ISSN:
0736-0266
Keywords:
Histomorphometry
;
Spinal fusion
;
Device-related osteoporosis
;
Stress shielding
;
Life and Medical Sciences
Source:
Wiley InterScience Backfile Collection 1832-2000
Topics:
Medicine
Notes:
Histomorphometric and microradiographic studies were performed on 28 beagle hounds 1 year of age, followed up for 6 months after an L5-L6 anterior and posterior spinal destabilization procedure - Group I (n = 7), destabilized surgical controls, Group II (n = 7), posterolateral bone grafting after destabilization; Group III (n = 7), Harrington rod instrumentation and posterolateral bone grafting after destabilization; and Group IV (n = 7), Luque instrumentation, and bone grafting after destabilization. Six months postoperatively, device-related osteoporosis occurred in spines treated with spinal instrumentation. Within the L5 vertebral body the mean trabecular width was less for the two groups with instrumentation (Groups III and IV) compared with the two groups without instrumentation (Groups I and II) (p 〈 0.001). The bone formation rate [mm3/(mm3 × year)] × 103, which is based on the mean distance between sequenced fluorochrome labels, for Group I (destabilized, nonfused, noninstrumented dogs) was more than twice that of the other three groups, which were all equivalent (p 〈 0.05). Clinical relevance: Stress shielding, or more correctly, device-related osteoporosis, probably can occur within vertebrae in response to rigid spinal instrumentation. However, the overall mechanical properties of vertebrae underlying spinal instrumentation are probably not at increased risk of fracture because the increase in cross-sectional area of the vertebra and incorporated fusion mass more than compensate for the loss of volumetric bone density.
Additional Material:
6 Ill.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1002/jor.1100070512
Permalink
