Altered orthognathic surgical sequencing and a modified approach to model surgery

Advances in orthognathic surgical treatment planning and in techniques for complex, simultaneous maxillary and mandibular repositioning have resulted in improved surgical accuracy. In traditional surgical sequencing, maxillary surgery is performed first; the maxilla is set, with or without an intermediate splint, using external reference points to verify and/or determine appropriate movement. However, errors in model surgery and intermediate splint fabrication can lead to surgical inaccuracy despite good surgical technique. In repositioning the maxilla first, when thin bony walls are present, and/or in conjunction with large mandibular advancements, maxillary shifting may occur when maxillomandibular fixation is applied. Soft tissue tension and surgical manipulation in this sequencing technique may result in a less desirable functional and esthetic outcome. This article presents an alternative to surgical sequencing and a modification of model surgery techniques to improve surgical accuracy, and thus predictability and stability of the results.