The downside to these prostheses includes the standard risks of surgery, the very low risk of infection — less than 2 percent in most patients, slightly higher in diabetics — and a slight drop in penis length versus a natural erection or other ED treatments. Also, unlike with other methods, any hope for a natural erection is abolished once a pump is implanted. The cost for surgical options varies, and insurance coverage is typically good.
Penile injection therapy, intracavernous injection, involves the injection of a vasodilator (a chemical that relaxes arteries to increase blood flow) into the penis. Penile injected therapy is recognized as the most effective nonsurgical treatment for erectile dysfunction. However, due to the invasive nature, it is often used in men who have failed or have contraindications to other treatments such as oral therapies.
Patients with both ED and cardiovascular disease who receive treatment with an oral PDE5 inhibitor require education regarding what to do if anginal episodes develop while the drug is in their system. Such education includes stressing the importance of alerting emergency care providers to the presence of the drug so that nitrate treatment is avoided.
The bad news: Men with diabetes are three times more likely to report having problems with sex than non-diabetic men. The most common sexual problem is Erectile Dysfunction, or ED, sometimes called impotence. Even worse, because ED is such a private issue, many men feel embarrassed to discuss the problem with their doctor, or even their partner, so the problem is never addressed.
The availability of phosphodiesterase-5 (PDE5) inhibitors—sildenafil, vardenafil, tadalafil, and avanafil—has fundamentally altered the medical management of ED. In addition, direct-to-consumer marketing of these agents over the last 15 years has increased the general public’s awareness of ED as a medical condition with underlying causes and effective treatments.
Implantable penile prostheses are usually considered a last resort for treating impotence. They are implanted in the corpora cavernosa to make the penis rigid without the need for blood flow. The semirigid type of prosthesis consists of a pair of flexible silicone rods that can be bent up or down. This type of device has a low failure rate but, unfortunately, it causes the penis to always be erect, which can be difficult to conceal under clothing.
One study by Palmer and colleagues evaluated sildenafil use in SB males with thoracic lesions (76). A prospective, blinded, randomized, placebo-controlled, dose-escalation, crossover study in 17 patients with SB and ED was performed. All study participates took sets of tablet in groups, two sets of placebo, one of 25 mg, and the last 50 mg. Overall response to the tablet sets was measured by IIEF response and self-report of erectile rigidity. Patients reported that taking 50 mg of sildenafil led to improved erections, duration of erections, frequency of erections and level of confidence compared to sildenafil 25 mg and more significantly compared to placebo. Of the five patients who reported side effects, two experienced mild hematological changes that reverted to baseline after study completion.
In comparison, 37% of men who had received external radiotherapy as their primary therapy reported the ability to attain functional erections suitable for intercourse, along with 43% of men who had received brachytherapy as primary treatment. Pretreatment sexual health-related quality of life score, age, serum prostate-specific antigen (PSA) level, race or ethnicity, body mass index, and intended treatment details were associated with functional erections 2 years after treatment. 
Alprostadil (also known as prostaglandin E1 [PGE1]) is the prominent known smooth-muscle dilator of the corpus cavernosum. Its mechanism of action is believed to be the promotion of intracellular accumulation of cyclic adenosine monophosphate, thereby causing decreased intracellular accumulation of calcium and resulting smooth muscle relaxation. Alprostadil can be delivered to the erectile tissue either via an intraurethral suppository that is massaged and then absorbed across the corpus spongiosum of the urethra to the corpora cavernosa, or directly injected into the corpora cavernosa. When administered urethrally, doses are substantially higher than when directly injected (typical dosing is 500 mcg to 1 mg intraurethral compared with 2.5 mcg to 20 mcg intracavernosal).