C5 palsy after cervical laminectomy: natural history in a 10-year series

C5 palsy is a well-known complication following cervical laminectomy, however the cause of this complication remains elusive, with many studies providing conflicting reports on prognosis and the impact of specific risk factors.To describe the natural history of and risk factors for C5 palsy after first time cervical laminectomy involving C4 and/or C5, in a large series with a high rate of postoperative palsy.This is a retrospective case series.Patients undergoing first time cervical laminectomy for degenerative spine pathologies at a single institution between January 2008 and July 2018. Adult patients were included if a complete laminectomy was performed at C4 or C5 for degenerative pathology and pre- and postoperative upright lateral x-rays were performed.The primary outcome measure was postoperative C5 palsy, defined as a decrease in strength of at least one point in deltoid and/or biceps within 30 days of operation. The secondary outcome measure was recovery of function.A retrospective database of patients who underwent posterior cervical spine surgery was created and further focused by utilizing specific Common Procedural Technology (CPT) codes associated with our desired patient population. Patients were excluded from our study if they had inadequate pre- and postoperative imaging, as well as patients with a history of prior cervical spine surgery, concurrent anterior surgery, intradural pathology, spinal tumor, or spinal trauma. Patient history, surgical specifics, and neurologic function were recorded.A total of 190 patients were treated by 13 surgeons. 53 (27.9%) developed C5 palsy postoperatively. Of patients with C5 palsy, 40 (75.5%) recovered to baseline strength, 46 (86.6%) had at least grade 4 strength at last follow up, and 4 (7.5%) had strength worse than baseline and motor grade less than 4. Median time to recovery was 2.0 (IQR: 0.18 to 8.24) months. Age, gender, preoperative motor score, number of levels decompressed, smoking history, and comorbidities were not associated with a significant increase in the odds of C5 palsy. Risk of C5 palsy increased by 35% for every additional level fused below C4.The risk of C5 palsy is increased with instrumentation caudal to C5 in operations addressing degenerative cervical pathology. This should be taken into consideration during operative planning. Overall prognosis of C5 palsy is good; however, incidence of this condition may be greater than previously reported.