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  • 1
    ISSN: 1432-1084
    Keywords: Key words: Stereolithography ; Rapid prototyping ; Computed tomography ; Calcaneal fracture ; ROC curves
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract. The purpose of this study was to evaluate and compare the diagnostic performance of stereolithography vs workstation-based three-dimensional (3D) reformations in intra-articular calcaneal fractures. A total of 30 intra-articular calcaneal fractures were examined using standard radiographs, coronal CT scans, and 2D and 3D reformations. The CT data were transferred to an outside institution, and stereolithograms were produced from photopolymer resin employing a laser beam system. 3D reformations and stereolithograms were analyzed in a blinded fashion by two staff radiologists. Receiver-operating-characteristic (ROC) curves were obtained for six clinically significant fracture components. Standard radiographs, coronal CT scans, and 2D reformations served as the standard of reference. The area under the ROC curves for 3D reformations and stereolithograms were 1.0 and 0.98 for abnormal tuber angles, 0.91 and 0.91 for anterior and middle talo-calcaneal joint involvement, 0.90 and 0.95 for involvement of the posterior talo-calcaneal joint, 0.65 and 0.78 for the presence of a lateral bulge, 0.80 and 0.81 for the involvement of the calcaneocuboidal joint, and 0.62 and 0.67 for the presence of a “tongue-type” fracture. No statistically significant difference was demonstrated for the two methods (Wilcoxon signed-rank test, p = 0.138). Based on our results stereolithograms did not prove to be statistically superior to workstation-based 3D reformations. Stereolithograms may still be useful for teaching purposes and for surgical planning at a thinking-efficacy level.
    Type of Medium: Electronic Resource
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  • 2
    Electronic Resource
    Electronic Resource
    Springer
    Der Unfallchirurg 100 (1997), S. 39-43 
    ISSN: 1433-044X
    Keywords: Schlüsselwörter Implantatwerkstoffe ; Hydroxylapatit ; Titan ; Stahl ; Biokompatibilität ; Fibroblasten-Zellinie (3T3) ; Osteoblasten-Zellinie (MC3T3-E1) ; humane Osteoblasten ; Zellproliferation (MTT) ; Alkalische Phosphatase (ALP) ; Key words Biomaterials ; Hydroxyapatite ; Titanium ; Steel ; Biocompatibility ; Fibroblast cell line (3T3) ; ``Osteoblast-like'' cell line (MC3T3-E1) ; Human osteoblasts ; Cellproliferation (MTT) ; Alkaline phosphatase activity (ALP)
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Two different types of cell-line and fresh human osteoblasts, cultured from cancellous bone grafts from the iliac crest, were used for the study. Three different biomaterials were compared regarding biocompatibility: titanium, steel and hydroxyapatite. The cells were fibroblast cell line (3T3), ``osteoblast-like'' cell line (MC3T3-E1), and fresh human osteoblasts (HOB) which we cultured in our laboratory. 5×104 cells of each type were seeded on the three different bone implants. All experiments were performed in triplicate. Cell proliferation and alkaline phosphatase activity were determined 24 and 72 h after the cells were plated on the biomaterials. Human osteoblast growth was better on titanium than on steel and hydroxyapatite. The most remarkable observation was the continuously decreasing alkaline phosphatase activity (ALP) of ``osteoblast-like'' cells (MC3T3-E1) and human osteoblasts (HOB) on hydroxyapatite. In conclusion, our in vitro observations suggest that the best cell/material interactions were with human osteoblasts (HOB) and titanium.
    Type of Medium: Electronic Resource
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  • 3
    Electronic Resource
    Electronic Resource
    Springer
    Langenbeck's archives of surgery 377 (1992), S. 211-215 
    ISSN: 1435-2451
    Keywords: Sonography ; Blunt abdominal trauma
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Description / Table of Contents: Zusammenfassung Vom 1. Juli 1989 bis zum 30. Juni 1991 wurden 312 Patienten mit stumpfem Bauch- oder Thoraxtrauma prospektiv erfaβt. Es handelte sich um 231 Mdnner und 81 Frauen im Alter von 15-88 Jahren (durchschnittlich 39,9 Jahre). Das Sonographieteam bestand aus einem erfahrenen Sonographen (〉 4000 Untersuchungen) und 3 Anfängern (〈 200 Untersuchungen zu Beginn der Studie). Der erfahrene Sonograph untersuchte 168, die Anfdnger zusammen 144 Patienten. Die Verteilung der Patienten erfolgte zufdllig und ohne Berück-sichtigung des Verletzungsausmaβes aufgrund des Dienstplans. Die Untersuchungen wurden im Rahmen der Primärdiagnostik mittels eines mobilen Schallgeräts in der chirurgischen Notfallstation durchgeführt. Sie bestanden in je 4 sonographischen Schnitten (rechter und linker, lateraler Längsschnitt; suprapubischer und epigastrischer Querschnitt) und dauerten ungefähr 2 min. Klinische Anzeichen für ein stumpfes Bauchtrauma konnten nur bei 64 Fallen gefunden werden, während bei 153 Patienten die klinischen Befunde wegen Intubation und Relaxation oder Paraplegic nicht verwerthar waren. Sensitivität und Spezifität der Sonographie für die Entdeckung von intraabdominaler Flüssigkeit betrug je 100 % beim Erfahrenen, respektive 96 und 100 % bei den Anfängern. Organläsionen konnten sonographisch durch den Erfahrenen bei 45 % und durch die Anfänger bei 36% der Fdlle dargestellt werden. Der erfahrene Sonograph diagnostizierte fälschlicherweise bei einem Patienten freies, intraabdominales Gas, welches radiologisch und durch den Verlauf nicht bestätigt werden konnte. Die Anfänger übersahen eine Milzruptur mit intraabdominaler Blutung, welche am 4. Tag durch Computertomographie entdeckt wurde. Je eine Milz-und Leberruptur wurden wegen des Fehlens einer intraabdominalen Blutung übersehen. Das Ziel der primären, sonographischen Untersuchung des traumatisierten Patienten ist der Nachweis von freier Flussigkeit. Angesichts unserer Resultate schieβen wir, daß eine beschränkte sonographische Erfahrung von ca. 200 Untersuchungen für die Diagnostik freier intraabdominaler Flussigkeit ausreicht.
    Notes: Summary Between July, 1st 1989 and June, 30th 1991, 312 patients were entered into a prospective study concerning the reliability of sonographic evidence in blunt abdominal trauma. There were 231 male and 81 female patients aged between 15 and 88 years (mean: 39.9 years). The sonographic team consisted of one experienced sonographer/surgeon (〉4000 examinations) and 3 sonographic beginners (〈 200 examinations at the start of the study). The experienced sonographer and the beginners examined 168 and 144 patients, respectively. Patient distribution to the two groups was done according to the sonographic duty roster without consideration of injury severity. The examination was performed with a mobile ultrasound unit at the surgical intake as part of the primary diagnostic work-up. It consisted of four sonographic views (right and left lateral longitudinal, suprapubic and epigastric transverse view) and took about 2 min. Clinical evidence supporting blunt abdominal trauma could only be found in 64 cases, while in 153 patients physical examination was equivocal due to assisted ventilation or paraplegia. Sensitivity and specificity for the clinical examination amounted to 80.6% and 44.5%, respectively. Sensitivity and specificity for the sonographic finding of intraabdominal liquid were 100 % each for the experienced sonographer and 96% and 100%, respectively for the beginners. Organ lesions were demonstrated with a sensitivity and specificity of 45 % and 99 % by the experienced and 36% and 100% by the beginners. The experienced sonographer misdiagnosed one case of free intraabdominal gas, which could not be corroborated both by clinical and radiological evidence. The patient was not operated on. The beginners misdiagnosed one ruptured spleen with intraabdominal liquid demonstrated on the 4th day after admission on CT-scan. Again no operation was necessary. One rupture of the liver and one rupture of the spleen each were missed by the beginners due to a lack of intraabdominal fluid. In the first case this was due to lethal blood loss through a ruptured thoracic aorta, in the second case the tear was so superficial it was quickly sealed by a clot. The goal of the primary sonographic examination in blunt abdominal trauma is the demonstration of intraabdominal liquid. Considering these results, we conclude that only limited sonographic experience is needed for the diagnosis of intraabdominal liquid.
    Type of Medium: Electronic Resource
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  • 4
    Electronic Resource
    Electronic Resource
    Springer
    Langenbeck's archives of surgery 379 (1994), S. 335-340 
    ISSN: 1435-2451
    Keywords: Appendicitis ; Ultrasound studies ; Diagnosis ; Prospective trial ; Laparotomy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Description / Table of Contents: Zusammenfassung Am Departement Chirurgie des Universitätsspitals Zürich wurden zwischen 1. Dezember 1990 und 31 Dezember 1992 302 Patienten mit klinischer Verdachtsdiagnose “akute Appendizitis” ausschließlich von 7 Chirurgen sonographisch beurteilt, wobei der “Instruktor” ein Chirurg mit mehrjdhriger Erfahrung in sonographischen Untersuchungstechniken war. Von den untersuchten Patienten/innen wurden 139 (46%) laparotomiert. 119 (39,4%) zeigten intraoperativ und histologisch eine Appendizitis, wovon klinisch 87 (28,8%), sonographisch 119 (39,4%) in der Erstbeurteilung als eindeutig positiv beurteilt wurden. Sonographisch falsch-positive und falsch-negative stellten sich bei je 10 (3,3%) Patienten heraus. Bei den 163 Patienten die nicht operiert werden mußten, konnte 60mal (19,9%) sonographisch eine andere Diagnose gestellt wurden. Bei negativen Sonographien, negativer oder fraglicher Klinik führte die klinische Beurteilung des Stationsoberarztes zur Operationsindikation. Zu “Negativlaparotomien” kam es bei kombinierter Beurteilung bei 10 (7,2%) Patienten. Für das ganze Sonographieteam betrugen Sensitivität und Spezifität 92 bzw. 95% und für die Klinik alleine 81 bzw. 80%. Die absolute Trefferquote der Sonographie betrug 92%. Die Sensitivität und Spezifität der 6 angelermen Chirurgen betrug 87 und 93%. Die Sonographie erreichte in der Hand der Chirurgen somit vergleichbare Resultate mit denen der Sonographiespezialisten und hat in unserer Klinik deshalb ihren festen Platz in der Abkldrung der akuten Appendizitis eingenommen.
    Notes: Abstract A number of studies have shown that ultrasound has an advantage over physical examination in the diagnosis of acute appendicitis. Most of these studies were conducted by experts in the field of ultrasonography. In this study the influence of experience on the results of the sonography of actue appendicitis were evaluated. All 203 patients admitted to our unit between December 1990 and December 1992 were examined physically and sonographically by a team of surgeons consisting of one experienced sonographer and six inexperienced surgical trainees. Laparotomy was performed in 136 patients (46%). Appendicitis was demonstrated histologically in 119 cases (39.4%). Initial clinical findings were positive in 87 (28.8%). Sonography was positive in 119 patients (39.4%). The 163 patients not operated on demonstrated other pathology on ultrasound in 60 cases (19.9%). The rate of negative laparotomies amounted to 7.2% in our study. Sensitivity and specificity for the sonographic diagnosis were 92% and 95%, respectively. They were only 81% and 80% for physical examination. Overall accuracy was 92% for sonography. Sensitivity and specificity for the inexperienced surgeons were 87% and 93%, respectively, while the experienced surgeon reached values of 97% and 98%, respectively. The results of both groups are comparable with values in the literature, suggesting that ultrasound evaluation of appendicitis is not a diagnostic tool limited to a few experienced sonographers.
    Type of Medium: Electronic Resource
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