LeFort I osteotomy is a surgical procedure used to reposition the maxilla (upper jaw) in cases of severe malocclusion or facial deformities. It involves cutting the maxilla from side to side, detaching it from the rest of the skull, and then repositioning it to correct the alignment of the upper and lower jaws. It's named after French surgeon René Le Fort who first described these types of facial fractures in the early 20th century.