High-frequency thermal coagulation to treat middle cluneal nerve entrapment neuropathy

Abstract

Objective Middle cluneal nerve entrapment (MCN-E) around the sacroiliac joint can elicit low back pain (LBP). Pain control can be obtained with anesthetic nerve blocks; however, when their effectiveness is transient, surgical release may be necessary. We investigated the efficacy of radiofrequency thermocoagulation (RFTC) in patients with MCN-E. Methods Between December 2018 and August 2019, 11 consecutive patients (4 men, 7 women; mean age 76.4 years) with intractable medial buttock pain due to MCN-E underwent MCN RFTC. The mean symptom duration was 49.5 months; pre-RFTC local MCN blocks provided pain relief for a mean of 7.7 days. The severity of pain in the medial buttock due to MCN-E was recorded before and 2, 6, 12, and 24 weeks after RFTC on the numerical rating scale (NRS) and the Roland-Morris Disability Questionnaire (RDQ). Results All patients reported pain alleviation; there were no complications. While there was a significant difference in the pre- and post-RFTC treatment NRS (p < 0.05), the RDQ scores were significantly lower only after 12 weeks. The duration of pain relief was significantly prolonged by RFTC (p < 0.05). Two patients suffered pain relapse 10 weeks post-RFTC; pain alleviation was obtained by re-RFTC performed 2 weeks after pain recurrence. Two other patients relapsed 20 and 21 weeks post-RFTC; their symptoms also disappeared by MCN block administered 24 weeks after they had undergone RFTC. Conclusion RFTC may safely control intractable LBP due to MCN-E.