Penile Implants

Potency always has been something special in human culture. Its effects even have been intertwined within early Common and Church laws in Europe. For instance, laws required that marriages be consummated, and, if not, it was grounds for annulment. Considering that this happened in an age where divorce was extremely rare shows the magnitude of the "offense" of impotency.

Although less drastic today, potency still plays a large part in men's self-image and impacts their relationship with their partners. Before 1960, urologic therapy for erectile dysfunction (ED) was rare. ED was branded a psychiatric disorder with little surgical role. More recently, insight has been gained into the pathophysiology of male sexual dysfunction, and both medical and surgical treatments of ED now are common.

Today, penile prostheses prove to be both reliable and durable, with approximately 20,000-30,000 devices implanted annually worldwide.

WHAT ARE PENILE PROSTHESES?

Penile prostheses are devices that are implanted completely within the body. They produce an erection-like state that enables the man who has one of these implants to have normal sexual intercourse.

Surgical therapy for erectile dysfunction consists mainly of the penile prostheses. Although both semi-rigid and inflatable devices are available, most men choose an inflatable PROSTHESIS because it results in a much more normal looking penis in both the flaccid and erect state.

Having a PROSTHESIS inserted does not change the ability to urinate, ejaculate, or have an orgasm.

DIFFERENT TYPES OF PENILE PROSTHESES

There are two erection chambers in the penis. All penile prostheses have a pair of components that are implanted within both of these erection chambers.

There are two basic types of PROSTHESIS. They are usually made of medical-grade plastic or silicone, and produce a degree of permanent penile rigidity that enables the man to have sexual intercourse.

The simpler type is the semi-rigid, malleable prosthesis. Malleable implants usually consist of paired rods, which are inserted surgically into the corpora cavernosa. A malleable rod PROSTHESIS can be bent downward for urination or upward for intercourse manually. Adjustment does not affect the width or length of the penis. This PROSTHESIS generally is considered for patients who are significantly obese, who have limited manual dexterity, or those who cannot have abdominal hardware such as reservoir balloons (i.e., patients having extensive abdominal surgery and those receiving peritoneal dialysis). The advantages of the semi-rigid devices are easier placement, less dependence on patient manual dexterity, lesser chance of part failure, and lower cost. The disadvantages are higher risk for device erosion, less concealability, and inability to change girth.

Inflatable cylinders are surgically placed inside the cavernous bodies and take over their function in erection.

Inflatable implants consist of paired cylinders, which are surgically inserted inside of the penis. These cylinders are expanded using pressurized fluid from a reservoir and a pump which is also surgically implanted. The patient inflates the cylinders by pressing on the small pump located under the skin in the scrotum. Inflatable implants can expand the length and width of the penis somewhat. These devices are often referred to as two-component penile prostheses. One component is the paired cylinders and the second component is the scrotal pump.

Three component inflatable penile prostheses have paired cylinders, a scrotal pump and an abdominal fluid reservoir. With these three component devices, a larger volume of fluid is pumped into the cylinders for erection and out of the cylinder when erection is no longer needed. Inflatable implants leave the penis in a more natural state when not inflated.

INDICATIONS FOR PENILE PROSTHESIS

The indications for penile PROSTHESIS placement are a motivated patient with ED who desires reconstitution of penile function adequate for intercourse and who has failed at least 1 (and usually several) more conservative treatment.

The treatments may include oral medications, PDE-5 inhibitor; intracavernosal injections of vasoactive substances, such as prostaglandin E1 (PGE1); intraurethral deposition of PGE1 pellets (medicated urethral system for erection [MUSE]); and vacuum-assist devices.

Patients with sickle cell anemia who have suffered priapism and/or cavernosal scarring also are potential candidates for inflatable penile PROSTHESIS. It offers not only a cure for their priapism, but it also provides them a close approximation to normal appearance and function.

Men with Peyronie's disease, which is a fibrous scar of the tunica albuginea, who have penile curvature may benefit from inflatable penile PROSTHESIS. The hydraulic effect of the PROSTHESIS can overcome the scar and help greatly to straighten the penis for adequate intercourse. Other surgeons place penile prostheses after excision and grafting of the Peyronie's plaque.

CONTRAINDICATIONS FOR PENILE PROSTHETICS

Some have listed psychogenic ED as a contraindication for penile PROSTHESIS implantation. However, patients with severe psychogenic ED that is longstanding and resistant to therapy might be considered for implant as long as they understand the treatment is permanent. Psychogenic ED usually is diagnosed through taking a careful sexual history and diagnostic testing, such as nocturnal penile tumescence (NPT) monitoring.

The clinician also may consider the patient's reliability for follow-up care as well as manual dexterity. If the patient cannot operate his device, he must have a supportive and willing partner who can help.

Patients with active/chronic infectious processes such as decubitus ulcers and venous stasis ulcers are at high risk for infecting their devices.

Replacement of a PROSTHESIS is often delayed after removal of an infected PROSTHESIS to allow adequate healing and eradication of the offending microorganism.

Follow-up care: Most men have pain after penile PROSTHESIS implantation for about four weeks. Initially, oral narcotic pain medication is required and driving is prohibited. If men limit their physical activity while pain is present, it usually resolves sooner. The patient is instructed to refrain from sexual activity for 6 weeks. After 6 weeks, the patient is instructed in the usage of the inflatable penile PROSTHESIS.

The surgery will permanently damage the individual's ability to have "natural" erections and should be regarded as permanent and non-reversible.

The ideal penile PROSTHESIS would result in a normal-appearing penis when flaccid and erect. However, prospective patients should be counseled that penile prostheses will not restore the full length once achieved by natural erections.

OUTCOMES AND PROGNOSIS

On average, patients may "wear-out" their PROSTHESIS in 4-8 years. However, as time goes by and technology improves, PROSTHESIS have become more durable.

Of men who have undergone this procedure, 95% are happy about their decision to have surgery. Patient satisfaction with surgery is bolstered by supportive staff and low infection and malfunction rates.

Complications of the implants include a reported 3% incidence of wound infection and malfunction of the PROSTHESIS. In case of trouble, surgery may be needed for removal and repair. There is no change in skin sensation and no change in ability to have an orgasm.

With steady improvements regarding PROSTHESIS material and construction, long-term survival of the modern implants show a lot of promise. Mechanical failure is more likely to occur with inflatable than with rod prostheses.

In summary, selection of the appropriate device for the individual patient is very important. Considerations include patient's preference and underlying medical condition, surgeon's preference, and cost of the device.