Internal hernia with volvulus after major abdominal reconstructions in pediatric urology - An infrequently reported and potentially devastating complication.

INTRODUCTION: Enterocystoplasty (EC), appendico- or ileovesicostomy (APV), and appendicocecostomy (APC) can facilitate continence and prevent renal damage for patients with congenital urologic or bowel disease. Bowel obstruction is a well-documented complication of these procedures, and the etiology of obstruction is variable. The aim of this study is to determine the incidence and describe the presentation, surgical findings, and outcomes of bowel obstruction from internal herniation due to these reconstructions. METHODS: In this single institution retrospective cohort study patients who underwent EC, APV, and/or an APC between 1/2011 and 4/2022 were identified via CPT codes within the institutional billing database. Records for any subsequent exploratory laparotomy during this same timeframe were reviewed. The primary outcome was an internal hernia of bowel into the potential space between the reconstruction and the posterior or anterior abdominal wall. RESULTS: Two hundred fifty seven index procedures were performed in 139 patients. These patients were followed for a median of 60 months (IQR 35-104 months). Nineteen patients underwent a subsequent exploratory laparotomy. The primary outcome occurred in 4 patients (including one patient who received their index procedure elsewhere) for a complication rate of 1% (3/257). The complications occurred between 19 months and 9 years after their index procedure (median 5 years). Patients presented with bowel obstruction; two patients also had sudden pain following an ACE flush. One complication was caused by small bowel and cecum passing around the APC and subsequently volvulizing. A second was caused by bowel herniating behind the EC's mesentery and the posterior abdominal wall. A third was caused by bowel herniating behind the APV mesentery and subsequently volvulizing. The exact etiology of fourth internal herniation is unknown. Of the three surviving patients, all required resection of ischemic bowel and 2 required resection of the involved reconstruction. One patient died intraoperatively from cardiac arrest. Only 1 patient required a subsequent procedure to regain lost function. CONCLUSION: Internal herniation caused by small or large bowel passing through a defect between the mesentery and abdominal wall or twisting around a channel occurred in 1% of 257 reconstructions performed over 11 years. This complication can arise many years after abdominal reconstruction, resulting in bowel resection and possibly takedown of the reconstruction. When anatomically possible and technically feasible, the surgeon should close any potential spaces created during the initial abdominal reconstruction.