Prognostic Factors of Percutaneous Radiofrequency Neurotomy for Chronic Low Back Pain

ABSTRACT

BACKGROUNDS Percutaneous radiofrequency neurotomy of posterior primary ramus has been in use as a treatment for persistent, mechanical low back pain for two decades. However, there has been limited studies regarding to prognostic factors related to outcome. We report our experience with at least 2-year follow up with special aftention on prognostic factors. METHODS: Of total 228 patients who underwent percutaneous radiofrequency neurotomy (PRN) of posterior primary ramus for refractory low back pain during last 3 years, 128 patients whose pain was considered to be originated from facets joints or their surrounding soft tissue and responded to temporary blocks were assigned to a group II. All patients had more than 6 months of pain. These patients were compared with 100 patients to whom PRN were provided for chronic nonspecific low back pain without all inclusion criteria (Group I). RF procedures were done under local anesthesia with C-arm intensifier guidance. Pain reliefs were estimated at 1week, 1month, 6months and 2 years using visual analog scale(VAS). For patients with more that 50% reduction of previous pain was regarded as positive responder. Various clinical variables such as age, sex, symptom duration, types of pain, bilaterality, and previous surgery were studied for prognostic factors. RESULTS: Positive responders were 56% at 1week, 46% at lmonth, 18% at 6months, and 13% at 2years after PRN in group I, and 78.9% at lweek, 75.4% at lmonth, 62.5% at 6months, and 54.7% at 2years in group II. Some variables were found to be significantly related to outcome including prominent local tenderness, percussion tenderness, combination of symptoms with pain on gefting up, extension, transitional movement, pain radiating to buttock and/or posterior thigh, and good immediate response. Age, sex, symptom duration, bilaterality, imaging study results, previous lumbar surgery, and degrees of pain relief from diagnostic block were not related to outcome. CONCLUSIONS: These results indicate that PRN of posterior primary ramus has a moderate overall long-term beneficial effect, with no morbidity in our series. But, the long-term good results will be anticipated only in properly selected patients with low back pain originating from facet joints and surrounding structures.