Improvement of the Respiratory Function in a Patient With Mandibular Retrognathia and Hyperdivergent Skeletal Pattern With Condylar Resorption by Le Fort I Osteotomy and Genioplasty.

[INTRODUCTION] This case report describes the multidisciplinary treatment of a patient with mandibular retrognathia and hyperdivergent skeletal pattern, condylar resorption, and severe obstructive sleep apnea (OSA).

[CASE PRESENTATION] A 42-year-old female patient presented with a chief complaint of mandibular retrognathia. The patient had no significant medical history, and her body mass index was 18.8. She had a +9.0 mm overjet and +1.0 mm overbite, and an Angle Class II molar relationship. Cephalometric analysis revealed SNA, SNB, and FMA of 76.0°, 67.5°, and 50.5°, respectively. Computed tomography (CT) images showed severe bilateral mandibular condylar head deformity due to resorption. Polysomnography revealed an apnea-hypopnea index (AHI) of 43.3, leading to a diagnosis of severe OSA. Correspondingly, continuous positive airway pressure (CPAP) therapy was started immediately.

[MANAGEMENT AND OUTCOMES] After 19 months of preoperative orthodontic treatment with preadjusted edgewise appliances, Le Fort I osteotomy was performed to impact the maxilla by 3.0 mm at the anterior and 4.0 mm at the posterior nasal spine. The mandible was autorotated 8.6° counterclockwise, reducing ANB from +8.5° to +2.0°. A genioplasty was also performed. After 8 months of postoperative orthodontic treatment, the AHI decreased to 2.3, and CPAP therapy was discontinued due to significant improvement in respiratory function. CT images showed an increase in the upper airway volume after orthognathic surgery. No remarkable morphological changes were observed in the mandibular condylar head during orthodontic treatment. Favorable occlusion was maintained with no apparent relapse after 21 months of retention.

[DISCUSSION] Unlike conventional maxillomandibular advancement for OSA, the surgical method described in this case study combines counterclockwise mandibular rotation and genioplasty to simultaneously improve respiratory function and craniofacial morphology in patients with hyperdivergent and Class II skeletal pattern accompanied by mandibular condylar head deformity.