO, aber auch gerade Platten in Frage. Die Operationen verlangen große Erfahrung. Behandlungsbedingte Komplikationen sind Nervenschäden, mangelhafte Repositionen, fehlplazierte Implantate, instabile Montagen, Reluxationen u. a. Postoperative Wundinfektionen sind bei Beachtung einer lückenlosen Asepsis niedrig. Dagegen findet man nach ausgedehnten Zugängen oft metaplastische Ossifikationen, die nur bei starker Ausbildung (Brooker III und IV) die Funktion des Hüftgelenks beeinträchtigen. Eine präventive Medikation mit Indometacin ist immer angezeigt. Die generelle Röntgenbestrahlung ist abzulehnen.
    Notizen: Summary Almost 50 % of acetabular fractures occur in polytraumatized patients; in over 80 % additional injuries are found. The surgical goal is anatomical restoration of the acetabulum and stable fixation, in order to avoid postoperative external fixation. Careful clinical and radiological evaluation is essential to successful surgery. Standard radiological investigations include an anteroposterior view of the pelvis, a “spot” radiograph of the affected hip as well as obturator and iliac oblique views. The latter arc is especially helpful in assessing the central segment of the acetabulum (“dome fragment”). The documentation of any primarily traumatic sciatic nerve lesion is very important, and the quality of reduction depends greatly on the timing of surgery. The operation should be performed as early as possible after the surgical procedure has been carefully planned. A 3-D CT scan provides good information in choosing the surgical approach for complex fractures. In most cases, adequate reduction cannot be accomplished without appropriate aids. For internal fixation, both curved ASIF plates and straight plates are used. The operation demands a high degree of experience. Postoperative complications include iatrogenic nerve palsy, insufficient reduction, incorrectly placed implants, unstable fixation, redislocation, etc. With scrupulous aseptic conditions, the postoperative wound infection rate is low. Ectopic bone formation can occur after extensive surgical approaches and may, depending on size (Brooker III and IV), impair the range of motion of the hip. Indometacin given perioperatively is always indicated. Postoperative radiation treatment should as a rule be viewed critically.
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  • 20
    Digitale Medien
    Digitale Medien
    Springer
    Der Anaesthesist 46 (1997), S. 38-42 
    ISSN: 1432-055X
    Schlagwort(e): Schlüsselwörter Spinalanästhesie ; Komplikationen ; Spinalkatheter ; Key words Spinal anaesthesia ; Complications ; Spinal catheter
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Beschreibung / Inhaltsverzeichnis: Abstract Life-threatening cardiovascular complications are a serious risk even for healthy patients during spinal/epidural anaesthesia. The incidence of fatal cardiovascular complications for epidural anaesthesia is 1:10000, for spinal anaesthesia 1:7000. In contrast, general anaesthesia has an overall mortality of only 1:28000. Administration of IV fluids to minimise the haemodynaemic reactions of beginning sympatholysis is not always sufficient. In this study, we examined whether fractionated application of local anaesthetics via a spinal catheter would provide better haemodynamic stability. Methods: In a prospective study, we examined the haemodynaemic reactions of 300 patients during single-dose (n=150) versus continuous spinal anaesthesia (CSA) (n=150). Isobaric bupivacaine 0.5% was given through a 29 G Quincke needle (3.5 ml) or a 28 G spinal catheter (1.5 ml as a bolus, followed by 1 ml/10 min until an anaesthetic level of T12 was reached). Results: The sensory and motor effects of both methods were comparable. The T12 level of anaesthesia was achieved with the single-dose method after 10.5 min and with the continuous method after 19.1 min. After single-dose anaesthesia, the blood pressure dropped by 16.5% and the heart rate by 12% compared to the control values. During CSA no significant blood pressure changes were recorded; the heart rate decreased by 8%. In 15 cases vasoconstrictors had to be given to stabilise the lowered blood pressure after single-dose anaesthesia. Conclusion: With the use of CSA, the haemodynamic effects of sympatholysis can be minimised. This method thus has advantages, especially for high-risk cardiovascular patients.
    Notizen: In dieser Arbeit sollte untersucht werden, ob die fraktionierte Lokalanästhetikaapplikation über einen Spinalkatheter zu einem stabileren Kreislaufverhalten beitragen kann. In einer prospektiv angelegten Studie wurde das Kreislaufverhalten von 300 Patienten unter einer Single-dose-Spinalanästhesie (n=150) und einer kontinuierlichen Spinalanästhesie (n=150) untersucht. Zur Anästhesie wurde isobares Bupivacain 0,5% verwendet, das über eine 29 G Quincke-Nadel (3,5 ml) oder einen 28 G Spinalkatheter (1,5 ml im Bolus, dann fraktioniert 1 ml/10 min bis zu einem Anästhesieniveau Th 12) gegeben wurde. Die sensible und motorische Qualität beider Verfahren war vergleichbar, das angestrebte Analgesieniveau Th 12 wurde unter der Single-dose-Spinalanästhesie nach 10,5 min erreicht, bei der kontinuierlichen Spinalanästhesie nach 19,1 min. Unter der Single-dose-Spinalanästhesie zeigte sich ein Abfall des Blutdrucks um 16,5% zum Ausgangswert und ein Abfall der Herzfrequenz um 12%. In 15 Verläufen mußten Vasokonstriktoren gegeben werden, um den Blutdruckabfall zu stabilisieren. Bei der kontinuierlichen Spinalanästhesie zeigten sich keine signifikanten Änderungen des Blutdrucks, die Herzfrequenz nahm um 8% ab. Mit der kontinuierlichen Spinalanästhesie werden die Auswirkungen der Sympathikolyse auf die Hämodynamik minimiert. Dieses Verfahren bietet daher bei kardiovaskulären Risikopatienten Vorteile gegenüber der einzeitigen Spinalanästhesie.
    Materialart: Digitale Medien
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  • 21
    Digitale Medien
    Digitale Medien
    Springer
    Der Anaesthesist 46 (1997), S. 697-703 
    ISSN: 1432-055X
    Schlagwort(e): Schlüsselwörter Ecstasy ; MDMA ; Intoxikation ; Komplikationen ; Key words Ecstasy ; MDMA ; Intoxication ; Complications
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Beschreibung / Inhaltsverzeichnis: Abstract The increased consumption of ”ecstasy” (MDMA, 3,4-methylenedioxy-methamphetamine) has also increased the number of life-threatening intoxications. From a Medline search of the years 1992–1996, reports were registered and evaluated. Besides cerebral, cardiorespiratory, renal, and hepatic symptoms, hyperthermia syndromes such as malignant hyperthermia, neuroleptic malignant syndrome, or the serotonin syndrome were common. In addition to a discussion of the intoxication symptoms and their acute and intensive-care therapy, the psychological and physiological effects of ”ecstasy” will be described. Some historical considerations of the topic are included in this review.
    Notizen: Zusammenfassung Die Zunahme des „Ecstasy”-Konsums (MDMA, 3,4-Methylendioxymethamphetamin) erhöhte ebenfalls die Anzahl lebensbedrohlicher Intoxikationen. Aus einer Medline-Recherche der Jahre 1992–1996 wurden Berichte über Intoxikationen erfaßt und ausgewertet. Intoxikation mit Ecstasy: Im Vordergrund steht neben zerebralen, kardiopulmonalen, renalen und hepatischen Symptomen auch das Hyperthermie-Syndrom im Sinne einer malignen Hyperthermie, eines neuroleptischen malignen Syndroms oder eines Serotonin-Syndroms. Neben der Diskussion der Intoxikationssymptome und deren möglicher Akut- und Intensivtherapie werden psychische und physische Wirkungen von „Ecstasy” beschrieben und zur Vervollständigung des Themas eine kurze historische Betrachtung der Droge gegeben.
    Materialart: Digitale Medien
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  • 22
    ISSN: 1432-1238
    Schlagwort(e): Key words Cardiac output ; Complications ; Cost ; Dopexamine ; High risk patients ; Intensive care ; Morbidity ; Mortality ; Oxygen delivery ; Resource use ; Surgery
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Abstract Objective: To investigate the cost implications of a treatment policy of a deliberate perioperative increase of oxygen delivery in high risk surgical patients. Design: A cost-effectiveness analysis comparing ‘protocol’ high risk surgical patients in whom oxygen delivery was specifically targeted towards 600 ml/min/m2 with ‘control’ patients. Interventions: In a randomised, controlled clinical trial we previously demonstrated a significant reduction in mortality (5.7% vs 22.2%, p=0.015) and morbidity (0.68±0.16 complications vs 1.35±0.20, p=0.008) in ‘protocol’ high risk surgical patients in whom oxygen delivery was specifically targeted towards 600 ml/min per m2 compared with ‘control’ patients. This current study retrospectively analysed the medical care and National Health Service resource use of each patient in the trial. Departmental purchasing records and business managers were consulted to identify M28.9nthe unit cost of these resources, and thereby the cost of treating each patient was calculated. Results: The median cost of treating a protocol patient was lower than for a control patient (£6,525 vs £7,784) and this reduction was due mainly to a decrease in the cost of treating postoperative complications (median £213 vs £668). The cost of obtaining a survivor was 31% lower in the protocol group. Conclusion: Perioperative increase of oxygen delivery in high risk surgical patients not only improves survival, but also provides an actual and relative cost saving. This may have important implications for the management of these patients and the funding of intensive care.
    Materialart: Digitale Medien
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  • 23
    Digitale Medien
    Digitale Medien
    Springer
    Intensive care medicine 23 (1997), S. 345-347 
    ISSN: 1432-1238
    Schlagwort(e): Key words Viral pneumonia ; Immunosuppression ; Complications
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Abstract Pneumonia caused by herpes simplex virus type 1 (HSV1) is rare and occurs in severely immunosuppressed patients. HSV1 can be detected in bronchoalveolar lavage (BAL) from patients presenting with respiratory failure, but its direct effect on disease is difficult to prove. We demonstrate the causative role of HSV1 in the case of a 44-year-old male with Crohn's disease who presented to the intensive care unit with the acute respiratory distress syndrome after surgery. BAL cells were cultured and immunofluorescence confirmed the presence of HSV1 during the first weeks of illness. Increased IgG titers confirmed the diagnosis of a recurrent HSV1 infection. A lung biposy specimen showed fibroproliferation without pathogens. Immunosuppressive therapy had been stopped and acyclovir was introduced at this time. The diagnostic difficulties in this patient underline the importance of early recognition of viral infection as a potential cause of severe pneumonia in severely ill, immunocompromised patients.
    Materialart: Digitale Medien
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  • 24
    ISSN: 1432-1084
    Schlagwort(e): Key words: Bile ducts ; Neoplasms ; Interventional procedure ; Implantation metastasis ; Complications
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Abstract. Percutaneous transhepatic biliary drainage (PTBD) is the basis for most biliary interventional procedures. We recently observed the occurrence of a subcutaneous implantation metastasis after PTBD in a patient with incurable cholangiocarcinoma. Although tumor cell seeding along the catheter tract is a very rare complication, we think that PTBD should be avoided when curative resection is planned.
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  • 25
    ISSN: 1432-1238
    Schlagwort(e): Key words Central venous catheterization ; Venobronchial fistula ; Cardiac surgery ; Complications
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Abstract. Venobronchial fistula is a rare complication of long-term central venous catheterization. We present the uncommon occurrence of a venobronchial fistula as an acute complication of central venous catheterization during open heart surgery. The factors responsible for this unusual complication and the methods to prevent it are discussed.
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  • 26
    ISSN: 1432-1920
    Schlagwort(e): Key words Anterior cervical surgery ; Complications ; Infection ; Computed tomography ; Magnetic resonance imaging
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Abstract We report a 44-year-old woman who developed an atypical retro-oesophageal abscess 4 years after anterior cervical surgery with fusion (ACSF). She presented with dysphagia but no fever or definite laboratory signs of inflammation. Delayed or chronic dysphagia following Cloward's operation is usually related to graft displacement. Infection may also, more rarely, be encountered in conjunction with dysphagia, but is typically associated with a classical clinical presentation and laboratory results. We recommend that in cases of delayed dysphagia without evidence of graft migration, the possibility of retropharyngeal infection should be considered, even in the absence of clinical signs or supporting laboratory evidence. MRI in this rare delayed complication is nonspecific but suggestive, and hence represents the imaging modality of choice in such situations.
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  • 27
    ISSN: 1432-1920
    Schlagwort(e): Key words Angioplasty ; Intracranial artery ; Complications ; Restenosis
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Abstract The purposes of this study were to determine the optimal time for initial follow-up angiography, the restenosis rate after successful intracranial percutaneous transluminal cerebral angioplasty (PTCBA), and finally to identify lesion-specific characteristics for predicting successful angioplasty. Thirty-five patients underwent PTCBA with follow-up angiography 3 and 12 months later. Although 27 lesions were adequately dilated, permanent complications occurred in 3 patients. The restenosis rate at 3 months was 29.6 %; patients without restenosis at 3 months remained free from vessel narrowing at 12 months. Restenosis occurred on severe, eccentric lesions, total occlusions or extremely angulated lesions. There was a strong correlation between sufficient dilatation and lower re- stenosis rate, and concentric and short lesions (type A). We conclude that the optimal time for initial angiographic follow-up is 3 months after PTCBA. PTCBA is most suitable for type A lesions with higher success, lower morbidity and lower restenosis rates.
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  • 28
    Digitale Medien
    Digitale Medien
    Springer
    Neuroradiology 39 (1997), S. 282-285 
    ISSN: 1432-1920
    Schlagwort(e): Key words Intervertebral disc ; hernia ; Nucleotomy ; Complications
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Abstract We reviewed the records of 243 patients treated at 271 disc levels to determine the incidence of side effects and complications of percutaneous nucleotomy. In our early experience there were 7 technical failures (2.5 % of all attempts), of which 6 were at the 5th disc level. The success rate dropped from 67 % at 3 months to 60 % 1 year after treatment due to recurrences in 16 patients (6.6 %). Extruded or sequestered fragments were found in 6 patients (2.4 %), and may have been caused by nucleotomy. However, only one was accompanied by aggravation of symptoms. Discitis was seen in 2 patients (0.8 %), both treated at two separate disc levels. About half the patients experienced increased low back pain, mean duration 9 days, after treatment, and 3 (1.2 %), of whom 2 also had nonorganic disorders, needed admission to hospital because of severe pain. Mild spasm and a sensation of instability were noted by 9.6 % and 25 % of the patients respectively. Injury to nerves, bowels, vessels or ureters or a dural leak never occurred. The study confirms earlier reports that the rate of serious complications is low.
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  • 29
    Digitale Medien
    Digitale Medien
    Springer
    Pediatric nephrology 11 (1997), S. 153-155 
    ISSN: 1432-198X
    Schlagwort(e): Key words: Acute renal failure ; Complications ; Multivariate analysis
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Abstract. Various factors were analyzed in 80 consecutive children under 16 years who had acute renal failure (ARF), for various prognostic factors. Overall mortality was 42.5%, with significantly higher levels seen in hemolytic uremic syndrome (68%, P 〈0.05) and associated with cardiac surgery (90.9%, P 〈0.01). Anuria (67.6% vs. 43.5%, P 〈0.05), need for dialysis (85.3% vs. 56.5%, P 〈0.05), neurological complications (50% vs. 6.3%, P 〈0.01), and respiratory complications (35.2% vs. 2.1%, P 〈0.01) were significantly higher in nonsurvivors than survivors. Multiple regression analysis showed the presence of neurological and respiratory complications to be poor prognostic factors.
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  • 30
    ISSN: 1432-198X
    Schlagwort(e): Key words: Bladder augmentation ; Renal failure ; Transplantation ; End-stage renal disease ; Complications
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Abstract. Ten consecutive patients with failure of urinary bladder augmentation (UBA) performed either prior to or after reaching end-stage renal disease (ESRD) were studied. Seven patients developed increased hydroureteronephrosis, infectious complications, and advanced to ESRD after UBA. The mean time to development of ESRD in patients who had UBA performed with moderate chronic renal failure (CRF) was 1.8 years. The UBAs in all seven patients were taken down prior to transplantation. Subsequently, five of these UBA-takedown patients have received kidney grafts and all have stable, good renal function. Three patients had their UBA performed after they reached ESRD, in preparation for renal transplantation. All three of these patients experienced recurrent urosepsis following transplantation, resulting in death in one patient and loss of graft in another. The third patient will undergo takedown of the UBA. This study suggests that UBA may possibly not be the best option for patients with moderate CRF and those awaiting transplantation.
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  • 31
    Digitale Medien
    Digitale Medien
    Springer
    Pediatric nephrology 11 (1997), S. 87-95 
    ISSN: 1432-198X
    Schlagwort(e): Key words: Angioaccess ; Arteriovenous fistula ; Graft ; Long-dwell catheters ; Complications
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Abstract. In the light of many years’ experience in hemodialysis access surgery, the different methods of creating vascular access for dialysis treatment in the pediatric population are described. After presenting the various access types using autologous blood vessels and also heterologous grafts, their specific spectrum of complications is discussed in detail. Summarizing our experience it has to be emphasized that there is no specific angioaccess for children and adolescents, and that most vascular access procedures used in adults are also suitable for use in the young.
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  • 32
    Digitale Medien
    Digitale Medien
    Springer
    Der Radiologe 37 (1997), S. 197-204 
    ISSN: 1432-2102
    Schlagwort(e): Schlüsselwörter Lebertransplantation ; Komplikation ; Radiologische Diagnostik ; Key words Liver transplantation ; Complications ; Radiological diagnosis
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Beschreibung / Inhaltsverzeichnis: Summary Introduction: Orthotopic liver transplantation (OLT) has become an accepted treatment for end-stage liver disease. However, postoperative complications result in significant patient morbidity and mortality. Early detection and treatment of these complications is therefore of utmost importance. Materials and methods: We retrospectively reviewed the postoperative complications of the patients who underwent OLT at our institution. Duplex Doppler sonography and cholangiography were the primary imaging modalities in postoperative evaluation of the transplanted liver. Other important techniques were CT, MRI, and angiography, which may contribute to a reliable diagnosis of vascular or biliary complications. Results: Second to primary organ dysfunction, vascular complications are the most frequent cause of graft loss. Thrombosis of the hepatic artery is the most common and most serious vascular complication, with a reported incidence from 4 to 42 %. Bile duct sludge, leaks and strictures are frequent complications after liver transplantation, which can contribute to graft dysfunction. Biliary tract complications usually occur within the first 3 months and require interventional radiological or surgical therapy. Since liver transplant recipients undergo immunosuppressive therapy, they are at increased risk of developing late post-transplant malignancies, which are best depicted by US, CT or MRI. However, radiological diagnosis of lymphoproliferative disorder has to be confirmed by liver biopsy. Conclusion: Cholangiography and Duplex sonography are routinely used in the postoperative evaluation of patients with OLT. CT, MRI, and angiography are problem-solving tools in equivocal cases.
    Notizen: Zusammenfassung Einleitung: Die orthotope Lebertransplantation hat sich zu einer etablierten Therapie bei Lebererkrankungen im Endstadium entwickelt. Der frühe Nachweis und die prompte Therapie eventueller Komplikationen sind für das Überleben des Patienten und des Organs entscheidend. Material und Methode: Es wurden im eigenen Krankengut die postoperativen Komplikationen nach OLT retrospektiv ausgewertet. Die Duplexsonographie und die Cholangiographie erwiesen sich als die primären Untersuchungsmethoden der Wahl zum Nachweis vaskulärer oder biliärer Komplikationen. CT, MRI und die Angiographie waren in Problemfällen wertvolle additive bildgebende Verfahren zur Diagnosesicherung. Ergebnisse: Nach der primären Organdysfunktion sind die vaskulären Komplikationen als häufigste Ursache für den Verlust des Spendeorgans anzuführen. Die Thrombose der A. hepatica ist die häufigste vaskuläre Komplikationen mit einer Inzidenz von 4–42 %. Galleleaks, -sludge und -strikturen sind häufige Komplikationen, die letztlich zu einer Dysfunktion des transplantierten Organs führen können. Biliäre Komplikationen treten gehäuft in den ersten 3 Monaten auf und erfordern eine interventionelle oder chirurgische Therapie. Da Patienten nach OLT einer immunsuppressiven Therapie unterliegen, sind sie einem erhöhten Risiko einen lymphoproliferativen Tumor zu entwickeln ausgesetzt. Diese Posttransplant-Tumore können mit US, CT und MRI ausgezeichnet abgegrenzt werden, erfordern jedoch eine Sicherung der Diagnose durch eine Feinnadelpunktion. Schlußfolgerung: Die postoperative Verlaufskontrolle und der Nachweis von Komplikationen nach OLT ist eine Domäne von Cholangiographie und Duplexsonographie. In Problemfällen kommen CT, MRI und Angiographie zum Einsatz.
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  • 33
    Digitale Medien
    Digitale Medien
    Springer
    Der Schmerz 11 (1997), S. 241-246 
    ISSN: 1432-2129
    Schlagwort(e): Schlüsselwörter Narkosekomplikationen ; Übelkeit ; Erbrechen ; Key words Anaesthesia ; Audit ; Complications ; Nausea ; Vomiting
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Beschreibung / Inhaltsverzeichnis: Summary Problem: Postoperative nausea and vomiting remains an important problem. Many risk factors have been identified; however, the importance of postoperative analgesic technique and patient expectation remain poorly defined. Methods:We prospectively collected data on postoperative nausea and vomiting (PONV) in four groups of randomly selected patients (n=50 per group) who received either simple analgesics, nurse-administered intravenous morphine (NAA), patient-controlled analgesia (PCA) with morphine or epidural analgesia with bupivacaine and fentanyl. Patients were questioned regarding any past history of PONV or motion sickness, their preoperative expectation of suffering PONV and satisfaction with their antiemetic therapy. Results: The incidence of nausea was higher in both morphine groups P〈0.05), women (P〈0.05), those less than the median age of their group (P〈0.05) and those with a past history of PONV (P〈0.05) or motion sickness (P〈0.05). Most patients did not expect to experience PONV (19.3%). The incidence of nausea was higher in those expecting to experience PONV than in those not expecting to suffer PONV (P〈0.01). Of those who received postoperative antiemetic treatment, 23.6% were dissatisfied or very dissatisfied with their therapy. Few patients received a prophylactic antiemetic drug (15%). Conclusions: Study results show that patient expectation is a potent predictor of postoperative nausea, a risk factor hitherto ignored in the anaesthetic literature, and that, in the provision of analgesia following major surgery, epidural analgesia is associated with less PONV than intravenous morphine.
    Notizen: Zusammenfassung Übelkeit und Erbrechen (PONV) sind nach wie vor ein Problem der postoperativen Phase. Viele Risikofaktoren sind bekannt, jedoch sind die Bedeutung der unterschiedlichen postoperativen analgetischen Regimes und die Erwartungshaltung der Patienten wenig untermauert. Patienten: Prospektiv wurden 4 randomisierte Patientengruppen untersucht (n=50/Gruppe), die postoperativ einfache Analgetika (Gruppe 1), durch eine Krankenschwester verabreichte i.v. Morphingaben (NAA; Gruppe 2), eine patientenkontrollierte Analgesie (PCA; Gruppe 3) und eine Epiduralanalgesie mit Bupivacain und Fentanyl (Gruppe 4) erhielten. Bei den Patienten wurde ermittelt, ob sie bei Voroperationen an Übelkeit und Erbrechen litten. Zusätzlich wurde die Erwartungshaltung der Patienten gegenüber PONV und deren Zufriedenheit mit der antiemetischen Therapie untersucht. Ergebnisse: Die Inzidenz von PONV war bei beiden Morphingruppen, bei Frauen, bei Patienten, die älter waren als der Median der Gruppe, und bei solchen Patienten, die in ihrer Vorgeschichte an PONV und Seekrankheit litten, höher. Die meisten Patienten hatten nicht erwartet, postoperativ Übelkeit und Erbrechen zu erleiden (19,3%). Bei Patienten, die präoperativ PONV erwarteten, war die Inzidenz höher als bei Patienten, die über diese Erwartungshaltung nicht berichteten (p〈0,01). Ein Viertel der Patienten (23,6%) war mit der postoperativen antiemetischen Behandlung unzufrieden oder sogar sehr unzufrieden. Eine präoperative Prophylaxe erhielten 15% der Patienten. Schlußfolgerung: Die Studie zeigt, daß die Erwartungshaltung der Patienten, an postoperativer Übelkeit und postoperativem Erbrechen zu leiden, ein in der Literatur unterschätzer Vorhersagefaktor ist. Bei der postoperativen Schmerztherapie bietet die Epiduralanalgesie im Vergleich zur i.v. Morphingabe deutliche Vorteile.
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  • 34
    Digitale Medien
    Digitale Medien
    Springer
    European radiology 7 (1997), S. 1218-1220 
    ISSN: 1432-1084
    Schlagwort(e): Key words: Bone cysts ; Fractures ; Complications ; Cortical defect ; MRI greenstick fractures
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Abstract. Posttraumatic bone-cyst formation is a known but rare process. Typical location is the distal radius, usually as a result of a greenstick fracture. The pathogenesis is unknown; however, subperiosteal migration of fat or hemorrhage with later absorption may cause cyst formation. We present the first reported case of MR imaging of this lesion. At MRI subperiosteal hemorrhage was found to be the cause of cyst formation.
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  • 35
    Digitale Medien
    Digitale Medien
    Springer
    European spine journal 6 (1997), S. 125-128 
    ISSN: 1432-0932
    Schlagwort(e): Pedicle fixation ; Posterior spine surgery ; Lumbar spine ; Complications
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Abstract Medial or lateral pedicle screw penetration with the potential to affect neural structures in a well-known and frequent problem associated with posterior spinal fusion. We evaluated the placement of pedicle screws (n = 141) in 36 patients following posterior lumbar spinal fusion with Socon or Kluger instrumentation via a lateral transpedicular approach. The examination was based on CT and MR images performed after removal of the instrumentation, on average 1 year after implantation. We found seven pedicle screws with lateral cortical penetration of the pedicle and five screws with medial cortical penetration of the pedicle (8.5% pedicle penetration overall). No severe radicular complications accompanied these pedicle penetrations. The mean insertion angles of the pedicle screws at the L4 level were 22.6° and 23.1° for the left and the right side, respectively. At the L5 level the mean insertion angle was 20.5° on the left side and 21.5° on the right, and at the S1 level the mean angle was 16.2° on the left and 15.2° on the right. The results of this study indicate that the lateral transpedicular approach is a safe procedure for pedicle screw insertion.
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  • 36
    Digitale Medien
    Digitale Medien
    Springer
    European spine journal 6 (1997), S. 402-405 
    ISSN: 1432-0932
    Schlagwort(e): Spinal surgery ; Pedicle screws ; Complications ; CT
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Abstract A prospective study of the accuracy of titanium pedicle screw placement in 30 low back operations was performed. The postoperative plain radiographs and CT reformation images were evaluated by two independent radiologists. Thirty-two out of 152 screws (21%) perforated the pedicle cortex. One-tenth of the perforations was detected with conventional radiography. In ten patients (33%) all the screws were located within the pedicle. The clinical significance of this study lies in the finding that pedicle perforations are more frequent than is generally believed and that, in spite of the many malplacements, no screw that perforated by less than 4.0 mm caused neurological problems. Only one nerve root lesion was detected.
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  • 37
    Digitale Medien
    Digitale Medien
    Springer
    Archives of gynecology and obstetrics 261 (1997), S. 9-13 
    ISSN: 1432-0711
    Schlagwort(e): Key words: Misoprostol ; Dinoprostone ; Labor induction ; Complications
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Abstract. Sixty five pregnant women who had the indication for labor induction were randomized in a clinical trial to receive 100 µg. intravaginal misoprostol or intracervical gel of 0.5 mg dinoprostone. The mean time from induction to delivery for the misoprostol group was 7.6±1.9 versus 8.2±5.9 (hours±SD) for the dinoprostone group. There were no significant differences between groups in gestational age, induced labor rates, type of delivery, fetal outcome and maternal complications. We found that intravaginal misoprostol tablet is as effective as intracervical dinoprostone for inducing second and third trimester labor.
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  • 38
    ISSN: 1433-0385
    Schlagwort(e): Key words: Inguinal hernia ; Drainage ; Complications ; Ultrasound. ; Schlüsselwörter: Leistenhernie ; Drainage ; Komplikationen ; Sonographie.
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Beschreibung / Inhaltsverzeichnis: Zusammenfassung. In einer prospektiven randomisierten Studie wurden im Rahmen der Shouldice-Reparation primärer Hernien 50 Patienten mit subcutaner Redon-Drainage und 50 Patienten ohne Drainage versorgt. Postoperativ erfaßten wir die Menge des produzierten Wundsekrets in der Drainageflasche sowie durch sonographische Volumetrie, das Maß der subjektiven Beeinträchtigung mittels visueller Analogskala, die Höhe der Entzündungsparameter sowie die Komplikationsrate. Am ersten postoperativen Tag fand sich im drainierten Kollektiv mit 36,0 ml eine signifikant erhöhte Flüssigkeitsproduktion im Vergleich zu 2,5 ml in der Gruppe ohne Drainage. Zwei Wundinfekte wurden ebenfalls im drainierten Kollektiv beobachtet. Percutane Serompunktionen waren bei 8 Patienten, die ohne Drainage operiert wurden, und bei 7 drainierten Patienten notwendig. Das subjektive Empfinden war durch die Drainage nur geringfügig (25,6 vs. 21,4 %, visuelle Analogskala) beeinträchtigt. Die Körpertemperatur war im Drainagekollektiv am 3. postoperativen Tag im Vergleich zur nicht drainierten Gruppe erhöht (37,2 vs. 36,7 °C). Das routinemäßige Einlegen einer Redon-Drainage bei der Reparation primärer Leistenhernien ist aus unserer Sicht nicht indiziert. Vielmehr sollte bei Auftreten einer subcutanen Flüssigkeitsansammlung großzügig die Indikation zur percutanen Punktion gestellt werden.
    Notizen: Summary. Following Shouldice repair of a primary inguinal hernia 50 patients were given subcutaneous Redon drains, while another 50 patients underwent operations without drains in a prospective randomized trial. The amount of postoperative wound secretion in the drainage bottle was added to fluid retention established by sonographic volumetric analysis. The degree of personal impairment was estimated by a visual analogue score. Inflammation parameters were recorded as well as the rate of complications. The drain group showed significantly increased fluid production in comparison to the group without drains on the 1st postoperative day (36.0 vs. 2.5 ml). Wound sepsis was found in two patients in the drain group. Seven patients with drains and eight patients without underwent percutaneous seroma puncture. The drain only slightly affected personal impairment (25.6 % vs 21.4 %, visual analogue score). Body temperature was elevated in the drain group on the 3rd day after operation (37.2 vs 36.7 °C). We believe there is no indication for the routine use of a Redon drain in the repair of a primary inguinal hernia. Instead, percutaneous puncture of subcutaneous fluid retentions should be performed.
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  • 39
    Digitale Medien
    Digitale Medien
    Springer
    European journal of plastic surgery 20 (1997), S. 202-204 
    ISSN: 1435-0130
    Schlagwort(e): Plastic day surgery ; Organization ; Complications ; Patient's opinion
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Abstract Day surgery is increasing. This article reviews the experiences of day plastic surgery during a period of five years. The evaluation shows a low rate of postoperative complications and a high degree of patient satisfaction. According to the author's opinion a considerable part of elective plastic surgery is suitable for day surgery.
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  • 40
    Digitale Medien
    Digitale Medien
    Springer
    Langenbeck's archives of surgery 382 (1997), S. 87-94 
    ISSN: 1435-2451
    Schlagwort(e): Hernia repair ; Mesh ; Complications ; Biocompatibility ; Rat model ; Hernienchirurgie ; Netz ; Komplikationen ; Biokompatibilität ; Ratte
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Beschreibung / Inhaltsverzeichnis: Zusammenfassung Die moderne Hernienchirurgie bedient sich zunehmend Kunstnetzkonstruktionen zur Bauchwandrekonstruktion. Trotz der unbestrittenen Vorteile der z.Z. verfügbaren Kunstnetze mehren sich Berichte über Spätkomplikationen nach der Implantation. Eine Optimierung der Kunstnetze ist notwendig, bedingt aber ein standardisiertes Tiermodell zur Evaluierung der Biokompatibilität auf funktioneller und morphologischer Ebene. In der vorliegenden Studie werden z.T. handelübliche Polypropylen-und Polyesternetze in einem standardisierten Rattenmodell implantiert und detailliert morphologisch und morphometrisch analysiert. Die morphologisch-morphometrischen Daten werden in Anschluß mit der Funktion der künstlichen Bauchwand korreliert. Zusammenfassend zeigen die Daten, daß die z.Z. gebräuchlichen Netzkonstruktionen überdimensioniert sind und zu einer deutlichen Funktionseinschränkung der künstlichen Bauchwand führen. Die Funktion wird dabei entscheidend durch den Entzündungs- und Fibrosegrad, durch das Fibrosemuster und durch die Zusammensetzung der Extrazellularmatrix beeinflußt. Fibrose und Entzündung werden jedoch weniger durch das Material an sich bestimmt, sondern durch die Materialdichte,-verarbeitung und-ober-fläche. Zukünftige Netzkonstruktionen der 2. Generation sollten zur Verbesserung der funktionell-morphologisch definierten Biokompatibilität eine Reduzierung der Materialmenge und eine materialspezifische Verarbeitung anstreben.
    Notizen: Abstract Modern surgical hernia repair depends increasingly on synthetic meshes for reconstruction of the abdominal wall. Despite the undisputed advantages of the synthetic meshes currently available, reports of late complications after implantation are accumulating. It is essential that the synthetic meshes be improved, but this makes a standardized animal model necessary for evaluation of their biocompatibility on both functional and morphological levels. In the present study, commercially available polypropylene and polyester meshes were implanted in a rat model, and detailed morphological and morphometric analysis were carried out. Correlations between the morphological and morphometric data and the function of the artificial abdominal wall were then sought. In summary, the data show that the mesh constructions currently available are oversized and definitely restrict the function of the artificial abdominal wall. The degree of inflammation and fibrosis, the pattern of fibrosis, and the composition of the extracellular matrix exert decisive influences on the function. Fibrosis and inflammation are caused less by the material itself, however, than by its density, the way it is processed, and its surface. Future, that is to say second-generated, mesh constructions should be designed with the aims of reducing the amount of material used and finding material-specific processing methods in mind, to improve the functionally and morphologically defined biocompatibility.
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  • 41
    Digitale Medien
    Digitale Medien
    Springer
    Langenbeck's archives of surgery 382 (1997), S. 192-196 
    ISSN: 1435-2451
    Schlagwort(e): Liver resection ; Infection ; Complications ; Multiple organ system failure ; Mortality ; Leberresektion ; Infektion ; Komplikationen ; Multiples Organversagen ; Mortalität
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Beschreibung / Inhaltsverzeichnis: Zusammenfassung Von 1986–1995 wurden 97 Patienten mit einem Alter 〉65 Jahre einer Leberresektion an der Abteilung für Allgemeinchirurgie des Krankenhauses Lainz, Wien, unterzogen. Das Durchschnittsalter der 39 Männer und 58 Frauen betrug 74±5,5 Jahre. Eine primäre Neoplasie der Leber war der Grund für die Leberresektion bei 35 Patienten, während 16 Patienten wegen eines Gallenblasenkarzinoms und 40 Patienten wegen Lebermetastasen reseziert wurden. In 73% der Patienten wurde eine größere Leberresektion (≥3 Segmente) bei einer gesamten Klinikmortalität von 13,5% durchgeführt. Bei 42 Patienten wurden 65 postoperative Komplikationen registriert, wobei Infektionen bei fast allen Patienten als Hauptproblem darstellten (95%). Die Histologie des Tumors hatte mehr Einfluß auf Klinikmortalität und Morbidität als die Größe der Leberresektion. Alle Komplikationen wurden bei Patienten mit maligner Grunderkrankung beobachtet (p=0,03). Eine ungünstige Auswirkung auf die postoperative Morbidität wurde bei Hepatikus- Gallenblasen-und cholangiozellularen Karzinomen beobachtet (p=0,003). Intraabdominale Infektionen wurden bei 25% unserer Patienten gefunden und waren in 58% auf Gallenleaks zurückzuführen, sie hatten aber keinen signifikanten Einfluß auf das Patientenüberleben. Pneumonie war die Komplikation, die sich besonders auf das Patientenüberleben auswirkte. Wenn eine Pneumonie als spätere Komplikation während eines komplizierten postoperativen Verlaufs auftrat, führte diese Konstellation bei allen betroffenen Patienten zum Tod (p=0,0001). Alle Patienten dieser Gruppe wiesen einen reduzierten Mobilisierungsgrad auf. Eine schwere präoperative Einschränkung der Leberfunktion hatte einen signifikanten Einfluß auf die postoperative Morbidität und Mortalität (p=0,003 und 0,01), ein Zusammenhang der sich bei einem Alter 〉80 Jahre noch verstärkte (p=0,002 und 0,004). Ein signifikantes Risiko für eine höhere postoperative Morbidität bestand nach rechten Lobektomien und erweiterten rechten Lobektomien (p=0,004). Zusammenfassend sind Infektionen mit nahezu jeder postoperativen Komplikation nach Leberresektionen im Alter assoziiert. Pneumonie stellt als Folgekomplikation ein prognostisch ungünstiges Zeichen bei älteren Patienten nach Leberresektionen dar. Patienten 〉65 Jahre und besonders jene 〉80 Jahre sterben eher an den vorwiegend infektiösen postoperativen Komplikationen. Bessere lokale Drainagen können möglicherweise die intraabdominalen Komplikationen reduzieren, und eine frühe Mobilisierung der Patienten ist möglicherweise in der Lage, die Rate systemischer, infektiöser Komplikationen und letztendlich die Klinikmortalität zu verbessern.
    Notizen: Abstract From 1986 to 1995, 97 patients older than 65 years of age underwent hepatic resection at the Department of General Surgery, Hospital Lainz, Vienna. The population consisted of 39 men and 58 women with a mean age of 74±5.5 years. Primary neoplasia was the cause of resection in 35 patients, gallbladder cancer in 16 patients, and metastatic disease to the liver in 40 patients. Six patients underwent hepatic resection because of benign disease. The overall rate of major resections (≥3 liver segments) was 73% and the overall mortality was 13.5%. Sixty-five postoperative complications were recorded in 42 patients, and infection was the leading problem in nearly all of these patients (95%). The histologic type of tumor rather than the magnitude of resection had an influence on clinical mortality and morbidity. All complications occurred in patients with malignant disease (P=0.03). Adverse effects on postoperative morbidity were observed in adenocarcinoma of the hepatic ducts, gallbladder carcinoma, and cholangiocellular carcinoma (P=0.003). Intra-abdominal infections were found in 25% of our patients and were due to biliary leakage in 58%, but had no significant impact on survival. Pneumonia was the leading complication in association with patient survival. All patients who developed pneumonia as a late complication during a complicated course died postoperatively (P=0.0001). All of these patients had a reduced grade of mobilization. Severe preoperative liver dysfunction carried a significantly higher risk for postoperative morbidity and mortality (P=0.003 and 0.01), which showed an incremental risk with age 〉80 (P=0.002 and 0.0004). Right lobectomies and extended right lobectomies carried a significantly increased risk for postoperative morbidity (P=0.004). Infection is associated with nearly every complication recorded after hepatic resection in the elderly. Pneumonia as a late complication poses a worse prognosis in elderly patients who underwent hepatic resection. Patients older than 65 years of age and especially those older than 80 years of age are more liable to succumb to complications that are predominantly infectious. Better local drainage procedures may reduce intra-abdominal infectious complications and early mobilization of the patients may improve the rate of systemic infectious complications and final outcome.
    Materialart: Digitale Medien
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  • 42
    Digitale Medien
    Digitale Medien
    Springer
    Langenbeck's archives of surgery 382 (1997), S. 192-196 
    ISSN: 1435-2451
    Schlagwort(e): Key words Liver resection ; Infection ; Complications ; Multiple organ system failure ; Mortality ; Schlüsselwörter Leberresektion ; Infektion ; Komplikationen ; Multiples Organversagen ; Mortalität
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Beschreibung / Inhaltsverzeichnis: Zusammenfassung Von 1986 – 1995 wurden 97 Patienten mit einem Alter 〉65 Jahre einer Leberresektion an der Abteilung für Allgemeinchirurgie des Krankenhauses Lainz, Wien, unterzogen. Das Durchschnittsalter der 39 Männer und 58 Frauen betrug 74±5,5 Jahre. Eine primäre Neoplasie der Leber war der Grund für die Leberresektion bei 35 Patienten, während 16 Patienten wegen eines Gallenblasenkarzinoms und 40 Patienten wegen Lebermetastasen reseziert wurden. In 73% der Patienten wurde eine größere Leberresektion (≥3 Segmente) bei einer gesamten Klinikmortalität von 13,5% durchgeführt. Bei 42 Patienten wurden 65 postoperative Komplikationen registriert, wobei Infektionen bei fast allen Patienten als Hauptproblem darstellten (95%). Die Histologie des Tumors hatte mehr Einfluß auf Klinikmortalität und Morbidität als die Größe der Leberresektion. Alle Komplikationen wurden bei Patienten mit maligner Grunderkrankung beobachtet (p = 0,03). Eine ungünstige Auswirkung auf die postoperative Morbidität wurde bei Hepatikus- Gallenblasen- und cholangiozellularen Karzinomen beobachtet (p = 0,003). Intraabdominale Infektionen wurden bei 25% unserer Patienten gefunden und waren in 58% auf Gallen-leaks zurückzuführen, sie hatten aber keinen signifikanten Einfluß auf das Patientenüberleben. Pneumonie war die Komplikation, die sich besonders auf das Patientenüberleben auswirkte. Wenn eine Pneumonie als spätere Komplikation während eines komplizierten postoperativen Verlaufs auftrat, führte diese Konstellation bei allen betroffenen Patienten zum Tod (p = 0,0001). Alle Patienten dieser Gruppe wiesen einen reduzierten Mobilisierungsgrad auf. Eine schwere präoperative Einschränkung der Leberfunktion hatte einen signifikanten Einfluß auf die postoperative Morbidität und Mortalität (p = 0,003 und 0,01), ein Zusammenhang der sich bei einem Alter 〉80 Jahre noch verstärkte (p = 0,002 und 0,004). Ein signifikantes Risiko für eine höhere postoperative Morbidität bestand nach rechten Lobektomien und erweiterten rechten Lobektomien (p = 0,004). Zusammenfassend sind Infektionen mit nahezu jeder postoperativen Komplikation nach Leberresektionen im Alter assoziiert. Pneumonie stellt als Folgekomplikation ein prognostisch ungünstiges Zeichen bei älteren Patienten nach Leberresektionen dar. Patienten 〉65 Jahre und besonders jene 〉80 Jahre sterben eher an den vorwiegend infektiösen postoperativen Komplikationen. Bessere lokale Drainagen können möglicherweise die intraabdominalen Komplikationen reduzieren, und eine frühe Mobilisierung der Patienten ist möglicherweise in der Lage, die Rate systemischer, infektiöser Komplikationen und letztendlich die Klinikmortalität zu verbessern.
    Notizen: Abstract From 1986 to 1995, 97 patients older than 65 years of age underwent hepatic resection at the Department of General Surgery, Hospital Lainz, Vienna. The population consisted of 39 men and 58 women with a mean age of 74±5.5 years. Primary neoplasia was the cause of resection in 35 patients, gallbladder cancer in 16 patients, and metastatic disease to the liver in 40 patients. Six patients underwent hepatic resection because of benign disease. The overall rate of major resections (≥3 liver segments) was 73% and the overall mortality was 13.5%. Sixty-five postoperative complications were recorded in 42 patients, and infection was the leading problem in nearly all of these patients (95%). The histologic type of tumor rather than the magnitude of resection had an influence on clinical mortality and morbidity. All complications occurred in patients with malignant disease (P = 0.03). Adverse effects on postoperative morbidity were observed in adenocarcinoma of the hepatic ducts, gallbladder carcinoma, and cholangiocellular carcinoma (P = 0.003). Intra-abdominal infections were found in 25% of our patients and were due to biliary leakage in 58%, but had no significant impact on survival. Pneumonia was the leading complication in association with patient survival. All patients who developed pneumonia as a late complication during a complicated course died postoperatively (P = 0.0001). All of these patients had a reduced grade of mobilization. Severe preoperative liver dysfunction carried a significantly higher risk for postoperative morbidity and mortality (P = 0.003 and 0.01), which showed an incremental risk with age 〉80 (P = 0.002 and 0.0004). Right lobectomies and extended right lobectomies carried a significantly increased risk for postoperative morbidity (P = 0.004). Infection is associated with nearly every complication recorded after hepatic resection in the elderly. Pneumonia as a late complication poses a worse prognosis in elderly patients who underwent hepatic resection. Patients older than 65 years of age and especially those older than 80 years of age are more liable to succumb to complications that are predominantly infectious. Better local drainage procedures may reduce intra-abdominal infectious complications and early mobilization of the patients may improve the rate of systemic infectious complications and final outcome.
    Materialart: Digitale Medien
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  • 43
    Digitale Medien
    Digitale Medien
    Springer
    Langenbeck's archives of surgery 382 (1997), S. 49-54 
    ISSN: 1435-2451
    Schlagwort(e): Key words Conventional reconstruction ; Abdominal aorta ; Complications ; Endovascular reconstructive surgery ; Schlüsselwörter Rekonstruktive Gefäßchirurgie der Beckenetage ; Komplikationen ; endovaskuläre Rekonstruktion
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Beschreibung / Inhaltsverzeichnis: Zusammenfassung Im Zeitraum von September 1985 bis Februar 1994 wurde bei 183 Patienten ein rekonstruktiver Eingriff im aortoiliakalen Bereich durchgeführt. Die Grunderkrankung war in 108 Fällen eine arterielle Verschlußkrankheit, in 75 Fällen ein abdominales Aortenaneurysma. Bei 120 Patienten wurde eine Bifurkationsprothese, bei 63 Patienten eine Rohrprothese implantiert. Die Früh- und Spätkomplikationen werden beschrieben, differenziert nach chirurgisch und nichtchirurgisch, wobei die chirurgischen Komplikationen im wesentlichen durch die Prothesenart und durch den Leistenanschluß bedingt waren, während die nichtchirurgischen Komplikationen vom Risikoprofil des Krankenguts abhängig waren. Die Unterschiede in der postoperativen Letalität ergaben sich durch die Dringlichkeit des Eingriffs. Der Stellenwert der endovaskulären Rekonstruktion im Vergleich zur rekonstruktiven Gefäßchirurgie wird diskutiert.
    Notizen: Abstract From September 1985 to February 1994, 183 pa- tients (arterial occlusive disease n = 108, abdominal aneurysm n = 75) underwent reconstruction of the abdominal aorta. In 120 patients an aorto-bi-iliac or aorto-bi-femoral reconstruction was performed and in 63 patients a tube-type reconstruction. The early and late postoperative complications are described. The complications were dependent on the choice of graft, the distal anastomosis and the preoperative risk factors. The mortality from elective repairs was compared with the mortality in emergency repairs. The role of endovascular reconstructive surgery in comparison to conventional reconstructive procedures is discussed.
    Materialart: Digitale Medien
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  • 44
    Digitale Medien
    Digitale Medien
    Springer
    Langenbeck's archives of surgery 382 (1997), S. 87-94 
    ISSN: 1435-2451
    Schlagwort(e): Key words Hernia repair ; Mesh ; Complications ; Biocompatibility ; Rat model ; Schlüsselwörter Hernienchirurgie ; Netz ; Komplikationen ; Biokompatibilität ; Ratte
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Beschreibung / Inhaltsverzeichnis: Zusammenfassung Die moderne Hernienchirurgie bedient sich zunehmend Kunstnetzkonstruktionen zur Bauchwandrekonstruktion. Trotz der unbestrittenen Vorteile der z.Z. verfügbaren Kunstnetze mehren sich Berichte über Spätkomplikationen nach der Implantation. Eine Optimierung der Kunstnetze ist notwendig, bedingt aber ein standardisiertes Tiermodell zur Evaluierung der Biokompatibilität auf funktioneller und morphologischer Ebene. In der vorliegenden Studie werden z.T. handelübliche Polypropylen- und Polyesternetze in einem standardisierten Rattenmodell implantiert und detailliert morphologisch und morphometrisch analysiert. Die morphologisch-morphometrischen Daten werden in Anschluß mit der Funktion der künstlichen Bauchwand korreliert. Zusammenfassend zeigen die Daten, daß die z.Z. gebräuchlichen Netzkonstruktionen überdimensioniert sind und zu einer deutlichen Funktionseinschränkung der künstlichen Bauchwand führen. Die Funktion wird dabei entscheidend durch den Entzündungs- und Fibrosegrad, durch das Fibrosemuster und durch die Zusammensetzung der Extrazellularmatrix beeinflußt. Fibrose und Entzündung werden jedoch weniger durch das Material an sich bestimmt, sondern durch die Materialdichte, -verarbeitung und -oberfläche. Zukünftige Netzkonstruktionen der 2. Generation sollten zur Verbesserung der funktionell-morphologisch definierten Biokompatibilität eine Reduzierung der Materialmenge und eine materialspezifische Verarbeitung anstreben.
    Notizen: Abstract Modern surgical hernia repair depends increasingly on synthetic meshes for reconstruction of the abdominal wall. Despite the undisputed advantages of the synthetic meshes currently available, reports of late complications after implantation are accumulating. It is essential that the synthetic meshes be improved, but this makes a standardized animal model necessary for evaluation of their biocompatibility on both functional and morphological levels. In the present study, commercially available polypropylene and polyester meshes were implanted in a rat model, and detailed morphological and morphometric analysis were carried out. Correlations between the morphological and morphometric data and the function of the artificial abdominal wall were then sought. In summary, the data show that the mesh constructions currently available are oversized and definitely restrict the function of the artificial abdominal wall. The degree of inflammation and fibrosis, the pattern of fibrosis, and the composition of the extracellular matrix exert decisive influences on the function. Fibrosis and inflammation are caused less by the material itself, however, than by its density, the way it is processed, and its surface. Future, that is to say second-generated, mesh constructions should be designed with the aims of reducing the amount of material used and finding material-specific processing methods in mind, to improve the functionally and morphologically defined biocompatibility.
    Materialart: Digitale Medien
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  • 45
    Digitale Medien
    Digitale Medien
    Springer
    European archives of oto-rhino-laryngology and head & neck 254 (1997), S. 384-386 
    ISSN: 1434-4726
    Schlagwort(e): Chronic otitis media ; Cholesteatoma ; Tympanomastoid surgery ; Complications ; Deafness
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Abstract Preoperative and postoperative bone conduction thresholds were compared in 181 chronic ears operated on over a 5-year period between 1990 to 1994. In the majority (92%) of cases the bone conduction thresholds remained unchanged (± 10 dB). Nine ears (5%) showed better thresholds after surgery, with improvements ranging from 11 dB to 25 dB. This improvement was especially noted in ears with severe tympanic pathology. One ear with a large labyrinthine fistula became totally deaf after surgery. In 5 ears (3%) bone-conduction thresholds deteriorated, but remained measurable at all frequencies tested. In these latter cases this impairment ranged from 11 dB to 27 dB. Cholesteatomatous ears having intact ossicular chains were found to be at the highest risk of inner ear damage when “canal wall-down” mastoidectomies were performed. Methods for prevention of sensorineural hearing loss following chronic ear surgery are discussed.
    Materialart: Digitale Medien
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  • 46
    Digitale Medien
    Digitale Medien
    Springer
    European journal of plastic surgery 20 (1997), S. 220-222 
    ISSN: 1435-0130
    Schlagwort(e): Pacemaker ; Complications ; Extrusion ; Salvage ; Greater omentum
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Abstract The extrusion of a pacemaker, due to infectious or mechanical problems, is a condition that usually requires the removal of the device and implantation of a new pacemaker. A case is presented in which an extruded pacemaker was successfully salvaged using the greater omentum as a wrap-around pedicled flap. The current protocol for salvaging exposed pacemakers at the authors' center is described.
    Materialart: Digitale Medien
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  • 47
    Digitale Medien
    Digitale Medien
    Springer
    European journal of plastic surgery 20 (1997), S. 77-79 
    ISSN: 1435-0130
    Schlagwort(e): Cleft lip and palate ; Complications ; Length of hospital stay
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Abstract We studied the occurrence of early complications of cleft lip and palate surgery by the retrospective study of 132 consecutive cases (160 procedures) operated between three and six months of age. Three children presented with major complications within the immediate postoperative period. All were treated successfully. A local complication directly related to the operation occurred in 7.5% of the cases within the first six postoperative days. In 17%, a general complication not directly related to the operation was observed. The majority of these general complications were cross infections during the hospital stay. These observations led us to reduce the hospital stay to one day for cleft lip and five days for cleft palate and cleft lip and palate operations without compromise to safety but with a reduction of the morbidity and hence the treatment costs and of the child-family disturbance.
    Materialart: Digitale Medien
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  • 48
    Digitale Medien
    Digitale Medien
    Chichester, West Sussex : Wiley-Blackwell
    Mathematical Methods in the Applied Sciences 20 (1997), S. 1469-1500 
    ISSN: 0170-4214
    Schlagwort(e): radiating solutions ; exterior boundary value problem in elasticity ; variable coefficients ; Engineering ; Numerical Methods and Modeling
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Mathematik
    Notizen: We use Hodge-Helmholtz decompositions of weighted Sobolev spaces to solve time-harmonic exterior-boundary value problems for perturbations of the (aδd+bdδ)-system (δ: the co-differential, a, b〉0). We prove, that a Fredholm alternative holds true, the eigensolutions decay polynomially at infinity, and that the positive eigenvalues do not accumulate. © 1997 B. G. Teubner Stuttgart-John Wiley & Sons Ltd.
    Materialart: Digitale Medien
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  • 49
    Digitale Medien
    Digitale Medien
    Chichester, West Sussex : Wiley-Blackwell
    Mathematical Methods in the Applied Sciences 20 (1997), S. 1551-1562 
    ISSN: 0170-4214
    Schlagwort(e): Engineering ; Numerical Methods and Modeling
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Mathematik
    Notizen: The Neumann problem for the Laplace equation in an exterior connected plane region bounded by closed and open curves is studied. The existence of classical solution is proved by potential theory. The problem is reduced to the Fredholm equation of the second kind, which is uniquely solvable. © 1997 by B. G. Teubner Stuttgart-John Wiley & Sons Ltd.
    Materialart: Digitale Medien
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  • 50
    Digitale Medien
    Digitale Medien
    Chichester, West Sussex : Wiley-Blackwell
    Mathematical Methods in the Applied Sciences 20 (1997), S. 1531-1549 
    ISSN: 0170-4214
    Schlagwort(e): gratings ; Helmholtz equation ; high frequencies ; geometric theory of diffraction ; transition regions ; finite element method ; error estimates ; Engineering ; Numerical Methods and Modeling
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Mathematik
    Notizen: A new numerical method is derived for the calculation of high-frequency asymptotic expansions of the scalar wave scattered by curved periodic structures. Optimal error estimates for this method are established. © 1997 B. G. Teubner Stuttgart-John Wiley & Sons Ltd.
    Zusätzliches Material: 5 Ill.
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
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  • 51
    Digitale Medien
    Digitale Medien
    Chichester, West Sussex : Wiley-Blackwell
    Mathematical Methods in the Applied Sciences 20 (1997), S. 1563-1598 
    ISSN: 0170-4214
    Schlagwort(e): Engineering ; Numerical Methods and Modeling
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Mathematik
    Notizen: We give a complete classification for breakdown in finite time or global existence of continuously differentiable solutions to hyperbolic systems of two first-order partial differential equations posed on a real bounded interval, with boundary damping and initial data of small magnitude. Structural bounds for the derivatives of the initial data which govern the behavior of the solution are brought to light. We isolate two classes of boundary damping: the strong damping forbids the solution to blow up after a time that we exhibit while the weak damping permits a late breakdown. The results are applied to nonlinear elasticity. © 1997 by B. G. Teubner Stuttgart-John Wiley & Sons Ltd.
    Zusätzliches Material: 4 Ill.
    Materialart: Digitale Medien
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  • 52
    Digitale Medien
    Digitale Medien
    Chichester, West Sussex : Wiley-Blackwell
    Mathematical Methods in the Applied Sciences 20 (1997), S. 31-45 
    ISSN: 0170-4214
    Schlagwort(e): Engineering ; Numerical Methods and Modeling
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Mathematik
    Notizen: No Abstract
    Materialart: Digitale Medien
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  • 53
    Digitale Medien
    Digitale Medien
    Chichester, West Sussex : Wiley-Blackwell
    Mathematical Methods in the Applied Sciences 20 (1997), S. 133-150 
    ISSN: 0170-4214
    Schlagwort(e): Engineering ; Numerical Methods and Modeling
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Mathematik
    Notizen: Solutions of linear elliptic partial differential equations in unbounded domains can be represented by boundary potentials if they satisfy certain conditions at infinity. These radiation conditions depend on the fundamental solution chosen for the integral representation. We prove some basic results about radiation conditions in a rather general framework.Fundamental solutions G are considered that are defined only on the complement of a compact set. It turns out, however, and we present examples for this, that the more interesting results only hold if G is defined on all of ∝n or if it is a Green function for an exterior boundary value problem. © 1997 by B.G. Teubner Stuttgart-John Wiley & Sons, Ltd.
    Materialart: Digitale Medien
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  • 54
    Digitale Medien
    Digitale Medien
    Chichester, West Sussex : Wiley-Blackwell
    Mathematical Methods in the Applied Sciences 20 (1997), S. 189-203 
    ISSN: 0170-4214
    Schlagwort(e): Engineering ; Numerical Methods and Modeling
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Mathematik
    Notizen: In the present paper, we deal with the long time behaviour of solutions for the generalized Benjamin-Bona-Mahony equation. By a priori estimates methods, we show this equation possesses a global attractor in Hk for every integer k≥2, which has finite Hausdorff and fractal dimensions. We also construct approximate inertial manifolds such that every solution enters their thin neighbourhood in a finite time. © 1997 by B.G. Teubner Stuttgart-John Wiley & Sons, Ltd.
    Materialart: Digitale Medien
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  • 55
    Digitale Medien
    Digitale Medien
    Chichester, West Sussex : Wiley-Blackwell
    Mathematical Methods in the Applied Sciences 20 (1997), S. 1185-1198 
    ISSN: 0170-4214
    Schlagwort(e): Engineering ; Numerical Methods and Modeling
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Mathematik
    Notizen: An explicit factorization of the Fourier symbol matrix functions generated by Sommerfeld diffraction problems with oblique derivatives is obtained. For this purpose a new prefactorization procedure is developed which makes use of factorization through weighted L2 spaces. These results yield a representation of a generalized inverse of the corresponding matrix Wiener-Hopf operator and the asymptotic behaviour of the solution at the edge of the screen. © 1997 by B. G. Teubner Stuttgart-John Wiley & Sons Ltd.
    Materialart: Digitale Medien
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  • 56
    Digitale Medien
    Digitale Medien
    Chichester, West Sussex : Wiley-Blackwell
    Mathematical Methods in the Applied Sciences 20 (1997), S. 1223-1238 
    ISSN: 0170-4214
    Schlagwort(e): Engineering ; Numerical Methods and Modeling
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Mathematik
    Notizen: We study a high-field version of the periodic Schrödinger-Poisson system, for which the Poisson equation includes nonlinear terms corresponding to a field-dependent dielectric constant. Using a Galerkin scheme, we prove global existence and uniqueness, and present the matrix equations for the numerical evaluation of the potential. © 1997 by B. G. Teubner Stuttgart-John Wiley & Sons Ltd.
    Materialart: Digitale Medien
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  • 57
    Digitale Medien
    Digitale Medien
    Chichester, West Sussex : Wiley-Blackwell
    Mathematical Methods in the Applied Sciences 20 (1997), S. 1199-1222 
    ISSN: 0170-4214
    Schlagwort(e): Engineering ; Numerical Methods and Modeling
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Mathematik
    Notizen: A generalized Hele-Shaw flow is derived and analysed in injection and compression moulding which contains non-isothermal and non-Newtonian rheological behaviour of the molten polymers as well as non-symmetric effects. The corresponding fixed domain formulations for the flow are investigated from a mathematical point of view. Different approaches for the determination of the temperature and some viscosity models are discussed. Together with an outline of the proposed solution algorithm special finite element techniques are described for the numerical treatment of this complex non-linear moving boundary problem. © 1997 by B. G. Teubner Stuttgart-John Wiley & Sons Ltd.
    Zusätzliches Material: 3 Ill.
    Materialart: Digitale Medien
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  • 58
    Digitale Medien
    Digitale Medien
    Chichester, West Sussex : Wiley-Blackwell
    Mathematical Methods in the Applied Sciences 20 (1997), S. 1239-1256 
    ISSN: 0170-4214
    Schlagwort(e): Engineering ; Numerical Methods and Modeling
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Mathematik
    Notizen: The Ginzburg-Landau equation which describes nonlinear modulation of the amplitude of the basic pattern does not give a good approximation when the Landau constant (which describes the influence of the nonlinearity) is small. In this paper a derivation of the so-called degenerate (or generalized) Ginzburg-Landau (dGL)-equation is given. It turns out that one can understand the dGL-equation as an example of a normal form of a co-dimension two bifurcation for parabolic PDEs. The main body of the paper is devoted to the proof of the validity of the dGL as an equation whose solution approximate the solution of the original problem. © 1997 by B. G. Teubner Stuttgart-John Wiley & Sons Ltd.
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  • 59
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    Digitale Medien
    Chichester, West Sussex : Wiley-Blackwell
    Mathematical Methods in the Applied Sciences 20 (1997), S. 1257-1269 
    ISSN: 0170-4214
    Schlagwort(e): Engineering ; Numerical Methods and Modeling
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Mathematik
    Notizen: The paper deals with the Dirichlet problem for the Stokes linear equation in a domain exterior to an open surface. With the help of the theory of boundary integral (pseudo-differential) equations uniqueness and existence theorems are proved in the Bessel-potential and Besov spaces and Cα-smoothness (with α〈1/2) of solution is established in the neighbourhood of the boundary of the open surface. © 1997 B. G. Teubner Stuttgart-John Wiley & Sons Ltd.
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  • 60
    Digitale Medien
    Digitale Medien
    Chichester, West Sussex : Wiley-Blackwell
    Mathematical Methods in the Applied Sciences 20 (1997), S. 1271-1281 
    ISSN: 0170-4214
    Schlagwort(e): Engineering ; Numerical Methods and Modeling
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Mathematik
    Notizen: In this paper the authors consider the initial boundary value problem of the ferromagnetic spin chain equation and prove the existence of the global attractor and finiteness of the Hausdorff and the fractal dimensions of the attractor. © 1997 B. G. Teubner Stuttgart-John Wiley & Sons Ltd.
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  • 61
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    Digitale Medien
    Chichester, West Sussex : Wiley-Blackwell
    Mathematical Methods in the Applied Sciences 20 (1997), S. 1283-1312 
    ISSN: 0170-4214
    Schlagwort(e): Engineering ; Numerical Methods and Modeling
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Mathematik
    Notizen: We regard the Schrödinger-Poisson system arising from the modelling of an electron gas with reduced dimension in a bounded up to three-dimensional domain and establish the method of steepest descent. The electrostatic potentials of the iteration scheme will converge uniformly on the spatial domain. To get this result we investigate the Schrödinger operator, the Fermi level and the quantum mechanical electron density operator for square integrable electrostatic potentials. On bounded sets of potentials the Fermi level is continuous and bounded, and the electron density operator is monotone and Lipschitz continuous. As a tool we develop a Riesz-Dunford functional calculus for semibounded self-adjoint operators using paths of integration which enclose a real half-axis. © 1997 B. G. Teubner Stuttgart-John Wiley & Sons Ltd.
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  • 62
    Digitale Medien
    Digitale Medien
    Chichester, West Sussex : Wiley-Blackwell
    Mathematical Methods in the Applied Sciences 20 (1997), S. 1313-1323 
    ISSN: 0170-4214
    Schlagwort(e): Engineering ; Numerical Methods and Modeling
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Mathematik
    Notizen: We investigate an initial-value problem modelling fragmentation processes where particles split into two or more pieces at a rate, γ, that not only depends on the sizes of the particles involved but also on time. The existence of non-negative, mass-conserving solutions is established by considering a truncated version of an associated non-autonomous abstract Cauchy problem. The latter has solutions of the form u(t)=Un(t,t0)f, t≥t0, where f is the known data at some fixed time t0≥0 and {Un(t,s)}t0≤s≤t≤T is a uniformly continuous evolution system. A limit evolution system {U(t,s)}t0≤s≤t≤T is shown to exist. Depending on the form of the known data f at time t0, the scalar-valued function u, obtained from the limit evolution system via u(x, t)=[U(t, t0)f](x) for a.e. x〉0, t≥t0, is a solution of either the original initial-value problem or an integral version of this problem. © 1997 B. G. Teubner Stuttgart-John Wiley & Sons Ltd.
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  • 63
    Digitale Medien
    Digitale Medien
    Chichester, West Sussex : Wiley-Blackwell
    Mathematical Methods in the Applied Sciences 20 (1997), S. 1325-1333 
    ISSN: 0170-4214
    Schlagwort(e): Engineering ; Numerical Methods and Modeling
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Mathematik
    Notizen: We study the boundedness and a priori bounds of global solutions of the problem Δu=0 in Ω×(0, T), (∂u/∂t) + (∂u/∂ν) = h(u) on ∂Ω×(0, T), where Ω is a bounded domain in ∝N, ν is the outer normal on ∂Ω and h is a superlinear function. As an application of our results we show the existence of sign-changing stationary solutions. © 1997 B. G. Teubner Stuttgart-John Wiley & Sons Ltd.
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  • 64
    Digitale Medien
    Digitale Medien
    Chichester, West Sussex : Wiley-Blackwell
    Mathematical Methods in the Applied Sciences 20 (1997), S. 1335-1344 
    ISSN: 0170-4214
    Schlagwort(e): Engineering ; Numerical Methods and Modeling
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Mathematik
    Notizen: In this note we investigate spatial bounds for the heat conduction equation with three relaxation times. We use energy methods similar to those considered in the study of the backward parabolic heat equation. Finally, we show that for any positive choice of the coefficients we may take initial data for which the solution is unstable when we suppose that the body is bounded. © 1997 B. G. Teubner Stuttgart-John Wiley & Sons Ltd.
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  • 65
    Digitale Medien
    Digitale Medien
    Chichester, West Sussex : Wiley-Blackwell
    Mathematical Methods in the Applied Sciences 20 (1997), S. 1345-1364 
    ISSN: 0170-4214
    Schlagwort(e): Engineering ; Numerical Methods and Modeling
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Mathematik
    Notizen: Continuous sedimentation of solid particles in a liquid takes place in a clarifier-thickener unit, which has one feed inlet and two outlets. The process is vital in a waste water treatment plant, where the particles consist of several biological components. The concentrations of these are modelled by a one-dimensional system of conservation laws with source term. It is shown how a unique solution can be obtained, and how analytical solutions are used to form a conservative numerical algorithm. © 1997 B. G. Teubner Stuttgart-John Wiley & Sons Ltd.
    Zusätzliches Material: 7 Ill.
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  • 66
    Digitale Medien
    Digitale Medien
    Chichester, West Sussex : Wiley-Blackwell
    Mathematical Methods in the Applied Sciences 20 (1997), S. 1389-1410 
    ISSN: 0170-4214
    Schlagwort(e): Engineering ; Numerical Methods and Modeling
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Mathematik
    Notizen: This paper is concerned with the existence and uniqueness of the steady-state solution of hydrodynamic model for semiconductor devices. Boundary conditions are prescribed by vorticity on inflow boundary as well as by electron density, temperature, and normal component of electron velocity on whole boundary. If the ambient temperature is large, and if both vorticity on inflow boundary and the variation of density on boundary are small, a unique subsonic solution exists. © 1997 by B.G. Teubner Stuttgart-John Wiley & Sons Ltd.
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  • 67
    Digitale Medien
    Digitale Medien
    Chichester, West Sussex : Wiley-Blackwell
    Mathematical Methods in the Applied Sciences 20 (1997), S. 1379-1388 
    ISSN: 0170-4214
    Schlagwort(e): Engineering ; Numerical Methods and Modeling
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Mathematik
    Notizen: The theory of high-frequency waves has been used to calculate first and second-order asymptotic solutions for the propagation of non-linear waves in a cylindrical symmetric flow of an electron plasma. The behaviour of acceleration waves and weak shock waves has been analysed through these solutions and Whitham's rule for a weak shock wave on any wavelet has been confirmed through the first-order solution. The appearance of a weak shock wave on any wavelet has been determined and its strength, the location, and the speed of propagation have been found from the asymptotic solution presented in this paper. © 1997 by B. G. Teubner Stuttgart-John Wiley & Sons Ltd.
    Zusätzliches Material: 4 Ill.
    Materialart: Digitale Medien
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  • 68
    Digitale Medien
    Digitale Medien
    Chichester, West Sussex : Wiley-Blackwell
    Mathematical Methods in the Applied Sciences 20 (1997), S. 1449-1457 
    ISSN: 0170-4214
    Schlagwort(e): Engineering ; Numerical Methods and Modeling
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Mathematik
    Notizen: Of concern are factored Euler-Poisson-Darboux equations of the type∏Nj=1(d2/dt2+(ρ/t)d/dt+Aj)u(t)=0,where, for example, Aj=-cjΔ, Δ being the Dirichlet Laplacian acting on L2(Ω), Ω⊂∝n, and 0〈c1〈…〈cN. More generally -Aj can be the square of the generator of a (C0) group on a Banach space. When the constant ρ is negative, the initial value problem for the factored EPD equation is ill-posed. Nevertheless, we determine how many initial conditions are necessary to guarantee uniqueness of a solution. This number jumps up as ρ crosses a negative integer from right to left. © 1997 by B. G. Teubner Stuttgart-John Wiley & Sons Ltd.
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  • 69
    Digitale Medien
    Digitale Medien
    Chichester, West Sussex : Wiley-Blackwell
    Mathematical Methods in the Applied Sciences 20 (1997), S. 151-177 
    ISSN: 0170-4214
    Schlagwort(e): Engineering ; Numerical Methods and Modeling
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Mathematik
    Notizen: We study on the initial-boundary value problem for some degenerate non-linear wave equations of Kirchhoff type with a strong dissipation:\documentclass{minimal} \begin{document} \[ u_{tt}=\left\| \nabla u\right\| ^{2\gamma }\Delta u-\Delta u_t=\left| u\right| ^\alpha u,\quad u(0)=u_0,\;u_t(0)=u_1,\;u|_{\partial \Omega }=0. \] \end{document}When the initial energy $E(u_0,u_1)\equiv \left\| u_1\right\| ⁁2+\frac 1{\gamma +1}\left\| \nabla u_0\right\| ⁁{2(\gamma +1)}-\frac 2{\alpha+2}\left\| u_0\right\| _{\alpha +2}⁁{\alpha +2}$ associated with the equations is non-negative and small, a unique (weak) solution exists globally in time and has some decay properties. When the initial energy E(u0,u1) is negative, the solution blows up at some finite time. In the proof we use the ‘modified potential well’ and ‘Concavity’ methods. © 1997 by B.G. Teubner Stuttgart-John Wiley & Sons, Ltd.
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  • 70
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    Digitale Medien
    Chichester, West Sussex : Wiley-Blackwell
    Mathematical Methods in the Applied Sciences 20 (1997), S. 179-187 
    ISSN: 0170-4214
    Schlagwort(e): Engineering ; Numerical Methods and Modeling
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Mathematik
    Notizen: We prove existence, in a small time interval, of a classical solution having a regular free boundary, (i.e. the level set {u=0}) of a multidimensional filtration problem. The key point to get the regularity of the level set {u=0} is the proof of an a priori estimate for the L∞-norm of ut. © 1997 by B.G. Teubner Stuttgart-John Wiley & Sons, Ltd.
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  • 71
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    Digitale Medien
    Chichester, West Sussex : Wiley-Blackwell
    Mathematical Methods in the Applied Sciences 20 (1997), S. 667-677 
    ISSN: 0170-4214
    Schlagwort(e): Engineering ; Numerical Methods and Modeling
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Mathematik
    Notizen: We study stationary solutions of the relativistic Vlasov-Maxwell system of plasma physics which have a special form introduced (in the classical setting) by Rudykh, Sidorov and Sinitsy and establish their existence under suitable assumptions on the ansatz functions. © 1997 by B. G. Teubner Stuttgart-John Wiley & Sons Ltd. Math. Meth. Appl. Sci., Vol. 20, 667-677 (1997).
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  • 72
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    Digitale Medien
    Chichester, West Sussex : Wiley-Blackwell
    Mathematical Methods in the Applied Sciences 20 (1997), S. 679-688 
    ISSN: 0170-4214
    Schlagwort(e): Engineering ; Numerical Methods and Modeling
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Mathematik
    Notizen: This paper addresses the question: when the frequency of collisions vanishes, will the solutions of the Landau system converge to the solutions of the Vlasov system? We give a positive answer to the question for solutions satisfying certain regularity conditions. © 1997 by B. G. Teubner Stuttgart-John Wiley & Sons Ltd. Math. Meth. Appl. Sci., Vol. 20, 679-688 (1997).
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  • 73
    Digitale Medien
    Digitale Medien
    Chichester, West Sussex : Wiley-Blackwell
    Mathematical Methods in the Applied Sciences 20 (1997), S. 783-803 
    ISSN: 0170-4214
    Schlagwort(e): Engineering ; Numerical Methods and Modeling
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Mathematik
    Notizen: The paper considers the non-linear stability of a non-hyperbolic system of conservation laws with both relaxation and diffusion, which is commonly used for the modeling of two-phase fluid flows. Global existence in time is proved for initial data with a sufficiently small H1 norm. This result heavily depends on the nice structure of the relaxation system, derived from the initial system by setting the relaxation variables to zero. © 1997 by B. G. Teubner Stuttgart-John Wiley & Sons Ltd.
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  • 74
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    Digitale Medien
    Chichester, West Sussex : Wiley-Blackwell
    Mathematical Methods in the Applied Sciences 20 (1997), S. 1045-1068 
    ISSN: 0170-4214
    Schlagwort(e): Engineering ; Numerical Methods and Modeling
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Mathematik
    Notizen: The goal of this paper is to establish that even for strongly non-linear Darcy's laws and strongly non-linear leaky boundary conditions on the bottom of the reservoirs the fluid flow through a porous dam is a well-posed problem for which existence of a solution can be established. In a simple case we provide also the exact solution to the problem. © 1997 B. G. Teubner Stuttgart-John Wiley & Sons Ltd.
    Zusätzliches Material: 2 Ill.
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  • 75
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    Digitale Medien
    Chichester, West Sussex : Wiley-Blackwell
    Mathematical Methods in the Applied Sciences 20 (1997), S. 1163-1169 
    ISSN: 0170-4214
    Schlagwort(e): Engineering ; Numerical Methods and Modeling
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Mathematik
    Notizen: Consider the problem of heat flow in a convex domain in ∝n with Dirichlet boundary condition and constant initial temperature. We show that the solution has a fixed hot spot if the domain is invariant under the action of an essential symmetry group. © 1997 by B. G. Teubner Stuttgart-John Wiley & Sons Ltd.
    Zusätzliches Material: 1 Ill.
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  • 76
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    Digitale Medien
    Chichester, West Sussex : Wiley-Blackwell
    Mathematical Methods in the Applied Sciences 20 (1997), S. 1171-1183 
    ISSN: 0170-4214
    Schlagwort(e): Engineering ; Numerical Methods and Modeling
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Mathematik
    Notizen: The paper considers a particular type of closed-loop for the wave equation in one space dimension with damping acting at an arbitrary internal point, for which the uniform stabilization with exponential decay rate is shown. Applications to chains of coupled strings are also discussed. © 1997 by B. G. Teubner Stuttgart-John Wiley & Sons Ltd.
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  • 77
    Digitale Medien
    Digitale Medien
    Chichester, West Sussex : Wiley-Blackwell
    Mathematical Methods in the Applied Sciences 20 (1997), S. 1365-1377 
    ISSN: 0170-4214
    Schlagwort(e): Engineering ; Numerical Methods and Modeling
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Mathematik
    Notizen: The paper is concerned with optimal control problem for a non-linear parabolic equation with non-homogenous boundary condition and quadratic cost. The control is acting in a nonlinear equation. We derive some results on the existence of optimal controls. Then we treat optimal control problem by Galerkin method and we prove the convergence of optimal values for approximated control problems to the one for the original problem. Finally, we apply the results to give a simple example. © 1997 by B. G. Teubner Stuttgart-John Wiley & Sons Ltd.
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  • 78
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    Digitale Medien
    Chichester, West Sussex : Wiley-Blackwell
    Mathematical Methods in the Applied Sciences 20 (1997), S. 1427-1448 
    ISSN: 0170-4214
    Schlagwort(e): Engineering ; Numerical Methods and Modeling
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Mathematik
    Notizen: It is proved that there is a (weak) solution of the equationut=a*uxx+b*g(ux)x+f,on ∝+ (where * denotes convolution over (-∞, t)) such that ux is locally bounded. Emphasis is put on having the assumptions on the initial conditions as weak as possible. The kernels a and b are completely monotone and if a(t)=t-α, b(t)=t-β, and g(ξ)∼sign(ξ)∣ξ∣γ for large ξ, then the main assumption is that α〉(2γ+2)/(3γ+1)β+(2γ-2)/(3γ+1). © 1997 by B. G. Teubner Stuttgart-John Wiley & Sons Ltd.
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  • 79
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    Digitale Medien
    Chichester, West Sussex : Wiley-Blackwell
    Mathematical Methods in the Applied Sciences 20 (1997), S. 1411-1425 
    ISSN: 0170-4214
    Schlagwort(e): Engineering ; Numerical Methods and Modeling
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Mathematik
    Notizen: This article treats the initial-boundary-value problem of viscoplasticity using unified constitutive models without a yield surface. Semi-discretization with the finite element method (FEM) leads to a system of differential-algebraic equations (DAE) with strongly non-linear evolution equations for the internal state variables. A special family of partitioned Runge-Kutta methods is introduced which allows an efficient time integration of the semidiscrete system. Coefficients for methods of order one, two, and three are given. Finally, numerical results for some two- and three-dimensional examples using the model of Hart are presented. In a second part we will give the theoretical background and state a proof of convergence for the algorithm presented in this paper. © 1997 by B. G. Teubner Stuttgart-John Wiley & Sons Ltd.
    Zusätzliches Material: 8 Ill.
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  • 80
    Digitale Medien
    Digitale Medien
    Chichester, West Sussex : Wiley-Blackwell
    Mathematical Methods in the Applied Sciences 20 (1997), S. 1459-1468 
    ISSN: 0170-4214
    Schlagwort(e): Engineering ; Numerical Methods and Modeling
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Mathematik
    Notizen: We prove that any solution of the problem(u+K*u)t+∑ai(u)uxi=0 on (0,∞)×∝Nwith spatially periodic initial data converges to a constant provided some non-degeneracy conditions on the kernel K and the non-linear functions ai,i=1,…,N are imposed. © 1997 B. G. Teubner Stuttgart-John Wiley & Sons Ltd.
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  • 81
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    Digitale Medien
    Chichester, West Sussex : Wiley-Blackwell
    Mathematical Methods in the Applied Sciences 20 (1997), S. 1501-1530 
    ISSN: 0170-4214
    Schlagwort(e): radiating solutions ; exterior boundary value problems in elasticity ; asymptotic expansions ; low-frequency behaviour ; Engineering ; Numerical Methods and Modeling
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Mathematik
    Notizen: We continue the study of the operators of generalized linear elasticity and investigate the behaviour of the solutions as the frequency tends to zero. We identify degenerate operators in terms of special solutions to the static problem which must be added to the usual Neumann series in order to describe the low frequency behaviour adequately. As a byproduct we construct solutions to the homogeneous static operator (‘spherical elastics’) which generalize the spherical harmonics and give rise to a ‘spherical elastics expansion’. © 1997 B. G. Teubner Stuttgart-John Wiley & Sons Ltd.
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  • 82
    Digitale Medien
    Digitale Medien
    Chichester, West Sussex : Wiley-Blackwell
    Mathematical Methods in the Applied Sciences 20 (1997), S. 1599-1616 
    ISSN: 0170-4214
    Schlagwort(e): Engineering ; Numerical Methods and Modeling
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Mathematik
    Notizen: The Dirichlet initial-boundary-value problem in the half-space ∝t×∝3+ for a non-linear hyperbolic system is studied. About the nonlinearity the null condition structure is imposed. Under the smallness conditions on the initial data the existence of low regularity solutions, on a given interval of time, is proved. © 1997 by B. G. Teubner Stuttgart-John Wiley & Sons Ltd.
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  • 83
    Digitale Medien
    Digitale Medien
    Chichester, West Sussex : Wiley-Blackwell
    Mathematical Methods in the Applied Sciences 20 (1997), S. 1617-1624 
    ISSN: 0170-4214
    Schlagwort(e): Engineering ; Numerical Methods and Modeling
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Mathematik
    Notizen: We develop aspects of Clifford analysis over the sphere and hyperbolae. We focus primarily on the hyperbola lying in the Minkowski type space ∝n,1. We show that in order to give a proper extension of basic results on Clifford analysis in Euclidean space to this context one needs to consider both hyperbolae lying in ∝n,1. We also introduce Bergman spaces of Lp left monogenic sections in this context and consider the decomposition of square integrable sections over suitable bundles constructed over subdomains of spheres and hyperbolae. The results presented here cover the necessary background to enable one to set up and solve boundary value problems for field-type equations over hyperbolae. In particular, one can study analogues of the Dirichlet problem for analogues of the Laplacian over hyperbolae and spheres. © 1997 B. G. Teubner Stuttgart-John Wiley & Sons Ltd.
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  • 84
    Digitale Medien
    Digitale Medien
    Chichester, West Sussex : Wiley-Blackwell
    Mathematical Methods in the Applied Sciences 20 (1997), S. 79-94 
    ISSN: 0170-4214
    Schlagwort(e): Engineering ; Numerical Methods and Modeling
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Mathematik
    Notizen: The limiting behaviour of solutions of a system of singularly perturbed equations is studied. The goal is to construct a dissipative feedback control synthesis that stabilizes the prescribed output functional along trajectories of solutions. The results are applied to a singularly perturbed Johnson-Sagelman-Oldroyd model of shearing motions of a piston driven flow of a non-Newtonian fluid. © 1997 by B.G. Teubner Stuttgart-John Wiley & Sons, Ltd.
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  • 85
    Digitale Medien
    Digitale Medien
    Chichester, West Sussex : Wiley-Blackwell
    Mathematical Methods in the Applied Sciences 20 (1997), S. 95-119 
    ISSN: 0170-4214
    Schlagwort(e): Engineering ; Numerical Methods and Modeling
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Mathematik
    Notizen: The three-dimensional steady state oscillation problems of the elasticity theory for homogeneous anisotropic bodies are studied. By means of the limiting absortion principle the fundamental matrices maximally decaying at infinity are constructed and the generalized Sommerfeld-Kupradze type radiation conditions are formulated. Special functional spaces are introduced in which the basic and mixed exterior boundary value problems of the steady state oscillation theory have unique solutions for arbitrary values of the oscillation parameter. Existence theorems are proved by reduction of the original boundary value problems to equivalent boundary integral (pseudodifferential) equations. © 1997 by B.G. Teubner Stuttgart-John Wiley & Sons, Ltd.
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  • 86
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    Digitale Medien
    Chichester, West Sussex : Wiley-Blackwell
    Mathematical Methods in the Applied Sciences 20 (1997), S. 205-217 
    ISSN: 0170-4214
    Schlagwort(e): Engineering ; Numerical Methods and Modeling
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Mathematik
    Notizen: The two-dimensional frictionless contact problem of linear isotropic elasticity in the half-space is treated as a boundary variational inequality involving the Poincare-Steklov operator and discretized by linear boundary elements. Quadratic growth of the energy near the solution is shown under weak regularity assumptions if the central axis of external forces intersects the boundary of the domain in a Lebesgue null set. Estimating the numerical range of the discrete Poincare-Steklov operator and properly modifying it, enables the application of an error estimate for semi-coercive variational inequalities. Optimal order of convergence is obtained in the underlying Sobolev space H1/2(∂Ω)2. © 1997 by B.G. Teubner Stuttgart-John Wiley & Sons, Ltd.
    Materialart: Digitale Medien
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  • 87
    Digitale Medien
    Digitale Medien
    Chichester, West Sussex : Wiley-Blackwell
    Mathematical Methods in the Applied Sciences 20 (1997), S. 219-243 
    ISSN: 0170-4214
    Schlagwort(e): Engineering ; Numerical Methods and Modeling
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Mathematik
    Notizen: The dependence on the small parameter ε of constants in Korn's inequalities is investigated for domains which are obtained by joining thin rods to an elastic spatial body. The external ends of the rods are clamped. The asymptotic accuracy of the derived inequalities is achieved by certain distribution of weight multipliers and powers of ε in L2-norms of displacements and their derivatives while the introduced weights differ for longitudinal and transversal components of displacement fields in the rods. © 1997 by B.G. Teubner Stuttgart-John Wiley & Sons, Ltd.
    Zusätzliches Material: 5 Ill.
    Materialart: Digitale Medien
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  • 88
    Digitale Medien
    Digitale Medien
    Chichester, West Sussex : Wiley-Blackwell
    Mathematical Methods in the Applied Sciences 20 (1997), S. 271-289 
    ISSN: 0170-4214
    Schlagwort(e): Engineering ; Numerical Methods and Modeling
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Mathematik
    Notizen: The aim of this paper is to investigate the behaviour as t→∞ of solutions to the Cauchy problem ut-Δut-νΔu-(b, ∇u)=∇⋅F(u), u(x, 0)=u0(x), where ν〉0 is a fixed constant, t≥0, x∊∝n. First, we prove that if u is the solution to the linearized equation, i.e. with ∇⋅F(u)≡0, then u decays like a solution for the analogous problem to the heat equation. Moreover, the long-time behaviour of u is described by the heat kernel. Next, analogous results are established for the non-linear equation with some assumptions imposed on F, p, and the initial condition u0. © 1997 by B.G. Teubner Stuttgart-John Wiley & Sons, Ltd.
    Materialart: Digitale Medien
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  • 89
    Digitale Medien
    Digitale Medien
    Chichester, West Sussex : Wiley-Blackwell
    Mathematical Methods in the Applied Sciences 20 (1997), S. 245-269 
    ISSN: 0170-4214
    Schlagwort(e): Engineering ; Numerical Methods and Modeling
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Mathematik
    Notizen: The article treats the question of how to numerically solve the Dirichlet problem for the Stokes system in the exterior of a three-dimensional bounded Lipschitz domain. In a first step, the solution of this problem is approximated by functions solving the Stokes system in a truncated domain and satisfying a suitable artificial boundary condition on the outer boundary of this truncated domain. In a second step, this new problem is approximately solved in finite element spaces related to a graded mesh as introduced by Goldstein [Math. Comp., 36, 387-404 (1981)]. The difference between this finite element approximation and the exact solution of the exterior Stokes problem is estimated in the norm of suitable unweighted L2-Sobolev spaces. These estimates are analogous to corresponding results which are known for the Poisson equation. © 1997 by B.G. Teubner Stuttgart-John Wiley & Sons, Ltd.
    Materialart: Digitale Medien
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  • 90
    Digitale Medien
    Digitale Medien
    Chichester, West Sussex : Wiley-Blackwell
    Mathematical Methods in the Applied Sciences 20 (1997), S. 291-314 
    ISSN: 0170-4214
    Schlagwort(e): Engineering ; Numerical Methods and Modeling
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Mathematik
    Notizen: Inverse problems for identification of the memory kernel in the linear constitutive stress-strain relation of Boltzmann type are reduced to a non-linear Volterra integral equation using Fourier's method for solving the direct problem. To this equation the contraction principle in weighted norms is applied. In this way global existence of a solution to the inverse problem is proved and stability estimates for it are derived. © 1997 by B. G. Teubner Stuttgart-John Wiley & Sons Ltd.
    Materialart: Digitale Medien
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  • 91
    Digitale Medien
    Digitale Medien
    Chichester, West Sussex : Wiley-Blackwell
    Mathematical Methods in the Applied Sciences 20 (1997), S. 369-381 
    ISSN: 0170-4214
    Schlagwort(e): Engineering ; Numerical Methods and Modeling
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Mathematik
    Notizen: We consider exact controllability of a system of two Schrödinger equations. These represent matter waves in adjacent potential wells with different potentials, one zero, the other a positive constant V0. The problem is formulated as a simultaneous boundary controllability problem, with Dirichlet control. Estimates for the controls, including an observability inequality, are proved using multiplier techniques. Then the Hilbert uniqueness method is used to obtain the exact controllability result. If V0 is sufficiently small, there exists a time T^(V0) such that the system is exactly controllable in times T〉T^(V0). © 1997 by B. G. Teubner Stuttgart-John Wiley & Sons Ltd.
    Materialart: Digitale Medien
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  • 92
    Digitale Medien
    Digitale Medien
    Chichester, West Sussex : Wiley-Blackwell
    Mathematical Methods in the Applied Sciences 20 (1997), S. 315-346 
    ISSN: 0170-4214
    Schlagwort(e): Engineering ; Numerical Methods and Modeling
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Mathematik
    Notizen: The Dirichlet problem for the Stokes system in a dihedral angle is considered. An explicit description of special solutions to the homogeneous problem which have the form\documentclass{minimal} \begin{document} \begin{eqnarray*} U(x) &=&\left| x\right| ^\lambda \sum_{0\leq k\leq \kappa }\frac{(\log \left| x\right|)^{\kappa -k}}{(\kappa -k)!}u^{(k)}(x/\left| x\right|), \\ P(x) &=&\left| x\right| ^{\lambda -1}\sum_{0\leq k\leq \kappa }\frac{(\log \left| x\right|)^{\kappa -k}}{(\kappa -k)!}p^{(k)}(x/\left| x\right|) \end{eqnarray*} \end{document}is given. © 1997 by B. G. Teubner Stuttgart-John Wiley & Sons Ltd.
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  • 93
    Digitale Medien
    Digitale Medien
    Chichester, West Sussex : Wiley-Blackwell
    Mathematical Methods in the Applied Sciences 20 (1997), S. 347-368 
    ISSN: 0170-4214
    Schlagwort(e): Engineering ; Numerical Methods and Modeling
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Mathematik
    Notizen: We consider an initial value problem for a system of equations describing the motion and the heat convection in a viscous and incompressible fluid which occupies a smooth region Ωt⊂∝3 depending on time.In the equation for the distribution of temperature in the fluid we take into account not only the convective term but also the term responsible for the dissipation of energy.We prove local in time existence and uniqueness of solutions of the considered problem, and global in time existence for sufficiently small data. © 1997 by B. G. Teubner Stuttgart-John Wiley & Sons Ltd.
    Materialart: Digitale Medien
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  • 94
    Digitale Medien
    Digitale Medien
    Chichester, West Sussex : Wiley-Blackwell
    Mathematical Methods in the Applied Sciences 20 (1997), S. 425-448 
    ISSN: 0170-4214
    Schlagwort(e): Engineering ; Numerical Methods and Modeling
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Mathematik
    Notizen: The work deals with boundary equations appearing if non-stationary problems for Maxwell system are solved with the help of surface-retarded potentials. The solvability of these equations is proved in some functional spaces of Sobolev type. © 1997 by B. G. Teubner Stuttgart-John Wiley & Sons Ltd.
    Materialart: Digitale Medien
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  • 95
    Digitale Medien
    Digitale Medien
    Chichester, West Sussex : Wiley-Blackwell
    Mathematical Methods in the Applied Sciences 20 (1997), S. 385-401 
    ISSN: 0170-4214
    Schlagwort(e): Engineering ; Numerical Methods and Modeling
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Mathematik
    Notizen: We consider the electromagnetic inverse scattering problem of determining the index of refraction of an isotropic inhomogeneous medium from a knowledge of the total electric near field data. We consider both the case of scattering by an infinite inhomogeneous cylinder and a bounded inhomogeneous region in space. We conclude by giving an application of our method to the problem of imaging leukemia in the upper leg by means of microwaves. © 1997 by B. G. Teubner Stuttgart-John Wiley & Sons Ltd.
    Zusätzliches Material: 6 Ill.
    Materialart: Digitale Medien
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  • 96
    Digitale Medien
    Digitale Medien
    Chichester, West Sussex : Wiley-Blackwell
    Mathematical Methods in the Applied Sciences 20 (1997), S. 449-459 
    ISSN: 0170-4214
    Schlagwort(e): Engineering ; Numerical Methods and Modeling
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Mathematik
    Notizen: Here we consider initial boundary value problems for parabolic equations in non-bounded (with respect to time) domains by using the single-layer potential. We discuss the solvability in anisotropic Hölder spaces of the boundary integral equations, to which original parabolic problems are reduced. We construct the special operators (regularizers) for these integral equations which transform them to equivalent integral Volterra equations of the second kind with weakly singular kernels. As a corollary we obtain the theorem about the classical solvability in anisotropic Hölder spaces for initial boundary value parabolic problems. © 1997 by B. G. Teubner Stuttgart-John Wiley & Sons Ltd.
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  • 97
    Digitale Medien
    Digitale Medien
    Chichester, West Sussex : Wiley-Blackwell
    Mathematical Methods in the Applied Sciences 20 (1997), S. 403-423 
    ISSN: 0170-4214
    Schlagwort(e): Engineering ; Numerical Methods and Modeling
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Mathematik
    Notizen: In this paper we prove an a posteriori error estimate for the symmetric coupling of finite elements and boundary elements applied to linear parabolic-elliptic interface problems. The discontinuous Galerkin method is used for the discretization in time. We present an adaptive algorithm for choosing the mesh size in space and time and we analyse the Hybrid Modified Conjugate Residual (HMCR) method as a solution method for the linear systems which arise. Computational results show that the number of HMCR-iterations grows slowly with the problem size. © 1997 by B. G. Teubner Stuttgart-John Wiley & Sons Ltd.
    Zusätzliches Material: 4 Ill.
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
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  • 98
    Digitale Medien
    Digitale Medien
    Chichester, West Sussex : Wiley-Blackwell
    Mathematical Methods in the Applied Sciences 20 (1997), S. 383-384 
    ISSN: 0170-4214
    Schlagwort(e): Engineering ; Numerical Methods and Modeling
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Mathematik
    Notizen: No Abstract
    Materialart: Digitale Medien
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  • 99
    Digitale Medien
    Digitale Medien
    Chichester, West Sussex : Wiley-Blackwell
    Mathematical Methods in the Applied Sciences 20 (1997), S. 477-493 
    ISSN: 0170-4214
    Schlagwort(e): Engineering ; Numerical Methods and Modeling
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Mathematik
    Notizen: Implicit one-step difference methods for quasilinear parabolic initial boundary value problems in two space variables and in polar coordinates are considered. Problems of this kind are suitable for the description of diffusion processes in plasma physics. Therefore, because of its special physical interest the dependence of the coefficients both on the solution and on its space derivatives (the fluxes) is included. The first part of this paper deals with proving convergence of the discrete approximations for vanishing step sizes. For this purpose, bounds for the inverse difference operators have to be derived previously. The nonlinear systems arising from the discretizations have exactly one solution for all step sizes being sufficiently small. In the second part of the article numerical tests are performed. © 1997 by B. G. Teubner Stuttgart-John Wiley & Sons Ltd.
    Zusätzliches Material: 9 Ill.
    Materialart: Digitale Medien
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  • 100
    Digitale Medien
    Digitale Medien
    Chichester, West Sussex : Wiley-Blackwell
    Mathematical Methods in the Applied Sciences 20 (1997), S. 521-545 
    ISSN: 0170-4214
    Schlagwort(e): Engineering ; Numerical Methods and Modeling
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Mathematik
    Notizen: This article establishes the existence of trapped-mode solutions of a linearized water-wave problem. The fluid occupies a symmetric horizontal channel that is uniform everywhere apart from a confined region which either contains a thin vertical plate spanning the depth of the channel or has indentations in the channel walls. A trapped mode corresponds to an eigenvalue of a non-local Neumann-Dirichlet operator for an elliptic boundary-value problem in the fluid domain. The existence of such an eigenvalue is established by generalizing previous results concerning spectral theory for differential operators to this non-local operator. © 1997 by B. G. Teubner Stuttgart-John Wiley & Sons Ltd.
    Zusätzliches Material: 6 Ill.
    Materialart: Digitale Medien
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