The irradiated human mandible: A quantitative study on bone vascularity.
OBJECTIVES
Hypovascularisation is thought to play an important role in the pathogenesis of osteoradionecrosis. The objective of this study was to assess the microvascular system in the irradiated mandibular bone marrow.


MATERIALS AND METHODS
Mandibular bone biopsies were taken from 20 irradiated patients and 24 controls. Blood vessels were visualized using CD34 antibody stain to detect endothelial cells. The vascular density (VD) and vascular area fraction (VAF) were measured. Mean vessel lumen area, perimeter and diameter of the vessels were calculated for each vessel. A distinction was made between large and small vessels (cut-off point <400 µm2).


RESULTS
Vascular density and vascular area fraction were lower in the irradiated group. The mean vascular perimeter and mean vascular diameter were higher in samples with a local radiation dose of ≥50 Gy, whereas the percentage of small vessels was lower. Larger vessel perimeter is associated with higher radiation dose. A longer interval between biopsy and radiotherapy is associated with a larger mean vessel perimeter and a lower percentage of small vessels.


CONCLUSIONS
Radiation dosages higher than 50 Gy mainly affect the smaller vessels. With increased time after irradiation, the share of smaller vessels in the mandibular bone marrow seems to decrease. In search of the exact mechanisms of irradiation damage and osteoradionecrosis of the mandible, the role of the microvascular system in the mandibular bone marrow should be further explored.
['Dekker|H|H|', 'Bravenboer|N|N|', 'van Dijk|D|D|', 'Bloemena|E|E|', 'Rietveld|D H F|DHF|', 'Ten Bruggenkate|Chr M|CM|', 'Schulten|E A J M|EAJM|']
D000328:Adult D000368:Aged D001706:Biopsy D001853:Bone Marrow D016022:Case-Control Studies D004307:Dose-Response Relationship, Radiation D005260:Female D006258:Head and Neck Neoplasms D006801:Humans D008297:Male D008334:Mandible D063168:Mandibular Osteotomy D008875:Middle Aged D010025:Osteoradionecrosis D011829:Radiation Dosage D050397:Radiotherapy, Intensity-Modulated D013997:Time Factors
Mandible Osteoradionecrosis Radiotherapy Microvascular network Microvasculature Microvessel Oral cancer