Treatment of low back pain elicited by superior cluneal nerve entrapment neuropathy after lumbar fusion surgery

OBJECT: Low back pain (LBP) attributable to fusion failure, implant failure, infection, malalignment, or adjacent segment disease may persist after lumbar fusion surgery (LFS). Superior cluneal nerve (SCN) entrapment neuropathy (SCNEN) is a clinical entity that can produce LBP. We report that SCNEN treatment improved LBP in patients who had undergone LFS. METHODS: Between April 2012 and August 2015, we treated 8 patients (4 men and 4 women ranging in age from 38 to 88 years; mean age, 69 years) with SCNEN for their LBP after LFS. Our criteria for the diagnosis of SCNEN included a trigger point over the posterior iliac crest 7 cm from the midline and numbness and radiating pain in the SCN area upon compression of the trigger point. Symptom relief was obtained in more than 75% of patients within 2 h of inducing a local nerve block at the trigger point in the buttocks. The mean postoperative follow-up period was 28 months (range, 9-54 months). RESULTS: LBP was unilateral in 3 and bilateral in 5 patients. The senior author (T.I.) operated all patients for SCNEN under local anesthesia because they reported recurrence of pain after the analgesic effect of repeat injections wore off. This led to a significant improvement of their LBP. CONCLUSIONS: SCNEN should be considered in patients reporting LBP after LFS. Treatment of SCNEN may be a useful option in patients with failed back surgery syndrome after LFS.