Preoperative Membranous Urethral Length Measurement and Continence Recovery Following Radical Prostatectomy: A Systematic Review and Meta-analysis

Abstract

Context: Membranous urethral length (MUL) measured prior to radical prostatectomy (RP) has been identified as a factor that is associated with the recovery of continence following surgery.

Objective: To undertake a systematic review and meta-analysis of all studies reporting the effect of MUL on the recovery of continence following RP.

Evidence acquisition: A comprehensive search of PubMed, EMBASE, and Scopus databases up to September 2015 was performed. Thirteen studies comprising one randomized controlled trial and 12 cohort studies were selected for inclusion.

Evidence synthesis: Four studies (1738 patients) that reported hazard ratio results. Every extra millimeter (mm) of MUL was associated with a faster return to continence (hazard ratio: 1.05; 95% confidence interval [CI]: 1.02-1.08, p<0.001). Eleven studies (6993 patients) reported the OR (OR) for the return to continence at one or more postoperative time points. MUL had a significant positive effect on continence recovery at 3 mo (OR: 1.08, 95% CI: 1.03-1.14, p=0.004), 6 mo (OR: 1.12, 95% CI: 1.09-1.15, p<0.0001). and 12 mo (OR: 1.12, 95% CI: 1.03-1.22, p=0.006) following surgery. After adjusting for repeated measurements over time and studies with overlapping data, all OR data combined indicated that every extra millimeter of MUL was associated with significantly greater odds for return to continence (OR: 1.09, 95% CI: 1.05-1.15, p<0.001).

Conclusions: A greater preoperative MUL is significantly and positively associated with a return to continence in men following RP. Magnetic resonance imaging measurement of MUL is recommended prior to RP.

Patient summary: We examined the effect that the length of a section of the urethra (called the membranous urethra) had on the recovery of continence after radical prostatectomy surgery. Our results indicate that measuring the length of the membranous urethra via magnetic resonance imaging before surgery may be useful to predict a longer period of urinary incontinence after surgery, or to explain a delay in achieving continence after surgery.

Keywords: Magnetic resonance imaging; Membranous urethra; Membranous urethral length; Meta-analysis; Prostate cancer; Systematic review; Urinary incontinence.

Fig. 1

T2-weighted (A) sagittal and (B) coronal magnetic resonance images^a for the measurement of membranous urethral length (MUL). ^aThe image was not taken from the studies included in this systematic review and meta-analysis.

Fig. 1

T2-weighted (A) sagittal and (B) coronal magnetic resonance images^a for the measurement of membranous urethral length (MUL). ^aThe image was not taken from the studies included in this systematic review and meta-analysis.

Fig. 2

Preferred Reporting Items for Systematic Reviews and Meta-analyses flow diagram presenting the outcome of the searches and selection of studies included in this review. MRI = magnetic resonance imaging; MUL = membranous urethral length.

Fig. 3

Forest plot of the risk of return to continence. CI = confidence interval; HR = hazards ratio; MUL = membranous urethral length; SD = standard deviation.

Fig. 4

Forest plot of the odds of return to continence at 3 mo. CI = confidence interval; OR = odds ratio; MUL = membranous urethral length; SD = standard deviation.

Fig. 5

Forest plot of the odds of return to continence at 6 mo. CI = confidence interval; OR = odds ratio; MUL = membranous urethral length; SD = standard deviation.

Fig. 6

Forest plot of the odds of return to continence at 12 mo. CI = confidence interval; OR = odds ratio; MUL = membranous urethral length; SD = standard deviation.