ERECTILE DYSFUNCTION or IMPOTENCE POST-RADICAL PROSTATECTOMY   

Impotence is simply described as the inability to achieve or maintain an erection suitable for sexual intercourse.

Impotence affects 20 million American men or about 10% of the entire male population and 35% of the men over the age of 60. An erection is created when the penis fills with blood much like a tire fills with air. Blood is pumped into the penis and not allowed out, and the more blood that is pumped in, the firmer the erection. The reasons for lack of erections are either the lack of appropriate filling of the penis or inappropriate emptying.

How Does an Erection Occur?
The penis contains two chambers, called the corpora cavernosa, which run the length of the organ.

A spongy tissue fills the chambers of the corpora cavernosa. The corpora cavernosa are surrounded by a membrane, called the tunica albuginea. The spongy tissue contains smooth muscles, fibrous tissues, spaces, veins, and arteries. The urethra, which is the channel for urine and ejaculate, runs along the underside of the corpora cavernosa.

Erection begins with sensory and mental stimulation. Impulses from the brain and local nerves cause the muscles of the penile arteries and the muscles of the spongy corpora cavernosa to relax, allowing blood to flow in and fill the open spaces in the spongy tissue. The blood creates pressure in the corpora cavernosa, making the penis expand. The tunica albuginea helps to trap the blood in the corpora cavernosa, thereby sustaining erection. The erection could be compared to the action of air in a bicycle tire. Air is forced into the inner tube under pressure. The inner tube (corpora cavernosa) presses against the outer tube (tunica albuginea) creating firmness. The blood is trapped in the corpora cavernosa sustaining the erection similar to the air trapped in the tire's inner tube.

Erection is reversed when muscles in the penis contract, stopping the inflow of blood and opening outflow channels and allowing the blood to return to the body's circulatory system.

If you are interested in a technical description of the events, read the following.
With sexual stimulation, the parasympathetic nerves transmit impulses through the pelvic plexus to the arterioles of the corpora cavernosa, causing the release of nitric oxide. Nitric oxide activates an enzyme called guanylate cyclase which results in increased levels of cyclic guanosine monophosphate or cGMP. It is cGMP causes the relaxation of the smooth muscles of the blood vessels in the corpora cavernosa. The increased arteriole inflow (from 2-5 ccs/minute to 70-100 ccs/minute) combined with an occlusion of the venous outflow by dilation of the spongy tissue of the corpora results in an erection. The erection is reversed when the cGMP is degraded or broken down by another enzyme called phosphdiesterase type 5 (PDE-5). The smooth muscles contract, reducing the arterial inflow and allowing increased venous drainage which effectively deflates the erection.

In actuality, the mechanisms are even more complicated than the one you've just read. Prostaglandins and vasoactive peptides (VIP) promote erections while PGF2-alpha and endothelins inhibit erections.

Why does Radical Prostatectomy cause Impotence?
For men who have had radical prostatectomy for cancer, the nerves that control the flow of blood into and out of the penis may be cut or removed. These nerves do not control the sensation to the penis, nor are they responsible for the orgasm that occurs with sexual intercourse. Only the firmness of the penis is affected.

If nerve sparing was attempted during your procedure, the return of erections could take as long as 6 to 18 months. Partial erections may return earlier and may be a sign of subsequent complete return of function, although not a guarantee. Partial recovery is actually quite common and does lend itself to some other options for treatment.    

MEDICAL TREATMENT   
Medical treatments for impotence after prostate cancer surgery do not usually play a significant role but a trial of any of the newer oral treatments before trying other therapies is quite reasonable. Unless pre-existing or current psychological problems have arisen, sex therapy is not often needed. Hormone treatments, usually testosterone, are often used in men with impotence. IT IS NOT TO BE CONSIDERED WHEN A DIAGNOSIS OF PROSTATE CANCER IS PRESENT. In most cases, the testosterone levels are normal after prostate surgery. Regardless, the use of testosterone has the potential of making any residual prostate cancer grow more quickly. Liver damage, high blood pressure are other problems too.

VIAGRA or LEVITRA or CIALIS
The drugs called sildenafil (or Viagra) or vardenafil (Levitra) or Cialis (tadenafil) improves erections in most men who have no known cause for difficulty with erections. Studies on men with known causes, such as diabetes, show it to be effective, but in a lower percentage of cases. Viagra or Cialis, Levitra work by increasing blood flow to the penis. Early studies show very few side effects. The drug does not directly cause erections, but enhance erections caused by sexual stimulation. It works by partially blocking an enzyme in the penis that is responsible for normally reversing erections. Some studies have shown 60-80% effectiveness in selected patients with difficulty maintaining erections. About 1 in 25 men discontinued therapy from side effects, which included headache, indigestion, visual disturbances, and flushing. Viagra, Cialis or Levitra, which will come in different dosages, has onset of action within 30-60 minutes. The effect last for four hours for Viagra and Levitra and about 24 hours for Cialis. Only one dose per day will be recommended. Diabetics and men who have had radical prostate or bladder surgery have a lower success rate with these drugs.

Important note: Patients who take or need nitroglycerin or nitrates for heart disease cannot use these drugs. A number of heart attacks, some causing death, have been reported since the introduction of Viagra. These appear to be due to the exertion of sexual intercourse or to the use of nitroglycerin with Viagra against doctor's orders. Patients with significant heart disease, whether using nitroglycrin or not, should be counselled about the risk of heart attack. Levitra should not be taken with alpha blockers, special medications used to treat blood pressure and voiding symptoms. Cialis may be taken with Flomax only if an alpha blocker is needed.

YOHIMBINE   
Yohimbine is a medication made from the bark of a tree that grows in India and Africa. Yohimbine acts on the nervous system and may also have some affect on increasing the male libido. It is considered homeopathic by medical doctors, that is, no definite uses are proven. The drug is very safe with uncommon side effects such as mild dizziness, nervousness, irritability, headaches and nausea rarely occuring. Some studies have suggested 10-20% of men will respond to the treatment with yohimbine, and it is necessary to take the medicine for a full two months before knowing whether it is going to work or not. However, a task force of specialists sponsored by the American Urological Association has recently determined that Yohimbine is no more effective than placebo. After prostate surgery, Yohimbine has little or no effect.

INJECTION THERAPY   
What is self-injection therapy? This involves the patient or his partner giving an injection of medication directly into the side of the penis to create an erection. The erection created is a natural one and usually begins 5 to 15 minutes after the injection. Not all patients respond to this type of treatment, but those that do should develop an erection that lasts anywhere from 30 to 120 minutes. About 70% of men find that their erections are satisfactory with self-injection therapy. The injections are given with a tiny needle and use very small amounts of medicine. The injections are relatively painless and are easily taught to the patient in one or two visits with the doctor.

The drugs used today include: prostaglandin (PGE-1 or Prostin or Alpoprostadil or Caverject), Papaverine hydrochloride and phentolamine (Regitine). All of these drugs have been approved by the FDA for uses other than impotence treatment. Only prostaglandin has been approved by the FDA for treating impotence. Papaverine and phentolamine have not yet been approved by the FDA for this specific purpose, although these two drugs were the initial ones used for self-injection therapy. However, considerable experience has been obtained by urologists over the past decade and the all three drugs mentioned above are considered safe for self-injection therapy.

RISKS
As mentioned, these medications have not been approved by the FDA and so technically need to be considered experimental. All medications have some potential risks and side effects and risks do exist with all of these drugs and the injections. These may include the possibility of bleeding or bruising from the injection, and the small chance of infection. One of the more common risks include the development of a prolonged erection or priapism (more than four hours). An episode of priapism might require a trip back to the physician or to the emergency room to receive other medications to counteract the self- injection medications and relieve the prolonged erection. Priapism happens in only a few percent of the patients. The patient does need to be aware that any erection lasting more than four hours needs to be dealt with by a physician. Another complication is the development of permanent scarring within the penis. The medications can be irritating to the penile tissues, and scarring is most often seen in patients who abuse the drug by using it too often. Scarring could create difficulty obtaining erections even with additional medication. If the scarring were severe, placement of a penile prosthesis, if that other option was chosen at a later time, might be difficult. Even rarer is the development of other medical problems. Papaverine has been known to cause changes in liver function tests which go away if the drug is stopped. Some men complain of dizziness, heart palpitations and/or a flushed feeling with these medications.

DISADVANTAGES OF SELF INJECTION TREATMENT
Self-injection treatment does require the patient or his partner to learn to give injections directly into the penis. The patient does need to return to the doctor for follow-up visits, particularly in the early phases of treatment. The patients cannot use the injections too often for fear of developing scarring and the self-injection treatment should be limited to once every four to seven days (range depends on medication type and initial response).

The injections are relatively costly and average costs depend on what combinations of medications are used. An injection may cost from $5 to $25 per injection, depending on which drugs are used.

URETHRAL SUPPOSITORIES
MUSE is the name of a new drug treatment and represents a unique approach for the treatment of erectile dysfunction. It is based on the discovery that the urethra (the tube in the penis for urine to pass from the bladder to the outside of the body) can absorb certain medications into the surrounding erectile tissues thereby creating an erection. The MUSE system uses prostaglandin E1, the same medication used in the self injection therapy, and has been approved by the FDA for the treatment of impotence.

An erection should begin within 5-10 minutes after administering MUSE. The duration of effect is approximately 30-60 minutes. However, the actual duration will vary from patient to patient.

The most common side effects that have been reported using MUSE are aching in the penis, testicles, legs and in the area between the scrotum and the rectum, warmth or burning sensation in the urethra, redness of the penis due to increased blood flow, and minor urethral bleeding or spotting due to improper administration

MUSE was released in early 1997 and more experience will be gained over the first few years that it is available to the public through their physicians. It is likely that MUSE will not be as effective as the self-injection therapy because of the variability of absorption of the medication and will most definitely be more expensive. The absence of needles however makes this form of therapy very attractive for those men in whom the treatment works.

VACUUM DEVICES   
External penile vacuum therapy is relatively new and is a nonsurgical, mechanical way of producing erections. The penis is placed within a hollow plastic cylinder, and a slight vacuum is created with a mechanical or electric pump. The vacuum and the negative pressure causes blood to flow into the penis. A rubberband-like device is then placed over the shaft of the penis at the base, trapping the blood in the penis. The erection can be used for up to 25 to 30 minutes. While serious injuries are rare, bruising, soreness or numbness of the penis is not uncommon. The device can usually be tried in the office at no charge and most manufacturers provide a money back guarantee. As mentioned above, this technique could be used in conjunction with self-injection therapy.

PENILE PROSTHESES   
Penile prosthetic implants can also be used for treating impotence and have been available since 1970. There are three types of prostheses that can be used. The simplest is the semi-rigid or malleable prosthesis. The implants which come in pairs are placed into the penile shaft giving the penis a modest erection which is unchanged. The rods are malleable so that they can be bent into certain positions for concealment, but the major problem with this type of prosthesis is the difficulty in concealing the prosthesis. The inflatable prosthesis is a more complicated surgical device in which two inflatable balloon cylinders are implanted within the penis, along with a pumping mechanism in the scrotum and a reservoir placed under the muscles of the abdomen. To obtain an erection, the pump is squeezed, pushing fluid from the reservoir into the hollow penile cylinders thereby creating an erection much like the patient's normal erection. A release valve allows the fluid to go back into the reservoir when the erection is no longer desired. This prosthesis is the most natural in some ways because it mimics normal activity, but there is a chance of mechanical breakdown or leakage of fluid that can occur at any time, and it does require a surgical procedure to implant the prosthesis. Self-contained implants are designed somewhat like the rigid prosthesis, but have an actual pump at the tip and a reservoir at the rear of the self-contained cylinder, which allows for an erection without the necessity of multiple other connected devices. These prostheses, while easier to implant, do not give the quality of erections or flaccidity of the multi-unit, implantable prosthesis.

Concerns recently about the safety of silicone products has been raised, including such thoughts as causing cancer and affecting the immune system. The liquid silicone used in breast implants caused enough concern for the FDA to remove them from the market. The solid silicone used in penile prosthesis most likely causes no harm and have been used for many decades with safety. Silicone is used in pacemakers, brain shunts and other prosthetics. The FDA, which tends to be extremely conservative has not suggested that they will take silicone products out of circulation. But, only time will tell how safe silicone really is.

ORAL MEDICATIONS FOR IMPOTENCE
Two new formulations of Viagra like drugs are to be released in the next year or two. Cialis (Lilly/ICOS) and Vardenafil (Bayer) may offer the same benefits as Viagra without the side effects.

A gel and a cream form of alpoprostadil (same drug as in MUSE and Caverject) that is placed on the penis is effective in about 40% of patients with little in the way of side effects to patient or partner. No release date has been set (Topiglan/Alprox TD).

Another new oral (taken by mouth) drug is apomorphine. This drug also seems to promote erections in men with psychogenic problems Apomorphine may also work in men having difficulty maintaining erections. Large studies are currently underway in the US to determine the safety and effectiveness of these drugs. Yet another oral drug is Vasomax (phentolamine). This medicine is still being tested and does not seem to have the effectiveness of Viagra with a 40% response in men tested. Both of these drugs are expected to have major delays before they are released, if ever.

All of the oral drugs have different modes of action and if one does not work, the others may. Combinations of drugs, (e.g. Viagra with another drug) and other techniques are being studied.

In recent European studies, a new injectable drug called VIP is being tested. VIP stands for vasoactive intestinal peptide. When mixed with phentolomine (Regitine), an older injectable drug, 80% of men had successful erections, even if they had failed other injectables. Studies are just beginning in the US.

Two other injectables being researched abroad are called moxislyte and forskolin Initial success rates of 80% are being reported. No US studies are yet completed.

North American studies of creams containing nitroglycerin that are applied to the penis have shown modest success in mild to moderate erectile dysfunction. Plans to study this drug in the US are planned. South American studies of creams containing prostaglandin (Alprox-TD) that are applied to the penis have shown modest success in mild to moderate erectile dysfunction. No plans to study this drug are planned in the US for now.


WHAT DOES NOT WORK   
At this point there is no evidence that nutritional supplements or vitamins have any significant bearing on sexual performance. The Food and Drug Administration has currently banned the sale or advertising of all nonprescription products for the treatment of male impotence because none had been scientifically shown to be effective. Yohimbine does not usually work after prostate cancer surgery or irradiation treatments.

Vascular surgery, a technique used rarely in men with known blood vessel abnormalities is not to be considered in post-prostatectomy impotence. Impotence is a treatable problem, which is not the inevitable consequence of aging, but is brought on by the surgical removal of the prostate or by radiation treatments. A multitude of treatment choices are available to assure that each patient has a good chance of a successful outcome.