Risk assessment of stone formation in stapled orthotopic ileal neobladder

Purpose: The increasing trend of performing radical cystectomy with a minimally invasive approach has made stapled neobladders an attractive alternative to hand-sewn pouches. To date, data on the incidence and clinical impact of stone formation in long surviving neobladder cases are scarce. We report a long-term, single-center experience of stapled orthotopic ileal neobladder and identify predictors of stone formation.

Materials and methods: From May 2001 to October 2012, 445 consecutive patients (388 male, 57 female) underwent radical cystectomy and stapled orthotopic ileal neobladder. Univariable and multivariable analyses were performed to identify independent predictors of an increased risk of stone formation.

Results: At a median followup of 41 months (IQR 16-58) neobladder stone formation occurred in 41 patients (9.2%). All of these patients successfully underwent endoscopic stone lithotripsy with 34 as outpatient procedures. On univariable Cox analysis only female gender (p = 0.001, HR 3.29, 95% CI 1.59-6.83) and intermittent self-catheterization (p <0.001, HR 15.2, 95% CI 5.87-39.5) were associated with an increased risk of stone formation. On multivariable analysis the only independent predictor of stone formation was intermittent self-catheterization (p = 0.001, HR 8.98, 95% CI 2.59-31.1).

Conclusions: In our series of stapled orthotopic ileal neobladders the rate of stone formation was comparable to that reported in the literature for completely hand-sewn ileal reservoirs. The only variable independently predictive of stone formation was intermittent self-catheterization.