Review & Opinions

Factors Affecting the Choice of a Penile Prosthesis  -  Survey of Opinions

Our panel of experts from around the globe discusses the Factors Affecting the Choice of a Penile Prosthesis. The authors include Drs Steven K Wilson, John Mulcahy, Drogo K. Montague, Santiago Richter, Osama Shaeer, and Sudhakar Krishnamurti. It is also interesting to read the nurses perspective on this issue presented by Ms Amanda Spillings.

Penile implants became popular with the introduction of effective models more than 30 years ago. Today they play a secondary but definitive role in the treatment of erectile dysfunction at those times when more conservative therapies have failed, are contraindicated or not desired. Improvements in reducing the incidence of infection, treating infection with antiseptic washes, enhancing device longevity, and instituting new surgical techniques for less patient morbidity have made prostehtics more acceptable to patients. Although the implantation of a penile prosthesis is the least often chosen and most invasive of all ED treatments, they carry the highest satisfaction rate among both patients and partners.

There are two broad categories of inflatable and semi-rigid rod types. The inflatables are further subdivided into three-piece and two-piece devices and the semi-rigid rods are segregated into mechanical and malleable. The semi-rigid or malleable prosthesis were initially much more popular than the three piece implant. The surgery was considerably easier, and there was less need for mechanical correction. Over the years, however, the multi-component implants were noted for less compromise in both flaccidity and erection, and their mechanical reliability steadily rose. This author recently reported 15-years device survival from revision at over 60% -- that placed them as some of the most reliable medical devices implanted in humans.

The biggest market in the world for penile implants is the United States where 75% of the devices are sold. In this market the three-piece comprises 70% of the market, the two-piece 20% and the semi-rigid rods 10%. In the rest of the world the marketplace is shared equally between semi-rigid rods and inflatable devices, mostly due to cost considerations.

Infections are the most disastrous complications of any implantable device. The two multi-component prosthesis manufacturers have taken steps to decrease the incidence of these problems by applying coatings to the prosthesis that are designed to retard bacterial growth. In 2001, AMS introduced InhibiZone, a patented antibiotic surface treatment that impregnates minocycline and rifampin into the external silicone surfaces of the components. Early reports show statistical improvement in infection reduction for first time implant patients in a single surgeon study and the manufacturer's databank study. Mentor/Coloplast more recently began to coat their three-piece devices with a hydrophilic coating that will absorb antibiotics into which the device is dipped. No clinical studies have been reported as yet but the manufacturer's databank study has shown a reduced rate of infection compared to the uncoated devices.

To date (3/07) only the three-piece devices have been coated in infection retardant materials. All things being equal, less risk of infection gives a powerful incentive to use these enhanced models exclusively. Unfortunately, in some clinical situations other factors are at play. Anatomic issues such as obesity, scarred retroperitonem or previous surgery may make reservoir placement of the three-piece difficult. Physician experience and skill are quite different amongst frequent and occasional implanters. The two-piece and the malleable rods tend to be the choices of the infrequent implanter in the anatomically challenged patient since the surgery is less complex. Patient finances in situations where 3rd party reimbursement is not available may require semi-rigid placement since prosthesis cost may be as little as 1/10 of the coated three-piece implants.

The good news is that published outcome studies have shown that regardless of which type of prosthesis is chosen, patient satisfaction is higher than with pills, shots or vacuum devices. A better question for readers of this editorial is not “what are the factors of choice” but, “Why are so few done in a world where the treatment of ED has become commonplace?”

Steven K Wilson, MD, FACS
Professor of Urology
University of Arkansas for Medical Sciences

Penile implants were the first consistently effective treatment of erectile dysfunction (ED) when introduced over 35 years ago. Changes in design have evolved and they have been perfected by the manufacturers so that the current models have very good mechanical reliability. The market for these devices has waxed and waned over the years with predictable trends. For the first 25 years there was steady growth as surgeons learned implantation techniques and patients were made aware of the benefits of these devices. The introduction of the PDE-5 inhibitors about 10 years ago resulted in a precipitous decline in the number of implants placed as widespread marketing of these effective oral agents fueled a shift toward this more conservative approach. The market has steadily increased over the past 5 years so that we are now placing penile impalnts at the same pace as in the pre-Viagra era. The early detection of prostate cancer with PSA screening has encouraged men to select curative treatments of this malignancy and all of these treatments result in a degree of ED often not treatable with medications. Many of these non-responders to the pills have chosen an implant as the way of managing their ED, contributing to the recent surge in the popularity of these devices.

A partner who encourages the patient to continue with sexual activity stressing the mutual pleasure and satisfaction achieved by both will help the patient with ED in choosing the appropriate treatment. Another patient who has a penile implant in place and who is willing to talk openly to prospective candidates for such a device will be a very positive resource. Questions about post operative pain, ejaculation, and sexual satisfaction can be answered and will allay much of the apprehension that a patient may have about proceeding with "another surgery".

Cost is an issue of concern when chosing an implant. In the USA there are 2 vendors and 2 basic types, inflatables and semirigid rods. Insurance coverage is variable and even the simplest of the semirigid rods may cost many thousands of dollars. Package deals which include all the costs associated with placement of the implant are common for cash paying patients. In other parts of the world a variety of less expensive malleable rod and silicone rod implants are available and are more popular due to the lower cost. If cost is not an issue the inflatable devices are usually preferred because of the more natural feel and appearance. The penis is hard during sexual activity and soft at other times. In the USA where the 2 major vendors sell 75% of their implants the ratio is 90% inflatables,10% semirigid rods. In the rest of the world these 2 companies sell about 50% inflatables, 50% semirigid rods. Locally manufactured and sold semirigid rod implants definitely have a great impact in certain parts of the world. Cost and insurance coverage should be thoroughly discussed before surgery with prospective implant recepients.

Manual dexterity is a concern as well in deciding between an inflatable and a semirigid rod implant. Patients with obvious limited or questionable finger mobility and strength will be very frustrated in attempting to operate an inflatable device and are more wisely encouraged to chose a semirigid rod prosthesis. Elderly patients who may appear spry and energetic often lack the dexterity to operate inflatable implants. An arbitrary age of 75 or older would be an appropriate one to recommend a semirigid rod implant to a patient, but this age certainly has exceptions in both directions.

When conservative measures fail patients with ED who wish to continue with sexual activity should definitely be encouraged to consider placement of a penile implant. The satisfaction rate with these devices among both patients and partners is in the range of 80-90% the highest by far of all the available treatments of ED. With proper discussion preoperatively of the expectations, limitations, and costs a gratifying result will be achieved in almost every case.

John Mulcahy, M.D.
Professor of Urology
Indiana University Medical Center

The idea of implanting a Penile Prosthesis (PP) may be very old through the History of Sexology; performing surgery was reported much later. Searching the Medical Literature, it seems the first description of a technique for PP implant (PPI) was published in 1936 [1]. The introduction of the inflatable penile prosthesis in 1973 was a breakthrough in the development of modern PP [2]. The indications for PPI continue even in the era of PDE5i.

Discussions regarding the Erectile Dysfunction (ED) treatment modality should include the partner, although this is not always possible. The PP recipient should be informed that there are other, less invasive ways, to solve his ED problem, and that it is advisable to try those before.

The decision making about the choice of a PP depends on three factors, the device, the surgeon and the patient, not necessarily in the same order of importance.

The ideal prosthesis should provide its recipient with an erection as close as normal to a physiologic erection. The types of currently available PP are malleable, inflatable two and three pieces. It is not the purpose of this paper to discuss the advantages or disadvantages of the different brands of PP. Previous to expose the patient to surgery, the patient should be well aware that PP provides good corporeal but not glandular erection and that the post-op penile length may seem shorter than the length he remembered having, before he suffered from ED. Malleable prostheses have fewer complications than three-piece inflatable prostheses, 50% versus 87%, respectively [3]. In many countries, PP is non-reimbursable, thus its price may be a limitation in decision making.

Certainly, the patient is the most important factor, being he (and his partner) those who should enjoy end results of successful surgery. Every man would like to be implanted the ideal PP. Nevertheless, there are other factors besides patient's will, which may affect that decision. Previous radical abdominal or pelvic surgery may difficult the implant of a three pieces PP [4]. Implant of a PP in the presence of Peyronie's disease and ED may need associated surgical procedures. Kadioglu et al. reported successful straightening of the penis in 35%, 30%, 33.3%, respectively, after implantation of a PP only, manual modeling, plaque incision and grafting [5]. In paraplegics, inflatable PP bears complication rate of 2.4% and 0% for self-contained and 3-piece, respectively, as compared to 18.1% for semirigid devices [6]. After surgery, the patient should have enough digital strength or dexterity to activate the device, although this may be a relative obstacle, since a cooperative partner may do that for him.

The surgeon should be skilled in PPI surgery, learning curve is significant. The 5-year survival outcomes with first prostheses for frequent implanters were superior to those of infrequent implanters, 70% versus 63%, respectively [3]. The experienced surgeon should manage gently the delicate structures he is operating on, as well as knowing how to deal with any intra-operative stumbling-blocks he may find, as described above.

Santiago Richter, M.D.
Deputy Head, Department of Urology
Head, Outpatient Clinic of Sexual Dysfunction
Chairman, The Israel Society for Sexual Medicine

References

1. Bogoras N
   First reported technique of Penile Implant after traumatic Penile Amputation.
   Pedicle skin graft supported by a costal cartilage
   Uber die volle plastische … Zentralbl. Chir 1936; 63:1271
   
2. Scott FB, Bradley WE, Timm GW
   Management of erectile impotence: Use of implantable inflatable prosthesis.
   Urology 1973;2:80-82.
   
3. Lotan Y, Roehrborn CG, McConnell JD, et al.
   Factors influencing the outcomes of penile prosthesis surgery at a teaching
   institution.
   Urology. 2003 Nov;62(5):918-21
   
4. Smaldone MC, Cannon GM Jr, Benoit RM
   Subcutaneous reservoir placement during penile prosthesis implantation
   Can J Urol. 2006 Dec;13(6):3351-2
   
5. Kadioglu A, Sanli O, Akman T, et al.
   Surgical Treatment of Peyronie's Disease: A Single Center Experience with 145
   Patients.
   Eur Urol. 2007 Apr 23; [Epub ahead of print]
   
6. Zermann DH, Kutzenberger J, Sauerwein D, et al.
   Penile prosthetic surgery in neurologically impaired patients: long-term followup.
   J Urol. 2006 Mar;175 (3 Pt 1):1041-4

In Egypt, public health insurance covers the cost for penile prosthesis implantation surgery in university hospitals, and funds part of the cost of the prosthesis itself, of which the patient bears the main bulk. The cost of the inflatable prosthesis is a burden compared to the average annual income of the vast majority. It is therefore that semi-rigid prosthesis is the primary choice for most patients.

As an example, through 18 years, the semi-rigid prosthesis has been implanted on the basis of 2-6 cases per month in Kasr-El Aini University Hospital, Cairo, Egypt. Our experience in this regard spans all kinds of etiologies for erectile dysfunction including diabetes. There is no case that we consider the semi-rigid prosthesis absolutely contraindicated for, though we would rather implant an inflatable prosthesis in diabetic cases who can afford its cost.

The issues of concealment and post-operative expectations as to penile girth are thoroughly discussed with candidates for surgery pre-operative. Diabetic patients are made aware of the relative superiority of the inflatable prosthesis.

On the other hand, the inflatable penile prosthesis is implanted in the private sector on a smaller scale. The two-piece prosthesis is the mainstay, rather than the three-piece, again, due to economic issues. Complication rate for implanting the semi-rigid prosthesis is by far un-alarming, and comparable to that of the inflatable prosthesis.

Osama Shaeer, M.D.
Department of Andrology
Faculty of Medicine, Cairo University, Egypt.

In the early days of penile prosthesis implantation, there were no other effective therapies for organic erectile dysfunction and men were usually satisfied with whatever implant they received. Today, effective systemic therapy and penile injection therapy are available; and when these treatments fail or are otherwise unacceptable, men may seek penile prosthesis implantation. When they do, they have higher expectations than they did thirty years ago.

The ideal penile prosthesis would provide penile flaccidity and erection close to that produced naturally. Three piece inflatable implants, which transfer a large volume of fluid into expandable cylinders for erection and back out of the cylinders for flaccidity, approach this ideal. When then should the patient and his surgeon consider anything other than a three piece inflatable device?

Factors limiting three piece inflatable prosthesis implantation are cost, patients' manual strength and dexterity, and placement of the fluid reservoir. The alternatives to three piece inflatable penile prostheses are the two piece inflatable prosthesis and non-inflatable (malleable and semi-rigid) penile prostheses.

The only two piece penile prosthesis currently available ( AMS Ambicor®)* has the same approximate cost and manual dexterity limitations of three piece inflatable prostheses.1 The only advantage for the two piece device is the absence of an abdominal fluid reservoir. When the Ambicor prosthesis is inflated, a small volume of fluid is transferred into non-distensible cylinders producing rigidity comparable to malleable devices. When the Ambicor is deflated, these non-distensible cylinders collapse achieving better flaccidity than malleable implants. The quality of flaccidity and especially erection with a two piece device, however, is usually less than that achieved by implanting a three piece inflatable device.

There are few situations in which the fluid reservoir of a three piece inflatable penile prosthesis cannot be placed. When the penoscrotal approach is used for device implantation, the reservoir is placed into the retropubic space by blinding puncturing the fascia in the floor of the external inguinal ring. If the ring cannot be located by palpation, a point just above the pubic tubercle is chosen for this fascial puncture. An alternative method for reservoir implantation involves making a separate lower abdominal incision to implant the reservoir extraperitoneally.

Malleable and semi-rigid penile prostheses do have the advantage of lower cost and little need for manual dexterity or strength. They also have a low incidence of mechanical failure. Disadvantages include constant penile rigidity, problems with concealment, a higher chance of erosion2, 3 and chronic pain.4, 5

Three piece inflatable penile prostheses are the gold standard for the prosthetic treatment of erectile dysfunction. When semi-rigid or malleable devices are chosen, it is usually either because of cost or manual dexterity considerations.

*American Medical Systems, Minnetonka, Minnesota, USA

References:

1. Levine LA, Estrada CR, Morgentaler A. Mechanical reliability and safety of, and patient satisfaction with the Ambicor inflatable penile prosthesis: results of a 2 center study. J Urol 2001;166(3):932-7.
2. Krane RJ, Freedberg PS, Siroky MB. Jonas silicone-silver penile prosthesis: initial experience in America. J Urol 1981;126(4):475-6.
3. Zermann DH, Kutzenberger J, Sauerwein D, Schubert J, Loeffler U. Penile prosthetic surgery in neurologically impaired patients: long-term followup. J Urol 2006;175(3 Pt 1):1041-4.
4. Dorflinger T, Bruskewitz R. AMS malleable penile prosthesis. Urol 1986;28:480-5.
5. Moul JW, McLeod DG. Experience with the AMS 600 malleable penile prosthesis. J Urol 1986;135:929-31.

Drogo K. Montague, M.D.
Glickman Urological and Kidney Institute
Cleveland Clinic
Cleveland, Ohio, USA

More erectile dysfunction gets medically addressed in the Indian sub-continent by specialists today than ever before. There is also a fair nation-wide distribution of implanting uroandrologists who are trained to do this kind of surgery at a basic level of proficiency at least. Yet, the numbers of ED patients opting for penile prosthetic implantation surgery as a definitive cure for their condition remains very small. Cost considerations are not the only important reason. While it is true that cost may place inflatable devices out of the reach of many, there is another reason. Many men in this part of the world are irrationally opposed to implantation surgery. They do not want rods and tubes inserted into their penises if they can help it.

The Shah semi-rigid prosthesis, manufactured by Surgiwear, is the most commonly used penile prosthesis in India. It is available as a pair of silicone rods in various sizes from 9 mm to 15 mm diameter. There are hinged and unhinged variants. The `hinge' is actually a mid-segment of differential rigidity that is positioned at the peno-pubic angle, and allows for concealment of the device. It has no metal core. The unhinged model has a homogenous consistency and is mainly recommended for smaller penises. If price alone is considered, the Shah prosthesis, at US $ 200, is cheap, even by Indian standards. However, the device is anything but ideal. For one, the hinge, though useful for concealment, makes for an unstable peno-pubic junction during sexual intercourse, and many patients find this to be a serious problem. Secondly, the two concentric removable sleeves that the product claims as a big plus in reduction of inventory, are anything but ideal. They are often so strongly adherent to one another that they are impossible to separate, and damage to the implant often ensues during the effort. The lengths of the prostheses too are poorly controlled and can vary by several millimeters even within the same pair. The rear tip extenders too are often unequal and fit poorly. Still, the Shah prostheses are 600 to 700 US $ cheaper than the imported AMS devices and are the unanimous choice of most patients. Conventional medical insurance does not cover the cost of penile prostheses in the Indian sub-continent.

American Medical Systems (AMS) sells its standard semi-rigid and inflatable prostheses in India too, but stocks and inventory are always a problem, and a few oft-opened boxes travel up and down the country erratically. Distributors cite low demand and high import duties as the reasons for this phenomenon. The result of all this is that there is always a waiting period before prostheses become available to an implanting surgeon. This is not a happy situation either for the patient or the surgeon. Other newer devices are simply not available. Mentor Corporation used to sell its prostheses in India earlier but has stopped now.

In summary, it may be fairly accurate to state that penile prosthetic implantation surgery still has a long way to go in this part of the world.

Sudhakar Krishnamurti, M.D.
Andromeda Andrology Center, Hyderabad, India [www.andrology.com]

Factors affecting the choice of penile prosthesis
A Nurses Perspective

I currently run a nurse-led penile prosthesis clinic which involves both pre-operative assessment and counselling of men considering implants. All men are given a choice of the type of prosthesis: either malleable, two-piece or three-piece inflatable type device, but ultimately their physical factors will have some standing in the final decision.

There are a number of factors involved, when assessing men's suitability for a penile prosthesis. Age should not be a main priority, however if the man lacks dexterity, an inflatable version may not be suitable. The prosthesis pump can be difficult to manipulate and difficult to stabilise if lack of dexterity is apparent. These men may be more suitable for the malleable or two piece version as they are easier to manipulate and cycle. Men with retracted penis' and/or incontinence, who find using convenes difficult may benefit from a malleable prosthesis to extrude the penis to allow application of a convene.

Diabetics tend to be most at risk of infection and those who have had multiple genital surgeries. With the advent of antibiotic films coated on the prosthesis, infection risks have certainly decreased, however, for poorly controlled diabetics, the risk is still intrinsic. There is mainly a lesser risk of infection with a malleable penile prosthesis compared to a three-piece penile prosthesis due to the existence of fewer components that could become infected. A malleable implant may be more suitable for these types of men.

Various scrotal pathologies including multiple surgeries, lymphoedema, hydradenitis, under developed scrotums, psoriasis or other potentially infected conditions may need a malleable implant. This could be approached by using an infra-pubic approach to avoid a scrotal skin incision which could decrease infection risks in this cohort of patients.

Malleable implants in men who have experienced acute priapism may be more suitable as previous interventions for example repeated aspirations increase the infection risk. It may be possible to insert an inflatable device a few weeks post priapism episode as infection may be reduced and fibrosis may not have fully occurred. Fibrosis will increase the difficulty of implantation and this will need consideration at the time of a priapism event.

Another factor to consider may be men who have prosthetics already present. Men who have had testicular implants or artificial urinary sphincters inserted may not have enough room in the scrotum to fit the inflatable versions.

Men who are restricted to wheelchairs should be given the choice of either prosthesis. If an inflatable prosthesis is chosen, the pump is placed towards the front of the scrotum to prevent pressure and potential erosion of the pump whilst in the chair. A factor to consider is whether the patient has pressure sores and whether this could pose a potential infection risk. Neuropaths and spinal cord injury patients have an altered or no sensation which would prevent the patient from identifying the pain of infection or erosion. In these cases an inflatable penile prosthesis may be a better choice for these patients as there would be less chance of erosion with the implant deflated.

Historically, men with augmented bladders would be advised to avoid an inflatable penile prosthesis due to the possibility of bladder damage during the procedure. This has been overcome, by placing the reservoir in the upper abdomen or more laterally to avoid damaging the augmented bladder. Alternatively, if it is still felt that an inflatable prosthesis is not suitable for these patients, a two-piece prosthesis is quite satisfactory. Relative contra-indications for reservoir placement include men with multiple abdominal trauma, crohns disease, colostomy and ileostomy to name a few.

Penile size determines what prosthesis to use and if a man has chosen a two-piece prosthesis, namely an AMS Ambicor, they need to have good length. The smaller Ambicor implants act more like malleable implants as there is a smaller inflation chamber and the reservoir is contained at the base of the cylinders. Patients should be warned/consented for this or be offered a Coloplast Excel. The cylinders of the Excel are completely inflation chambers. The pump, however, is larger than the Ambicor as this accommodates more fluid.

There are a number of indications that would determine the use of an inflatable device as more appropriate. Younger men with small families may need to conceal an erection as this may be inappropriate around young children. Men who perform sports that require communal showering facilities or those who wear tight swim wear may feel uncomfortable with a rigid erection on display. The younger and single patients are more likely to decide on an inflatable as this will provide an erection that is rigid enough for penetration yet flaccid enough to look natural.

In all situations, the couple's decision is paramount to ensure satisfaction levels are high. If a couple are informed of all the risks and factors involved in implantation, the correct implant for that particular man will chosen. Costs are an issue in some countries and this may be the final factor to affect the type of implant chosen.

Amanda Spillings
Clinical Nurse Practitioner to Mr. David Ralph