Metronidazole and cefuroxime concentrations in tunnelized facial artery myomucosal island flaps

Tunnelized Facial Artery Myomucosal (FAMM) island flaps are used for reconstruction after oral cavity cancer surgery but may be vulnerable to compromised perfusion. This study evaluated the tissue concentrations of cefuroxime and metronidazole in tunnelized FAMM island flaps compared with buccal submucosa. Five patients undergoing oral cavity cancer resection with tunnelized FAMM flap reconstruction received intravenous cefuroxime (1,500 mg every 8 h) and metronidazole (500 mg every 12 h). Microdialysis probes were placed in the flap and buccal submucosa, with parallel plasma sampling during steady state. Pharmacokinetic parameters, cefuroxime %T>MIC, and metronidazole AUC_0-24h/MIC were compared across compartments. Treatment targets were ≥50%T>MIC and AUC_0-24h/MIC ≥70. Both antibiotics reached pharmacodynamic targets for common oral pathogens (MIC 2 µg/mL) in all compartments. Cefuroxime %T>MIC exceeded 90% at MIC 2 µg/mL and ranged 71-88% at MIC 4 µg/mL. Metronidazole AUC_0-24h/MIC ratios were 120-151 at MIC 2 µg/mL and 60-76 at MIC 4 µg/mL. The lowest exposures occurred in the single patient with complete flap necrosis. Despite altered pharmacokinetics in tunnelized FAMM island flaps, standard perioperative dosing of cefuroxime and metronidazole provides adequate tissue exposure for typical oral cavity pathogens.