Kyphotic malalignment after anterior cervical fusion is one of the factors promoting the degenerative process in adjacent intervertebral levels

Abstract

The aim of this study was to determine whether postoperative malalignment of the cervical spine after anterior interbody fusion surgery promotes degenerative changes in the neighboring intervertebral discs. Forty-two patients who underwent anterior interbody fusion surgery for cervical spondylosis and disc herniation (34 men, 8 women) were followed for an average of 9.8 years. The average age at surgery was 50.2 years. Twenty-three patients underwent a single-level fusion, 17 underwent two-level fusion, and 2 had three levels fused. The Japanese Orthopaedic Association cervical myelopathy score, with a normal score 17 points, was 11.7 before surgery and 14.9 at follow-up. Neurological status was significantly improved postoperatively, and the improvement was preserved thereafter in most cases (paired t-test, P P P<0.04, respectively). Our findings suggest that one of the factors promoting degenerative change in adjacent intervertebral levels after anterior cervical fusion for degenerative disorders is postoperative kyphotic change in the cervical spine and the fused segment.