Outcomes with culture-directed antibiotics following microvascular free tissue reconstruction for osteonecrosis of the jaw

Abstract

Objectives: Radiation (ORNJ) and bisphosphonate-related (BRONJ) osteonecrosis of the jaw represent challenging entities to treat, with many patients requiring segmental resection and reconstruction with microvascular free tissue transfer (MFTT) in the setting of failed conservative therapy. Microvascular reconstruction is associated with higher post-operative complication rates when performed for advanced osteonecrosis versus oncologic defects. We hypothesize that basing antibiotic therapy on cultures obtained from the healthy bone marrow following resection during MFTT for ORNJ or BRONJ reduces rates of post-operative wound and surgical complications.

Materials and methods: In a retrospective cohort study spanning January 2016 to October 2018, 44 patients undergoing MFTT for ORNJ or BRONJ were identified. Patients were categorized into two cohorts: residual healthy marrow culture (n = 11; RHM), treated with antibiotics guided by cultures from healthy appearing mandible, and all others (n = 33; AO), treated with antibiotics guided by cultures from resected necrotic bone or purulent drainage. Patient, reconstruction, and outcome variables were compared via appropriate statistical tools.

Results: 81.8% of the RHM cohort versus 24.2% of the AO cohort received long-term IV antibiotics. Rates of post-operative wound complications, including those necessitating operative management, were significantly lower in the RHM cohort. Rates of flap failure were similar across both groups.

Conclusion: Administration of long-term IV antibiotics directed by native mandible cultures may decrease complication rates following MFTT for ORNJ or BRONJ by treating residual, smoldering infection. Concurrently, transplantation of well-vascularized free tissue likely improves antibiotic delivery. Findings are crucial for the development of a standardized treatment algorithm following microvascular reconstruction for advanced osteonecrosis.

Keywords: Head and neck cancer; Microvascular free tissue transfer; Oral cancer; Osteonecrosis; Osteoradionecrosis; Post-operative antibiotic therapy.