Abstract
Introduction: Following surgical discectomy for pro-lapsed lumbar intervertebral disc, a proportion of patients develop leg symptoms on the side contra-lateral to the original surgery. Among other causes, subsequent disc space narrowing together with on-going degenerative changes may cause root entrapment in the lateral recess or in the intervertebral canal at the level of the previous disc prolapse.
It has been previously reported that the results of discectomy are less successful in patients with pre-existing spinal stenosis. It may be argued that patients with a narrow spinal canal would be more prone to the development of contra-lateral symptoms. The aim of this study was to determine whether any measurement on the pre-operative CT scan could predict the development of contra-lateral symptoms, or provide an indication for prophylactic decompression of the contra-lateral side at the time of the original surgery.
Materials & Methods: In a retrospective cohort of 43 patients following lumbar discectomy, eight subsequently developed symptoms on the contra-lateral side of whom three required subsequent contra-lateral surgery. A relationship was demonstrated between a measurement taken on the pre-operative CT scan (the oblique sub-facet distance) and the occurrence of contra-lateral symptoms following discectomy.
Conclusion: An oblique sub-facet distance of 8mm or less predicted the development of contra-lateral symptoms with a sensitivity of 75 % and a specificity of 74%.
Theses abstracts were prepared by Professor Roger Lemaire. Correspondence should be addressed to EFORT Central Office, Freihofstrasse 22, CH-8700 Küsnacht, Switzerland.
