Accuracy of cephalometry in measurements of postoperative migration of the maxilla after Le Fort I osteotomy.

The aim of the study was to evaluate the accuracy of cephalometry when point A is used to assess the migration of the maxilla following Le Fort I osteotomy. In 10 consecutive patients, postoperative migration of the maxilla was studied by means of cephalometry and x-ray stereometry. Because the precision and accuracy of the x-ray stereometric method are known to be high, this method was used as a norm against which the results obtained by cephalometry were compared. The values of postoperative migration obtained by cephalometric analysis exceeded the corresponding values obtained by x-ray stereometry in all but four recordings. In 16 of 40 recordings, migration in opposite directions was found. The differences were statistically significant. Cephalometric analysis may be an inaccurate tool for postoperative follow-up of minor segment migration such as that usually found after osteotomies.