ANATOMIC POSITION OF A HERNIATED NUCLEUS PULPOSUS PREDICTS THE OUTCOME OF LUMBAR DISKECTOMY

The purpose of this study was to determine whether the anatomic positi on of a lumbar disc herniation has any significant effect on the clini cal outcome of lumbar discectomy. Between January 1988 and March 1993, 80 patients with simple disc herniations undenvent lumbar discectomy for herniated nucleus pulposus. We reviewed preoperative computed tomo graphy scans after discography and magnetic resonance imaging of the l umbar spine. Disc herniations were classified as central, paracentral, intraforaminal, extraforaminal, or multiregional broad-based protrusi ons. The Smiley-Webster evaluation scale, which divided patients into groups with excellent, good, fair, and poor clinical outcome and evalu ated the long-term need for pain medication, was applied. The postoper ative evaluation period ranged from 6 to 48 months. The clinical outco me was then correlated with the different positions of herniations. Th e frequencies of the clinical outcomes were compared using the chi(2) test. We found a poorer clinical outcome that was statistically signif icant in patients with central herniations and with multiregional prot rusions. Most herniations occurred at the L4-L5 level (58.7%). However , the level of disc herniation was not found to be a predictor of clin ical outcome. Form and anatomic position of the lumbar disc herniation are of prognostic value for the outcome of lumbar discectomy. Further studies are required to confirm our preliminary results and eventuall y help improve surgical indications for lumbar discectomy.