Methods of antibiotic instillation in porous orbital implants.
OBJECTIVE
Soaking porous implants in antibiotic solution at the time of implantation is often recommended to promote fibrovascular ingrowth and reduce risk of infection. This study evaluated antibiotic penetration in porous implants using different instillation techniques.


METHODS
Penetration of methylene blue in three 20-mm diameter porous implants (hydroxyapatite, porous polyethylene, and aluminum oxide) was measured using 4 different techniques: 1) soaking in dye for 5 minutes; 2) compressing the implant in dye in a 60-ml syringe for 1 and 2 minutes; 3) aspirating dye through the implants in a 60-ml syringe for 1 and 2 minutes; and 4) direct injection of dye in the center of the implants. Each implant was cut in half to measure penetration in 4 quadrants by 2 independent observers.


RESULTS
Soaking the implants for 5 minutes resulted in 6 mm penetration of dye from the surface in hydroxyapatite and no penetration in the others. Compressing or aspirating implants in dye for both 1 minute and 2 minutes resulted in complete penetration to the center in all implants. Direct injection resulted in complete distribution in hydroxyapatite, localized within 4 mm of the injection site in porous polyethylene, and no penetration in aluminum oxide.


CONCLUSIONS
Best penetration of fluid in all implants was achieved with aspiration or compression within a syringe. If an implant becomes infected, topical instillation of antibiotic is unlikely to reach the sites of infected pores. Direct injection of antibiotic may be helpful for porous implants providing the needle pore does not get blocked while penetrating the implant as it did with the 3 aluminum oxide implants tested in this study.
Badilla
Jaime
J
Department of Ophthalmology, University of British Columbia, Vancouver, Canada.
Dolman
Peter J
PJ
D000537:Aluminum Oxide; D000900:Anti-Bacterial Agents / Q000008:administration & dosage*; D001672:Biocompatible Materials; D017886:Durapatite; D008751:Methylene Blue / Q000008:administration & dosage*; D020273:Orbital Implants; D020959:Polyethylene
D000900:Anti-Bacterial Agents; D001672:Biocompatible Materials; D020959:Polyethylene; D017886:Durapatite; D000537:Aluminum Oxide; D008751:Methylene Blue