Penile Prosthesis

Penile Prosthesis

Almost 3.000 years ago, the Chinese already used ivory sticks to complete and assist penile erection. The world effective experience dates back to 30 years, with the advent of the first synthetic-material prosthesis, the acrylic resin, placed between the tunica albuginea and Buck's fascia. Later, penile prostheses as they are known today turned up, placed inside the corpora cavernosa.

Since the development of other options, prostheses have assumed a much smaller role in the treatment of erectile dysfunction. However, various types of prostheses are still in routine use are:

Penile Injections

a) Semirigid, malleable rods can also be inserted into the penis to provide penile erection.

Semirigid, malleable rods

b) Two piece inflatable prosthesis, the pump and reservoir are in the scrotum and are used to inflate the cylinders into the erect position. The cylinders are then deflated by pressing a valve at the base of the pump to return the fluid to the reservoir

Semirigid, malleable rods

c) In a three piece inflatable prosthesis, the pump is in the scrotum and the reservoir is in the abdomen.

Semirigid, malleable rods
  • Problems with intracavernosal drugs and external devices (unwilling to consider them, failure to respond to them, unable to continue with them)
  • Penile fibrosis from injection
  • Peyronie's disease with impotence
  • Damage after priapism Psychological impotence
  • After all other treatments have failed.

Each type has advantages and disadvantages, which should be matched to the patient's individual preferences.

These devices are the same shape and size at all times, but may be straightened or flexed for concealment. They have less tendency than the inflatable devices for mechanical wear and are surgically easier to place. However, penile flaccidity, concealment, and girth are not optimal. The rods are usually placed through circumcision-like or penile-scrotal incisions.

The malleable prosthesis does not change the length and girth of the penis during "tumescence" and "detumescence." Malleable implants usually consist of paired rods, which are inserted surgically into the corpora cavernosa, the twin chambers running the length of the penis. The user manually adjusts the position of the penis and, therefore, the rods. Adjustment does not affect the width or length of the penis.

Malleable Rods
Malleable Prosthesis

The semirigid device consists of two rods that are easier and less expensive to implant than the inflatable cylinders. Once implanted, the semirigid device needs no follow-up adjustments, however it produces a penis which constantly remains semi-erect

The malleable prosthesis is preferable for patients with poor manual dexterity or those with spinal cord injuries who need a prosthesis to facilitate application of a condom catheter.

The malleable (shown at the right) are rods that can be bent so the penis can folded down or up to be erect. Two rods are inserted.

The inflatable implant is a common penile prosthesis

    The inflatable devices are either:
  • Two-piece systems with a single combination scrotal pump and reservoir
  • Three-piece devices with a separate scrotal pump and a muscle reservoir placed in the retropubic or retroperitoneal space.
Malleable Rods
Implantation

Implantation of the multicomponent inflatable prosthesis requires placement of inflatable cylinders into each corpus, the reservoir into the perivesical or preperitoneal space, and the pump into the scrotum (on the right side for right-handed patients, on the left for the left-handed). This device connects through a tube to a flexible fluid reservoir and a pump. The pump is shaped like a testicle and inserted in the scrotum. When the pump is squeezed, the fluid is forced into the inflatable cylinders implanted inside the penis, producing an erection.

Both types increase in girth, and the three-piece devices also increase in length.

The inflatable cylinders produce a more natural effect. The patient is able to simulate an erection by using a pump located in the scrotum.

Two-piece systems are particularly useful for patients in whom placement of an abdominal reservoir would be difficult or impossible. They are also somewhat easier to place surgically, but produce approximately 80% to 85% of the girth change and rigidity of the three-piece unit and less flaccidity when deflated.

Two-piece system

The three-piece devices offer the best flaccidity, rigidity, and girth, particularly suitable for patients who have a significant curvature of the penis due to Peyronie's disease.

Two Piece

Three-piece device

Three piece penile prosthesis in which the pump alone sits in the scrotum and the reservoir lies in the lower abdominal wall.

Three Piece

How it works

How it works

A patient in whom a three part inflatable prosthesis has been implanted.

It shows the placement of the reservoir behind the abdominal wall.

The pump is in the scrotal sac. At the top of the pump is the inflation site which is squeezed to push fluid into the cylinders. At the bottom of the pump is the deflation site which is squeezed to allow the fluid to return to the reservoir

The cylinders are in the penis
Reservoir Angle

Here is another angle to give a better idea where the parts are located

This illustrates the direction of the flow of the fluid into the cylinders, to produce the erection, when the inflation pump is squeezed repeatedly.

Note the reservoir at the top is now deflated.

By holding the deflation site and squeezing the penis, the fluid returns to the reservoir and the penis is flaccid again.

Inflatable Pump

Postoperative Photograph of the Efficacy of an Inflatable Pump.

Inflated Pump After Insertion

Appearance of a penis after insertion of an inflatable prosthesis, with the device deflated (top) and inflated (left)

In spite of being the most invasive of the procedures for the treatment of erectile dysfunction, the major advantages of the penile prostheses are: the relative spontaneity associated with their use, their applicability to and effectiveness in patients with all types of organic dysfunction and importantly, high patient and partner satisfaction (90% to 95%).