THE POSTOPERATIVE LUMBAR SPINE - EVALUATION OF EPIDURAL SCAR OVER A 1-YEAR PERIOD

PURPOSE: We documented the morphological changes on enhanced MR imagin g studies that occur in epidural scar over a period of 1 year after lu mbar diskectomy.METHODS: The study population was culled from a random ized, multicenter clinical trial designed to evaluate the efficacy of a device inhibiting postoperative epidural fibrosis after single-level , unilateral laminectomy/diskectomy for herniated lumbar disk. Analysi s was restricted to 71 control subjects who did not receive the device . All patients underwent surgery after receiving clinical and MR exami nations, with follow-up MR studies at 6 and 12 months. Evaluation of a ll MR images was performed by one interpreter, who was blinded to trea tment arm and clinical findings. The extent of epidural scar seen at t he 6- and 12-month MR examinations was graded on a scale of 0 to 4 for each quadrant at each imaging section encompassing the surgical level . RESULTS: Eighty-five percent of the patients had no change in the am ount of anterior epidural scar between the 6- and 12-month MR examinat ions; 75% of the patients showed no change in the amount of posterior epidural scar between the 6- and 12-month examinations. CONCLUSION: Th e majority of our patients had no change in the amount of epidural sca rring visible at enhanced MR imaging over a 1-year period after lumbar laminectomy/diskectomy.