Study design: A prospective cross-sectional analytic approach was taken.
Objectives: 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.
Summary of background data: Previous studies have employed either zygapophyseal joint blocks or discography, but in no studies have both procedures been performed.
Methods: Ninety-two consecutive patients with chronic low back pain were studied using both discography and blocks of the zygapophyseal joints.
Results: 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.
Conclusions: In patients with chronic low back pain, the combination of discogenic pain and zygapophyseal joint pain is uncommon.