Outcomes and related factors of c5 palsy following cervical laminectomy with instrumented fusion compared with laminoplasty

Study Design. A retrospective study. Objective. The aim of this study was to analyze the clinical outcomes and related factors of C5 palsy (C5P) following posterior cervical laminectomy with fusion (LF) compared with laminoplasty (LP). Summary of Background Data. C5P is more common after LF than after LP. There have not been any studies on C5P-LF compared with C5P-LP. Methods. We retrospectively analyzed consecutive cases that underwent cervical LF for nontraumatic cervical myelopathy or myeloradiculopathy (CMR). To analyze the related factors, C5PLF and non-C5P-LF groups were compared. To assess the clinical parameters, preoperative diagnosis, clinical symptoms, surgical procedures, and outcome instruments were analyzed. Radiographically, we analyzed preoperative maximal spinal cord compression ratio, presence of C4-5 foraminal stenosis (FS), and correction angles on the sagittal plane. To compare with C5PLP, we analyzed the incidence, time of onset, grade of muscle weakness, other accompanying cervical nerve root palsies, recovery time, and degree of final recovery in the C5P-LF and the C5P-LP groups of 100 consecutive LPs. Results. A total of 90 LF patients were enrolled (M:F=54:36, mean age 61.1 yr, mean follow-up 35 months). C5P occurred in 26 patients (28.9%), and 14 cases (53.8%) demonstrated other cervical nerve root palsies. Clinically significant differences were observed between the C5P-LF and non-C5P-LF groups with regard to preoperative clinical diagnosis (CMR 88.5:42.2%, P<0.001) and presence of preoperative upper extremity weakness (57.7:32.3%, P=0.02). Comparison between the C5P-LF and C5P-LP groups showed significant differences between incidence (28.9:4%), mean grade of weakness (2.1:3.5), accompanying nerve root symptoms (53.8:0%), recovery time (20.8:10.5 weeks), and incidence of incomplete recovery (15.4:0%). Conclusion. C5P-LF patients showed higher incidence, more severe weakness, frequent involvement of multiple cervical nerve roots, and longer recovery time than C5P-LP patients. Preoperative clinical manifestation of CMR and preexisting upper extremity weakness were the related factors of C5 palsy.