We wanted to investigate the efficacy of percutaneous radiofrequency (RF) neurotomy of the medial branch for the management of chronic low back pain due to lumbar zygapophysial joint dysfunction.

Thirteen patients who had unremitting chronic low back pain for more than 6 months and whose VAS scores were over 7 were selected on the basis of double comparative nerve blocks. The patients consist of three males and 10 females, and their nean age was 67 years. Sensory stimulation was performed to detect the "pathologic branches" that were responsible for pain generation. RF neurotomy was performed using a lesion generator at 80 C for 90 seconds. The postoperative outcome was classified, depending on the degree of pain reduction, as excellent (> or = 75%), good (50-75%), and poor (<50%). Follow-up evaluation was performed at 6 weeks, 3 months and 6 months after surgery.

The mean number of medial branches was 6.2. Eleven patients had bilateral disease and two had unilateral disease. Sensory stimulation was positive in all patients with a mean amplitude of 4.5V (range: 0.15-6 V). The L5 dorsal ramus was the most frequently involved segment, and this was followed by L4, L3 and L2. The number of lesionings for each medial branch was 3.7. The surgical outcome was graded as excellent (53%), good (23%), and poor (24%) after 6 months of follow-up. Transient backaches were noticed in two patients; however, complications were not observed. Recurrences were not demonstrated during the follow-up period

We conclude that RF neurotomy of the medial branches is an efficient method to substantially alleviate the chronic low back pain caused by zygapophysial joint dysfunction.