104. Zoledronic acid decreases infection burden in mouse model of spine implant Infection

BACKGROUND CONTEXT Bisphosphonatesare commonly used in the orthopedic patient population to manage osteoporosis and other metabolic bone diseases. There is also increasing support for bisphosphonateuse in the perioperative setting, to minimize osteolysisand bone loss. Additionally, bisphosphonatesare known to affect the host immune system; however, their effect on implant infections, which are notoriously difficult to treat, remains largely unknown. PURPOSE The purpose of this study was to assess the effect of zoledronic acid(ZA) on spinal implant infection in our validated mouse model. METHODS Twenty-six 8-week-old C57BL/6 mice were included in the study. Twelve were treated with 250 ug/kg of ZA,12 with normal saline via retro-orbital injection on the day of surgery, and the remaining 2 were sterile controls. A stainless steel pin was then placed into the L4 spinous processesof all mice and site was inoculated with 1E+3 CFUs of bioluminescentXen36 Staphylococcus aureus in experimental groups. Infection burden was monitored with in vivo bioluminescence imagingat pre-determined intervals. RESULTS Following an initial similar increase after surgery and inoculation, mice treated with ZA showed a decreased bacterial burden as compared to infected control group (p CONCLUSIONS The indications for ZA use continue to expand, and it is often used in the perioperative setting. In our validated mouse model of spine implant infection, ZA decreases bacterial burden as compared to controls. Further investigation is required to determine the effects of dosing, location of infection and to explore possible mechanisms by which ZA exerts this effect. These findings may suggest a further benefit to bisphosphonateuse in the perioperative setting. FDA DEVICE/DRUG STATUS Unavailable from authors at time of publication.