Penile Implants An implantable penile prosthesis (artiﬁcial device) is another treatment option that has improved in design in recent years. All penile implants place prosthetic tubes inside the penis to mimic the engorgement process and create an erection. Since the 1950s, thousands of men have been treated suc- cessfully with implants. These devices work best for men who can ejaculate and have orgasms even if they cannot achieve erections.
Implants are effective in treating most types of erectile dysfunction. They have a 90 percent success rate when both partners are informed about how they work and what their limitations are. Men with penile implants do not require intensive follow-up treatment after implantation, and no medications or injections are required. In addition, once the implant is in place and functioning, there are no additional costs. The newer prostheses are very reliable, with a chance of mechanical failure in the range of only 2 to 4 percent per year.
One drawback of the implantable penile prostheses is that their placement per- manently changes the internal structure of the penis. If the prosthesis is ever removed, normal erections do not return. There is also a small (3 to 5 percent) chance of infection that could require removal of the implant. Some men develop
surgical or anesthetic complications or experience numbness at the head of the penis and uncomfortable intercourse. Also, because the erection is not caused by increased blood ﬂow to the penis, the head of the penis is not part of the erection, and this softness may bother some men.
There are three types of penile prostheses currently available:
• Inﬂatable penile prostheses are the most natural-feeling of the penile implants, because the penis can be either erect or ﬂaccid. These two-piece or three-piece implants are made of soft tubes of silicone or similar material. The tubes are ﬁlled with a sterile liquid that comes from a small reservoir placed either under the muscles of the abdomen (three-piece implant) or in the scro- tum (two-piece implant). A tiny pump in the scrotum is used to move the ﬂuid from the reservoir to the tubes. The more ﬂuid that is pumped into the tubes, the ﬁrmer and larger the erection. When the erection is no longer desired, the pump is deactivated and the ﬂuid returns to the reservoir, leaving the penis soft again. The major advantage of an inﬂatable penile implant is that it pro- vides a more natural erection that the user can control. One major disadvan- tage is that this type of device is slightly more complicated to implant and, because it has more mechanical parts, there is an increased risk of leaks, twist- ing of the tubes, or mechanical failure.
• Self-contained inﬂatable implants use paired silicone cylinders that have a pump at the tip of the prosthesis. A reservoir within the shaft of the device allows ﬂuid to transfer in such a way that the cylinder becomes ﬁrm. The advantage of this device is that surgery is slightly simpler than that for a two- or three-piece inﬂatable prosthesis. The major disadvantage is that the inﬂat- able portion does not signiﬁcantly increase the girth of the penis. The penis is also not as soft or as easily concealed when deﬂated.
• Semirigid prostheses are made from silicone-covered bendable metal rods.
They allow the penis to be rigid enough for penetration but ﬂexible enough to be concealed in a curved position. They are the simplest and least expensive of all implants and have the least chance of mechanical failure. The major problem with semirigid implants is that the penis is always semierect. Even with bendable implants, concealment can be a problem with certain types of clothing. Another disadvantage is that the erection depends on the size and rigidity of the prosthesis. This type of prosthesis is not routinely used.