Perfusion sphincterometry for objective evaluation of postprostatectomy intrinsic sphincter deficiency

Objectives. Male urinary incontinence secondary to intrinsic sphincter deficiency (ISD) is a possible complication of transurethral resection of the prostate (TURP) or radical prostatectomy (RP). For objective assessment of urinary sphincteric competence, we used perfusion sphincterometry (PS) to measure the retrograde urethral perfusion pressure (RUPP). Methods. A retrospective and prospective analysis of 60 neurologically normal patients of varying continence status was performed. The subjects were divided into three groups: continent patients with no previous prostate surgery (group 1), continent patients after prostatectomy (group 2), and incontinent patients after prostatectomy (group 3). All patients underwent PS with the technique described. All incontinent patients (group 3) had a filling cystometrogram (CMG) to rule out detrusor instability. Results. Continent patients with no prior prostate surgery (group 1) had a mean RUPP of 101 ± 16 cm H₂O; continent postprostatectomy patients (group 2) had a mean RUPP of 77 ± 14 cm H₂O; and incontinent postprostatectomy patients (group 3) had a mean RUPP of 36 ± 11 cm H₂O. The differences were statistically significant (P <0.001). There was no statistically significant difference in RUPP when the patients in groups 2 and 3 were stratified into TURP and RP groups. Conclusions. PS is a simple and accurate technique for objective evaluation of lower sphincter competence. Patients with stress incontinence after prostatectomy have a statistically significant decrease in RUPP compared with continent controls. In combination with cystourethroscopy and filling CMG, PS can be useful in the evaluation of postprostatectomy incontinence.