Risk factors for outcome and complications of dorsal foraminotomy in cervical disc herniation.

BACKGROUND Dorsal foraminotomy is a standard operative procedure for lateral cervical disc herniation. Factors associated with surgical complications and clinical outcome in dorsal foraminotomy of cervical disc herniation were evaluated in a retrospective cohort study. METHOD Thirty-nine patients were operated upon for unilateral, monosegmental, mediolateral cervical disc herniation (+/- associated spondylosis) from 1997 to 1999. Preoperative radiologic imaging and surgical reports were analyzed. Motor disfunction, neck irritation, and radicular pain were evaluated. Outcome was ranked according to modified Odom's criteria at 6 weeks and 1 year postoperatively. RESULTS Six weeks after injury 7 of 39 patients (18%) showed neck irritation. No new neurologic deficit was seen. All patients with preoperative paresis improved; two had early relapses of a medial soft disc prolapse (2/39). Residual radicular pain was seen in 3 of 39 patients (8%) within 30 days postoperatively, necessitating surgical revision. Factors of surgical failure were associated spondylosis (2/3) and residual mediolateral disc protrusion (1/3). In one patient with associated spondylosis, local pain due to a symptomatic fracture of the lateral process of D1 resolved after revision. Duration of preoperative radicular pain was identified as a risk factor for unfavorable outcome. CONCLUSION In lateral cervical disc herniation, associated spondylosis or medial disc protrusion poses a significant risk of surgical failure and complications of dorsal foraminotomy. Reducing the radicular failure rate by enlarging the bony decompression may lead to local failure. In well-selected patients with a lateral cervical free disc fragment, dorsolateral foraminotomy is successful and safe.