9.6\ LeFort I Osteotomy

9.6.1\ Discussion

The LeFort I osteotomy procedure and its modifications are commonly performed to correct malocclusion and maxillomandibular deformities. LeFort I osteotomies and modifications thereof are performed in conjunction with other procedures, such as sagittal split osteotomies and approaches to the skull base via a transoral route. The standard procedure involves separating and moving forward the anterolateral walls of the maxillary sinus, inferior portion of the nasal cavity, and pterygoid plates. Fixation of the osteotomy fragments can be accomplished using microfixation plates and screws. Alternatively, maxillary distractors can be used to gradually correct the deformity as osteogenesis progresses. Bone grafts can also be

applied adjacent to the osteotomy site in order to promote healing. Diagnostic imaging may be used to assess postoperative alignment, for which highresolution CT with 3D reformats is particularly insightful (Fig. 9.11). Anatomical complications occur in 2 to 3% of cases and include deviation of the nasal septum, nonunion of the osteotomy gap, and impingement upon the nasolacrimal duct (Fig. 9.12), while significant infections, such as abscesses or maxillary sinusitis, occur in approximately 1% of cases. Furthermore, perforation of the periosteum in the maxillary sinuses can lead to herniation of the buccal fat pad, which may not only obscure the surgical field but can lead to sinus obstruction (Fig. 9.13). Neurovascular injury involving the palatine canal can occur with pterygomaxillary disjunction when the osteotomy extends too far posteriorly beyond the piriform rim (Fig. 9.14).

Fig. 9.11  LeFort I osteotomy with microfixation plate. Preoperative 3D CT image (a) shows maxillary underjet associated with midface hypoplasia. Postoperative 3D CT images (b and c) show bilateral LeFort I osteotomies

secured with plates and screws, resulting in improved dental occlusion. Bilateral sagittal split osteotomies were also performed

Fig. 9.12  Nasolacrimal duct obstruction following LeFort I osteotomy with internal fixation. Axial CT images show a bone fragment (arrow) displaced into the right nasolacrimal duct by the adjacent screw

Fig. 9.13  LeFort I surgery with buccal fat herniation into the maxillary sinus. Axial CT image shows portions of buccal fat within the bilateral maxillary sinuses

Fig. 9.14  Palatine canal disruption. Axial CT image shows the LeFort osteotomy traversing the right greater palatine canal (arrow)