Experimental data support the concept of cavernosal damage and suggest a protective role for daily dosage of a PDE5-I ; however , similar data have not yet been replicated in humans .
Penile rehabilitation programs are common in clinical practice , but there is no definitive evidence to support their use or the best treatment strategy .
PDE5-Is are efficacious and safe in young patients with normal preoperative erectile function who have undergone bilateral nerve-sparing radical prostatectomy .
On-dem and use of a PDE5-I may be at least as efficacious as daily use .
PDE5-I use in penile rehabilitation programs is not supported by rigorous level 1 evidence -based medicine .
PDE5-Is are an efficacious and safe treatment for post-RP ED in properly selected patients .
The experimental results on the protective role of daily dosages of PDE5-Is , while robust , have not been replicated in humans .
CONTEXT  Erectile dysfunction ( ED ) after radical prostatectomy ( RP ) has a significant negative impact on a patient 's health-related quality of life .
Phosphodiesterase type 5 inhibitors ( PDE5-Is ) have recently been utilized not only as a treatment of ED in this population but also as a preventive strategy in penile rehabilitation programs .
OBJECTIVE To eluci date the pathophysiologic mechanisms of post-RP ED , to assess the need for rehabilitation following surgery , and to analyze the basic scientific evidence and clinical applications of PDE5-Is for the prevention and treatment of ED .
EVIDENCE SYNTHESIS Post-RP ED has many factors .
Cavernosal nerve injury induces pro-apoptotic factors ( ie , loss of smooth muscle ) and pro-fibrotic factors ( ie , an increase in collagen ) within the corpora cavernosa .
Preserved postoperative penile size correlates well with maintained erectile function after bilateral nerve-sparing radical retropubic prostatectomy.
OBJECTIVES Controversial data on penile length after  radical retropubic prostatectomy  are available . We hypothesised that postoperative penile size correlates to erectile function following bilateral nerve-sparing radical retropubic prostatectomy  ( BNSRRP ) . METHODS Thirty-three consecutive patients with a preoperative erectile function domain of the International Index of Erectile Function ( IIEF-EF ) score indicating full potency ( > or = 26 ) were prospect ively enrolled . All patients underwent BNSRRP performed by one high-volume surgeon . All patients were preoperatively evaluated by IIEF-EF ,  analysis of comorbidities , physical examination  , and  penile power colour Doppler ultrasound using intracavernosal injection of prostagl and in E(1 ) ( PGE(1 ) ) 20 microg plus audiovisual and manual genital stimulation .  Penile length and circumference were measured in flaccidity and at maximum erection . Six months postoperative , patients were assessed with the same protocol plus general assessment questions investigating penile structure and function . Statistical analysis was performed with an independent sample t test . RESULTS Mean patient age was 56.5 yr . We found no difference between the preoperative and the 6-mo postoperative mean IIEF-EF domain score ( 27.2 vs , 26.7 , respectively ; p = 0.35 ) . No difference was found in penile colour Doppler evaluation between the preoperative and postoperative periods ( all p values > or = 0.3 ) . We found no differences in penile length and circumference between the preoperative and postoperative evaluation either in the flaccid or in the erect state . Mean flaccid penile length ( cm ; preop vs. postop ) : 13.2 vs. 13 ( p = 0.6 ) . Mean flaccid penile circumference ( cm ; preop vs. postop ) : 11.1 vs. 11 ( p = 0.7 ) . Mean erect penile length ( cm ; preop vs. postop ) : 16.8 vs. 16.5 ( p = 0.08 ) . Mean erect penile circumference ( cm ; preop vs. postop ) : 15.6 vs. 15.3 ( p = 0.2 ) . CONCLUSIONS This is the first report on penile changes in flaccidity and at maximum erection after BNSRRP in patients treated by one high-volume surgeon . The postoperative preservation of erectile function positively correlated with the maintenance of penile length following surgery . We found no change in penile size after surgery
Experimental data support the concept of cavernosal damage and suggest a protective role for daily dosage of a PDE5-I ; however , similar data have not yet been replicated in humans .
Penile rehabilitation programs are common in clinical practice , but there is no definitive evidence to support their use or the best treatment strategy .
PDE5-Is are efficacious and safe in young patients with normal preoperative erectile function who have undergone bilateral nerve-sparing radical prostatectomy .
On-dem and use of a PDE5-I may be at least as efficacious as daily use .
PDE5-I use in penile rehabilitation programs is not supported by rigorous level 1 evidence -based medicine .
PDE5-Is are an efficacious and safe treatment for post-RP ED in properly selected patients .
The experimental results on the protective role of daily dosages of PDE5-Is , while robust , have not been replicated in humans .
CONTEXT  Erectile dysfunction ( ED ) after radical prostatectomy ( RP ) has a significant negative impact on a patient 's health-related quality of life .
Phosphodiesterase type 5 inhibitors ( PDE5-Is ) have recently been utilized not only as a treatment of ED in this population but also as a preventive strategy in penile rehabilitation programs .
OBJECTIVE To eluci date the pathophysiologic mechanisms of post-RP ED , to assess the need for rehabilitation following surgery , and to analyze the basic scientific evidence and clinical applications of PDE5-Is for the prevention and treatment of ED .
EVIDENCE SYNTHESIS Post-RP ED has many factors .
Cavernosal nerve injury induces pro-apoptotic factors ( ie , loss of smooth muscle ) and pro-fibrotic factors ( ie , an increase in collagen ) within the corpora cavernosa .