The low pressure urethra as a factor in failed retropubic urethropexy.

Eighty-six patients with preoperative and postoperative urodynamic studies who underwent modified Burch colposuspensions were divided into two groups, one with a urethral closure pressure of 20 cm H2O or lower, and one with a pressure over 20 cm H2O. The two groups were comparable except for a difference in age (53.3 versus 46.6 years; P less than .01). There were significant differences between the two groups in both preoperative and postoperative functional lengths and closure pressures (P less than .01). The low-urethral-pressure group had a 54% failure rate, compared with 18% in the group with urethral closure pressures above 20 cm H2O (P less than .0005). Low urethral pressure was found to be a significant independent risk factor for patients under the age of 50, but not independent of age in women over 50 years old. Patients under the age of 50 who have urethral closure pressures of 20 cm H2O or lower are at high risk of surgical failure when undergoing a modified Burch colposuspension (P less than .0002). These patients should not be considered appropriate candidates for this procedure.