|Year : 2006 | Volume
| Issue : 3 | Page : 251-254
Penile prostheses: Are they obsolete?
DK Montague, KW Angermeier
Cleveland Clinic Lerner College of Medicine of Case Western Reserve University, Section of Prosthetic Surgery and Genitourethral Reconstruction, Glickman Urological Institute, Cleveland Clinic Foundation, Cleveland, OH, USA
D K Montague
Glickman Urological Institute, A/100, Cleveland Clinic Foundation, 9500 Euclid Avenue, Cleveland, OH 44195
Source of Support: None, Conflict of Interest: None
| Abstract|| |
PURPOSE: The purpose of this review was to examine the role of penile prosthesis implantation in the era of multiple treatment options for erectile dysfunction (ED). METHODOLOGY: A literature search was performed to identify reports of three-piece inflatable penile prosthesis survival, free of mechanical failure in which results were given as Kaplan-Meier projections. Patient and partner satisfaction articles were also identified and reviewed. CONCLUSIONS: With multiple treatment options for ED, the percentage of men going on to penile prosthesis implantation is decreasing. However, because of the attractiveness of new treatment options and increased public awareness, more men with ED are presenting today for treatment. Penile prosthesis implantation is the only option which is applicable to nearly every man with ED and thus penile prosthesis implantation continues to play an important role in the management of ED. Patient and partner satisfaction with penile prosthesis implantation, particularly with three-piece inflatable devices, is higher than for any other treatment option.
Keywords: Erectile dysfunction, inflattable prosthesis, malleable prosthesis, prosthesis
|How to cite this article:|
Montague D K, Angermeier K W. Penile prostheses: Are they obsolete?. Indian J Urol 2006;22:251-4
| Introduction|| |
For many years impotence, the preferred term today is erectile dysfunction (ED), was assumed in most cases to be due to psychogenic causes. Indeed, until the inflatable penile prosthesis was introduced in 1973, urologists had little interest in either the evaluation or treatment of ED. From 1973 until the mid-1980s the primary treatment for ED was penile prosthesis implantation, unless the disorder was felt to be temporary in which case sex therapy was recommended. In the mid-1980s penile injection therapy was introduced and about the same time vacuum erection device therapy became medically acceptable. Intraurethral prostaglandin E 1 , a way of delivering a vasoactive drug directly to the corpora cavernosa without injection using a needle, was developed just after the mid-1990s. Shortly before the turn of the century another major advance was made with the introduction of sildenafil citrate (Viagra, Pfizer), the first systemic drug for ED demonstrating significant efficacy. Now two other drugs in this class of PDE5 inhibitors are also available: vardenafil HCl (Levitra, Bayer, GlaxoSmithKline) and tadalafil (Lilly-ICOS).
Penile prosthesis implantation has thus gone from being almost the sole treatment for ED to being only one of several effective treatment options. What is the role of penile prosthesis implantation today in the era of effective systemic therapy and other nonsurgical treatments?
The initial treatment for almost all men with ED is a trial with one or more of the PDE 5 inhibitors. Men who fail treatment with the systemic PDE 5 inhibitors may wish to try using a vacuum erection device. With adequate instructions many men are able to use vacuum devices for successful coitus. However, in our experience men and their partners frequently find this form of treatment unacceptable either because of the discomfort associated with the use of the device or because of the interference this treatment imposes on lovemaking.
The next step in treatment is intracavernosal drug therapy with vasoactive medications being delivered to the corpora cavernosa either by direct injection or by introduction into the distal urethra. These methods of treatment, especially direct injection, are often successful in terms of restoring the ability to have coitus. Adverse effects with injection include pain with erection, penile fibrosis and prolonged erections., Drawbacks of intraurethral medication include pain with erection and relatively low efficacy. As with the use of vacuum erection devices, both injection therapy and intraurethral drug therapy interfere with the act of lovemaking; however, most couples find these methods more acceptable. For various reasons penile injection programs report drop-out rates of 50% or more.,
Because vacuum erection devices, intraurethral medication and penile injection therapies are capable of producing erections independent of sexual stimulation, they are all potentially useful in cases where nerves are not intact. However, these modalities do not work in all men; and for some men even when they do work they are unacceptable.
Penile prosthesis implantation, therefore, is indicated in men with organic ED when nonsurgical treatments have either failed or are unacceptable. Unlike other treatment options which will work in some but not all men, penile prosthesis implantation is the only treatment option which is potentially effective in all men with erectile dysfunction. Finally, among treatments for ED, penile prosthesis implantation has the highest patient and partner satisfaction rates.,,,,
We have thus seen how treatment for ED has changed from penile prosthesis implantation being the only available treatment 30 years ago for the majority of men with ED to today where fewer than 10% of men with ED are likely to be treated with implantation of a prosthetic device. Thirty years ago, however, when penile prosthesis implantation was almost the sole treatment, relatively few men came forward to seek relief from their ED. Today with numerous attractive therapies available and greater public awareness concerning the medical aspects of ED, vastly increased numbers of men with erection problems are presenting for treatment. It is likely therefore that penile prosthesis implantation will not only remain as a legitimate treatment option for ED, but it is also possible that the numbers of men being treated with this option will increase significantly.
| The ideal penile prosthesis|| |
In the era of patient's goal-directed therapy where treatment of ED is usually dictated by patient and partner wishes, penile prosthesis implantation needs to compete with other treatment options. When men elect penile prosthesis implantation, they are less likely to be satisfied than they used to be with the limited cosmetic and functional results obtainable from the implantation of semi-rigid rod or malleable prostheses. Even two-piece inflatable prostheses usually result in significant compromise in terms of prosthetic flaccidity and erection. The ideal penile prosthesis would produce flaccid and erect states which come as close as possible to normal. To do this a large volume of fluid must be transferred into expanding penile cylinders for erection and back out of the cylinders for flaccidity. Devices capable of doing this are three-piece inflatable prostheses. These devices have three parts: paired penile cylinders, a small scrotal pump and a large abdominal fluid reservoir. Finally, the ideal penile prosthesis should provide with inflation not only penile rigidity but also both girth and length expansion.
Two companies manufacture three-piece inflatable prostheses. Mentor (Santa Barbara, California, U.S.A.) produces the Mentor Alpha I, the Mentor Alpha I narrow back and the Mentor Titan [Figure - 1] devices. American Medical Systems (AMS) (Minnetonka, Minnesota, U.S.A.) produces the AMS 700 CX, the AMS 700 CXR and the AMS 700 Ultrex inflatable prostheses. One penile prosthesis, American Medical System's AMS 700 Ultrex [Figure - 2], approaches the ideal of providing both girth and length expansion. While the Ultrex penile prosthesis cylinders can expand 15-17% in length outside the body, the amount of length expansion obtained by individual patients depends on the elastic characteristics of their corpora.
| Tailoring cylinder selection to the patient's needs|| |
The AMS 700 CX prosthesis has cylinders which are of the same diameter as the AMS Ultrex and produce the same amount of girth expansion; however, they produce no length expansion. The AMS 700 CXR prosthesis has cylinders with a smaller diameter and a rear tip that is specially designed for insertion into small or fibrotic corpora. Like the CX cylinders, the CXR cylinders provide only girth expansion.
The AMS 700 CX cylinders have better straightening properties than the Ultrex and we prefer them in men with Peyronie's disease and ED. Also for men with long, narrow penises, CX cylinders provide better rigidity. Men with corporeal fibrosis have limited stretch in their penises and would not benefit from the length expanding characteristics of the Ultrex cylinders. Furthermore, in these men often it is not possible to dilate the corpora sufficiently to place standard diameter CX or Ultrex cylinders. For these reasons we have found the AMS 700 CXR cylinders with their small diameter and narrow rear tip to be ideal in men with corporeal fibrosis which limits dilation. The AMS 700 CXR device replaces a similar device with narrow cylinders, the AMS 700 CXM prosthesis.
Taking these factors into consideration, we select the type of AMS three-piece prosthesis as follows. For first-time penile prosthesis recipients, if the penis has at least 2 cm of stretch, we select the Ultrex device. For men with a long, narrow penis we select the CX device and we also use the CX cylinders in men who have both ED and Peyronie's disease. For men with corporeal fibrosis following priapism, CXR cylinders are usually required. Rarely, other first-time prosthesis recipients have a penis small enough to require the small size CXR cylinders.
For secondary or repeat penile prosthesis recipients, we use CX cylinders in circumstances where penile length expansion should be avoided, for example after previous urethral erosion or distal cylinder crossover. For men with corporeal fibrosis owing to removal of an infected penile prosthesis, we will use CXR cylinders if corporeal dilation is limited as it often is in these cases. For other secondary penile prosthesis recipients, we will select the Ultrex cylinders if the penis has at least 2 cm of stretch.
| Freedom from mechanical failure|| |
The ability of the Ultrex cylinders to provide length expansion was associated initially with a higher rate of cylinder failure. The Ultrex cylinders were introduced in 1990. After recognizing the decreased durability of these cylinders, American Medical Systems increased the strength of the middle fabric layer of the Ultrex cylinders in 1993. We showed that this modification of the middle fabric layer significantly improved Ultrex cylinder survival.
Current Kaplan-Meier five-year projections for freedom from mechanical failure for today's three-piece inflatable penile prostheses are: Mentor Alpha-1 92.6%, AMS 700 CX 90.8% and AMS 700 Ultrex 93.7%. We recently showed a 10-year Kaplan-Meier projection for freedom from mechanical failure for the AMS 700 CX and the AMS 700 CXM of 81.3%.
Reducing penile prosthesis infections
In 2001 American Medical Systems introduced InhibiZone,TM an antibiotic rifampin-minocycline coating, for their three-piece inflatable penile prostheses. Carson reported that the infection rate with noncoated implants was 1.61% and for InhibiZone-coated prostheses it was 0.68%. In 2002 Mentor introduced the Mentor Titan three-piece inflatable prosthesis with a hydrophilic polyvinylpyrrolidone coating which reduces bacterial adherence and absorbs antibiotics. The infection rate in the coated group was 1.06% and in the noncoated group it was 2.07%.
| Conclusions|| |
In the era of multiple treatment options for ED, penile prosthesis implantation will be the chosen treatment modality for a relatively small percentage of men with this disorder. However, because of the attractiveness of some of these therapies, especially oral systemic therapies and because of expanded public awareness, many more men are presenting for treatment of ED and the number of men who will ultimately undergo penile prosthesis implantation may increase significantly.
Penile prosthesis implantation is the only option which is applicable to nearly every man with this disorder. Furthermore, among treatment options for ED, penile prosthesis implantation has the highest reported patient and partner satisfaction rates. Men receiving treatment for ED today have higher expectations than they did previously and when they elect to have a prosthesis inserted, they are less likely than before to be satisfied with a semi-rigid rod or even a two-piece inflatable device. Three-piece inflatable penile prostheses manufactured by American Medical Systems and Mentor provide penile flaccidity and erection which approach normal. One three-piece device, the AMS 700 Ultrex prosthesis, provides with inflation not only girth but also length expansion. With a three-piece inflatable prosthesis one cylinder type is not optimal for all patients and cylinder selection should be tailored to the patient's needs.
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[Figure - 1], [Figure - 2]