Sildenafil preserves intracorporeal smooth muscle after radical retropubic prostatectomy

Early use of vasoactive agents has been shown to rehabilitate erectile function after nerve sparing radical retropubic prostatectomy (RRP). The loss of intracorporeal smooth muscle (SM) and an increase in intracorporeal fibrosis have been demonstrated in vasculogenic impotence and implicated in permanent post-RRP erectile dysfunction. We assessed the effect of sildenafil on SM content after RRP.

A total of 40 potent volunteers with prostate cancer underwent RRP and were divided into 2 treatment groups, namely 1-50 mg sildenafil and 2-100 mg sildenafil every other night for 6 months beginning the day of catheter removal. Percutaneous biopsy was performed using general anesthesia prior to incision for RRP. Another biopsy was performed using local anesthesia 6 months later. Volunteers were excluded prior to the second biopsy if they discontinued sildenafil. Biopsies were stained for SM and connective tissue, and analyzed by computer in at least 15 different fields. The paired Student t test was used for statistical analysis.

A total of 11 patients in group 1 and 10 in group 2 underwent the second biopsy. In group 1 there was no statistically significant change in mean SM content preoperatively to postoperatively (51.52% and 52.67%, respectively). In group 2 there was a statistically significant increase in mean SM content 6 months after RRP (42.82% vs 56.85%, p <0.05).

Early use of sildenafil after RRP may preserve intracorporeal SM content. At higher doses post-RRP sildenafil may increase SM content. The effect on the return of potency is not known but maintaining the pro-erectile ultrastructure is integral to rehabilitating post-RRP erectile function.