The influence of expansion on intraoperative bone blood flow in multisegmental maxillary osteotomies: an experimental study

The aim of the presented study was to investigate the effect of maxillary expansion in multisegmental Le Fort I osteotomies on bone blood flow. Five sheep underwent a three-piece total maxillary osteotomy. Bone blood flow was measured intraoperatively by laser Doppler flowmetry in the premaxilla, the lateral segments and the mandible before osteotomy, after osteotomy and segmentation as well as after 4 mm, 8 mm and 12 mm expansion with a Hyrax screw. A significant reduction in blood flow was seen after osteotomy and segmentation with a factor of 3.10 and between 4 mm and 8 mm expansion with a factor of 1.81. No significant differences could be found between 0 mm and 4 mm widening or between 8 mm and 12 mm widening. These results suggest that expansion of more than 4 mm in multisegmental osteotomies enhances the risk of avascular sequelae. As greater maxillary widening has been carried out in many cases without avascular complications, further research on additional factors, influencing the recovery of perfusion, is needed.