The Surgery Treatement of Anterior Cutaneous Nerve Entrapment Syndrome (ACNES)

Abstract

Anterior cutaneous nerve entrapment syndrome (ACNES) is an under-recognised cause of chronic abdominal wall pain caused by entrapment of the anterior cutaneous branches of the lower thoracic intercostal nerves. This report describes the diagnosis and surgical management of a 36-year-old man with a three-year history of localised left abdominal wall pain that was aggravated by physical activity. Extensive investigations and interventions, including urological assessment, surgery, diagnostic laparotomy, fibrogastroscopy, colonoscopy, computed tomography, magnetic resonance imaging, and Novocain blockades, failed to identify the cause of or relieve the pain. Clinical examination demonstrated a tender area measuring approximately 1 cm² along the lateral border of the left rectus abdominis muscle and a positive Carnett’s sign. As no intra-abdominal, retroperitoneal, or abdominal wall pathology was identified, ACNES was diagnosed. Surgical exploration through a left pararectal incision revealed local thickening of a nerve within the Th11 neurovascular bundle where it traversed the anterior rectus sheath. The affected segment and the nerve within the overlying Th11 neurovascular bundle were resected, and the tendon sheath was reconstructed. The postoperative course was uneventful. The characteristic pain resolved immediately after the patient regained consciousness, and he remained pain-free during movement and at rest at the two-week assessment. This case suggests that focused clinical evaluation and targeted neurectomy may provide symptom relief in carefully selected patients when conservative measures have failed.