Ultrasound-guided hydrodissection for anterior cutaneous nerve entrapment syndrome: A case series.

Abstract

Anterior cutaneous nerve entrapment syndrome (ACNES) is an uncommon, non-emergent cause of chronic abdominal wall pain arising from entrapment of the terminal branches of the T7-T12 intercostal nerves at the anterior rectus sheath. It is usually recognized only after laboratory and imaging studies have excluded intra-abdominal causes, often after repeated evaluations. Prior abdominal surgery is a recognized risk factor due to fascial scarring. Ultrasound-guided hydrodissection with 5% dextrose in water (D5W) and dilute lidocaine has been described in case reports as a minimally invasive treatment that may relieve pain and release the entrapped nerve. We present two patients who developed post-surgical ACNES following laparoscopic Roux-en-Y gastric bypass and laparoscopic cholecystectomy, respectively. Each presented to the ED with severe abdominal wall pain (NRS 9/10 and 10/10) and negative intra-abdominal workup. Both patients met diagnostic criteria including positive Carnett's sign, positive pinch test, and >90% pain reduction after ultrasound-guided hydrodissection. On chart review, pain relief was sustained at 6 weeks (Case 1) and 4 weeks (Case 2), and neither patient received other treatment after discharge. In these selected patients, bedside ultrasound-guided hydrodissection was feasible and was followed by rapid pain relief. Prospective, comparative studies are needed to establish its place within the ACNES treatment algorithm and to assess durability beyond the short-term follow-up reported here.