Maxillary Posterior Segmentation Using an Oscillating Saw in Le Fort I Posterior or Superior Movement Without Pterygomaxillary Separation

Displacement Patterns of the Maxilla During Parallel and Rotational Setback Movements: A Finite Element Analysis

BACKGROUND The purpose of this analysis was to evaluate the displacement patterns of the maxilla under parallel and rotational setbacks using the finite element method (FEM). MATERIAL AND METHODS A three-dimensional (3D) finite element model of a hemimaxilla was constructed. Through a conventional Le Fort I osteotomy, 2 and 3 mm of posterior movement in a parallel and rotational manner were simulated and the displacement pattern of the maxilla in each movement type was evaluated. RESULTS Both parallel and rotational setbacks resulted in lateral and inferior displacement of the maxillary segment. The largest inferior displacement was 3.0 mm and the largest lateral displacement was 1.84 mm. All lateral displacements in the anterior region were found to be more than 1 mm. CONCLUSIONS The results of this study may provide insight into how the maxilla tends to move during total maxillary setback surgery.

Is an osteotome necessary for pterygomaxillary dysjunction or dysjunction through the tuberosity during Le Fort I osteotomy? A systematic review

Pterygomaxillary dysjunction with an osteotome is commonly used to mobilise the maxilla during Le Fort I osteotomy, despite the risk of serious complications. Different instruments and positions have been tried, including dysjunction through the tuberosity. Down fracture by digital pressure alone has also been advocated, but to our knowledge has not been widely adopted. We have therefore reviewed published papers to see if there is any clinical or anatomical evidence for the use of osteotomes to mobilise the maxilla vertically during a Le Fort I osteotomy for either pterygomaxillary dysjunction or dysjunction through the tuberosity. We found only one paper that analysed the anatomy of the pterygomaxillary fissure and described small bony bridges and syncondroses across the joint. We found no clinical or anatomical evidence for the use of osteotomes in pterygomaxillary separation or separation through the tuberosity. A large clinical trial on down fracture of the maxilla by digital pressure alone showed no serious complications, and we found no strong evidence to justify the use of osteotomes in pterygomaxillary dysjunction or dysjunction through the tuberosity. We have successfully used digital pressure alone in 138 consecutive Le Fort I osteotomies, and we encourage our colleagues to consider adopting this approach.