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Predictive validity of preoperative CT scans and the risk of pedicle screw loosening in spinal surgery


Bredow, Jan; Boese, C K; Werner, C M L; Siewe, J; Löhrer, L; Zarghooni, K; Eysel, P; Scheyerer, M J (2016). Predictive validity of preoperative CT scans and the risk of pedicle screw loosening in spinal surgery. Archives of Orthopaedic and Trauma Surgery, 136(8):1063-1067.

Abstract

INTRODUCTION Pedicle screw fixation is the standard technique for the stabilization of the spine, a clinically relevant complication of which is screw loosening. This retrospective study investigates whether preoperative CT scanning can offer a predictor of screw loosening. METHODS CT-scan attenuation in 365 patients was evaluated to determine the mean bone density of each vertebral body. Screw loosening or dislocation was determined in CT scans postoperatively using the standard radiological criteria. RESULTS Forty-five of 365 patients (12.3 %; 24 male, 21 female) suffered postoperative screw loosening (62 of 2038 screws) over a mean follow-up time of 50.8 months. Revision surgeries were necessary in 23 patients (6.3 %). The correlation between decreasing mean CT attenuation in Hounsfield Units (HU) and increasing patient age was significant (p < 0.001). Mean bone density was 116.3 (SD 53.5) HU in cases with screw loosening and 132.7 (SD 41.3) HU in cases in which screws remained fixed. The difference was statistically significant (p = 0.003). CONCLUSION The determination of bone density with preoperative CT scanning can predict the risk of screw loosening and inform the decision to use cement augmentation to reduce the incidence of screw loosening.

Abstract

INTRODUCTION Pedicle screw fixation is the standard technique for the stabilization of the spine, a clinically relevant complication of which is screw loosening. This retrospective study investigates whether preoperative CT scanning can offer a predictor of screw loosening. METHODS CT-scan attenuation in 365 patients was evaluated to determine the mean bone density of each vertebral body. Screw loosening or dislocation was determined in CT scans postoperatively using the standard radiological criteria. RESULTS Forty-five of 365 patients (12.3 %; 24 male, 21 female) suffered postoperative screw loosening (62 of 2038 screws) over a mean follow-up time of 50.8 months. Revision surgeries were necessary in 23 patients (6.3 %). The correlation between decreasing mean CT attenuation in Hounsfield Units (HU) and increasing patient age was significant (p < 0.001). Mean bone density was 116.3 (SD 53.5) HU in cases with screw loosening and 132.7 (SD 41.3) HU in cases in which screws remained fixed. The difference was statistically significant (p = 0.003). CONCLUSION The determination of bone density with preoperative CT scanning can predict the risk of screw loosening and inform the decision to use cement augmentation to reduce the incidence of screw loosening.

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Additional indexing

Item Type:Journal Article, refereed, original work
Communities & Collections:04 Faculty of Medicine > University Hospital Zurich > Department of Trauma Surgery
Dewey Decimal Classification:610 Medicine & health
Language:German
Date:August 2016
Deposited On:25 Oct 2017 15:06
Last Modified:09 Dec 2017 03:03
Publisher:Springer
ISSN:0936-8051
Publisher DOI:https://doi.org/10.1007/s00402-016-2487-8
PubMed ID:27312862

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