What is the role of prosthetic devices in the treatment of erectile dysfunction (ED)?

Updated: Aug 08, 2018
  • Author: Edward David Kim, MD, FACS; Chief Editor: Edward David Kim, MD, FACS  more...
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Answer

In the past, the placement of prosthetic devices within the corpora was the only effective therapy for men with organic ED. At present, however, it is the last option considered, even though more than 90% of men with an implant would recommend the procedure to their friends and relatives. Before selecting this form of management, the patient and his sexual partner should be counseled regarding the benefits and risks of this procedure (see Table 2 below). [108, 109]

Table 2. Advantages and Disadvantages of Different Types of Penile Implants for Erectile Dysfunction (Open Table in a new window)

Treatment

Advantages

Disadvantages

Semirigid or malleable rod implants

Simple surgery

Relatively few complications

No moving parts

Least expensive implant

Success rate of 70-80%

Highly effective

Constant erection at all times

May be difficult to conceal

Does not increase width of penis

Risk of infection

Permanently alters or may injure erection bodies

Most likely implant to cause pain or erode through skin

If unsuccessful, interferes with other treatments

Fully inflatable implants

Mimics natural process of rigidity-flaccidity

Patient controls state of erection

Natural appearance

No concealment problems

Increases width of penis when activated

Success rate of 70-80%

Highly effective

Relatively high rate of mechanical failure

Risk of infection

Most expensive implant

Permanently alters or may injure erection bodies

If unsuccessful, interferes with other treatments

Self-contained inflatable unitary implants

Mimics natural process of rigidity-flaccidity

Patient controls state of erection

Natural appearance

No concealment problems

Simpler surgical procedure than that required for fully inflatable prosthesis

Success rate of 70-80%

Highly effective

Sometimes difficult to activate the inflatable device

Does not increase width of penis

Mechanical breakdowns possible

Long-term results not available

Risk of infection

Relatively expensive

Permanently alters or may injure erection bodies

If unsuccessful, interferes with other treatments

Implants are usually used for men who have not experienced success with other therapies or who require penile reconstructions. Men who have undergone a radical prostatectomy for prostate cancer and in whom a nerve-sparing procedure was not performed or was not successful often do not respond to oral PDE5 inhibitors, and these men are good candidates for a penile implant. The same is true for men treated with radiation therapy, though more of these men tend to respond to oral agents.

Daily use of a vacuum erection device for a month before implantation of a penile prosthesis may prove beneficial. A randomized controlled trial by Canguven et al found that this strategy was associated with a significantly greater mean stretched penile length on the day of surgery; in addition, surgeons reported easier corporal dilatation intraoperatively. [110]

There is some evidence to suggest that an additional benefit may be gained by some men who have an implant but also take an oral PDE5 inhibitor. Sexual stimulation and sensation are enhanced.

Penile prostheses can be divided into the following 2 broad categories:

  • Semirigid
  • Inflatable

With the semirigid prosthesis, 2 matching cylinders are implanted into the corpora cavernosa (see the image below). These devices provide enough rigidity for penetration and rarely break. The major drawbacks are the cosmetic appearance of the penis (which remains semierect at all times), the need for surgery, and the destruction of the natural erectile mechanism when the prosthesis is implanted.

Two rigid cylinders have been placed into the corp Two rigid cylinders have been placed into the corpora cavernosa. This type of implant has no inflation mechanism but provides adequate rigidity to the penis to allow penetration.

The inflatable devices consist of 2 Silastic or Bioflex cylinders inserted into the corpora cavernosa, a pump placed in the scrotum to inflate the cylinders, and a reservoir that is contained either within the cylinders or in a separate reservoir placed beneath the fascia of the lower abdomen (see the images below). The inflatable prosthesis generally remains functional for 7-10 years before a replacement may be necessary. Improvements in these devices have resulted in a failure rate lower than 10%.

This inflatable penile prosthesis has 3 major comp This inflatable penile prosthesis has 3 major components. The 2 cylinders are placed within the corpora cavernosa, a reservoir is placed beneath the rectus muscle, and the pump is placed in the scrotum. When the pump is squeezed, fluid from the reservoir is transferred into the 2 cylinders, producing a firm erection. The deflation mechanism is also located on the pump and differs by manufacturer.

Patient acceptance of these devices is very high, with nearly 100% of recipients expressing satisfaction. Part of this enthusiasm is related to the failure of other therapies and the highly motivated patient population.

Rajpurkar and Dhabuwala reported significantly better erectile function and satisfaction with a penile implant than with sildenafil or intracavernosal alprostadil (PGE1). [111] This was a nonrandomized study in which all 138 subjects were initially offered sildenafil. The mean follow-up was 19.54 months, and questionnaires were used to obtain the data.

Complications include infections (occurring in 2% of patients), erosion of the device through the urethra or skin (2%), and painful erections (1%). The development of an antibiotic-coated device has further reduced the infection rate. Patients should also be counseled that the penis does not lengthen as much as with normal erections.


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