Middle cluneal nerve entrapment neuropathy attributable to lumbar disc herniation

Background Middle cluneal nerve entrapment neuropathy (MCN-EN) is a known cause of low back pain (LBP). Here, we succeeded in treating a patient with a lumbar disc herniation who actually had MCN-EN with a nerve block and neurolysis. Case Description A 52-year-old female presented with severe left lower back and lateral thigh pain making it difficult to walk. The lumbar MRI revealed a disc herniation on the left at the L5/S1 level. On palpation, we identified a trigger point on the buttock where the MCN penetrates the long posterior sacroiliac ligament between the posterior superior and inferior iliac spine. Two left-sided MCN blocks, followed by the left MCN neurolysis procedure, were performed under local anesthesia. At the last follow-up, 10 months after surgery, the LBP has not recurred, and she requires no medications for pain control. Conclusion Here, a patient with a left-sided L5S1 disc herniation and low back/leg pain was successfully treated for MCN-EN with nerve block followed by neurolysis.