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.