A penile prosthesis is a device that is implanted inside the penis with the aim of providing it with the necessary rigidity to be able to penetrate and thus maintain sexual intercourse. Regardless of the type, it essentially consists of two cylinders that are placed inside the corpora cavernosa and eventually replace them to achieve a state of erection or flaccidity. Given that a surgical operation is necessary to place it, and because once it is implanted it is not possible to resume other treatments, it constitutes the last of the steps among the therapeutic options for erectile dysfunction. It does, however, present the best satisfaction rates among all of them. Although it is a relatively simple surgery, it has been shown that implantations performed in expert high-volume centres reduce the complications associated with the operation.
Despite the fact that devices to treat erectile dysfunction have been used since ancient times, the first modern prostheses were developed in the 1970s. Since then, they have evolved and improved in aspects such as durability, reliability, protection against infection and appearance of the penis, both during erection and flaccidity.
There are different types of prostheses available today:
1. Malleable prostheses
They consist of two silicone cylinders with a rigid but malleable skeleton (normally, made of silver). Each cylinder is inserted into the corpora cavernosa after making an incision. This way, the penis is left with the necessary consistency for penetration. The disadvantage of these prostheses is that the penis is constantly maintained in a state of rigidity, and it is only possible to change its position.
However, it presents two big advantages: they are more affordable and easier to use, since it is not necessary to activate and deactivate them. The postoperative period and recovery are also usually faster.
2. Hydraulic prostheses
In these prostheses, the cylinders are hollow and, thanks to the hydraulic mechanism, they are filled with serum to achieve an erection. Depending on the complexity of the mechanism, they are divided into:
» Two-component: The cylinders are united with a pump hosted in the scrotum. This way, when the patient presses the pump, the serum will pass to the inflatable cylinders, thus achieving rigidity. To deflate the prosthesis, it is sufficient to press on the corpora cavernosa until they are completely emptied.
» Three component: they are the most functional. They resemble a natural erection and achieve an almost physiological state of flaccidity. In addition to the cylinders, they consist of a pump (which is placed in the scrotum) and a reservoir (behind the pubic bone) connected to each other. This pump has two buttons for emptying and filling the cylinders. During the emptying phase, the serum is stored in the reservoir. They are, on the contrary, the ones with the highest economic cost.
There are several ways to place the prosthesis. The incision may be subpubic (behind the pubic bone), subcoronal (under the glans) or penoscrotal (between the base of the penis and the scrotum). The choice depends on the surgeon and the type of prosthesis.
As with other operations, the placement of a prosthesis may present complications, such as urinary retention, or the appearance of haematomas or oedemas, which will not lead to long-term problems. However, the most feared complication is infection of the device, which can lead to its removal. Therefore, measures to prevent infections are very strict and make them infrequent, affecting only 1-8% of the cases. The mechanical malfunction rate at 5 years is approximately 10%.
One of the frequently asked questions for patients who are considering a prosthesis is whether sexual desire, orgasm sensation and ejaculation may be affected. Prosthesis implantation surgery does not interfere with any of these three aspects. Likewise, the patient should know that the length of the penis will not be increased and, in fact, in some cases a shortening of 1-2 cm is observed.
