Does preoperative joint space affect accuracy in splint-based Le Fort I osteotomy?

In splint-based Le Fort I osteotomy (LFI), variations in condyle-fossa relationship can influence surgical accuracy. The aim of this study was to investigate the impact of the preoperative joint space (JS) on surgical errors. This retrospective study included patients status post splint-based maxilla-first LFI at a single institution in a 7-month period. Preoperative JS was measured on preoperative cone-beam computed tomography (CBCT), while angular and linear surgical movements at the maxillary dental midline (U1) were measured using regional voxel-based registration. In 26 eligible subjects, the mean absolute linear and angular errors were 0.82-1.18 mm and 0.87-1.21°, respectively. The greatest superior and posterior preoperative JS correlated with mediolateral (P = 0.020) and anteroposterior (P = 0.019) error, respectively. JS was not associated with angular errors (P > 0.05). Laterality of the greater posterior preoperative JS was associated with the mediolateral linear error (P = 0.026). Regression analysis showed that 3.92 mm posterior preoperative JS resulted in 1 mm anteroposterior error, and a left-to-right posterior preoperative JS differential of 1.35 mm resulted in 1 mm mediolateral error. Vertical and anteroposterior preoperative JS can affect accuracy in maxilla-first splint-based LFI. Routine preoperative evaluation can help identify at-risk cases.