Mechanism of continence after repair of posterior urethral disruption: evidence of rhabdosphincter activity.
Controversy exists regarding continence mechanisms in patients who undergo posterior urethral reconstruction after pelvic fracture. Some evidence suggests that continence after posterior urethroplasty is maintained by the bladder neck or proximal urethral mechanism without a functioning distal mechanism. We studied distal urethral sphincter activity in patients who have undergone posterior urethroplasty for pelvic fracture. A total of 12 patients who had undergone surgical repair of urethral disruption involving the prostatomembranous region underwent videourodynamics with urethral pressure profiles at rest, and during stress and hold maneuvers. Bladder pressure and urethral pressure, including proximal and distal urethral sphincter activity and pressure, were assessed in each patient. All 12 patients had daytime continence of urine postoperatively with a followup after anastomotic urethroplasty of 12 to 242 months (mean 76). Average maximum urethral pressure was 71 cm H2O. Average maximum urethral closure pressure was 61 cm H2O. The average urethral pressure seen during a brief hold maneuver was 111 cm H2O. Average functional sphincteric length was 2.5 cm. Six of the 12 patients had clear evidence of distal urethral sphincter function, as demonstrated by the profile. Continence after anastomotic urethroplasty for posttraumatic urethral strictures is maintained primarily by the proximal bladder neck. However, there is a significant contribution of the rhabdosphincter in many patients.