Adjacent Segment Disease Developing Dependence on Preoperative Adjacent Disc Degenerative Changes

Abstract

Introduction The causes of adjacent segment disease (ASD) after lumbar spinal fusion are controversial today. Although the role of initial degenerative changes in the adjacent discs is not fully studied many authors have noted the special importance of them. Object To determine the importance of the preoperative degenerative changes of adjacent segment in the development of symptomatic ASD after short lumbar fusion. Materials and Methods Retrospective study of 78 patients who underwent short 360° fusion lumbar surgery from 2006 to 2010 for the treatment of degenerative lumbar spine with follow-up at least 3 years. All patients had no preoperative radiographic instability signs of the adjacent levels with normal height of the adjacent discs. We compare 2 groups: first group include 38 patients with the pre existing initial degenerative changes of adjacent discs according MRI and scored by Pfirrmann modified classification with 2-5 grade. The second group include 40 patients with no pre existing changes of the adjacent discs according MRI. There were 67% females. Mean age of 58 years (range 23-78). Mean follow-up of 4 years (3-7 years). MRI evaluation of adjacent segment condition and bend lateral radiographs were performed on the preoperative and follow-up visits. Adjacent segment condition was evaluated by MRI and scored with Pfirrmann modified classification. Results In the I group symptomatic ASD was found in 3 cases (7,9%) during 1 year follow-up. There were no cases with increasing the stage of degenerative changes by Pfirrmann according MRI. 3 years f/up in I group showed increasing symptomatic ASD to the 17 cases (44,7%). 76% of them required revision surgery. 11 patients had increasing the degenerative changes to 6-7 stage by Pfirrmann with no clinical manifestation. In the II group at 1 year f/up 2 patients (5%) had symptomatic ASD. At 3 years f/up the number of patients with symptomatic ASD was increased to 6 (15%). 50% of them required revision surgery. Conclusion Our study showed that the great role in the development of the symptomatic ASD after short lumbar fusion is belong to pre existing initial degenerative changes of adjacent discs. Patients with preoperative disc degenerative changes have statistically significant increasing risks of developing symptomatic ASD. Disclosure of Interest None declared References Hilibrand AS, Robbins M. Adjacent segment degeneration and adjacent segment disease: the consequences of spinal fusion? Spine J 2004;4(6, Suppl)190S-194S Park P, Garton HJ, Gala VC, Hoff JT, McGillicuddy JE. Adjacent segment disease after lumbar or lumbosacral fusion: review of the literature. Spine 2004;29(17):1938–1944