Penile implant infection control strategies vary widely

San Diego-There is a great deal of variation in infection control strategies among surgeons who implant penile prostheses, prompting the need for detailed guidelines that may be difficult to formulate, two groups reported at the Sexual Medicine Society of North America 2009 annual meeting.

"I trained in a program in Chicago and we did a lot of implants using a certain protocol," said Jason Greenfield, MD, assistant professor of clinical urology at Columbia University Medical Center, New York. "Then I did a fellowship at Duke that did a lot of implants, and their antibiotic protocol was entirely different. And in my reading I come across many other experts that do it differently.

To better understand the differences in infection control practice patterns, Dr. Greenfield and colleague Matthew Wosnitzer, MD, surveyed 216 urologists, 52 of whom were SMSNA members. They asked 10 questions pertaining to antibiotic selection for primary and revision penile prosthesis implantation.

All 216 respondents reported use of intraoperative antibiotics, most commonly vancomycin (Vancocin) and gentamicin (Garamycin). But some differences were observed between SMSNA and non-SMSNA members:

"Many surgeons aren't changing their protocols when they're doing a re-operation," Dr. Greenfield said. "They're treating a re-operation the same as a 'virgin' implant. Your risk of infection is significantly higher in revision implant surgery."

Dr. Greenfield said he was also surprised at how many urologists are no longer prescribing postoperative oral antibiotics. Some are simply cutting back, he noted, while others have completely eliminated the practice.

In fact, 29% of urologists surveyed in each group reported changing their overall antibiotic practice patterns in the past 5 years. And 7% have been approached by their institutions and asked to change (p=.8).

A similar survey conducted by investigators at Memorial Sloan-Kettering Cancer Center, New York comprised 129 urologists, with the most noticeable differences found between American and non-American urologists.

Physicians fail to obtain pre-op culture

But even surgeons within the U.S. seem to disagree over certain elements of penile prosthesis infection control. For example, almost half (43%) of all physicians who responded to the survey do not routinely obtain a preoperative urine culture.

"A positive urine culture has been identified as a risk factor for infection, so this was surprising and concerning," said senior author John P. Mulhall, MD, director of the Male Sexual and Reproductive Program at Memorial Sloan-Kettering.

American urologists in the survey take ≥10 minutes for preoperative patient skin scrub, whereas the non-American responders report a prep time of ≤5 minutes. There was also a difference in the length of time U.S. surgeons give postoperative antibiotics (4 to 7 days) versus others in the survey (>7 days).

As for specific antibiotic use, most respondents use an aminoglycoside combined with another intravenous antibiotic-most commonly vancomycin in the U.S. and a cephalosporin-type drug elsewhere.

Guidelines needed

All of these differences suggest an urgent need for some sort of consensus statement or guidelines governing penile implant infection measures. According to Dr. Mulhall, that's easier said than done.

"The absence of such guidelines is reflective of the lack of level 1 evidence-based medicine surrounding anti-implant infection maneuvers," he said. "The field has advanced little in this respect in 20 years despite the fact that implant infection is a devastating outcome for the patient that requires surgical intervention."

Dr. Greenfield added: "The problem is that, in order to have guidelines, you have to have good studies to back them up. And in that regard you're talking about a placebo-controlled trial. How do you do that with penile prostheses and antibiotics? So we're really basing what we're doing off of animal studies or laboratory work, which obviously isn't perfect."