DOES PRESENCE OF “SIGNIFICANT BACK PAIN” AFFECT OUTCOMES IN LUMBAR DECOMPRESSION SURGERY?

Abstract

Although many authors have emphasised the importance of lumbar spinal decompression surgery for “leg dominant pain”, there is little objective evidence on the outcomes of surgery for varying degrees of back pain compared to leg pain. Moreover, it is unclear whether patients with radicular or claudication type leg pain, presenting with significant back pain as well, would benefit from surgical decompression. This study evaluated the outcomes of patients with

1. (i.) leg dominant pain compared to patients with

2. (ii.) leg pain along with significant back pain.

A prospective cohort of consenting adult patients, who have consecutively undergone elective primary posterior lumbar decompression surgery at a single academic institution by sub-specialty spinal surgeons were evaluated with longitudinal follow-up using standardised outcomes instruments. The cohort was analyzed into those with

1. (i.) leg dominant pain and those with

2. (ii.) significant back pain relative to their leg pain based on pre-operative VAS scores.

Univariate and multivariate analyses were used to adjust for potential confounding effects of demographic, surgical, waiting list and psychosocial factors.

Of the eighty-five eligible patients, sixty-nine (81.3%) had at least one year follow-up with a mean follow-up time of seventeen months. Baseline factors were similar between the two groups except for back and leg pain and wait times for consultation after referral. Patients with significant back pain waited significantly longer (p = 0.04) for consultation after referral than those with leg dominant pain. Significantly (p = 0.002) more patients (93%) in the leg dominant pain group reported clinically significant improvement in the Oswestry than the significant back pain group (59%). This effect remained after multivariate adjustments for other baseline factors.

This study is one of the first to provide objective evidence to support the notion that the primary indication and best predictor of outcome for lumbar decompression surgery is leg dominant pain. Presence of significant back pain, despite presence of leg pain, is a strong predictor of poorer post-operative results. Further research is required to determine if the current long waiting lists are a causative factor for development of significant back pain in surgical candidates.