Pulsed radiofrequency treatment of the lumbar medial branch for facet pain: a retrospective analysis.

The use of pulsed radiofrequency (PRF) for treatment of the medial branch is controversial. A retrospective study of the results of PRF treatment of the medial branch in 48 patients with chronic low back pain was carried out. Patients who did not respond were offered treatment with conventional radiofrequency heat lesions. Patients were included who had low back pain and >50% pain relief following a diagnostic medial branch block. The mean age was 53.1 +/- 13.5 years, the mean duration of pain was 11.4 +/- 10.9 years (range 2-50). Nineteen patients had undergone surgery. Pain scores on a numeric rating scale of 1-10 were noted before and after the diagnostic nerve block, before the procedure, and at 1-month and 4-month follow-up. PRF was applied for 2 minutes at a setting of 2 x 20 ms/s and 45 V at a minimum of two levels using a 22G electrode with a 5 mm active tip. Heat lesions were made at 80 degrees C for 1 minute. OUTCOME DEFINITION: A successful outcome was defined as a >60% improvement on the numeric rating scale at 4-month follow-up. In 21/29 nonoperated patients and 5/19 operated patients, the outcome was successful. In the unsuccessful patients who were subsequently treated with heat lesions, the success rate was 1/6. The setup of our study does not permit a comparison with the results of continuous radiofrequency (CRF) for the same procedure, other than the detection of an obvious trend. When comparing our results with various studies on CRF of the medial branch such a trend could not be found. Based on these retrospective data, prospective and randomized trials, for example, radiofrequency vs PRF are justified.