What About Unintended Consequences?
The question of unintended consequences of topical vancomycin powder application may still be relevant, despite a low risk of developing resistant strains. The typical target of vancomycin powder application is Staphlococcus aureus, especially methicillin-resistant Staphlococcus aureus (MRSA), but this is not the only cause of surgical site infection.
Another common infection that should not be overlooked is Cutibacterium acnes, (formerly known as Propionibacterium acnes), which is particularly troublesome in shoulder and spine surgery where the bacteria commonly reside on the skin and cause acne.
Research published in Antimicrobial Agents and Chemotherapy found the best agents against the bacteria are penicillin G, cephalothin, and ceftriaxone. The study, “Antimicrobial Susceptibility of Propionibacterium acnes Isolates from Shoulder Surgery,” found that vancomycin is effective against C. acnes biofilms only at very high concentrations (≥128 μg/ml). Research on C. acnes is important in light of recent findings confirming concerns of biofilm production by the bacteria on PEEK implants.
Another study pertaining to surgical site infection in spinal surgery was published in the June 2020 issue of The Spine Journal, “Early adherence and biofilm formation of Cutibacterium acnes (formerly Propionibacterium acnes) on spinal implant materials.” The group from Brown University and Rhode Island Hospital ascertained the time to adherence and biofilm formation of C. acnes on several common spine implant materials: polyether ether ketone (PEEK), cobalt chromium, stainless steel, titanium, and titanium alloy.
The authors found that C. acnes adhered to PEEK quickly and began to form a biofilm as early as 8 hours after application. All of the metal implants showed little-to-no adherence and no biofilm production up to 24 hours after application. These results add to the growing body of evidence suggesting that PEEK is far from an ideal material for spine surgery and its continued use should be questioned.
The North American Spine Society (NASS) last updated its guideline, “Antibiotic Prophylaxis in Spine Surgery,” in 2013. The literature reviewed supports the use of prophylactic antibiotics but has not found evidence that any form of prophylaxis is effective at totally eliminating infection. The guidelines also provide consensus statements suggesting the use of vancomycin powder in instrumented, or complicated spine surgery, or for patients with comorbidities such as diabetes, neuromuscular disease, cord injury, or trauma.
Conclusion: Vancomycin Inexpensive Add-On
While some of the studies reviewed here provide conflicting outcomes regarding the use of vancomycin powder, the fact remains that it is an inexpensive add-on to use during open spine surgery or joint reconstruction with few repercussions. Larger, randomized trials, or more extensive retrospective studies across multiple institutions could provide better evidence concerning the efficacy of vancomycin powder, but funding for such a study is unlikely for such an inexpensive drug. Additionally, the data from these studies favors materials other than PEEK, such as titanium or titanium alloy, which are widely available.
