Natural History and Predictors of Parastomal Hernia after Robot-Assisted Radical Cystectomy and Ileal Conduit Urinary Diversion.

PURPOSE:We investigated the prevalence of and variables associated with parastomal hernia and its outcomes after robot-assisted radical cystectomy and ileal conduit creation for bladder cancer. MATERIALS AND METHODS:We retrospectively reviewed the records of patients who underwent robot-assisted radical cystectomy at our institution. Parastomal hernia was defined as the protrusion of abdominal contents through the stomal defect in the abdominal wall on cross-sectional imaging. Parastomal hernia was further described in terms of patient and hernia characteristics, symptoms, management and outcomes. The Kaplan-Meier method was used to determine time to parastomal hernia and time to surgery. Multivariate stepwise logistic regression was done to evaluate variables associated with parastomal hernia. RESULTS:A total of 383 patients underwent robot-assisted radical cystectomy and ileal conduit creation. Of the patients 75 (20%) had parastomal hernia, which was symptomatic in 23 (31%), and 11 (15%) underwent treatment. Median time to parastomal hernia was 13 months (IQR 9-22). Parastomal hernia developed in 9%, 23% and 32% of cases at 1, 2 and 3 years, respectively. Patients with parastomal hernia had a significantly higher body mass index (30 vs 28 kg/m2, p = 0.02), longer overall operative time (357 vs 340 minutes, p = 0.01) and greater blood loss (325 vs 250 ml, p = 0.04). On multivariate analysis operative time (OR 1.25, 95% CI 1.21-3.90, p <0.001), a fascial defect 30 mm or greater (OR 5.23, 95% CI 2.32-11.8, p <0.001) and a lower postoperative estimated glomerular filtration rate (OR 2.17, 95% CI 1.21-3.90, p = 0.01) were significantly associated with parastomal hernia. CONCLUSIONS:Symptoms develop in approximately a third of patients with parastomal hernia and 15% will require surgery. The risk of parastomal hernia plateaued after postoperative year 3. Longer operative time, a larger fascial defect and lower postoperative kidney function were associated with parastomal hernia.