Brachytherapy-mediated bone damage in a rat model investigating maxillary osteoradionecrosis

Area of Science:

• Oral and Maxillofacial Surgery
• Radiation Oncology
• Animal Models in Research

Background:

• Osteoradionecrosis (ORN) is a severe complication of radiation therapy to the head and neck.
• Understanding the specific vulnerabilities of different jawbones to radiation is crucial for improving patient outcomes.
• A rat model of mandibular ORN has been recently developed, providing a basis for comparison.

Purpose of the Study:

• To evaluate the clinical and radiologic effects of targeted radiotherapy on the rat maxilla.
• To compare these findings with the established rat model of mandibular osteoradionecrosis (ORN).

Main Methods:

• A prospective, controlled animal study involving Sprague-Dawley rats.
• Experimental group received catheter-assisted high-dose-rate brachytherapy; control group received sham therapy.
• Micro-computed tomography was used to quantify bone volume in the dental extraction socket post-radiation.

Main Results:

• Rats receiving brachytherapy showed mucosal scarring, unlike controls.
• A significant reduction in bone volume to total volume ratio was observed in the irradiated maxilla (0.21 vs. 0.49, P=.01).
• No bone exposure was clinically observed in the maxilla, despite radiologic evidence of bone injury.

Conclusions:

• The rat maxilla is susceptible to radiogenic bone injury, evidenced by decreased bone volume after radiotherapy.
• The maxilla exhibits a more benign clinical course compared to the mandible in this ORN model.
• Differences in bone structure and microenvironment may explain the lower incidence of clinical maxillary ORN in patients.