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 .
A prospective study measuring penile length in men treated with radical prostatectomy for prostate cancer.
PURPOSE Some patients report that the penis is smaller after radical retropubic prostatectomy for prostate cancer . We performed a prospect i ve study which measured penile length before and after radical retropubic prostatectomy . MATERIAL S AND METHODS A total of 124 men consented to penile measurements before radical prostatectomy performed by the same surgeon . Repeat measurements were performed at 3-month intervals following surgery . Penile measurements ( cm . ) consisted of flaccid length , stretched length , depth of prepubic fat pad and circumference . Statistical analysis of penile measurements was performed using the paired sample s and independent Student 's t test , Pearson 's correlation and analysis of variance . RESULTS Mean patient age was 59.1 ( range 42 to 76 ) . No patient had a penile abnormality , for example Peyronie 's disease , or history of penile or urethral surgery . The size of the penis was significantly smaller after prostatectomy , and there was a significant difference for flaccid ( p < 0.001 ) , stretched ( p < 0.001 ) , prepubic fat pad ( p = 0.02 ) and circumference measurements ( p < 0.01 ) . Twelve patients ( 19 % ) had a 15 % or greater decrease in stretched penile length . When dichotomizing groups at the cut point of 15 % decrease , the independent t test of prostate size was not significant ( t[df 36.7 ] = -1.83 , p = 0.076 ) . Nerve sparing was not significant in relation to change in penile stretched length , ( F[df 2 , 62 ] = 0.501 , p = 0.609 ) . CONCLUSIONS Our findings support observations of decreased penile length after radical prostatectomy . Men should be counseled before radical prostatectomy that penile shortening may occur
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 .