C5 nerve root palsy after cervical laminoplasty and posterior fusion with instrumentation

STUDY DESIGN: Consecutive case series. OBJECTIVE: To compare the incidence and clinical characteristics of postoperative fifth cervical nerve root palsy (C5 palsy) in patients with cervical myelopathy treated by laminoplasty alone and laminoplasty with posterior instrumentation. SUMMARY OF BACKGROUND DATA: In patients who have multilevel cervical myelopathy with reducible kyphosis or instability, the authors have performed laminoplasty together with instrumented fusion to restore lordosis and stability. There seems to be a high incidence of postoperative C5 palsy in these patients. METHODS: Seventy-three patients with a mean age of 60.5 years and multilevel cervical myelopathy treated by laminoplasty from 1995 to 2005 were reviewed. Incidence, side, and severity of muscle weakness from patients with C5 palsy after posterior instrumented fusion (instrumented group) was compared with those without instrumentation (noninstrumented group). Radiologic parameters were assessed to identify predisposing factors. RESULTS: Overall 10 of 73 (14%) patients developed the C5 palsy, of which 5 (50%) of 10 patients were in instrumented group, and 5 of 63 (8%) patients were in noninstrumented. Three of 5 (60%) had the palsy on the same side of the opened lamina in the instrumented group, in the same proportion as the noninstrumented. Three (60%) patients in instrumented group developed deltoid weakness grade 1, but none in the noninstrumented had weaker than grade 3. All of the palsied in the instrumented group recovered within 2 years after surgery without removal of implant. Of the 5 patients with the palsy in the instrumented group, 3 had anterolisthesis before surgery and posterior translation of C4 on C5 by the surgery, and no patient without the palsy had the anterolisthesis. CONCLUSIONS: Posterior cervical fusion using instrumentation for restoration of lordotic alignment combined with laminoplasty is highly associated with severe postoperative C5 palsy in patients with multilevel cervical myelopathy and C4 anterolisthesis.