Erectile Dysfunction After Nerve-Sparing Prostatectomy in a Diabetic
A 58-year-old man with type 2 diabetes (10 years, HbA1c 7.8%, on metformin and gliclazide) undergoes robot-assisted radical prostatectomy with bilateral nerve sparing for Gleason 3+4 disease. Preoperatively his IIEF-5 was 18 (mild ED) and he had morning erections. Three months postop his IIEF-5 is 5 and he reports no spontaneous erections. He is on tamsulosin 0.4 mg and amlodipine 10 mg. His PSA is undetectable. He asks about 'the blue pill' and whether he will ever have normal erections again.
1. How do you counsel him on the expected natural history of erectile function after nerve-sparing prostatectomy, and what factors modify recovery in his case?
Read the worked answer
Natural history: After bilateral nerve-sparing RARP, potency recovery is a gradual process over 12–24 months; many men have no spontaneous erections at 3 months. Recovery rates of 'adequate for intercourse' erections are roughly 60–80% at 2 years with bilateral nerve sparing in preoperatively potent men, but substantially lower in diabetics and older men.
Modifiers in this patient:
- Diabetes (10 years, HbA1c 7.8%) - endothelial and cavernosal nerve dysfunction; preop IIEF-5 of 18 already indicates mild ED, so his baseline reserve is reduced. This is the dominant negative modifier.
- Age 58 - favorable relative to older men.
- Bilateral nerve sparing - favorable.
- Medications: tamsulosin is not a major contributor; amlodipine can cause mild ED but is unlikely the main driver.
- Time: 3 months is early; do not declare failure.
Counseling points:
- Set realistic expectations: full recovery is possible but not guaranteed; the diabetic subgroup has lower rates.
- Emphasize that penile rehabilitation (regular oxygenation of cavernosal tissue) may improve outcomes, though evidence for hard endpoints is modest.
- Address cardiovascular risk: ED is a marker of endothelial dysfunction; optimize HbA1c, lipids, BP, and smoking.
- Screen for depression and relationship factors.
Do not promise return of 'normal' erections; frame it as maximizing function.
2. He wants to start 'the blue pill.' What is your first-line pharmacologic approach, and how do you sequence therapy if PDE5 inhibitors fail?
Read the worked answer
First-line: PDE5 inhibitor.
- Start with sildenafil 50 mg taken 30–60 min before sex, or tadalafil 10 mg daily or 20 mg on demand. Daily tadalafil has the advantage of spontaneity and is often preferred post-prostatectomy.
- Counsel on technique: needs sexual stimulation; avoid high-fat meals with sildenafil; onset 30–60 min.
- Contraindications: concurrent nitrates (absolute), recent stroke/MI, severe hypotension. Check BP; his amlodipine is fine.
- Titrate to maximum tolerated dose (sildenafil 100 mg, tadalafil 20 mg) before declaring failure; at least 4–6 attempts.
If PDE5i fail - stepwise escalation:
- Optimize PDE5i dose and timing; consider daily dosing for rehabilitation.
- Vacuum erection device - non-invasive, effective, especially useful for rehabilitation and as a bridge.
- Intracavernosal injection (alprostadil, or trimix of papaverine/phentolamine/alprostadil) - highly effective; counsel on priapism risk and technique.
- Intraurethral alprostadil - less effective but an option for needle-averse patients.
- Penile prosthesis - definitive surgical option for refractory cases; best satisfaction rates but irreversible.
Rehabilitation concept: Some evidence supports early regular PDE5i or vacuum therapy to prevent cavernosal fibrosis, though hard-outcome data are limited. Discuss as a reasonable strategy rather than proven standard.
Key trap: Do not declare PDE5i failure at 3 months with one attempt at 50 mg - dose and technique optimization matter.
3. He asks whether testosterone would help. How do you evaluate and counsel him regarding testosterone therapy in this setting?
Read the worked answer
Evaluation before considering testosterone:
- Confirm hypogonadism biochemically: Total testosterone drawn in the morning (before 10 am) on two separate occasions, plus SHBG or free testosterone if borderline. Symptoms alone are insufficient.
- In this patient: His preop IIEF-5 of 18 and morning erections suggest his testosterone was likely adequate; postop ED is primarily neurovascular, not hormonal. Testosterone is unlikely to be the main lever.
Counseling on testosterone therapy (TTh):
- Benefit: Modest improvement in libido and possibly erectile function in men with confirmed hypogonadism; little benefit in eugonadal men.
- Risks: Erythrocytosis (monitor hematocrit; hold if >54%), acne, gynecomastia, possible worsening of sleep apnea, and suppression of spermatogenesis (irrelevant here if not fertility-desiring, but discuss).
- Prostate cancer concern: In a man with treated prostate cancer, TTh is not absolutely contraindicated but requires caution and shared decision-making; discuss with oncology. Current evidence does not show increased recurrence in appropriately selected men, but data are limited.
- Cardiovascular: Controversial; avoid in men with recent cardiovascular events.
Practical approach:
- Check morning testosterone. If low on two occasions and symptomatic (low libido, fatigue), consider a trial of TTh with 3-month reassessment.
- Do not use testosterone as a substitute for PDE5i in a man with post-prostatectomy ED and normal testosterone.
- Key trap: Do not start testosterone empirically for post-prostatectomy ED without confirming hypogonadism; and do not ignore the prostate cancer history.