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Rev Urol. 2005; 7(Suppl 2): S51–S57.
PMCID: PMC1477598

Penile Prosthesis Implantation for End-Stage Erectile Dysfunction after Radical Prostatectomy

Abstract

When erectile dysfunction occurs after radical prostatectomy and phosphodiesterase-5 inhibitor therapy fails, second-line therapies such as vacuum constriction devices, intraurethral prostaglandins, and penile injection therapy should be offered. When second-line therapies are not effective or acceptable to the man and his partner, penile prosthesis implantation becomes the treatment of choice. Today’s 3-piece inflatable devices offer flaccidity and erection that approach the natural state. Design improvements have resulted in devices that have freedom from mechanical failure ranging from 92% to 94%. Antibiotic and hydrophilic coatings have reduced infection rates.

Key words: Erectile dysfunction, Penile prostheses, Radical prostatectomy

The pioneering work of Walsh1 in the development of nerve-sparing radical prostatectomy has enabled men to choose this method for treating prostate cancer without the nearly inevitable result of loss of erectile function. Unfortunately, a nerve-sparing procedure is not always possible, and even when nerve sparing is attempted, it is not always successful. The other articles in this supplement cover nonsurgical methods for treating erectile dysfunction (ED) after radical prostatectomy. When these methods fail or otherwise prove unacceptable to the patient and his partner, penile prosthesis implantation should be considered.

Because the recovery of nerve function after nerve-sparing radical prostatectomy is time dependent, penile prosthesis implantation is usually delayed for at least 1 year following prostatectomy. Men should have adequate trials of systemic therapy with repeated exposure to the oral phosphodiesterase-5 (PDE-5) inhibitors over the course of the first postoperative year. When treatment trials with these agents fail, patients and their partners should be counseled regarding second-line treatment options such as vacuum constriction devices, intraurethral prostaglandin, and penile injection therapy. If these second-line treatments fail or are unacceptable, penile prosthesis implantation is the next option. Patients undergoing bilateral non-nerve-sparing radical prostatectomy should still have a treatment trial with a PDE-5 inhibitor and then be presented with second-line treatment options. Systemic therapy, however, is unlikely to be successful, and if second-line therapies fail or are rejected, penile prosthesis implantation may be considered at any time after non-nerve-sparing prostatectomy.

Informed Consent

The patient and, whenever possible, his partner should be counseled about the various types of penile prostheses. Today’s penile prostheses all include paired intracorporeal components to produce artificial erections (Table 1). The simplest devices are semirigid or malleable implants. These devices produce permanent penile rigidity usually adequate for coitus. Advantages of these devices include ease of implantation, ease of use, and very low risk of mechanical failure. Disadvantages include permanent erection, problems with concealment, and increased risk of chronic pain and/or erosion.

Table 1
Penile Prosthesis Options

The Dura II™ implant marketed by American Medical Systems (AMS; Minnetonka, MN) is a mechanical rod prosthesis, which has easier upward and downward placement compared with malleable devices. This paired intracorporeal device has a series of interlocking polysulfone disks held together by a central cable with a spring on each end. Advantages include ease of implantation, ease of use, and superior positioning in both the up and down positions. Disadvantages include theoretical increased risk of mechanical failure compared with malleable devices, problems with concealment, and the potentially increased risk of erosion and/or chronic pain. Published experience with this device includes a multicenter study2 in which 91% of patients were satisfied 2 years after receiving the implant and a prospective patient satisfaction study in which 85% of patients would have the prosthesis implanted again and 88% would recommend it to a friend.3

Inflatable or hydraulic prostheses consist of paired fluid-filled intracorporeal cylinders and 1 or 2 additional components. AMS produces the Ambicor® device, which is the only 2-piece prosthesis currently available. Paired hydraulic cylinders comprise the first piece, and the second piece is a small scrotal pump. When this device is inflated, the cylinders become rigid without expanding. The erection produced is similar to that provided by semirigid rod implants. When the device is deflated, the cylinders collapse and lose a portion of their rigidity. Advantages of the Ambicor device include ease of implantation, no need for an abdominal fluid reservoir, and improved concealment compared with malleable semirigid prostheses. Disadvantages include increased risk of mechanical failure, the need for instructing the patient on its use, and compromise in flaccidity and erection compared with 3-piece inflatable prostheses. Published experience with the Ambicor prosthesis is limited to 1 study of 131 recipients who were followed for 12 to 73 months (mean 43.3).4 Mechanical failure occurred in 3 (2.3%). Patient satisfaction was 96.4%, and partner satisfaction was 91.2%.

Three-piece inflatable prostheses consist of a pair of expanding intracorporeal cylinders, a scrotal pump with release mechanism, and an abdominal fluid reservoir. Three-piece inflatable prostheses are produced by 2 companies: AMS and Mentor Corporation (Santa Barbara, CA). In 3-piece inflatable penile prostheses, repetitively squeezing the scrotal pump transfers fluid from the abdominal fluid reservoir into penile cylinders, which expand and become rigid. Advantages include penile flaccidity and erection that come closest to those produced naturally, ease of concealment, and low risk of chronic pain and/or erosion. Disadvantages include the increased skill required for implantation, the need to teach the patient how to inflate and deflate the device, and increased risk of mechanical failure.

As noted, the 3-piece inflatable prostheses come closest to producing normal flaccidity and erection. The patient should understand, however, that the prosthetic erection does not include the glans and, for most men, is shorter than their normal erections. This reduced length is partly the result of the lack of glans erection; however, it should be noted that inflatable penile prosthesis cylinders, with the exception of the 700 Ultrex™ (AMS) cylinder, expand only in girth. In addition to the inability of today’s prostheses to duplicate the full length of normal erections, the penis may be shortened after radical prostatectomy.5 In our experience, when men are dissatisfied after successful penile prosthesis implantation, it is usually because of reduced penile length. When counseling the patient before penile prosthesis implantation, we demonstrate his flaccid stretched penile length and tell him this will be the approximate length of his prosthetic erection.

Many men with ED from other causes, such as vascular disease or diabetes mellitus, have normal libido, and most have normal penile sensation and are able to have orgasm with ejaculation. After radical prostatectomy, ejaculation is absent; however, most men are able to reach orgasm. The patient should be aware that penile implants only produce prosthetic erections and they will not restore libido, sensation, orgasm, or ejaculation if they are absent.

Although local anesthesia has been used for penile prosthesis implantation, most patients receive spinal or general anesthesia and are discharged on the same day or after a 23-hour stay. The degree and duration of postoperative discomfort varies, but most patients have some local discomfort for up to 4 to 6 weeks. Men should not drive while taking pain medication with sedating properties. To avoid reservoir displacement from the retropubic space, we proscribe heavy lifting for 4 weeks. In most cases, sedentary work is possible in 2 weeks and full activity is possible in 4 weeks.

Infection should be specifically discussed, because infection in the space around the prosthesis invariably requires device removal. Erosion is often linked to infection. Erosion of the scrotal pump, for example, is almost always caused by infection. Erosion of a cylinder or a malleable rod is often associated with tissue damage during implantation or with the presence of a too-large intracorporeal component, and if this is not treated early with removal, it frequently results in infection. The patient should also be made aware of the possibility of mechanical failure requiring revision or replacement of the device.

Three-Piece Inflatable Penile Prostheses

In the United States, 3-piece inflatable penile prostheses are the most frequently implanted devices for the treatment of ED. Mentor produces the Mentor Alpha I® (Figure 1) and a smaller-diameter Mentor Alpha I® narrow-base implant. The latter device is useful in small penises and when corporeal dilation is limited due to fibrosis. Inflation of these Mentor devices results in cylinder girth expansion and rigidity. In 1992, the Mentor pump was modified to improve mechanical reliability.6

Figure 1
Mentor Alpha I® inflatable penile prosthesis. Courtesy of Mentor Corporation, Santa Barbara, CA.

American Medical Systems produces two 3-piece implants whose cylinders provide girth expansion and rigidity (700 CX™ and the narrow-diameter 700 CXR™) as well as 3-piece implants whose cylinders provide both girth and length expansion along with rigidity (700 Ultrex™). The smaller-diameter devices are useful when corporeal dilation is limited due to fibrosis or when the penis is small.

The AMS 700 Ultrex™ (Figure 2) offers length expansion that varies between 1 and 4 cm, with a mean of 1.9 cm.7 Because the device’s length-expanding ability resulted in poorer mechanical reliability,8 the cylinders were modified in 1993.9

Figure 2
American Medical Systems 700 Ultrex™ inflatable penile prosthesis. Courtesy of American Medical Systems, Minnetonka, MN.

Five-year survival free of mechanical failure for today’s 3-piece inflatable penile prostheses following Mentor’s 1992 pump modification and AMS’s 1993 Ultrex cylinder modification is as follows: AMS CX/CXM, 92%,8 AMS 700 Ultrex, 94%,9 and Mentor Alpha I, 94%.6

Surgical Approaches for 3-Piece Inflatable Penile Prosthesis Implantation

Surgical approaches for 3-piece inflatable penile prosthesis implantation include the infrapubic and the penoscrotal. The advantages of the infrapubic approach are implantation of the fluid reservoir under direct vision and concealment of tubing under Scarpa’s fascia. Disadvantages of the infrapubic approach include limited corporeal exposure, possible damage to the dorsal nerves of the penis with resultant sensory loss, and the inability to anchor the pump in the scrotum. Although damage to the dorsal nerves of the penis seldom occurs with the initial implant procedure, it is a risk during revision when electro-surgical dissection is used to expose the cylinders.

Advantages of the penoscrotal approach include improved corporeal exposure, lack of damage to the dorsal penile nerves, and the ability to anchor the scrotal pump. A disadvantage is possible damage to the urethra; however, unlike the dorsal penile nerves, the urethra is easily seen, avoided, and repaired if necessary. Another disadvantage is the possibility of the tubing being palpable subcutaneously at the base of the penis. However, this can be avoided by implanting the cylinders and pump as separate components and routing the pump tubing through the back wall of the scrotal pouch. The tubing is then cut short and the tubing and connectors buried in the scrotum under dartos fascia. This is also the maneuver that helps anchor the pump in the scrotum. Another disadvantage of the penoscrotal approach is the need to blindly implant the fluid reservoir into the retropubic space.

The Abdominal Fluid Reservoir

The best flaccidity and erection with prosthetic devices are achieved with the 3-piece inflatable devices in which a large amount of fluid can be transferred into expanding cylinders for erection and back out of the cylinders for flaccidity. These devices require a fluid reservoir that is too large for the scrotum. The retropubic or prevesical space is the best place for these reservoirs. In our experience, blind placement of these reservoirs into the prevesical space after radical prostatectomy is readily and easily accomplished using the penoscrotal approach.

To do this safely, the bladder must be empty; therefore, a catheter attached to gravity drainage is inserted and the bladder is emptied. The surgeon introduces his or her index finger into the penoscrotal incision and moves it up to the external inguinal ring. If the external ring is not palpable, a point for reservoir insertion just above the pubic tubercle is chosen. The finger in the ring protects the spermatic cord, and the surgeon uses closed Metzenbaum scissors placed medial to the finger just above the pubic bone. The scissors are inserted through the fascia that forms the floor of the external ring. This fascia is scarred after radical retropubic prostatectomy, and piercing this thickened fascia may take more than one attempt. When all layers of the fascia are penetrated, the surgeon can feel the back of the symphysis pubis and the catheter balloon in the empty bladder. Although the fascia is scarred after radical retropubic prostatectomy, the retropubic space is maintained and we have always been able to enter it successfully. A nasal speculum with long blades is used to maintain the opening in the fascia while the empty reservoir is inserted. The reservoir is then filled with normal saline, and a back pressure test is performed to avoid a high reservoir pressure, which contributes to autoinflation. A 65 mL reservoir should accommodate at least 50 mL of fluid at zero pressure, and a 100 mL reservoir should accommodate at least 85 mL. If the reservoir does not accommodate this much fluid, it likely is not in the true retropubic space.

Reservoir insertion in this manner can also be safely performed after inguinal hernia repair, unless mesh was used in the repair. If the patient has had bilateral inguinal hernia repairs with mesh or if he has had a cystictomy, so that reservoir insertion in this manner would place the reservoir intraperitoneally, we would place the reservoir higher, through a second incision, in an extraperitoneal location. A disadvantage to reservoir placement extraperitoneally is an increased chance of prosthesis autoinflation. Alternatively, the Ambicor prosthesis, which does not have an abdominal reservoir, may be chosen. The Ambicor prosthesis would also be advisable in a patient who has a femoral-femoral vascular bypass.

Penile Prosthesis Implantation When Erectile Deformity Is Present

Erectile deformity in men who have had a radical prostatectomy may occur for at least 2 reasons. First, some of these men chose penile injection therapy, which is associated with fibrosis complications that may result in erectile curvature.10 Second, men who have had radical prostatectomy may have erections with reduced rigidity, making these erections more susceptible to buckling injuries during coitus. These injuries are thought to be underlying factors in the development of Peyronie disease.11

The majority of men who choose penile prosthesis implantation in our practice choose a 3-piece inflatable prosthesis. Whenever possible, we use the AMS 700 Ultrex device because this implant allows both girth and length expansion. However, we have shown that in men with penile curvature due to Peyronie disease, using the girth only—expanding cylinders of the AMS 700 CX device allows better correction of the curvature.12 We therefore use the AMS 700 CX or CXR device when treating ED in men who also have erectile deformity (penile curvature).

Penile Prosthesis Implantation After External Radiation Therapy

Penile prosthesis implantation can be safely performed in men who have had radical prostatectomy and external radiation therapy. We have not noticed increased difficulty during 3-piece penile prosthesis implantation, nor have we noted an increased risk of device infection or erosion in these patients. Only the crura are exposed to some radiation, and it is usually possible to dilate the crura with Metzenbaum scissors to the point at which a normal-size cylinder can be implanted. If not, the Mentor Alpha I narrow-base cylinder or the AMS CXM or CXR cylinder can be used.

Penile Prosthesis Implantation After Androgen Deprivation Therapy

A subset of men who have had radical prostatectomy may also be receiving androgen deprivation therapy. In our practice, we have not experienced any difficulty in implanting penile prostheses in terms of dilating the corpora or implanting cylinders. The scrotal skin in these men, however, is thin and easily injured. Care should be taken in developing the sub-dartos pouch for the pump, as the usual amount of force may produce scrotal injury.

Dual Device Implantation

Simultaneous implantation of a penile prosthesis and an artificial urinary sphincter is possible but carries the theoretical increased risk of infection because of the longer operating time. If an infection occurs under these circumstances, removal of both devices is likely to be necessary. We often recommend that the artificial urinary sphincter be implanted first, with penile prosthesis implantation done as a second procedure following successful activation of the artificial urinary sphincter. During the second procedure, the pump for the penile prosthesis is implanted in a lateral sub-dartos pouch on the side opposite the artificial urinary sphincter pump.

Wilson and colleagues13 have described simultaneous implantation of the artificial urinary sphincter and a 3-piece inflatable penile prosthesis through a single transverse upper scrotal incision. This has the advantage of a single incision but results in sphincter cuff placement more distally around the urethra. Distal cuff placement may result in a higher cuff erosion rate, and the distally placed cuff may not provide the same degree of continence as a more proximally placed cuff. Longer follow-up with Wilson’s single-incision procedure is needed to assess these theoretical risks.

The male bulbourethral sling has recently become popular, probably because it is easier to implant and costs less than the artificial sphincter.14 Longer follow-up, however, is necessary to demonstrate whether the short-term favorable results with slings will prove durable. Simultaneous implantation of a penile prosthesis and the male sling should be possible.

New Prosthesis Coatings

In 2001, AMS introduced parylene, a coating for the inner and outer surfaces of the silicone portions of their 3-piece inflatable cylinders. Parylene reduces friction, and on bench testing has been shown to extend cylinder life from 3.7 million to 12.9 million cycles (data supplied by AMS).

In 2001, AMS also made available as an option an antibiotic coating, InhibiZone,™ for their 3-piece inflatable devices. The coating is a combination of rifampin and minocycline. In first-time implant procedures, this coating has been shown to reduce the infection rate at 180 days from 1.61% to 0.68%.15 In revision surgeries, in which the infection rate is usually higher, this coating has reduced the rate at 180 days from 2.41% to 1.36%.16

In September 2002, Mentor introduced a polyvinylpyrrolidine hydrophilic coating for their Alpha I device. This coating, Titan,™ reduces bacterial adherence and allows the surgeon to immerse the prosthesis in an antibiotic solution, which then adheres to the surface of the implant. This hydrophilic coating reduced the infection rate for implanted devices from 2.07% to 1.06%.17

Satisfaction After Penile Prosthesis Implantation

Satisfaction with erectile function and treatment is significantly higher after penile prosthesis implantation than after treatment with sildenafil citrate or after intracavernous prostaglandin E1 injection.18,19 Studies including partners have also shown high satisfaction rates when men undergo penile prosthesis implantation.2022

Conclusions

When nerve sparing during radical prostatectomy fails or is not possible, treatment with oral PDE-5 inhibitors is initiated. If that fails, second-line therapies such as vacuum constriction devices, intraurethral prostaglandin, or penile injections should be considered. Penile prosthesis implantation is indicated when these options fail or otherwise prove unacceptable to the man and his partner. Today’s devices have improvements that make them more natural and more durable and that reduce infection. Penile prosthesis implantation continues to have the highest satisfaction rates of all ED treatment options.

Main Points

  • When treatment trials with phosphodiesterase-5 inhibitors fail, patients and their partners should be counseled regarding second-line treatment options such as vacuum constriction devices, intraurethral prostaglandin, and penile injection therapy. If these second-line treatments fail or are unacceptable, penile prosthesis implantation should be considered.
  • The 3-piece inflatable prostheses come closest to producing normal flaccidity and erection. The patient should understand, however, that the prosthetic erection does not include the glans and, for most men, is shorter than their normal erections.
  • Surgical approaches for 3-piece inflatable penile prosthesis implantation include the infrapubic and the penoscrotal.
  • Penile prosthesis implantation can be performed safely in men who have had external radiation therapy and in those who are on androgen deprivation therapy.
  • Simultaneous implantation of a penile prosthesis and an artificial urinary sphincter is possible but carries the theoretical increased risk of infection because of the longer operating time.
  • New coatings for 3-piece inflatable prostheses have extended the lives of the devices and have reduced rates of infection.

References

1. Walsh PC. Radical prostatectomy, preservation of sexual function, cancer control. Urol Clin North Am. 1987;14:663–673. [PubMed]
2. Kearse WS , Jr, Sago AL, Peretsman SJ, et al. Report of a multicenter clinical evaluation of the Dura-II penile prosthesis. J Urol. 1996;155:1613–1616. [PubMed]
3. Ferguson KH, Cespedes RD. Prospective long-term results and quality-of-life assessment after Dura-II penile prosthesis placement. Urology. 2003;61:437–441. [PubMed]
4. 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;166:932–937. [PubMed]
5. Savoie M, Kim SS, Soloway MS. A prospective study measuring penile length in men treated with radical prostatectomy for prostate cancer. J Urol. 2003;169:1462–1464. [PubMed]
6. Wilson SK, Cleves MA, Delk JR., 2d Comparison of mechanical reliability of original and enhanced Mentor Alpha I penile prosthesis. J Urol. 1999;162(3 pt 1):715–718. [PubMed]
7. Montague DK, Lakin MM. Early experience with the controlled girth and length expanding cylinder of the American Medical Systems Ultrex penile prosthesis. J Urol. 1992;148:1444–1446. [PubMed]
8. Daitch JA, Angermeier KW, Lakin MM, et al. Long-term mechanical reliability of AMS 700 series inflatable penile prostheses: comparison of CX/CXM and Ultrex cylinders. J Urol. 1997;158:1400–1402. [PubMed]
9. Milbank AJ, Montague DK, Angermeier KW, et al. Mechanical failure of the American Medical Systems Ultrex inflatable penile prosthesis: before and after 1993 structural modification. J Urol. 2002;167:2502–2506. [PubMed]
10. Chew KK, Stuckey BGA, Earle CM, et al. Penile fibrosis in intracavernosal prostaglandin E1 injection therapy for erectile dysfunction. Int J Impot Res. 1997;9:225–229. [PubMed]
11. Devine CJ , Jr, Somers KD, Jordan SG, Schlossberg SM. Proposal: trauma as the cause of the Peyronie’s lesion. J Urol. 1997;157:285–290. [PubMed]
12. Montague DK, Angermeier KW, Lakin MM, Ingleright BJ. AMS 3-piece inflatable penile prosthesis implantation in men with Peyronie’s disease: comparison of CX and Ultrex cylinders. J Urol. 1996;156:1633–1635. [PubMed]
13. Wilson S, Delk JI, Henry G, Siegel A. New surgical technique for sphincter urinary control system using upper transverse scrotal incision. J Urol. 2003;169:261–264. [PubMed]
14. Schaeffer AJ, Clemens JQ, Ferrari M, Stamey TA. The male bulbourethral sling procedure for post-radical prostatectomy incontinence. J Urol. 1998;159:1510–1515. [PubMed]
15. Carson CC., 3d Efficacy of antibiotic impregnation of inflatable penile prostheses in decreasing infection in original implants. J Urol. 2004;171:1611–1614. [PubMed]
16. Carson CI. Initial success with the AMS 700 series inflatable penile prosthesis with InhibiZone antibiotic surface treatment: a retrospective review of revision cases incidence and comparative results versus non-treated devices. J Urol. 2004;171:236.
17. Wolter C, Hellstrom W. The hydrophilic-coated inflatable penile prosthesis: 1-year experience. J Sexual Med. 2004;1:221–224. [PubMed]
18. Rajpurkar A, Dhabuwala C. Comparison of satisfaction rates and erectile function in patients treated with sildenafil, intracavernous prostaglandin E1 and penile implant surgery for erectile dysfunction in urology practice. J Urol. 2003;170:159–163. [PubMed]
19. Sexton WJ, Benedict JF, Jarow JP. Comparison of long-term outcomes of penile prostheses and intracavernosal injection therapy. J Urol. 1998;159:811–815. [PubMed]
20. Beutler LE, Scott FB, Karacan I, et al. Women’s satisfaction with partners’ penile implant: inflatable vs noninflatable prosthesis. Urology. 1984;24:552–558. [PubMed]
21. Pedersen B, Tiefer L, Ruiz M, Melman A. Evaluation of patients and partners 1 to 4 years after penile prosthesis surgery. J Urol. 1988;139:956–958. [PubMed]
22. McLaren RH, Barrett DM. Patient and partner satisfaction with the AMS 700 penile prosthesis. J Urol. 1992;147:62–65. [PubMed]

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