Preoperative Clinical and Radiographic Variables Predict Postoperative C5 Palsy.

Background: Postoperative C5 palsy affects 8% of patients undergoing posterior cervical decompression. It is associated with a period functional disability that may exceed 12 months and increase direct care costs > $2000.
Methods: All patients undergoing posterior cervical decompression at a single tertiary-care facility for degenerative conditions were evaluated for preoperative imaging, clinical presentation, surgical operation, and postoperative course. We sought to identify those variables predictive of postoperative C5 palsy.
Results: Of 221 included patients (mean age, 63 years; 54% male), 12.2% experienced C5 palsy. On univariate analysis, C5 palsy was associated with foraminal diameter (P = 0.0005), spinal cord cross-sectional area (P = 0.11), number of levels undergoing laminectomy (P = 0.14), and clinical presentation of dropping objects (P = 0.07), hand clumsiness (P = 0.13), or paresthesias in the upper extremities (P = 0.08). Foraminal diameter (odds ratio, 0.31 per mm increase; 95% confidence interval, 0.16-0.60; P < 0.001) and patient report of gait disturbance (odds ratio, 0.53; 95% confidence interval, 0.33-0.85; P = 0.008) were the only significant predictors on multivariate analysis. A foraminal diameter <2 mm had 2-fold greater odds of postoperative C5 palsy. A receiver operating curve for the multivariate logistic model had an associated C-statistic of 0.7818. The absolute error of this model was 9.3% on internal validation.
Conclusions: Foraminal stenosis most strongly predicted postoperative C5 palsy. A proof-of-concept model incorporating foramen size, as well as clinical complaints of paresthesias, hand clumsiness, and gait abnormality, successfully predicts the occurrence of postoperative palsy with an overall accuracy of 78%.
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