Le Fort I osteotomy and postoperative neurosensory disturbances of the infraorbital nerve: a retrospective cohort study.

Neurosensory disturbances in the infraorbital nerve territory are recognized sequelae of Le Fort I osteotomies; however, the operative factors contributing to their occurrence remain insufficiently defined. The authors retrospectively analyzed 102 skeletally mature patients with class II or III malocclusion who underwent Le Fort I combined with bilateral sagittal split ramus osteotomy. Using the preoperative and 1-week postoperative computed tomography scans, the anterior nasal spine displacement, maxillary molar impaction, maxillary advancement, shortest distance from the infraorbital foramen to the maxillary osteotomy line, and infraorbital foramen-to-fixation plate distance were quantified. Trigeminal somatosensory evoked potentials were recorded preoperatively, immediately postoperatively, and 6 months postoperatively to objectively assess infraorbital nerve function. Neurosensory disturbances were defined as postoperative prolongation of infraorbital nerve latency relative to each patient's preoperative baseline. Immediate postoperative neurosensory disturbances were observed in of 49 out of 102 patients (48.0%). Compared with the non-neurosensory disturbance group, the neurosensory disturbance group exhibited greater maxillary molar impaction (P = 0.012) and shorter infraorbital foramen-to-fixation plate distances (P < 0.0001); significant differences were also noted in the trigeminal somatosensory evoked potential-derived sensory threshold (P = 0.042), N45 latency (P < 0.0001), and stimulation intensity (P < 0.0001). Stimulation intensity negatively correlated with the infraorbital foramen-to-fixation plate distance (R2 = 0.344; P < 0.0001). All neurosensory disturbances resolved completely within 6 months. A shorter infraorbital foramen-to-fixation plate distance and larger maxillary impaction were associated with immediate postoperative infraorbital nerve neurosensory disturbances. Accurate preoperative estimation of planned movements and plate positioning that maximizes clearance from the infraorbital foramen may help reduce the risk of neurosensory disturbances after Le Fort I osteotomy.