Lumbar zygapophyseal joint injections in patients with chronic lower back pain.

BACKGROUND This study was designed to assess the diagnostic value and clinical benefits of lumbar zygapophyseal joint injections in patients with chronic lower back pain. METHODS Two hundred and seventy-seven patients (136 males and 141 females, aged 15-82 years) with chronic lower back pain were enrolled in the trial and met the following criteria: pain for more than 1 year; no root signs; and no history of back surgery. Under fluoroscope, a 0.8-1.5 mL mixture of lidocaine, betamethasone dipropionate and iopamidol (1:1:0.5) was injected into each joint after intra-articular localization of the needle tip was confirmed. A questionnaire with a pain scale was administered immediately or the day after injection, and then after 1, 3, 6 and 12 weeks. Partial arthrograms were reviewed by a radiologist. RESULTS Four hundred and forty-nine joint injections were performed in 277 patients (L3-4, n = 76; L4-5, n = 272; L5-S1, n = 101). Bilateral injections were performed in 117 patients (42.2%). The study group comprised 204 patients (73.6%) with an excellent or good response, whereas the control group comprised the remaining 73 patients (26.4%). The rates of good response in the study group were 72.1% (147/204) after 3 weeks, 40.7% (83/204) after 6 weeks, and 31.4% (64/204) after 12 weeks. Partial arthrograms revealed 25 patients (9.0%) with synovial cysts (L3-4, n = 3; L4-5, n = 14; L5-S1, n = 8); 23 of these patients (92.0%) had a good response to the injections. Five of the 6 patients with spondylolysis (83.3%), having abnormal communication between the injected and contiguous joint, had a good response to the injections. The abovementioned, abnormal partial-arthrogram findings correlated significantly with the rate of good response to the injections. Although 3 patients had contrast medium extravasated into the epidural space during injection, none of the 277 patients had deteriorating lower back pain after the injections. CONCLUSION Lumbar zygapophyseal joint injections, as a useful diagnostic tool for facet joint syndrome, could also have useful palliative effects in the management of chronic lower back pain.