PREVALENCE AND CLINICAL-FEATURES OF LUMBAR ZYGAPOPHYSIAL JOINT PAIN -A STUDY IN AN AUSTRALIAN POPULATION WITH CHRONIC LOW-BACK-PAIN

Objectives-To determine the prevalence of pain arising from the zygapo physial joint in patients with chronic low back pain and to determine whether any clinical features could distinguish patients with and with out such pain. Methods-Sixty three patients with chronic low back pain were studied prospectively. All patients underwent a detailed history and physical examination as well as a series of intra-articular zygap ophysial joint injections of 0.5% bupivacaine starting at the symptoma tic level to a maximum of three levels or until the pain was abolished . They also received injections of normal saline into paraspinal muscl es to act as controls. Results-All patients proceeded with the injecti ons. Twenty (32%; 95% confidence interval (CI) 20 to 44%) obtained gre ater than 50% relief of their pain following the administration of sal ine. Fifty seven patients completed the study; 23 of them (40%; 95% CI 27 to 53%) failed to obtain relief following the injection of saline but obtained relief following one or more intra-articular injections o f local anaesthetic. None of the historical features or clinical tests could discriminate those patients with and those without zygapophysia l joint pain. Conclusion-Pain originating from the zygapophysial joint is not uncommon, but this study failed to find any clinical predictor s in patients with such pain.