[Relationship between prostate apex depth and early recovery of urinary continence after laparoscopic radical prostatectomy].

OBJECTIVE: To evaluate the relationship between recovery of urinary continence after laparoscopic radical prostatectomy (LRP) and preoperative prostate apex depth (PAD) on magnetic resonance imaging (MRI). METHODS: We retrospectively analyzed 184 patients with pathologic confirmed prostate carcinoma who underwent LRP in Department of Urology, Peking University Third Hospital. All the patients received MRI examination before surgery. Membranous urethral length (MUL) was defined as the distance from the apex of prostate to the level of the urethra at penile bulb on the coronal image. PAD was defined as the distance from the apex of prostate to the suprapubic ridge line on sagittal MRI. PAD ratio (PADR) was defined as PAD/pubic height. All the patients received extraperitoneal LRP. The patients' reporting freedom from using safety pad (0 pad/d) were defined as urinary continence. Univariate and multivariate regression analyses were used to identify independent predictors of early continence recovery after LRP. Kaplan-Meier analyses and log-rank test were used to compare time to continence recovery between the groups. RESULTS: For all the 184 patients, the average age was (69.0±7.7) years, the ave-rage mass index(BMI) was (25.07±3.29) kg/m2, and the pre-biopsy PSA was (16.80±21.99) g/L. For all the patients who underwent MRI preoperatively, the mean PV was (39.35±25.25) mL and the mean MUL was (14.0±3.7) mm. The mean PAD was (24.52±4.97) mm and the mean PADR was 0.70±0.14. The continence rate for all the patients after LRP was 62.0% and 96.2% in three months and one year. The patients achieving early continence recovery had significant smaller PV (P=0.049), longer MUL (P < 0.001) and higher PADR (P=0.005). Multivariate analysis revealed MUL (P < 0.001) and PADR (P=0.032) were predictors of continence recovery after LRP. Kaplan-Meier analyses and Log-rank test revealed that MUL (≥14 mm vs. < 14 mm, P < 0.001) and PADR (≥0.70 vs. < 0.70, P < 0.001), PV(< 50 mL vs. ≥50 mL, P=0.001) were all significantly associated with continence recovery. CONCLUSION: MUL and PADR are independent predictors of early continence recovery after LRP. MUL, PADR and PV are significantly associated with recovery of urinary continence.