The European Hernia Society classification applied to the rare cases of parastomal hernia after ileal conduit urinary diversion: a retrospective cohort of 96 patients.

INTRODUCTION To determine the incidence and classification of parastomal hernia (PH) following ileal conduit urinary diversion and to identify risk factors for PH development. METHODS We performed a retrospective review of our cystectomy database which includes benign and malignant cases from 2011-2016. Patients with an abdominal CT at 24 ± 2 months post-operation were included. PH were classified according to the European Hernia Society (EHS) system. Regression analyses were performed on variables associated with parastomal hernia. RESULTS A total of 96 patients were included in the study. The incidence of PH on CT is 20.2% at one year and 28.1% at two years. Using the EHS classification, the majority of PH was small (≤ 5 cm), but up to 50% were associated with a concomitant incisional hernia. On multivariable analysis, (C-index = 0.71), obesity was associated with a higher risk of PH (OR = 2.8, 95% CI 1.06-7.42, p = 0.04), whereas prior tobacco use was associated with a lower risk of PH at 2 years (OR = 0.23, 95% CI 0.09-0.63, p < 0.01). CONCLUSIONS Hernia after ileal conduit is common with radiographic rates approaching 30% at two years, with obesity being an independent risk factor. The relationship between prior tobacco use and a lower hernia rate may be limited to this study but presents an opportunity for future investigation. No difference in PH rates were observed between open and minimally invasive surgery and between intracorporeal and extracorporeal conduits.