Objective: To evaluate the relationship between recovery of urinary continence after laparoscopic radical prostatectomy (LRP) and preoperative/postoperative membranous urethral length (MUL) on magnetic resonance imaging.
Methods: We retrospectively analyzed 69 patients with pathologic confirmed prostate carcinoma who underwent laparoscopic radical prostatectomy. Preoperative MUL was defined as the distance from the apex of prostate to the level of the urethra at penile bulb on the coronal image. Postoperative MUL was defined as the distance from the bladder neck to the level of the urethra at the penile bulb on the coronal image. MUL-retained rate was defined as the percentage of postoperative MUL to preoperative MUL. All patients received extraperitoneal LRP. Patients reported freedom from using safety pad (0 pad/d) were defined as urinary continence. Multivariate Logistic 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 69 patients, the average age was (71.4±8.6) years. The prostate specific antigen before biopsy was (23.40±30.31) μg/L, and the mean preoperative prostatic volume by magnetic resonance imaging was (39.48±22.73) mL. The mean preoperative MUL was (13.0±3.3) mm, the mean postoperative MUL was (12.3±3.4) mm, and the mean MUL-retained rate was 93.9%±6.2%. The continence rate for all the patients after LRP was 57.9% and 97.1% in three months and one year, respectively. The patients achieving early continence recovery had significant smaller prostatic volume (P=0.028), longer preoperative MUL and postoperative MUL (P < 0.001). Multivariate Logistic regression analyses revealed postoperative MUL (P < 0.001) were predictors of continence recovery after LRP. Kaplan-Meier analyses and Log-rank test revealed that preoperative MUL (≥14 mm vs. < 14 mm, P < 0.001) and postoperative MUL (≥13 mm vs. < 13 mm, P < 0.001), MUL-retained rate (< 94% vs. ≥94%, P < 0.001) were all significantly associated with continence recovery.
Conclusion: Post-operative MUL was independently predictors of early continence recovery after LRP. Preoperative MUL, postoperative MUL and MUL retained rate were significantly associated with recovery of urinary continence.
目的: 探讨术前及术后膜性尿道长度(membranous urethral length，MUL)与腹腔镜根治性前列腺切除术(laparoscopic radical prostatectomy，LRP)后控尿功能恢复的相关性。
方法: 回顾性分析经组织病理学诊断为前列腺腺癌并于北京大学第三医院行LRP的患者69例，患者均于LRP术前及术后行磁共振检查。术前MUL定义为前列腺尖部尿道至阴茎球部尿道之间的距离，术后MUL定义为膀胱颈口至阴茎球部尿道之间的距离，MUL留存比定义为术后MUL占术前MUL的百分比。所有患者均行腹膜外LRP，自术后第1个月起每月对患者的控尿功能恢复情况进行随访，以全天不需要使用尿垫为控尿功能恢复标准。应用Logistic多因素回归分析影响术后3个月控尿功能恢复的危险因素，Kaplan-Meier法绘制LRP术后患者控尿功能恢复曲线，Log-rank检验比较各组间术后控尿功能恢复曲线的统计学意义。
结果: 69例患者平均年龄(71.4±8.6)岁；穿刺前平均前列腺特异抗原(23.40±30.31) μg/L；术前磁共振测量前列腺体积(prostatic volume，PV)为12.20~128.48 mL，平均(39.48±22.73) mL；术前MUL为5~22 mm，平均(13.0±3.3) mm；术后MUL为4~22 mm，平均(12.3±3.4) mm；MUL留存比为80%~100%，平均93.9%±6.2%。LRP术后3个月和12个月69例患者控尿率分别为57.9%(40/69)和97.1%(67/69)。单因素分析表明，PV(P=0.028)、术前MUL(P＜0.001)和术后MUL(P＜0.001)是LRP术后3个月尿失禁的影响因素；多因素分析显示，术后MUL＜13 mm是LRP术后3个月尿失禁发生的独立危险因素(P＜0.001)。Log-rank检验提示，术前MUL≥14 mm、术后MUL≥13 mm和MUL留存比≥94%的患者术后控尿功能恢复分别优于术前MUL＜14 mm、术后MUL＜13 mm和MUL留存比＜94%的患者，差异具有统计学意义(P=0.001)。
结论: 术前MUL、术后MUL和MUL留存比与LRP术后控尿功能恢复存在相关性，术后MUL较短是术后3个月尿失禁发生的独立危险因素。
Keywords: Laparoscopy; Magnetic resonance imaging; Membranous urethral length; Prostatectomy; Urinary incontinence.