New insights into the pathogenesis of penile shortening after radical prostatectomy and the role of postoperative sexual function

Purpose: We assessed penile changes after radical prostatectomy by performing serial penile measurements. The potential effect of nerve sparing surgery and the recovery of erectile function on the degree of penile shortening were also evaluated. Materials and Methods: A total of 126 consecutive patients were enrolled. Penile measurements were taken immediately before surgery, at catheter removal, and at 3, 6 and 12 months postoperatively. Sexual function was assessed at baseline and at 3, 6 and 12 months using the erectile function domain of the International Index of Erectile Function. Results: The maximum degree of shortening was noted at the time of catheter removal (mean 0.84 cm, CI 0.62-1.06, p < 0.0001 for stretched penis). All penile parameters showed a lesser but significant decrease at all subsequent intervals. Univariate analysis revealed that baseline penile length was the only variable significantly associated with stretched penile length at catheter removal. Age, nerve sparing surgery and the recovery of erectile function were strong predictors of penile size 1 year after surgery. Multivariate analysis showed that nerve sparing surgery (<0.0001) and the recovery,of erectile function (p = 0.053) were independent predictors of the final changes in penile size. Conclusions: Penile shortening after radical prostatectomy peaks at the time of catheter removal and it continues to a lesser but still significant degree for at least 1 year. Nerve sparing surgery and recovery of erectile function appeared to have an independent protective effect on penile length loss at 1 year. These figures should be taken in consideration when counseling patients for radical prostatectomy.