Post prostatectomy ED is multi-factorial – due to damage to nerves, arteries, and subsequent failure of veno-occlusive mechanism.
- Cavernous nerves injured during procedure – either resected, or in nerve sparing procedures neuropraxia due to retraction and thermal injury
- Accessory pudendal arteries and arterioles of neurovascular bundle may be damaged or resected
- Cavernosal hypoxia from loss of erections immediately post-operatively leads to corporal smooth muscle apoptosis and fibrosis -> loss of veno occlusive mechanism
Incidence is hard to define. Contemporary series report post prostatectomy erectile dysfunction at 60 – 70 %, but definitions vary (self-reported, IIEF scores, need for medical therapies, percentage with good erections prior, etc.)
Erections may take 6 – 24 months to recover after nerve sparing procedures.
Risk factors
Penile rehabilitation
The goal of penile rehab is to proactively use strategies after surgery to increase the chance of erectile function returning to baseline pre-operative state.
It aims to achieve this by promoting blood flow and preventing hypoxia to the cavernosa in the period after surgery where neuropraxia may be recovering, and therefore prevent or reduce the development of cavernosal smooth muscle fibrosis.
2 large randomised trials had conflicting evidence.
- One showed nightly sildenafil (50 or 100 mg) had an improvement in recovery of spontaneous erections (27 vs 4 %)
- One showed no difference in recovery between on demand or nightly dosing of vardenafil
Cochrane review 2018 – low quality of evidence, but scheduled PDE5i use may not promote erectile function any more than on-demand use.
Animal studies show prevention of corporal fibrosis with PDE5i.
The utility of PDE5 inhibitors in patients with non nerve sparing procedures may be low.
Second line therapies with ICI and VEDs are useful in those who don’t respond to PDE5i.
- Early implementation of VEDs may preserve penile length – but there are questions are long term use due to theoretically potentiating cavernosal fibrosis from ischaemia and acidosis.
There is no consensus on ideal rehabilitation strategy in a well informed patient who wishes to pursue it. 25 mg daily sildenafil or 5 mg daily tadalafil, plus on-demand dosing of full dose tablets seems pragmatic.
Non responders to tablets should probably change to injections reasonably early to try and prevent loss of length and fibrosis.
ICI may then lead to better outcomes compared with PDE5i alone.
Don’t neglect psychological impact – bundle with therapists, online bundles etc.
Other sexual dysfunction following radical prostatectomy
- Anejaculation
- Climacturia
- Loss of penile length
- Increased risk of Peyronie’s and curvature
- Psychosexual impairment, changes in libido and mental health