Incidence Of C5 Nerve Root Palsy Following Laminoplasty And Laminectomy Hybrid Decompression For The Treatment Of Cervical Spondylotic Myelopathy

ObjectiveC5 nerve root palsy is well known as a relatively rare complication following cervical decompressive surgery,and it may significantly affect the satisfaction of operation.Some author reported that individuals after Laminectomy surgery had a lower prevalence than those after Laminoplasty.In cervical spondylotic myelopathy(CSM)patients with hypertrophic ligamentum flavum(HLF),the dorsal canal elements are one cause of compression of the spinal cord.To remove the HLF completely while partially preserving the posterior wall of the spinal canal,we have developed a hybrid decompression protocol,laminectomy at the C3,C5,and C7levels and laminoplasty at the C4 and C6 levels with spinous process autograft using the Centerpiece Plate Fixation System The purpose of the current study was to evaluate the incidence of C5 nerve root palsy in laminoplasty hybrid laminectomy decomprseeion for the treatment of cervical spondylotic myelopathy.Patients and methodsWe retrospective 191 patients with CSM who underwent laminoplasty and laminectomy hybrid decomprseeion between January 2010 and October 2016.The191 patients with a mean age of 63.9±8.3 years(range,43-81 years).The mean follow-up period were 18.2±4.4 months(range,12–32months).The clinical data including age,operative level,blood loss,operative time,C5 nerve root palsy,incidence and degree of axial pain,pre-and post-Japanese Orthopedic Association(JOA)score and JOA recovery rates.The radiologic data including C2–7 Cobb angle,cervical ROM,the expansion degree and the drift-back distance of the spinal cord was calculated using the MRI image.ResultsThe surgery time of laminoplasty and laminectomy hybrid decomprseeion was145.1±13.2 with a decompression length of 5.0 lamina.Mean intraoperative blood loss was 155.2±24.1mL.JOA score increased from 8.4±2.1 preoperatively to13.5±2.2 postoperatively(P<0.05).The postoperative JOA score suggested that neurological function improved significantly with a recovery rate of 63.3%.The incidence rate of palsy of C5 nerve root palsy,which occurred in only 2 patients who recovered to useful function(the paralyzed muscles recovered to 4 grade and the sensory recovered obviously,with self-care ability)over a 3-months period,was 1.0%.Only four patients complained of postoperative axial pain.The incidence rate of postoperative axial pain was 2.1%.The mean postoperative VAS score was 1.9.The cervical ROM and C2–7 Cobb angle decreased postoperatively(P<0.05),but no patient was noted to have kyphosis.MRI indicated that the cross-sectional area at the level of maximum compression of the dural sac increased from 94.1±19.3 to169.4±22.7 mm~2 pre-and 6 months postoperatively(P<0.05).The posterior shift of the spinal cord was 3.38±0.52 mm 6 months postoperatively.There were no significant differences in cervical lordosis,the cross-sectional area at the level of maximum compression of the dural sac or the posterior shift of the spinal cord between 6 months postoperatively and 1 year postoperatively(P>0.05).ConclusionJOA scores and recovery rates suggested that laminoplasty hybrid laminectomy decomprseeion could be effective in decompressing the spinal cord,with low rate of C5 nerve root palsy and axial pain.