Penile rehabilitation is a term most often used to describe treatment men may receive after having surgery on their prostate to treat prostate cancer. These surgeries often lead to erectile dysfunction, and penile rehabilitation involves a variety of treatments designed to allow a man to have erectile functioning to facilitate the sex life he would like. Broadly speaking penile rehabilitation simply refers to an organized way of resolving penile and erectile difficulties after some sort of trauma to the penis has occurred.
Penile rehabilitation focuses on protecting nerves, blood supply, and the integrity of smooth muscle, all of which plays a role in erectile functioning. It may include the use of prescription drugs and well as physical rehabilitation of the penis. Researchers continue to explore new options (including electric stimulation), but their effectiveness in humans hasn't been established.
While penile rehabilitation is common, and there has been research on its effectiveness, most researchers agree that the bulk of the research has suffered from methodological problems, and the actual effectiveness of one technique over another is up for debate. There is now an attempt to establish research protocols that will allow us to compare different forms of penile rehabilitation across studies.
Garcia, F.J. & Brock, G. "Current State of Penile Rehabilitation After Radical Prostatectomy" Current Opinion in Urology Vol. 20, No. 3. (2010): 234-240.