Risk factors for C5 palsy after anterior cervical decompression

Objective: To investigate risk factors for C5 palsy following anterior cervical decompression (ACD). Methods: A retrospective analysis was made on clinical data from 100 patients with cervical spondylotic myelopathy (CSM) admitted to the Department of Spine Surgery of The Third Hospital of Hebei Medical University from January 2015 to June 2017. All the patients underwent ACD. In terms of the criteria for diagnosing postoperative C5 palsy, the patients were divided into the palsy group and the non-palsy group. The patients in the two groups were compared in the basic data, the Japanese Orthpaedic Association (JOA) scores, changes in the values of cervical lordosis, the sagittal diameters of C4/C5 intervertebral foramina, and the incidence of preoperative hyper-intense signal changes within the spinal cord at C4-C5. Multivariate logistic regression analysis was employed for exploring the risk factors for C5 palsy. Results: The patients in the two groups differed insignificantly in basic data (age, sex,operative time, intraoperative blood loss, and course of disease). The postoperative JOA scores in the palsy group were significantly lower than those in the non-palsy group(P < 0.001). The changes in the values of cervical lordosis before and after surgery in the paralyzed group were greater than those in the non-palsy group, but sagittal diameters of C4/C5 intervertebral foramina were remarkably larger in the non-palsy group than in the palsy group (all P < 0.001). The incidence of preoperative hyper-intense signal changes within the spinal cord at C4-C5 varied insignificantly between the two groups. Multivariate logistic regression analysis demonstrated that changes in the values (greater than 6.5 degrees) of cervical lordosis before and after surgery, and sagittal diameter (less than 2.2 mm) of C4/C5 intervertebral foramina were risk factors for the presence of postoperative C5 palsy. Conclusion: For patients with CSM who had undergone ACD, changes in the values of cervical lordosis before and after surgery, changes in the values of cervical lordosis, and the sagittal diameter of C4/C5 intervertebral foramina are risk factors for presence of postoperative C5 palsy.