Medicine:Penile prosthesis

A penile prosthesis, or penile implant, is a medical device which is surgically implanted within the corpora cavernosa of the penis during a surgical procedure. The device is indicated for use in men with organic or treatment-resistant impotence or erectile dysfunction that is the result of various physical conditions such as cardiovascular disease, diabetes, pelvic trauma, Peyronie's disease, or as the result of prostate cancer treatments. Less commonly, a penile prosthesis may also be used in the final stage of plastic surgery phalloplasty to complete female to male gender reassignment surgery as well as during total phalloplasty for adult and child patients that need male genital modification.

Reasons for use

A penile implant is one treatment option available to individuals who are unable to achieve or maintain an erection adequate for successful sexual intercourse or penetration. Its primary use is for men with erectile dysfunction from vascular conditions (cardiovascular disease, high blood pressure, diabetes), congenital anomalies, iatrogenic, accidental penile or pelvic trauma, Peyronie's disease, or as a result of prostate cancer treatments. This implant is normally considered when less invasive medical treatments such as oral medications (PDE5 inhibitors: Viagra, Levitra, Cialis), penile injections, or vacuum erection devices are unsuccessful, provide an unsatisfactory result, or are contraindicated. For example, many drugs used to treat erectile dysfunction are unsuitable for patients with heart problems and may interfere with other medications.

Sometimes a penile prosthesis is implanted during surgery to alter, construct or reconstruct the penis in phalloplasty. The British Journal of Urology International reports that unlike metoidioplasty for female to male sexual reassignment patients, which may result in a penis that is long but narrow, current total phalloplasty neophallus creation using a musculocutaneous latissimus dorsi flap could result in a long, large volume penis which enables safe insertion of any type of penile prosthesis.

This same technique enables male victims of minor to serious iatrogenic, accidental or intentional penile trauma injuries (or even total emasculation) caused by accidents, child abuse or self-mutilation to have penises suitable for penile prosthesis implantation enabling successful sexual intercourse.

In some cases of genital reconstructive surgery, implantation of a semirigid prosthesis is recommended for three months after total phalloplasty to prevent phallic retraction. It can be replaced later with an inflatable one.

Types of devices

There are two primary types of penile prosthesis: noninflatable semirigid devices, and inflatable devices. Noninflatable, semirigid devices consist of rods implanted into the erection chambers of the penis and can be bent into position as needed for sexual penetration. With this type of implant the penis is always semi-rigid and therefore may be difficult to conceal.

Hydraulic, inflatable prosthesis also exist and were first described in 1973 by Brantley Scott et al. These saline-filled devices consist of inflatable cylinders placed in the erection chambers of the penis, a pump placed in the scrotum for patient-activated inflation/deflation, and a reservoir placed in the abdomen which stores the fluid. The device is inflated by squeezing the pump several times to transfer fluid from the reservoir to the chambers in the penis. After intercourse, a valve next to the pump is manually operated, allowing fluid to be released from the penis (not instantaneously; squeezing the penis may be necessary), causing the penis to return to a flaccid or semi-flaccid condition. Almost all implanted penile prosthesis devices perform satisfactorily for a decade or more before needing replacement. Some surgeons recommend these due to the opinion that they are more easily concealed and provide the highest levels of patient/partner satisfaction.

Three piece inflatable penile prosthesis

Advantages

• Mechanical failure rates are low: most often inability to deflate the penis because of pump failure; less often inability to inflate the prosthesis; and sometimes disconnection or failure of the reservoir.
• IPP (Inflatable Penile Prostheses) are easily concealable under clothing including swimsuits or jeans.
• The erection can be maintained as long as necessary, or as long as desired without any of the potentially serious complications of organic priapism.
• Psychological and emotional well-being is enhanced in a proportion of men who undergo implant surgery. Some studies indicate a high level of patient satisfaction, attributable in part to improved technology in the prosthesis itself, improved surgical techniques making the procedure less painful, and more reasonable patient expectations.
• Inflation of the device can be accomplished discreetly.

Disadvantages

• The glans does not enlarge and sexual penetration may be awkward. The penis also may not be as firm as a natural erection.
• Some models do not deflate easily; some degree of manual dexterity is required to operate any of the inflatable models, making them inappropriate for men with other neurological disorders such as stroke or Parkinson's disease.
• The penis may not be completely flaccid, depending upon the model of prosthesis (most usually seen in semi-rigid or malleable implants).
• Many men lose between 1–2 cm (.25 to .75 in) in length.
• Following surgery, patients experience one to two weeks of moderate or occasionally severe pain, usually controlled with analgesics. This is most often due to scrotal swelling, which can be quite profound at times. Normal sexual intercourse can be resumed six to eight weeks post-operatively, pending clearance from the surgeon.
• Not all men report complete satisfaction with the prosthesis.
• Some studies indicate a partner satisfaction rate of 70% or less, due, some studies suggest, to heightened or unreasonable expectations. Many surgeons are now recommending that both partners be counseled pre-operatively regarding outcome and expectations.
• The inflation of the devices is not instantaneous.
• It can be difficult to conceal a prosthesis because the scrotal components are hard and irregularly shaped. A partner feeling the scrotum will notice this.
• Manual stimulation can be painful.
• There is a 2-10% complication rate, mainly as a result of infection or device failure. Complications include: uncontrolled bleeding after the surgery possibly leading to re-operation, scar tissue formation, erosion (tissue around the implant may break down) requiring removal or mechanical failure leading to re-operation and removal.

External links

• Medscape
• https://web.archive.org/web/20090314071253/http://cat.inist.fr/?aModele=afficheN&cpsidt=862126