Recovery of urinary continence after radical prostatectomy: association with urethral length and urethral fibrosis measured by preoperative and postoperative endorectal magnetic resonance imaging

Abstract

Background: Limited data on endorectal magnetic resonance imaging (MRI) features and urinary continence after radical prostatectomy (RP) are available.

Objective: To assess whether recovery of urinary continence after RP is associated with endorectal MRI findings regarding preoperative and postoperative membranous urethral length (MUL), percent change in MUL, and postoperative urethral and periurethral fibrosis.

Design, setting, and participants: Sixty-four patients who received an MRI scan before and after RP for localized prostate cancer were evaluated in a retrospective study at a single institution.

Intervention: All patients underwent RP.

Measurements: The postoperative scan was performed to detect local recurrence in patients with rising levels of prostate-specific antigen. Urinary continence was graded on a five-point scale. MUL was measured on T2-weighted images. Urethral and periurethral fibrosis was graded from 0 to III based on axial T2-weighted images. Univariate Cox proportional hazards regression was performed to assess variables associated with continence.

Results and limitations: Forty-eight patients regained continence following surgery. The median follow-up for patient who were incontinent at their last assessment was 7 mo. The median interval from RP to postoperative endorectal MRI was 10 mo. A longer preoperative or postoperative MUL was associated with superior continence (both p<0.01). The MUL loss ratio was significantly associated with postoperative continence (p=0.02). Patients with a high grade of postoperative periurethral fibrosis tended to have worse postoperative continence; nevertheless a statistical correlation was not reached (hazard ratio: 0.64, p=0.16). This is a retrospective study.

Conclusions: Preoperative and postoperative MUL and the MUL loss ratio are related to the recovery time and level of urinary continence after RP. Therefore, preservation of urethral length during surgery is recommended. Periurethral fibrosis might impede the recovery of continence after RP by altering the elasticity of the external sphincter.