Three-dimensional positioning of the maxilla using novel intermediate splints in maxilla-first orthognathic surgery for correction of skeletal class III deformity

Objectives Successful orthognathic surgery requires accurate transfer of the intraoperative surgical plan. This study aimed to (1) evaluate the surgical error of a novel intermediate splint in positioning the maxilla during maxilla-first orthognathic surgery and (2) determine factors influencing surgical error. Materials and methods This prospective study examined 83 patients who consecutively underwent Le Fort I osteotomy for correction of skeletal class III deformity using a novel intermediate splint and a bilateral sagittal split osteotomy. Surgical error was the outcome variable, measured as the difference in postoperative translational and rotational maxillary position from the virtual plan. Measures included asymmetry, need and amount for mandibular opening during fabrication of intermediate splints, and planned and achieved skeletal movement. Results Mean errors in translation for vertical, sagittal, and transversal dimensions were 1.0 +/- 0.7 mm, 1.0 +/- 0.6 mm, and 0.7 +/- 0.6 mm, respectively; degrees in rotation for yaw, roll, and pitch were 0.8 +/- 0.6, 0.6 +/- 0.4, and 1.6 +/- 1.1, respectively. The transverse error was smaller than sagittal and vertical errors; error for pitch was larger than roll and yaw (both p < 0.001). Error for sagittal, transverse, and roll positioning was affected by the achieved skeletal movement (roll, p < 0.05; pitch and yaw, p < 0.001). Surgical error of pitch positioning was affected by planned and achieved skeletal movement (both p < 0.001). Conclusions Using the novel intermediate splint when performing Le Fort I osteotomy allowed for accurate positioning of the maxilla. Clinical relevance The novel intermediate splint for maxillary positioning can be reliably used in clinical routines.