INTRODUCTION: Anterior approach lumbar spine surgery is generally performed for the treatment of symptomatic disc degeneration after non-operative interventions have failed to provide adequate pain relief. Such procedures include anterior lumbar interbody fusion (ALIF), lumbar total disc replacement (TDR), or a combination of both (hybrid). Though the pain mechanisms are likely very different, the occurrence of new onset leg pain after transforaminal lumbar interbody fusion (TLIF) is well-documented, while there is much less information on this occurrence after anterior approach surgery. The purpose of this study was to investigate the incidence of new onset leg pain after anterior lumbar spine surgery and its clinical course.
METHODS: The study was based on a consecutive series of 330 patients who underwent anterior approach surgery for the treatment of symptomatic disc degeneration. Patients were excluded if the new onset pain was clearly related to iatrogenic injury or nerve root impingement (n=3). Data were collected by chart review and included general descriptives (sex, age, height, and weight), procedure performed, postoperative new leg pain occurrence, resolution of such pain, and the time to resolve if such occurred.
RESULTS: The mean age in the study group was 43.2 years, and 57.9% of the patients (n=191) were male. The procedures performed included: 237 TDR, 69 ALIF, and 24 hybrid. Most patients (n=246) had 1-level operations, with 77 receiving 2-level operations and 7 received 3-level operations. Of the total patients, 83 (25.2%) experienced postoperative new onset leg pain which was not present preoperatively. Logistic regression analysis found that the only factor significantly related to new onset leg pain was involvement of L5-S1 in the surgery (p<0.05). Investigating this further, new onset pain occurred in 28.6% of patients if L5-S1 was involved in the surgery versus 15.3% if this level was not operated (p<0.05). The new onset leg pain resolved in 57 (68.7%) patients at an average of 3.5 months (range: 1 to 18 months). The mean follow-up of patients with unresolved leg pain was 8.5 months, ranging from 1 to 41 months.
DISCUSSION: The results of this study found that new onset leg pain occurred in approximately 25% of patients undergoing anterior approach surgery and resolved in the majority of patients at an average of 3.5 months. Many of the patients were managed acutely with gabapentin. The mechanism for new onset leg pain after anterior approach surgery is not known, but surgeons and patients should be aware of its occurrence and course.