Abdominal Wall Pseudohernia Secondary to Subcostal Nerve Entrapment After Lateral Spinal Surgery: A Case Report

Abdominal wall pseudohernia is an uncommon condition characterized by laxity of the abdominal wall without a fascial defect, typically resulting from denervation of the abdominal wall musculature. Subcostal nerve injury is a rare but important cause, particularly following lateral spinal approaches. We present the case of a 75-year-old man with multiple prior spinal surgeries who developed a persistent left lateral abdominal wall pseudohernia. The condition persisted for 1 year despite conservative management; therefore, surgical exploration was undertaken. Intraoperative findings demonstrated dense perineural fibrosis with complete encasement of the subcostal nerve. Functional assessment using nerve stimulation revealed diminished motor response. Neurolysis was performed with restoration of contraction of the abdominal wall musculature following decompression. The patient experienced complete resolution of abdominal wall laxity within 1 month postoperatively.