Effects of Various Combinations of Anterior Cervical Decompression Procedures on Postoperative C5 Palsy

<p>Introduction: Postoperative C5 palsy (C5P) is a common complication after cervical spine decompression surgery. The etiology of C5P after anterior cervical decompression with spinal fusion (ASF) has not yet been fully described. Among anterior cervical decompressive procedures, both corpectomy and discectomy are important surgical methods, and both have their peculiar advantages and disadvantages. Corpectomy induces excessive dural expansion and shortening of the fixed segments. We thought that the environmental changes occurring after corpectomy might cause C5P, but it is unknown whether corpectomy affects the incidence of C5P. In the present study, we analyzed the effects of various combinations of decompression procedures on the incidence of C5P.</p><p>Methods: We retrospectively analyzed 839 patients who underwent ASF at a single institution. The surgical choice to use corpectomy, discectomy, or hybrid decompression (corpectomy combined with discectomy for an adjacent segment) was based on same treatment strategy depending on local compressive pathology and presenting clinical symptoms. For assessing the effects of various combinations of decompression procedures on C5P and the disc segments operated, we used an original "decompression combination score," which integrated both factors.</p><p>Results: C5P occurred in 57 (6.8%) patients. C5P did not occur immediately after surgery; the mean latency from surgery to its development was 4.6±5.6 days. A larger number of operated disc segments were significantly associated with C5P (p < 0.01). The incidences of C5P following various decompression procedures around the C4/5 segments were as follows: C4 and C5 corpectomy (10.1%) > C4 corpectomy (5.8%) > C5 corpectomy (4.8%) > C4/5 discectomy (4.1%). The decompression combination score was significantly higher in patients with C5P than in those without C5P (1.8 points vs. 1.5 points; p < 0.01). Higher scores were significantly associated with C5P (p < 0.01). Multivariate analysis revealed male sex [odds ratio (OR): 3.77, 95% confidence interval (CI): 1.72-8.26], higher decompression combination score (OR: 2.09, 95% CI: 1.28-3.44), and older age (OR: 1.08, 95% CI: 1.04-1.11) as significant risk factors. The estimated optimal cutoff values for predicting C5P using receiver-operating characteristic curve analysis were 1.5 points for the decompression combination score (area under the curve: 0.656) and 59 years for age (area under the curve: 0.675).</p><p>Conclusions: While performing ASF, C4/C5 corpectomy increased the incidence of C5P, whereas C4/C5 discectomy decreased the risk. The lower incidence of postoperative C5P after discectomy may be due to minimizing the tethering effect. As a preventive measure against C5P after ASF, corpectomy should be avoided, and discectomy is recommended as much as possible.</p>