Re: Is It Just Enough to Keep Long Membranous Urethra for Providing Early Continence After Robot-Assisted Laparoscopic Radical Prostatectomy?

Dear Editor:

We read the article by Haga and colleagues with great interest. ¹ The early continence is recently a hot topic, specifically at the time of catheter removal in follow-up after robot-assisted laparoscopic radical prostatectomy (RARP). The article is interesting and contributes science with distinctive statistical findings. According to the study, if the postoperative membranous urethral length (MUL) was longer than 17 mm, early continence could be provided according to multivariate analyses.

Hakimi and colleagues reported importance of stretched and long urethra for continence after RARP. ² Furthermore, Rocco and colleagues concluded the benefits of posterior reconstructions in bladder neck. ³ Srougi and colleagues disagreed with benefits of preserving bladder neck after open radical prostatectomy. ⁴ Haga and colleagues pointed out that early acquisition of urinary continence had not been adequately revealed from the perspective of urethral and vesical anatomical features after RARP. In view of these conflicting data, we evaluated important parts of continence after RARP at a glance.

Recently, surgical techniques and anatomic details of male pelvis have been reinvestigated for continence after RARP. Magnified vision is one of the well-known benefits of laparoscopic and robot-assisted laparoscopic surgery. Thus, anatomical details can be better identified. Moreover, robot-assisted laparoscopic surgery has more advantages than the laparoscopic one with 360°-rotating wrested-end effector instruments. Besides, classical anatomic details are repeated as preprostatic urethra includes muscle fibers of external urinary sphincter. ⁵ The preserved neurovascular bundle could contribute continence by stimulating muscle fibers. A long membranous urethra includes much more muscle fibers of external urethral sphincter. If the surgeon can ensure urethral stump long during RARP, this may contribute continence after RARP. In contrast, most of the positive surgical margin (PSM) belongs to apex of prostate and every patient has his unique anatomical shape of apex. Sometimes apex of prostate may extend forward on urethra. Surgeons should be careful during apical dissection of prostate in terms of not leaving PSM, providing long urethra, and preserving neurovascular bundle. Haga and colleagues concluded that the postoperative MUL was the most important factor for recovery of urinary continence in the early postoperative period after RARP. ¹ We disagree with them. In a previous study, we showed effects of preserving bladder neck in terms of keeping internal sphincter for urinary continence after RARP. ⁶ We also described very early continence after RARP, at time of catheter removal. In brief, the fatty connective tissue between bladder neck and prostate was introduced, and circular muscle fibers of internal sphincter were seen and preserved, in all patients. ⁶ In addition, we agree with Haga and colleagues ¹ that long urethral stump was also necessary for continence after RARP. However, it should be with preserved bladder neck (internal sphincter) for very early continence. ⁶

Finally, surgeons who perform RARP should consider anatomic details of male pelvis. The main factors of continence are to preserve bladder neck (internal sphincter) and to provide long membranous urethra, after RARP. Thus, very early continence can be provided at the time of catheter removal, after RARP.