Short Term Outcomes and Prognostic Factors Based on Radiofrequency Thermocoagulation on Lumbar Medial Branches

Choi, Byung In; Kweon, Tae Dong; Park, Kyung Bae; Lee, Youn Woo

Abstract

BACKGROUND: Lumbar zygapophysial joints are a common source of chronic lower back pain and radiofrequency thermocoagulation (RF) of the medial branches (MB) has been shown to be effective at providing substantial pain relief for chronic low back pain.Therefore, we carried out this study to determine the short term outcomes and prognostic factors of RF on the MB of patients with lumbar facet syndrome.
METHODS
We performed RF in fourteen patients who showed greater than 80% pain relief up to three times after a diagnostic MB block was conducted using 0.3 ml of 0.5% bupivacaine.Using 10 cm curved electrodes with 10-mm active tip, a 60 second, 80 degrees C lesion was made after electrical stimulation at 50 Hz for sensory and 2 Hz for motor nerve testing.The degree of pain relief was then assessed after 2 weeks, and again after 3 months using a visual analog scale (VAS) and a four point Likert scale.The outcome was regarded as 'success' if at least a 50% reduction in the VAS was observed.Possible prognostic factors between the two groups were also evaluated.
RESULTS
The success rate was 71.4% (10/14) after three months of follow-up. However, there were transient complications, such as neuritis like syndrome, in 4 patients. In addition, short symptom duration and low minimal voltage (< 0.4 V) for sensory stimulation were shown to be the relevant prognostic factors for a successful outcome.
CONCLUSIONS
RF may be an alternative to repeated MB block or intraarticular injection for palliation of lumbar facet syndrome. For better outcomes, early diagnosis and strict patient selection should be coupled with efforts to avoid anatomically incorrect RF.