Preservation of the smooth muscular internal (vesical) sphincter and of the proximal urethra during retropubic radical prostatectomy: description of the technique.

We describe our technique for preservation of the smooth muscular internal (vesical) sphincter and proximal urethra during radical retropubic prostatectomy. The first steps of the prostatectomy reflect the standard retropubic prostatectomy; whereas for the final phases, the procedure continues in an anterograde manner with incision of the fibers of the detrusor muscle at the insertion of the ventral surface of the base of the prostate. At this level, the inner circular muscle of the bladder neck forms a sphincteric ring of smooth muscle that covers the longitudinally-oriented smooth muscle component of the urethra that extends distally to the verumontanum; these two proximal structures represent the internal sphincter that envelops and locks the proximal urethra. A blunt dissection is continued until the ring-shaped vesical sphincter is separated from the prostate and the longitudinally-oriented smooth muscle component of the urethral musculature is identified. The base of the prostate is then gently separated from the urethra and from the bladder until the maximal length of the urethral musculature is isolated and preserved. Finally, a urethra-urethral anastomosis is carried out and the ventral stitches are placed through the circular fibres of the bladder neck. In all cases we carry out circumferential biopsies of the proximal urethra and of the base of the prostate. The described technique is a feasible and safe method for preservation of the internal urethral sphincter. Despite the enthusiasm regarding our positive functional results, further studies with larger series are required to confirm these findings.