Complications of inflatable penile prostheses

A narrative review of the management of benign prostatic hyperplasia in patients undergoing penile prosthesis surgery

Penile prosthesis surgery is an effective and durable treatment modality for patients who have failed conservative management for erectile dysfunction (ED). Thorough patient counseling and appropriate preoperative workup lay the foundation for a successful outcome. While the risk of infection of penile prosthesis is rare, it is a dreaded complication with dire consequences. The goal of the prosthetic surgeon is to minimize the risk of preventable complications. Given the common prevalence of benign prostatic hyperplasia (BPH) in this patient population, it is essential that providers are familiar with the implications and nuances of managing both conditions in order to maximize the chances of a favorable result. Due to the relatively infrequent nature of complications associated with the management of BPH in the setting of a penile prosthesis, literature regarding this topic is scarce. In this narrative review we present our own case series illustrating some of the most common scenarios that a prosthetic surgeon may encounter. We have included our suggestions for management in these difficult situations based on our clinical experience. In the following review we have highlighted the importance of identifying and treating BPH in penile implant candidates to reduce postoperative morbidity and to offer critical insights into managing BPH-related complications this population.

Prospective evaluation of neomycin serum concentrations after direct corpora cavernosa irrigation during penile prosthesis placement

OBJECTIVES

To determine if toxic serum levels of neomycin are generated after direct corpora cavernosa irrigation during penile prosthesis placement.

METHODS

We have used an infection prophylaxis technique that involves directly irrigating the corpora cavernosa tissue (through the corporotomy) with 0.5% neomycin solution. Serum neomycin concentrations were measured at 1 hour and 4 hours after irrigation in 13 patients undergoing penile prosthesis placement. A subset of patients who had preimplant and postimplant serum creatinine concentrations was evaluated for changes in renal function.

RESULTS

The mean 1-hour postirrigation serum neomycin level was 1.2 micrograms/mL and the mean 4-hour postirrigation level was 1.2 micrograms/mL. These serum neomycin concentrations are lower than those thought to be necessary to produce nephrotoxicity or ototoxicity. Renal function was not significantly affected by the neomycin irrigation.

CONCLUSIONS

Although aminoglycosides are ototoxic and neomycin has the highest nephrotoxic potential of the aminoglycosides, we conclude that direct irrigation of the corpora cavernosa with 0.5% neomycin solution does not produce significant systemic exposure to result in nephrotoxicity or ototoxicity. One-time prophylactic neomycin irrigation remains an effective, safe, and economic adjunct to penile prosthesis placement.

The Hydroflex penile prosthesis: a test case for the introduction of new urological technology

The AMS Hydroflex* penile prosthesis was introduced for commercial distribution in 1985 but 5 years later this device was no longer available on the United States market. In an attempt to understand why this device, which initially enjoyed substantial popularity, was abruptly withdrawn from the market, patients who underwent implantation at the University of Wisconsin were interviewed and a critical analysis of the Food and Drug Administration approval process of medical devices was performed. An AMS Hydroflex penile prosthesis was implanted in 17 patients (mean age 57.7 years, range 27 to 84 years). The followup period ranged from 37 to 73 months with a mean of 58 months, and 3 patients died within that time. Of the remaining patients 10 (71%) were satisfied with the device in the first months after implantation but only 6 (43%) were satisfied at the time of followup, 9 (64%) were more satisfied with sexual relationships after receiving the prosthesis and 7 (50%) found the prosthesis simple to operate. Mechanical failure was noticed by 11 patients (79%), of whom 5 (45%) underwent further surgery. Classification of medical devices started with the enactment of the Medical Device Amendment to the Federal Food, Drug and Cosmetic Act, May 28, 1976. All medical devices that were in commercial distribution at that time were classified in 3 regulatory control categories depending upon the degree of regulation necessary to assure safety and effectiveness of each device. Before May 28, 1976 no approved application was necessary for marketing medical devices, and the Food and Drug Administration has variable amounts of information about safety and effectiveness of the different devices marketed prior to that date. Since May 1976 approved applications have been mandated for new or significantly changed devices. The specific process by which the Hydroflex prosthesis, as well as other medical devices, is approved is critically reviewed.

Intraluminal device pressures in 3-piece inflatable penile prostheses: the "pathophysiology" of mechanical malfunction

The role of intraluminal device pressure in the development of mechanical failures in 3-piece inflatable penile prostheses was investigated in a 2-part study. An in vitro study was performed in which mean intraluminal device pressures were recorded in Mentor IPP, Mentor Alpha-1, AMS 700 CX and AMS Ultrex devices. At maximum inflated volumes mean intraluminal device pressures exceeded 600 and 1,000 mm. Hg at rest, and 850 and 1,300 mm. Hg following external loading in Mentor and AMS products, respectively. The AMS 700 CX was associated with the highest mean intraluminal device pressure, with values approaching 1,400 mm. Hg following external loading. A 4-year clinical review at our institution was performed comparing the mechanical malfunctions in 51, 3-piece implants with connectors between the pump and cylinders (AMS 700 CX) to the mechanical malfunctions of 50, 3-piece implants with pre-connected tubing between the pump and cylinders (Mentor Alpha-1). Fluid leaks were identified in 16% of the former and 4% of the latter devices. It is proposed that the high intraluminal device pressures are an important factor in the pathophysiology of the mechanical malfunctions in 3-piece inflatable penile prostheses and that connectors are considered components at risk for pressure-associated fluid leaks. The ideal penile prosthesis should maintain the superior rigidity and cosmetic features of the 3-piece inflatable penile prosthesis. However, the device should be pre-connected and designed to mimic more closely the anatomy of the human penis to achieve functional erections at lower intraluminal device pressure values.

Risk factors associated with penile prosthesis infection

We reviewed all 269 patients who underwent penile prosthetic implantation during the last 10 years. The data were analyzed to determine the rate of penile prosthesis infection and to determine the risk factors associated with these infections in this group. We also examined the effect of strict surgical technique, intraoperative scrub and perioperative antibiotics on these implant infections. All patients had perioperative antibiotics, an intraoperative shave and a 15-minute intraoperative skin preparation. There were 162 semirigid and 107 inflatable prostheses inserted. Mean followup was 32 months (range 2 to 123 months). Only 6 patients had an infection, with 5 prostheses being removed. All 6 patients had a history of urinary tract infection. Furthermore, all 6 patients had either a neurogenic bladder (4), diabetes (1) or an ileal conduit (1), which increased the risk of a urinary tract infection. Cultures of the infected prostheses revealed only enteric organisms. No staphylococci were cultured. We conclude that perioperative antibiotics, intraoperative shave and scrub, and strict surgical technique resulted in a low prosthesis infection rate (1.9%) in these patients. However, a group of patients still exist that despite these precautions are at risk for infection due to conditions that may predispose them to urinary tract infections.

Mechanical complications associated with mentor inflatable penile prosthesis

The Mentor inflatable penile prosthesis was developed in an attempt to decrease the mechanical failure rate of the various prostheses' components. We herein report on the reliability of the device in 46 men implanted with the Mentor device from December 1982 to June 1987. Prior to manufacturer device modification in 1985, mechanical failure mainly attributable to input tubing cracks occurred in 10 of 30 implantations. Since device improvement in April 1985, the mechanical failure rate has decreased to 4 percent. The Mentor inflatable penile prosthesis has been a mechanically reliable device since design improvement in 1985.

Patient satisfaction with Mentor inflatable penile prosthesis

Patient satisfaction with the Mentor inflatable penile prosthesis was assessed by sending a thirty-six-item questionnaire to 251 patients who had undergone implantation of the device by the senior author (D.C.M.). A total of 152 (61%) of the patients responded. Recovery time, satisfaction, reasons for dissatisfaction, perceptions of erection quality, and psychosexual parameters were evaluated. Eight-eight percent of the patients were engaging in regular sexual activity. Depending on the definition of satisfaction, 81-89 percent of the respondents reported that they were satisfied with the prosthesis. Sixty-eight percent of the survey group were satisfied with the length, width, and firmness of their prosthetic-induced erection. The majority of patients reported improvement in psychosexual functioning after implantation. Reasons for dissatisfaction included inadequate penile length, insufficient firmness, and difficulty with inflation and deflation of the penile cylinders.

Duraphase penile prosthesis--results of clinical trials in 63 patients

The Duraphase penile prosthesis was implanted in 63 patients at 4 investigative sites during clinical trials. This device is a semirigid rod that is bendable and provides good support to the erection. Mechanical complications included 4 instances of cable breakage rendering the device nonfunctional. Of 57 patients questioned 55 were pleased with the results after 4 months. Ease of insertion and exceptional bendability are other features that make this device attractive.

Complications associated with penile implants used to treat impotence

The complications associated with a variety of penile prostheses used in the treatment of 302 men with erectile dysfunction are described. Infection of the prostheses resulted in their removal from 11 patients (3.6%), antibiotic therapy and replacement in five men. Mechanical failures required reoperation in 43 men (14.2%); however, recent advances in prosthesis design have reduced this type of malfunction. Adverse psychological reactions prompted removal of the prostheses from two men. Despite these complications, this surgery is remarkably effective.

Corporeal septal necrosis secondary to penile cylinder aneurysmal dilatation

A case report of necrosis of the corporeal septum secondary to aneurysmal dilatation of a penile prosthesis cylinder is presented. Recommendations are made for surgical management.

Penile prosthesis surgery: review of ten-year experience and examination of reoperations

Our ten-year experience from September, 1975, to December, 1985, with 417 penile prostheses in 290 patients is presented. Arteriosclerosis and diabetes mellitus were the two most common causes of impotence in our patient population. The Scott inflatable penile prosthesis accounted for the majority of all implants and all device failures. Complications leading to device failure and/or reoperation occurred in 36 percent of all prostheses. However, including repairs, 91 percent of patients were left with a functional prosthesis. Examination of reoperated patients showed an average increase in corporeal length of 1.67 cm with repeat prosthesis operations (p less than 0.001). No increase in incidence of prosthesis failure could be shown after multiple reoperations.

Five-year followup of the Scott inflatable penile prosthesis and comparison with semirigid penile prosthesis

The Scott inflatable penile prosthesis remains one of the most popular devices available for the surgical treatment of impotence despite high complication and reoperation rates. We present our 5-year followup of 116 inflatable prostheses placed before 1981 in 85 patients, with a 61 per cent overall 5-year complication rate. The incidence of complications by year after operation showed that most (22 per cent) devices failed within 1 year after implantation, with failure rates gradually decreasing to 6 and 7 per cent during years 4 and 5, respectively. Of 85 patients receiving an inflatable prosthesis 61 per cent underwent reoperation during the 5-year followup. A 5-year overall complication rate of only 14 per cent was seen in 29 Small-Carrion semirigid prostheses implanted during the same time. The results of numerous recent improvements in the design and structure of the Scott inflatable penile prosthesis to prevent mechanical device failure remain to be tested over the long term.

Surgical complications related to insertion of penile prostheses with emphasis on infection and cost

We initiated a prospective study of penile prosthesis implant surgery to evaluate risk factors for infection and other complications. Twenty-one patients admitted for surgery or related complications were evaluated over a seven-month period. The two types of penile prostheses implanted were (1) inflatable and (2) semi-rigid. Nine of 21 patients (43%) developed postoperative complications. Although cephapirin and gentamicin were given prophylactically, four of nine patients had four wound infections and one case of pneumonia. One case of Bacteroides fragilis bacteremia was due to stool incontinency during surgery. In two of the wound infections, removal and reinsertion of the prosthesis was necessary. Other complications included hypotension during surgery, prosthesis malfunction and malposition, and urethral tears. There were no significant associations between infection and age, length of surgery, or type of prosthesis used. These complications contributed to prolonged hospital stay and readmission (87 extra days for the infected patients at a cost of $44,000). Antibiotic costs to treat the infections totaled $1,900. Prospective evaluation by infection control practitioners of various elective surgeries can be useful in quantitating the complication rate and targeting patients at risk, with the goal of minimizing hospital costs.

Severe penile curvature after implantation of an inflatable penile prosthesis

We describe 6 cases of penile curvature following implantation of inflatable penile prostheses. Exploration revealed severe scarring of the corpora cavernosa, which produced the curvature in 4 patients. In all 4 cases this area was incised and the defect was filled with a polytetrafluoroethylene vascular graft. The penis was straightened and the prosthesis functioned normally. The remaining 2 patients were treated with inflation for 8 weeks with resolution of the curvature. To our knowledge, these cases represent the first reported complications produced by abnormal scar tissue outside of the inflammatory pseudocapsule after implantation of an inflatable penile prosthesis.

Late hematogenous infection of penile prostheses

Late deep wound infection caused by hematogenous bacterial spread from a remote focus is a rare but disastrous complication of prosthetic devices. Six patients with probable late hematogenous infection are described. The initial implantation was free of contamination and infection, and a long functional interval ensued. A febrile process associated with a painful, swollen penis followed a probable remote infection source that was not covered with prophylactic antibiotics. All prostheses required removal. Prophylactic antibiotics may prevent these late hematogenous infections.

Periprosthetic infections

A retrospective review of all patients undergoing implantation of a penile prosthesis or an artificial urinary sphincter was done. A total of 15 infections occurred in 556 prosthesis recipients, for an infection rate of 2.7 per cent. More than 50 per cent of the infections were caused by staphylococcal organisms. All infections became evident within 1 year after implantation except for 1 that was not apparent until 2 1/2 years later. Infections were not more common in diabetics compared to nondiabetics.

Infectious complications of penile prosthetic implants

An infectious complication involving placement of a penile prosthesis is a disastrous event. A review of more than 300 devices placed between 1979 and 1984 at this center reveals an infectious complication rate of 8.3 per cent. Perioperative risk factors predisposing to infection included reoperation for technical failures, inadequate antibiotic coverage (specifically for Staphylococcus epidermidis), failure to perform a circumcision at the time of placement in uncircumcised patients and simultaneous placement with an artificial urinary sphincter device. No group of patients nor type of prosthesis was more susceptible to the development of a postoperative infection.

Mentor inflatable penile prosthesis

Technical complications requiring frequent surgical revision of the most commonly used penile component prosthesis have led to the development of a new inflatable device that has been implanted in 202 patients. This hydraulic device provides excellent functional qualities; no connector separations, aneurysms, or ruptures have been encountered in these patients. Reoperations became necessary in 8 per cent of these patients. Cosmetic and functional results are good, and patient acceptance has been excellent.

A technique of maintaining penile prosthesis position to prevent proximal migration

A technique for proximal reconstruction of the corpora cavernosa using a synthetic vascular graft fashioned into a cup is described. In 6 cases this procedure was critical and successful in the repair of the corpora cavernosa associated with the placement of a penile prosthesis.

Erosion of an inflatable penile prosthesis reservoir into an ileal conduit

We report an unusual complication of an inflatable penile prosthesis. The penile prosthesis reservoir had been placed intra-abdominally and it eroded into an ileal conduit. The reservoir was removed endoscopically but the patient ultimately required creation of a new ileal conduit. Placement of reservoirs intraperitoneally risks erosion into the bowel.

An unusual complication of the inflatable penile prosthesis

We report a case of erosion of a corporeal cylinder of the Mentor penile prosthesis. The management and possible etiology are discussed.

Experience with the Mentor inflatable penile prosthesis

We present our experience with the new Mentor inflatable penile prosthesis for the treatment of organic impotence. Technical complications requiring frequent revision of the most commonly used inflatable prosthesis have led to the development of a new device, which we have used in 116 patients. This hydraulic device provides excellent functional qualities. No connector separations, aneurysms or ruptures have been encountered. Reoperations became necessary in 10.5 per cent of the patients. Cosmetic and functional results were good, and patient acceptance has been excellent.

Bacterial biofilm in persistent penile prosthesis-associated infection

The ultrastructural microbiology of 2 cases of infection associated with rigid penile prostheses was studied. The persistence of these infections appeared to be related to the mode of growth of the bacteria in protected biofilms adherent to the inert surface of the prosthesis.

Long-term followup in patients with an inflatable penile prosthesis

An inflatable penile prosthesis was implanted in 95 patients between 1977 and 1983. The patients were divided into 3 groups with roughly equal numbers studied during 2-year intervals. Of the prostheses 48 per cent have been revised or removed, or have failed during followup. The complication rate increased with the duration of followup.

The inflatable penile prosthesis, reoperation and patient satisfaction: a comparison of statistics obtained from patient record review with statistics obtained from intensive followup search

Of 179 patients who received the inflatable penile prosthesis 43 per cent have required reoperation, 60 per cent of which were performed for mechanical failure. An attempt to evaluate the adequacy of chart review in assessing current function and patient satisfaction was made by comparing reports obtained by chart review to those obtained by direct patient interview. Results showed that if chart review alone was used malfunction would have been underestimated by 13 per cent and patient satisfaction overestimated by 21 per cent. The importance of direct followup in evaluating patients with the inflatable penile prosthesis is demonstrated.

The inflatable penile prosthesis: failure of the rear tip extender in reducing the incidence of cylinder leakage

Of 184 patients who have received an inflatable penile prosthesis at our institution since 1974, 43 per cent have undergone reoperation, the majority of which were owing to cylinder leakage. Comparison by life-table analysis of cylinders placed before and after introduction of the rear tip extender does not show an improvement in cylinder survival to date.

Revised surgical technique to improve survival of penile cylinders for the inflatable penile prosthesis

A revised surgical technique to implant the inflatable penile prosthesis cylinder into the corpora cavernosa was used in 85 men. The technique places the inlet tube to the cylinder at the distal edge of the incision in the tunica albuginea. All sutures used to reapproximate the tunica are placed proximally over the solid components of the cylinder, eliminating the chance of sutures eroding the inflatable portion. The patients were followed for 12 to 24 months and have had no cylinder malfunctions.

Clinical experience with Scott inflatable penile prosthesis in 150 patients

The Scott inflatable penile prosthesis was implanted in 150 patients with organic (89%) and psychologic (11%) impotency from 1979 to 1982. The patients were followed up for an average of twenty-five (6-46) months. A satisfactory result was achieved in 133 (89%) patients. Forty-nine major complications occurred in 38 patients. Forty-four surgical procedures were performed in 33 patients to correct mechanical or technical complications (32), replace the device (9), or remove the device (3). Two patients refused corrective surgery, and the complications could not be corrected in 2 patients. Cylinder leaks (15), leaks at tubing/connector junctions (14), and cylinder aneurysms (7) were responsible for most of the mechanical failures. Additional refinements in surgical technique will not eliminate these problems. Device modifications should be made to increase cylinder durability, to eliminate the need for suture ligation of tubing/connector junctions, and to assure symmetrical cylinder expansion.

Complications of penile prosthesis surgery for impotence

Complications and their management in 1,207 cases of semirigid rod prosthesis for erectile failure are presented. Major complications occurred in 7.8 per cent of the cases. Complications and management of 84 cases of impotence treated with inflatable penile prostheses also are discussed. Mechanical problems occurred in 44 per cent of the cases and medical complications occurred in 10 per cent.