DEVELOPMENT OF DEGENERATIVE SPONDYLOSIS OF THE LUMBAR SPINE AFTER PARTIAL DISKECTOMY - COMPARISON OF LAMINOTOMY, DISKECTOMY, AND POSTEROLATERAL DISKECTOMY

Study Design. The development of degenerative spondylosis after succes sful operative decompression of the affected nerve root was prospectiv ely evaluated in a comparative case series of 100 patients with a hern iated lumbar nucleus pulposus, Objectives, The objective of this study was to compare the relative incidence of degenerative spondyloarthros is after successful posterior laminotomy and discectomy and posterolat eral extradural discectomy for decompression of a compromised lumbar n erve root. Summary of Background Data, The relationship between the ra diographic appearance of degenerative spondylosis and prior operative procedures has been controversial and at times contradictory. The post erior operative approach with a partial discectomy has been associated with a significant incidence of postoperative degenerative spondylosi s and intraneural and perineural fibrosis, complications that may be m inimized, or perhaps even eliminated, with the posterolateral evacuati on of the offending intervertebral disc fragment. Methods, Each patien t had: 1) not responded favorably to nonoperative treatment, 2) a pers istent radiculopathy, 3) correlative imaging studies with no preoperat ive spondyloarthrosis and 4) minimum 2-year follow-up. Fifty patients were treated by posterior laminotomy and discectomy and fifty were tre ated by a posterolateral extradural discectomy. Postoperative spondylo sis was graded based on the radiographic presence or absence of osteop hytes, the intervertebral disc height, the vertebral body alignment ac id the facet joint changes. Results, At an average postoperative follo w-up of 65 months, the incidence of a one grade increase in degenerati ve spondylosis was 80% of the laminotomy and discectomy patients as co mpared to 39% of the posterolateral discectomy patients. Conclusions, The increased incidence of spondyloarthrosis with the posterior approa ch suggests that minimally invasive posterolateral extradural procedur es should be considered for the decompression of a compromised lumbar nerve root,