The relative contributions of the disc and zygapophyseal joint in chronic low back pain.

Abstract

A prospective cross-sectional analytic approach was taken. This study sought to determine the relative contribution of the disc and the zygapophyseal joint as a pain source in patients with chronic low back pain. Previous studies have employed either zygapophyseal joint blocks or discography, but in no studies have both procedures been performed. Ninety-two consecutive patients with chronic low back pain were studied using both discography and blocks of the zygapophyseal joints. Thirty-six patients (39%) had at least one positive discogram as defined by exact pain reproduction, an abnormal image, and a negative control. Eight patients responded to both a screening zygapophyseal joint block using lignocaine and a confirmatory block using bupivacaine. Only three patients had both a positive discogram and a symptomatic zygapophyseal joint. In patients with chronic low back pain, the combination of discogenic pain and zygapophyseal joint pain is uncommon.