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Impotence
The term "impotence," as
applied to the title of this conference, has traditionally been used to
signify the inability of the male to attain and maintain erection of the
penis sufficient to permit satisfactory sexual intercourse. However,
this use has often led to confusing and uninterpretable results in both
clinical and basic science investigations. This, together with its
pejorative implications, suggests that the more precise term "erectile
dysfunction" be used instead to signify an inability of the male to
achieve an erect penis as part of the overall multifaceted process of
male sexual function.
This process comprises a variety of physical aspects with important
psychological and behavioral overtones. In analyzing the material
presented and discussed at this conference, this consensus statement
addresses issues of male erectile dysfunction, as implied by the term
"impotence." However, it should be recognized that desire,
orgasmic capability, and ejaculatory capacity may be intact even in the
presence of erectile dysfunction or may be deficient to some extent and
contribute to the sense of inadequate sexual function.
Erectile dysfunction affects millions of men. Although for some men
erectile function may not be the best or most important measure of
sexual satisfaction, for many men erectile dysfunction creates mental
stress that affects their interactions with family and associates. Many
advances have occurred in both diagnosis and treatment of erectile
dysfunction. However, its various aspects remain poorly understood by
the general population and by most health care professionals. Lack of a
simple definition, failure to delineate precisely the problem being
assessed, and the absence of guidelines and parameters to determine
assessment and treatment outcome and long-term results, have contributed
to this state of affairs by producing misunderstanding, confusion, and
ongoing concern. That results have not been communicated effectively to
the public has compounded this situation.
Cause-specific assessment and treatment of male sexual dysfunction
will require recognition by the public and the medical community that
erectile dysfunction is a part of overall male sexual dysfunction. The
multifactorial nature of erectile dysfunction, comprising both organic
and psychological aspects, may often require a multidisciplinary approach
to its assessment and treatment. This consensus report addresses these
issues, not only as isolated health problems but also in the context of
societal and individual perceptions and expectations.
Erectile dysfunction is often assumed to be a natural concomitant of
the aging process, to be tolerated along with other conditions
associated with aging. This assumption may not be entirely correct. For
the elderly and for others, erectile dysfunction may occur as a
consequence of specific illnesses or of medical treatment for certain
illnesses, resulting in fear, loss of image and self-confidence, and
depression.
For example, many men with diabetes mellitus may develop erectile
dysfunction during their young and middle adult years. Physicians,
diabetes educators, and patients and their families are sometimes
unaware of this potential complication. Whatever the causal factors,
discomfort of patients and health care providers in discussing sexual
issues becomes a barrier to pursuing treatment.
Erectile dysfunction can be effectively treated with a variety of
methods. Many patients and health care providers are unaware of these
treatments, and the dysfunction thus often remains untreated, compounded
by its psychological impact. Concurrent with the increase in the
availability of effective treatment methods has been increased
availability of new diagnostic procedures that may help in the selection
of an effective, cause-specific treatment. This conference was designed
to explore these issues and to define the state of the art.
To examine what is known about the demographics, etiology, risk
factors, path physiology, diagnostic assessment, treatments (both
generic and cause-specific), and the understanding of their consequences
by the public and the medical community, the National Institute of
Diabetes and Digestive and Kidney Diseases and the Office of Medical
Applications of Research of the National Institutes of Health, in
conjunction with the National Institute of Neurological Disorders and
Stroke and the National Institute on Aging, convened a consensus
development conference on male impotence on December 7-9, 1992. After 1
1/2 days of presentations by experts in the relevant fields involved
with male sexual dysfunction and erectile impotence or dysfunction, a
consensus panel comprised of representatives from urology, geriatrics,
medicine, endocrinology, psychiatry, psychology, nursing, epidemiology,
biostatistics, basic sciences, and the public considered the evidence
and developed answers to the questions that follow.
WHAT ARE THE PREVALENCE AND CLINICAL,
PSYCHOLOGICAL, AND SOCIAL IMPACT OF IMPOTENCE (CULTURAL, GEOGRAPHICAL,
NATIONAL, ETHNIC, RACIAL, MALE/FEMALE PERCEPTIONS AND INFLUENCES)?
Prevalence and Association with Age
Estimates of the prevalence of impotence depend on the definition
employed for this condition. For the purposes of this consensus
development conference statement, impotence is defined as male erectile
dysfunction, that is, the inability to achieve or maintain an erection
sufficient for satisfactory sexual performance. Erectile performance has
been characterized by the degree of dysfunction, and estimates of
prevalence (the number of men with the condition) vary depending on the
definition of erectile dysfunction used.
Appallingly little is known about the prevalence of erectile
dysfunction in the United States and how this prevalence varies
according to individual characteristics (age, race, ethnicity,
socioeconomic status, and concomitant diseases and conditions). Data on
erectile dysfunction available from the 1940's applied to the present
U.S. male population produce an estimate of erectile dysfunction
prevalence of 7 million.
More recent estimates suggest that the number of U.S. men with
erectile dysfunction may more likely be near 10-20 million. Inclusion of
individuals with partial erectile dysfunction increases the estimate to
about 30 million. The majority of these individuals will be older than
65 years of age. The prevalence of erectile dysfunction has been found
to be associated with age. A prevalence of about 5 percent is observed
at age 40, increasing to 15-25 percent at age 65 and older. One-third of
older men receiving medical care at a Department of Veterans' Affairs
ambulatory clinic admitted to problems with erectile function.
Causes contributing to erectile dysfunction can be broadly classified
into two categories: organic and psychological. In reality, while the
majority of patients with erectile dysfunction are thought to
demonstrate an organic component, psychological aspects of
self-confidence, anxiety, and partner communication and conflict are
often important contributing factors.
The 1985 National Ambulatory Medical Care Survey indicated that there
were about 525,000 visits for erectile dysfunction, accounting for 0.2
percent of all male ambulatory care visits. Estimates of visits per
1,000 population increased from about 1.5 for the age group 25-34 to
15.0 for those age 65 and above. The 1985 National Hospital Discharge
Survey estimated that more than 30,000 hospital admissions were for
erectile dysfunction.
Clinical, Psychological, and Social Impact
Geographic, Racial, Ethnic, Socioeconomic, and Cultural Variation in
Erectile Dysfunction. Very little is known about variations in
prevalence of erectile dysfunction across geographic, racial, ethnic,
socioeconomic, and cultural groups. Anecdotal evidence points to the
existence of racial, ethnic, and other cultural diversity in the
perceptions and expectation levels for satisfactory sexual functioning.
These differences would be expected to be reflected in these groups'
reaction to erectile dysfunction, although few data on this issue appear
to exist.
One report from a recent community survey concluded that erectile
failure was the leading complaint of males attending sex therapy
clinics. Other studies have shown that erectile disorders are the
primary concern of sex therapy patients in treatment. This is consistent
with the view that erectile dysfunction may be associated with
depression, loss of self-esteem, poor self-image, increased anxiety or
tension with one's sexual partner, and/or fear and anxiety associated
with contracting sexually transmitted diseases, including AIDS.
Male/Female Perceptions and Influences. The diagnosis of erectile
dysfunction may be understood as the presence of a condition limiting
choices for sexual interaction and possibly limiting opportunity for
sexual satisfaction. The impact of this condition depends very much on
the dynamics of the relationship of the individual and his sexual
partner and their expectation of performance. When changes in sexual
function are perceived by the individual and his partner as a natural
consequence of the aging process, they may modify their sexual behavior
to accommodate the condition and maintain sexual satisfaction.
Increasingly, men do not perceive erectile dysfunction as a normal part
of aging and seek to identify means by which they may return to their
previous level and range of sexual activities. Such levels and
expectations and desires for future sexual interactions are important
aspects of the evaluation of patients presenting with a chief complaint
of erectile dysfunction.
In men of all ages, erectile failure may diminish willingness to
initiate sexual relationships because of fear of inadequate sexual
performance or rejection. Because males, especially older males, are
particularly sensitive to the social support of intimate relationships,
withdrawal from these relationships because of such fears may have a
negative effect on their overall health.
WHAT ARE THE RISK FACTORS CONTRIBUTING TO IMPOTENCE?
CAN THESE BE UTILIZED IN PREVENTING DEVELOPMENT OF IMPOTENCE?
Physiology of Erection
The male erectile response is a vascular event initiated by neuronal
action and maintained by a complex interplay between vascular and
neurological events. In its most common form, it is initiated by a
central nervous system event that integrates psychogenic stimuli
(perception, desire, etc.) and controls the sympathetic and
parasympathetic innervations of the penis. Sensory stimuli from the penis
are important in continuing this process and in initiating a reflex arc
that may cause erection under proper circumstances and may help to
maintain erection during sexual activity.
Parasympathetic input allows erection by relaxation of trabecular
smooth muscle and dilation of the helicine arteries of the penis. This
leads to expansion of the lacunar spaces and entrapment of blood by
compressing venules against the tunica albuginea, a process referred to
as the corporal veno- occlusive mechanism. The tunica albuginea must
have sufficient stiffness to compress the venules penetrating it so that
venous outflow is blocked and sufficient tumescence and rigidity can
occur.
Acetylcholine released by the parasympathetic nerves is thought to
act primarily on endothelial cells to release a second
nonadrenergic-noncholinergic carrier of the signal that relaxes the
trabecular smooth muscle. Nitric oxide released by the endothelial
cells, and possibly also of neural origin, is currently thought to be
the leading of several candidates as this nonadrenergic-noncholinergic
transmitter; but this has not yet been conclusively demonstrated to the
exclusion of other potentially important substances (e.g., vasoactive
intestinal polypeptide). The relaxing effect of nitric oxide on the
trabecular smooth muscle may be mediated through its stimulation of
guanylate cyclase and the production of cyclic guanosine monophosphate (cGMP),
which would then function as a second messenger in this system.
Constriction of the trabecular smooth muscle and helicine arteries
induced by sympathetic innervation makes the penis flaccid, with blood
pressure in the cavernosal sinuses of the penis near venous pressure.
Acetylcholine is thought to decrease sympathetic tone. This may be
important in a permissive sense for adequate trabecular smooth muscle
relaxation and consequent effective action of other mediators in
achieving sufficient inflow of blood into the lacunar spaces. When the
trabecular smooth muscle relaxes and helicine arteries dilate in
response to parasympathetic stimulation and decreased sympathetic tone,
increased blood flow fills the cavernous spaces, increasing the pressure
within these spaces so that the penis becomes erect. As the venules are
compressed against the tunica albuginea, penile pressure approaches
arterial pressure, causing rigidity. Once this state is achieved,
arterial inflow is reduced to a level that matches venous outflow.
Erectile Dysfunction
Because adequate arterial supply is critical for erection, any
disorder that impairs blood flow may be implicated in the etiology of
erectile failure. Most of the medical disorders associated with erectile
dysfunction appear to affect the arterial system. Some disorders may
interfere with the corporal veno-occlusive mechanism and result in
failure to trap blood within the penis, or produce leakage such that an
erection cannot be maintained or is easily lost.
Damage to the autonomic pathways innervating the penis may eliminate
"psychogenic" erection initiated by the central nervous
system. Lesions of the somatic nervous pathways may impair reflexogenic
erections and may interrupt tactile sensation needed to maintain
psychogenic erections. Spinal cord lesions may produce varying degrees
of erectile failure depending on the location and completeness of the
lesions. Not only do traumatic lesions affect erectile ability, but
disorders leading to peripheral neuropathy may impair neuronal
innervation of the penis or of the sensory afferents. The endocrine
system itself, particularly the production of androgens, appears to play
a role in regulating sexual interest, and may also play a role in
erectile function.
Psychological processes such as depression, anxiety, and relationship
problems can impair erectile functioning by reducing erotic focus or
otherwise reducing awareness of sensory experience. This may lead to
inability to initiate or maintain an erection. Etiologic factors for
erectile disorders may be categorized as neurogenic, vasculogenic, or
psychogenic, but they most commonly appear to derive from problems in
all three areas acting in concert.
Risk Factors
Little is known about the natural history of erectile dysfunction.
This includes information on the age of onset, incidence rates
stratified by age, progression of the condition, and frequency of
spontaneous recovery. There also are very limited data on associated
morbidity and functional impairment. To date, the data are predominantly
available for whites, with other racial and ethnic populations
represented only in smaller numbers that do not permit analysis of these
issues as a function of race or ethnicity.
Erectile dysfunction is clearly a symptom of many conditions, and
certain risk factors have been identified, some of which may be amenable
to prevention strategies. Diabetes mellitus, hypogonadism in association
with a number of endocrinologic conditions, hypertension, vascular
disease, high levels of blood cholesterol, low levels of high density
lipoprotein, drugs, neurogenic disorders, Peyronie's disease, priapism,
depression, alcohol ingestion, lack of sexual knowledge, poor sexual
techniques, inadequate interpersonal relationships or their
deterioration, and many chronic diseases, especially renal failure and
dialysis, have been demonstrated as risk factors. Vascular surgery is
also often a risk factor. Age appears to be a strong indirect risk
factor in that it is associated with an increased likelihood of direct
risk factors. Other factors require more extensive study. Smoking has an
adverse effect on erectile function by accentuating the effects of other
risk factors such as vascular disease or hypertension. To date,
vasectomy has not been associated with an increased risk of erectile
dysfunction other than causing an occasional psychological reaction that
could then have a psychogenic influence. Accurate risk factor
identification and characterization are essential for concerted efforts
at prevention of erectile dysfunction.
Prevention
Although erectile dysfunction increases progressively with age, it is
not an inevitable consequence of aging. Knowledge of the risk factors
can guide prevention strategies. Specific antihypertensive,
antidepressant, and antipsychotic drugs can be chosen to lessen the risk
of erectile failure. Published lists of prescription drugs that may
impair erectile functioning often are based on reports implicating a
drug without systematic study. Such studies are needed to confirm the
validity of these suggested associations. In the individual patient, the
physician can modify the regimen in an effort to resolve the erectile
problem.
It is important that physicians and other health care providers
treating patients for chronic conditions periodically inquire into the
sexual functioning of their patients and be prepared to offer counsel
for those who experience erectile difficulties. Lack of sexual knowledge
and anxiety about sexual performance are common contributing factors to
erectile dysfunction. Education and reassurance may be helpful in
preventing the cascade into serious erectile failure in individuals who
experience minor erectile difficulty due to medications or common
changes in erectile functioning associated with chronic illnesses or
with aging.
WHAT DIAGNOSTIC INFORMATION SHOULD BE OBTAINED IN
ASSESSMENT OF THE IMPOTENT PATIENT? WHAT CRITERIA SHOULD BE EMPLOYED TO
DETERMINE WHICH TESTS ARE INDICATED FOR A PARTICULAR PATIENT?
The appropriate evaluation of all men with erectile dysfunction
should include a medical and detailed sexual history (including
practices and techniques), a physical examination, a psycho-social
evaluation, and basic laboratory studies. When available, a
multidisciplinary approach to this evaluation may be desirable. In
selected patients, further physiologic or invasive studies may be
indicated. A sensitive sexual history, including expectations and
motivations, should be obtained from the patient (and sexual partner
whenever possible) in an interview conducted by an interested physician
or another specially trained professional. A written patient
questionnaire may be helpful but is not a substitute for the interview.
The sexual history is needed to accurately define the patient's specific
complaint and to distinguish between true erectile dysfunction, changes
in sexual desire, and orgasmic or ejaculatory disturbances. The patient
should be asked specifically about perceptions of his erectile
dysfunction, including the nature of onset, frequency, quality, and
duration of erections; the presence of nocturnal or morning erections;
and his ability to achieve sexual satisfaction. Psychosocial factors
related to erectile dysfunction should be probed, including specific
situational circumstances, performance anxiety, the nature of sexual
relationships, details of current sexual techniques, expectations,
motivation for treatment, and the presence of specific discord in the
patient's relationship with his sexual partner. The sexual partner's own
expectations and perceptions should also be sought since they may have
important bearing on diagnosis and treatment recommendations.
The general medical history is important in identifying specific risk
factors that may account for or contribute to the patient's erectile
dysfunction. These include vascular risk factors such as hypertension,
diabetes, smoking, coronary artery disease, peripheral vascular
disorders, pelvic trauma or surgery, and blood lipid abnormalities.
Decreased sexual desire or history suggesting a hypogonadal state could
indicate a primary endocrine disorder. Neurologic causes may include a
history of diabetes mellitus or alcoholism with associated peripheral
neuropathy. Neurologic disorders such as multiple sclerosis, spinal
injury, or cerebrovascular accidents are often obvious or well defined
prior to presentation. It is essential to obtain a detailed medication
and illicit drug history since an estimated 25 percent of cases of
erectile dysfunction may be attributable to medications for other
conditions. Past medical history can reveal important causes of erectile
dysfunction, including radical pelvic surgery, radiation therapy,
Peyronie's disease, penile or pelvic trauma, prostatitis, priapism, or
voiding dysfunction. Information regarding prior evaluation or treatment
for "impotence" should be obtained. A detailed sexual history,
including current sexual techniques, is important in the general history
obtained. It is also important to determine if there have been previous
psychiatric illnesses such as depression or neuroses.
Physical examination should include the assessment of male secondary
sex characteristics, femoral and lower extremity pulses, and a focused
neurologic examination including perianal sensation, anal sphincter
tone, and bulbocavernosus reflex. More extensive neurologic tests,
including dorsal nerve conduction latencies, evoked potential
measurements, and corpora cavernosal electromyography lack normative
(control) data and appear at this time to be of limited clinical value.
Examination of the genitalia includes evaluation of testis size and
consistency, palpation of the shaft of the penis to determine the
presence of Peyronie's plaques, and a digital rectal examination of the
prostate with assessment of anal sphincter tone.
Endocrine evaluation consisting of a morning serum testosterone is
generally indicated. Measurement of serum prolactin may be indicated. A
low testosterone level merits repeat measurement together with
assessment of luteinizing hormone (LH), follicle-stimulating hormone
(FSH), and prolactin levels. Other tests may be helpful in excluding
unrecognized systemic disease and include a complete blood count,
urinalysis, creatinine, lipid profile, fasting blood sugar, and thyroid
function studies.
Although not indicated for routine use, nocturnal penile tumescence
(NPT) testing may be useful in the patient who reports a complete
absence of erections (exclusive of nocturnal "sleep"
erections) or when a primary psychogenic etiology is suspected. Such
testing should be performed by those with expertise and knowledge of its
interpretation, pitfalls, and usefulness. Various methods and devices
are available for the evaluation of nocturnal penile tumescence, but
their clinical usefulness is restricted by limitations of diagnostic
accuracy and availability of normative data. Further study regarding
standardization of NPT testing and its general applicability is
indicated.
After the history, physical examination, and laboratory testing, a
clinical impression can be obtained of a primarily psychogenic, organic,
or mixed etiology for erectile dysfunction. Patients with primary or
associated psychogenic factors may be offered further psychologic
evaluation, and patients with endocrine abnormalities may be referred to
an endocrinologist to evaluate the possibility of a pituitary lesion or
hypogonadism. Unless previously diagnosed, suspicion of neurologic
deficit may be further assessed by complete neurologic evaluation. No
further diagnostic tests appear necessary for those patients who favor
noninvasive treatment (e.g., vacuum constrictive devices, or
pharmacologic injection therapy). Patients who do not respond
satisfactorily to these noninvasive treatments may be candidates for
penile implant surgery or further diagnostic testing for possible
additional invasive therapies.
A rigid or nearly rigid erectile response to intracavernous injection
of pharmacologic test doses of a vasodilating agent (see below)
indicates adequate arterial and veno-occlusive function. This suggests
that the patient may be a suitable candidate for a trial of penile
injection therapy. Genital stimulation may be of use in increasing the
erectile response in this setting. This diagnostic technique also may be
used to differentiate a vascular from a primarily neuropathic or
psychogenic etiology. Patients who have an inadequate response to
intracavernous pharmacologic injection may be candidates for further
vascular testing. It should be recognized, however, that failure to
respond adequately may not indicate vascular insufficiency but can be
caused by patient anxiety or discomfort. The number of patients who may
benefit from more extensive vascular testing is small, but includes
young men with a history of significant perineal or pelvic trauma, who
may have anatomic arterial blockage (either alone or with neurologic
deficit) to account for erectile dysfunction.
Studies to further define vasculogenic disorders include
pharmacologic duplex grey scale/color ultrasonography, pharmacologic
dynamic infusion cavernosometry/ cavernosography, and pharmacologic
pelvic/penile angiography. Cavernosometry, duplex ultrasonography, and
angiography performed either alone or in conjunction with intracavernous
pharmacologic injection of vasodilator agents rely on complete arterial
and cavernosal smooth muscle relaxation to evaluate arterial and
veno-occlusive function. The clinical effectiveness of these invasive
studies is severely limited by several factors, including the lack of
normative data, operator dependence, variable interpretation of results,
and poor predictability of therapeutic outcomes of arterial and venous
surgery. At the present time these studies might best be done in
referral centers with specific expertise and interest in investigation
of the vascular aspects of erectile dysfunction. Further clinical
research is necessary to standardize methodology and interpretation, to
obtain control data on normals (as stratified according to age), and to
define what constitutes normality in order to assess the value of these
tests in their diagnostic accuracy and in their ability to predict
treatment outcome in men with erectile dysfunction.
WHAT ARE THE EFFICACIES AND RISKS OF BEHAVIORAL,
PHARMACOLOGICAL, SURGICAL, AND OTHER TREATMENTS FOR IMPOTENCE? WHAT
SEQUENCES AND/OR COMBINATION OF THESE INTERVENTIONS ARE APPROPRIATE?
WHAT MANAGEMENT TECHNIQUES ARE APPROPRIATE WHEN TREATMENT IS NOT
EFFECTIVE OR INDICATED?
General Considerations
Because of the difficulty in defining the clinical entity of erectile
dysfunction, there have been a variety of entry criteria for patients in
therapeutic trials. Similarly, the ability to assess efficacy of
therapeutic interventions is impaired by the lack of clear and
quantifiable criteria of erectile dysfunction. General considerations
for treatment follow:
- Psychotherapy and/or behavioral therapy may be useful for some
patients with erectile dysfunction without obvious organic cause,
and for their partners. These may also be used as an adjunct to
other therapies directed at the treatment of organic erectile
dysfunction. Outcome data from such therapy, however, have not been
well-documented or quantified, and additional studies along these
lines are indicated.
- Efficacy of therapy may be best achieved by inclusion of both
partners in treatment plans.
- Treatment should be individualized to the patient's desires and
expectations.
- Even though there are several effective treatments currently
available, long-term efficacy is in general relatively low.
Moreover, there is a high rate of voluntary cessation of treatment
for all currently popular forms of therapy for erectile dysfunction.
Better understanding of the reasons for each of these phenomena is
needed.
Psychotherapy and Behavioral Therapy
Psychosocial factors are important in all forms of erectile
dysfunction. Careful attention to these issues and attempts to relieve
sexual anxieties should be a part of the therapeutic intervention for
all patients with erectile dysfunction. Psychotherapy and/or behavioral
therapy alone may be helpful for some patients in whom no organic cause
of erectile dysfunction is detected. Patients who refuse medical and
surgical interventions also may be helped by such counseling. After
appropriate evaluation to detect and treat coexistent problems such as
issues related to the loss of a partner, dysfunctional relationships,
psychotic disorders, or alcohol and drug abuse, psychological treatment
focuses on decreasing performance anxiety and distractions and on
increasing a couple's intimacy and ability to communicate about sex.
Education concerning the factors that create normal sexual response and
erectile dysfunction can help a couple cope with sexual difficulties.
Working with the sexual partner is useful in improving the outcome of
therapy. Psychotherapy and behavioral therapy have been reported to
relieve depression and anxiety as well as to improve sexual function.
However, outcome data of psychological and behavioral therapy have not
been quantified, and evaluation of the success of specific techniques
used in these treatments is poorly documented. Studies to validate their
efficacy are therefore strongly indicated.
Medical Therapy
An initial approach to medical therapy should consider reversible
medical problems that may contribute to erectile dysfunction. Included
in this should be assessment of the possibility of medication-induced
erectile dysfunction with consideration for reduction of polypharmacy
and/or substitution of medications with lower probability of inducing
erectile dysfunction.
For some patients with an established diagnosis of testicular failure
(hypogonadism), androgen replacement therapy may sometimes be effective
in improving erectile function. A trial of androgen replacement may be
worthwhile in men with low serum testosterone levels if there are no
other contraindications. In contrast, for men who have normal
testosterone levels, androgen therapy is inappropriate and may carry
significant health risks, especially in the situation of unrecognized
prostate cancer. If androgen therapy is indicated, it should be given in
the form of intramuscular injections of testosterone enanthate or
cypionate. Oral androgens, as currently available, are not indicated.
For men with hyperprolactinemia, bromocriptine therapy often is
effective in normalizing the prolactin level and improving sexual
function. A wide variety of other substances taken either orally or
topically have been suggested to be effective in treating erectile
dysfunction. Most of these have not been subjected to rigorous clinical
studies and are not approved for this use by the Food and Drug
Administration (FDA). Their use should therefore be discouraged until
further evidence in support of their efficacy and indicative of their
safety is available.
Intracavernosal Injection Therapy
Injection of vasodilator substances into the corpora of the penis has
provided a new therapeutic technique for a variety of causes of erectile
dysfunction. The most effective and well-studied agents are papaverine,
phentolamine, and prostaglandin E[sub 1]. These have been used either
singly or in combination. Use of these agents occasionally causes
priapism (inappropriately persistent erections). This appears to have
been seen most commonly with papaverine. Priapism is treated with
adrenergic agents, which can cause life-threatening hypertension in
patients receiving monoamine oxidase inhibitors. Use of the penile
vasodilators also can be problematic in patients who cannot tolerate
transient hypotension, those with severe psychiatric disease, those with
poor manual dexterity, those with poor vision, and those receiving
anticoagulant therapy. Liver function tests should be obtained in those
being treated with papaverine alone. Prostaglandin E[sub 1] can be used
together with papaverine and phentolamine to decrease the incidence of
side effects such as pain, penile corporal fibrosis, fibrotic nodules,
hypotension, and priapism. Further study of the efficacy of multitherapy
versus monotherapy and of the relative complications and safety of each
approach is indicated. Although these agents have not received FDA
approval for this indication, they are in widespread clinical use.
Patients treated with these agents should give full informed consent.
There is a high rate of patient dropout, often early in the treatment.
Whether this is related to side effects, lack of spontaneity in sexual
relations, or general loss of interest is unclear. Patient education and
followup support might improve compliance and lessen the dropout rate.
However, the reasons for the high dropout rate need to be determined and
quantified.
Vacuum/Constrictive Devices
Vacuum constriction devices may be effective at generating and
maintaining erections in many patients with erectile dysfunction and
these appear to have a low incidence of side effects. As with
intracavernosal injection therapy, there is a significant rate of
patient dropout with these devices, and the reasons for this phenomenon
are unclear. The devices are difficult for some patients to use, and
this is especially so in those with impaired manual dexterity. Also,
these devices may impair ejaculation, which can then cause some
discomfort. Patients and their partners sometimes are bothered by the
lack of spontaneity in sexual relations that may occur with this
procedure. The patient is sometimes also bothered by the general
discomfort that can occur while using these devices. Partner involvement
in training with these devices may be important for successful outcome,
especially in regard to establishing a mutually satisfying level of
sexual activity.
Vascular Surgery
Surgery of the penile venous system, generally involving venous
ligation, has been reported to be effective in patients who have been
demonstrated to have venous leakage. However, the tests necessary to
establish this diagnosis have been incompletely validated; therefore, it
is difficult to select patients who will have a predictably good
outcome. Moreover, decreased effectiveness of this approach has been
reported as longer term followups have been obtained. This has tempered
enthusiasm for these procedures, which are probably therefore best done
in an investigational setting in medical centers by surgeons experienced
in these procedures and their evaluation.
Arterial revascularization procedures have a very limited role (e.g.,
in congenital or traumatic vascular abnormality) and probably should be
restricted to the clinical investigation setting in medical centers with
experienced personnel. All patients who are considered for vascular
surgical therapy need to have appropriate preoperative evaluation, which
may include dynamic infusion pharmaco-cavernosometry and cavernosography
(DICC), duplex ultrasonography, and possibly arteriography. The
indications for and interpretations of these diagnostic procedures are
incompletely standardized; therefore, difficulties persist with using
these techniques to predict and assess the success of surgical therapy,
and further investigation to clarify their value and role in this regard
is indicated.
Penile Prostheses
Three forms of penile prostheses are available for patients who fail
with or refuse other forms of therapy: semirigid, malleable, and
inflatable. The effectiveness, complications, and acceptability vary
among the three types of prostheses, with the main problems being
mechanical failure, infection, and erosions. Silicone particle shedding
has been reported, including migration to regional lymph nodes; however,
no clinically identifiable problems have been reported as a result of
the silicone particles. There is a risk of the need for reoperation with
all devices. Although the inflatable prostheses may yield a more
physiologically natural appearance, they have had a higher rate of
failure requiring reoperation. Men with diabetes mellitus, spinal cord
injuries, or urinary tract infections have an increased risk of
prosthesis-associated infection. This form of treatment may not be
appropriate in patients with severe penile corporal fibrosis, or severe
medical illness. Circumcision may be required for patients with phimosis
and balanitis.
Staging of Treatment
The patient and partner must be well informed about all therapeutic
options including their effectiveness, possible complications, and
costs. As a general rule, the least invasive or dangerous procedures
should be tried first. Psychotherapy and behavioral treatments and
sexual counseling alone or in conjunction with other treatments may be
used in all patients with erectile dysfunction who are willing to use
this form of treatment. In patients in whom psychogenic erectile
dysfunction is suspected, sexual counseling should be offered first.
Invasive therapy should not be the primary treatment of choice. If
history, physical, and screening endocrine evaluations are normal and
nonpsychogenic erectile dysfunction is suspected, either vacuum devices
or intracavernosal injection therapy can be offered after discussion
with the patient and his partner. These latter two therapies may also be
useful when combined with psychotherapy in those with psychogenic
erectile dysfunction in whom psychotherapy alone has failed. Since
further diagnostic testing does not reliably establish specific
diagnoses or predict outcomes of therapy, vacuum devices or
intracavernosal injections often are applied to a broad spectrum of
etiologies of male erectile dysfunction.
The motivation and expectations of the patient and his partner and
education of both are critical in determining which therapy is chosen
and in optimizing its outcome. If single therapy is ineffective,
combining two or more forms of therapy may be useful. Penile prostheses
should be placed only after patients have been carefully screened and
informed. Vascular surgery should be undertaken only in the setting of
clinical investigation and extensive clinical experience. With any form
of therapy for erectile dysfunction, long-term followup by health
professionals is required to assist the patient and his partner with
adjustment to the therapeutic intervention. This is particularly true
for intracavernosal injection and vacuum constriction therapies.
Followup should include continued patient education and support in
therapy, careful determination of reasons for cessation of therapy if
this occurs, and provision of other options if earlier therapies are
unsuccessful.
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