Successful Nerve Block Therapy for Lateral Cutaneous Nerve Entrapment Syndrome (LACNES) Triggered by Exercise

This report presents a case of a 59-year-old man who experienced pain in the left abdomen during abdominal exercises, which gradually improved. Pain recurred in the same area one year later and gradually worsened, rendering him unable to work. The strongest tender point, with a positive Carnett's sign, was noted on the flank. Ultrasonography revealed a 5 × 10 mm mass shadow in the internal oblique muscle. Trigger point injection at the same site was remarkably effective. Lateral cutaneous nerve entrapment syndrome caused by a crush injury due to abdominal exercises was diagnosed. Nerve block therapy provided effective pain relief.