Abstract
Prospective Study Design. 198 consecutive patients with back pain leg pain with MRI scan showing disc prolapse were operated from June 2001 to January 2004. In 22 patients it was found that the cause of nerve root compression was a localised venous plexus and the disc was intact.
Objectives: To emphasize the fact that the clinical presentation of a localised venous plexus of epidural veins in the lumbar spine can resemble that of an acute disc prolapse.
Summary of Background data: After reporting 6 cases of this type in Spine Volume 28 Number 1 we designed a prospective study of all discetomies done in our institution. Our outcome suggests that the finding of enlarged epidural veins during lumbar spine disc decompression is relatively common, but it is only recently that they have been implicated as the cause of the presenting symptoms.
Methods and Results: 198 patients presented with severe low back pain accompanied by sciatica, which had begun acutely. Physical examination in most of these patients showed the presence of neurological signs in the affected leg. The diagnosis of possible disc prolapse with nerve compression was demonstrated by MRI scan. However , at surgery, in 22 patients the intervertebral disc appeared to be relatively normal without any bulge and intact annulus, but a large venous structure in the form of plexus of epidural vein compressing the nerve root was found in the spinal canal.. The configuration of this venous plexus matched the MRI findings. The symptoms were relieved by decompression of the spinal canal and ablation of the veins.
Conclusion: Lumbar spine venous plexi of epidural veins can cause nerve root compression and the MRI image of a localised plexus of epidural veins can closely resemble that of a prolapsed intervertebral disc. Could this be the cause of failed back syndrome in patients who have already undergone decompression and discetomy? Wenger et al show success rate of 92.5% to 94.7% after discetomy but still there is an failure rate of 7.5 to 5.3% leading to failed back syndrome. The incidence of symptomatic lumbar epidural varices is said to be low. Zimmerman et al quoted their incidence as 0.067% and Hanley et al 5%. Our study shows an incidence of 11.11%.
Theses abstracts were prepared by Professor Roger Lemaire. Correspondence should be addressed to EFORT Central Office, Freihofstrasse 22, CH-8700 Küsnacht, Switzerland.
