Comparison of orthotopic sigmoid and ileal neobladders: continence and urodynamic parameters

The objective this of the study was to compare continence rates and urodynamic parameters among patients who had undergone orthotopic bladder substitution with sigmoid or ileal segments.

Continent urinary reservoirs were constructed in 112 patients. Fifty patients received a sigmoid neobladder (SN) and 62 patients an ileal neobladder (IN). Thirty-four patients with an SN (mean age 64.4 years), and 20 with an IN (mean age 57.8 years) agreed to postoperative urodynamic evaluation at a median time after surgery of 18 and 37 months, respectively. Continence and urodynamic parameters were compared in both groups.

The average reservoir capacity of the SN (296 ml) was lower than the IN (546 ml). The majority of patients voided by the Valsalva maneuver and achieved good peak flow rates [SN group 16.6 (range 7-32) ml/s, IN group 25.5 (range 5-35) ml/s]. Of the patients with an SN 26 (76%) and with an IN 15 (75%) emptied to near completion with a post-void residual (PVR) of less than 100 ml. Daytime continence was achieved in 90% of IN patients and 85% of SN patients. Only 9% of patients with an SN and 60% of patients with an IN were continent at night.

A neobladder constructed from detubularized ileum or sigmoid achieves adequate capacity with a satisfactory daytime continence rate. Nighttime incontinence in patients with IN can be at least partly explained by periods of high pressure due to neobladder contractions in combination with a relaxed sphincter during sleep. The low nighttime continence rate of the SN is probably related to its small functional capacity.