Erectile Dysfunction

Erectile dysfunction is defined as the inability to attain an erection of sufficient rigidity for vaginal penetration or inability to sustain an erection of sufficient duration for intercourse that is satisfying to both male and female partner.

Demographics:

Erectile dysfunction is prevalent in men aged 40 to 70 years and increases with age. Population studies estimate that 10 to 20 million men suffer ED, and 30 million men suffer at least partial ED. In years past, impotence was frequently attributed to psychological causes (psychogenic ED), but today, at least 80% of ED is likely due to physiologic causes such as vascular (decreased arterial blood flow or venous insufficiency), neurologic (nerve injury following surgery or neurologic diseases), or endocrine (hormone) abnormalities.

In the past, men have been inclined to suffer ED without seeking medical evaluation or treatment. Today, due to the increase in public awareness and the advent of several treatment options, men with ED are more likely to seek treatment that offers opportunity to regain sexual function and restitution of an important quality of life activity.

Physiology of erection:

Erections normally occur at the time of physical or mental sexual stimulation which leads to an increase in blood flow to the erectile tissues in the penis. In addition, a decreased outflow of blood from the penis (venous outflow) occurs which maintains the rigidity of the erectile tissues during sexual activity. The vascular response is a consequence of nerves within the erectile tissues producing a chemical (cyclic GMP or cGMP) that decreases resistance of blood inflow to the penis. The penile tissues also produce an enzyme, phosphodiesterase-5 (or PD-5) that degrades the cGMP, reversing the increase in blood inflow. PD-5 is blocked by a class of medications known as PD-5 inhibitors (including Viagra, Cialis, and Levitra) thereby slowing the degradation of cGMP and, consequently, promoting and sustaining the erection. However, the response to these medications depends upon the primary sexual stimulation that initiates the increase cGMP release.

Causes other than vascular may account for erectile dysfunction. Nerve injury or neurologic disease may interfere with stimulation of blood flow to the penis during sexual stimulation. Thus, spinal nerve injury, injury of the nerves adjacent to the prostate during prostate surgery, or neurologic diseases such as stroke, peripheral neuropathy, or multiple sclerosis may be primary or contributing factors that result in impotence. Hormone abnormalities, especially decrease in male hormone (testosterone), can cause ED. Psychogenic causes of erectile dysfunction are recognized but are not as common as previously thought. The erectile response is dependent upon the integrity of the autonomic nervous system that can be affected by stress, anxiety, depression, and other psychological conditions.

Risk factors for ED:

Erectile dysfunction is correlated with increase in age, but other independent risk factors that further increase risk of ED include cardiovascular disease, diabetes, smoking, and drug or alcohol abuse. In fact, erectile dysfunction may be the first symptom of vascular disease that prompts evaluation for coronary artery disease or hypertension- both of which may lead to serious life threatening illness (stroke, heart attack). Therefore, evaluation of impotence offers an opportunity to assess other conditions that may be treated to avert other medical complications.

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Evaluation of erectile dysfunction:

Currently, evaluation consists of non-invasive screening for contributing factors (urine analysis to rule out diabetes, pulse and blood pressure measurement to rule out hypertension, physical exam to rule out serious vascular disease, blood testing to assess hormone abnormalities and screen for prostate cancer). Measurement of blood serum PSA (a screening test for prostate cancer) and serum testosterone and prolactin (hormones that can affect erectile function) provide the urologist with information that will guide treatment options or lead to more specific testing. Abnormalities in urine (sugar indicating diabetes, white blood cells indicating infection, red blood cells indicating possible abnormalities in the urinary tract such as enlarged prostate or kidney/ bladder cancer) or vital signs (high blood pressure indicating need to treat hypertension), or physical exam (which might reveal more serious vascular abnormalities) may lead to further evaluation by your urologist or primary care physician.

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Treatment options:

The available treatment options have increased over the past decade with choices which range from oral medications to surgical insertion of penile prosthetics. These choices are briefly summarized below. In general, treatments are tailored to treat the underlying cause and to utilize the least invasive therapy that is applicable. Thus, while surgical therapy offers the highest satisfaction with the greatest probability of success, operation is never the first choice in treatment because it is not reversible and carries the greatest risk.

Oral medication:

Medications which consist of PD-5 inhibitors (Viagra, Cialis, Levitra) are first line therapy for most patients. Approximately 70% of men will have a positive response to medical therapy including men with diabetes or hypertension. However, successful treatment of impotence in hypertensive or diabetic men does not eliminate the need to evaluate and treat these medical diseases. Dose of medication is adjusted to the lowest effective dose.

Vacuum erection device:

The vacuum erection device (VED) offers a cost effective method of reinstituting erectile function with few risks. The device is placed over the penis and a vacuum pump creates a negative pressure that increases blood flow into the erectile tissues. Once the penis is rigid, an elastic ring is slipped over the base of the penis to prevent blood outflow during intercourse.

Urethral suppository:

A urethral suppository (MUSE) containing alprostadil is inserted into the urethra where it dissolves, releasing medication which is absorbed into the erectile tissues and acts to increase blood inflow. Dose is adjusted up to the lowest effective dose (too high a dose may result in an erection lasting more than four hours- priapism- which requires emergency treatment).

Corporal injection therapy:

Direct injection of medications such as alprostadil directly into the erectile tissues has been effective in treating erectile dysfunction. The medication is provided in prepackaged syringes for use when needed. Single medication or combination of several drugs that are synergistic (work by different mechanisms) can be prepared by local pharmacists to provide optimal medical therapy. Like the urethral suppository, corporal injection treatment is dose (and number of medications included) adjusted up to the lowest effective dose to reduce probability of priapism. The patient must learn careful and sterile injection technique to avoid injury or complications. Erections induced by pharmacologic injection therapy do not rely on sexual stimulation.

Penile prosthesis:

Insertion of a penile prosthesis provides a treatment that will work in the majority of men who suffer impotence regardless of the cause. The penile prostheses are divided into two categories: semi-rigid and inflatable.

Semi-rigid prosthesis is essentially a rod inserted into the erectile compartments of the penis (two rods, one into each compartment). The prosthesis remains rigid in the penis but is flexible at the base of the penis so that the penis can be hinged downward when not active in sex.

The inflatable penile prosthesis consists of two cylinders placed in the erectile compartments and a pump device that is concealed in the scrotum and a reservoir placed behind the pubic bone. The patient pumps fluid from the reservoir to the cylinders when preparing to engage in sexual activity. After sexual intercourse, the pump valve is released and fluid returns to the reservoir. Thus, the cylinders are flaccid between sexual episodes.

Both prostheses are completely concealed. The advantage of the inflatable prosthesis is the more natural erection: when inflated, increasing in rigidity, length, and girth; when deflated, the return to a more natural flaccid state. The semi-rigid prosthesis maintains a static length, girth, and rigidity. The disadvantage of the inflatable penile prosthesis is the need to activate using a mechanical device, the increased cost of a more sophisticated mechanism, and the greater complexity of insertion (although the incision is similar for both procedures). Both prostheses share a risk of infection although this is extremely low (< 1%) and the potential for delayed infection. The semi-rigid prosthesis has a higher rate of erosion through penile tissues while the inflatable penile prosthesis has an extremely low risk of mechanical failure.

As noted earlier, the highest patient satisfaction is in those who have undergone insertion of penile prosthesis. Despite the advances in technology and the decrease in complications or malfunction noted in the past 30 years, we do not recommend surgical implant of prosthetics as first-line therapy.

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The University of Cincinnati Urology Division is one of the leading urology programs, not just in Cincinnati, but in the U.S. UC Urology provides quality health care using the most advanced technology and state-of-the-art diagnostic treatments. Many of our urologists are recognized in multiple national and local "Best Doctors" and "Top Doctors" listings. We provide minimally invasive surgical treatments which include laparoscopic, robot-assisted laparoscopic and endourologic procedures as well as comprehensive care for all urologic conditions.