Penile implants coated with antibiotics show long-term efficacy

March 1, 2010

Researchers from several institutions are now reporting lower infection rates with penile implants coated or impregnated with antibiotics over the long term.

Key Points

San Diego-It is known that penile implants coated or impregnated with antibiotics produce lower short-term, post-surgical infection rates than implants not treated with antibiotics, but researchers from several institutions are now reporting lower infection rates over the long term, as well.

Two groups in particular presented follow-up data covering at least 7 years at the Sexual Medicine Society of North America's 2009 annual meeting. Both found statistically significant differences in infection rates between treated and non-treated implants.

At 84 months follow-up, infection revision rates in the antibiotic group (1.77%) were significantly lower than those in the uncoated group (3.09%, p<.0001).

"I was a bit surprised that there continued to be an advantage for coated implants even at 6 or 7 years out," said Dr. Carson. "The two curves did not tend to come together over time, which I thought we might see."

"I think there are good data that antibiotic-impregnated implants should be the clinical standard," Dr. Carson noted. "If there is any downside to them at all, it's that they're slightly more expensive than regular implants. But they reduce infections by a statistically and clinically significant amount, and over time they will enhance the longevity and functional life of implants."

In a second study, researchers from Tulane University, New Orleans compared rates of infection among men who received implants with a hydrophilic coating and soaked in an antibiotic solution with those whose implants did not include the hydrophilic coating.

Their review comprised more than 26,000 procedures over 9½ years and two different types of implants: the Alpha 1 (Coloplast, Minneapolis) and the Titan (Coloplast). Both are three-piece prostheses, but the Titan employed a hydrophilic coating across all components, whereas the Alpha 1 did not.

Among the 17,900 Titan implants, there were 279 infections reported (1.6%). Among the 8,825 Alpha 1 implants, total infections were 358 (4%, p=.0001).

"The ability of the hydrophilic coating to provide better antimicrobial protection makes biologic sense," said Brian Richardson, MD, a urology resident at Tulane, working with Wayne Hellstrom, MD, and Arthur Caire, MD. "The antibiotic solution used to soak the prosthetic likely remains active for a longer period of time, thus decreasing the rate of infection and hopefully creation of a biofilm."

Dr. Richardson added that although the evidence "is compelling enough to advocate the hydrophilic-coated prosthesis as the standard" for the Titan implant, further investigation is required to discern which antibiotic is most effective for use in the pre-implant soak.

Dr. Carson has served as a consultant to American Medical Systems, and a co-author of his study is an employee of the company.