Clinical Paper Orthognathic Surgery Changes in posterior airway space, pulmonary function and sleep quality, following bimaxillary orthognathic surgery S. M. Gokce, S. Gorgulu, H. S. Gokce, O. Bengi, F. Sabuncuoglu, F. Ozgen, H. Bilgic: Changes in posterior airway space, pulmonary function and sleep quality, following bimaxillary orthognathic surgery. Int. J. Oral Maxillofac. Surg. 2012; 41: 820–829. # 2012 International Association of Oral and Maxillofacial Surgeons. Published by Elsevier Ltd. All rights reserved. S. M. Gokce 1 , S. Gorgulu 1 , H. S. Gokce 2 , O. Bengi 1 , F. Sabuncuoglu 1 , F. Ozgen 3 , H. Bilgic 4 1 Gulhane Military Medical Academy, Dental Sciences Center, Department of Orthodontics, Etlik, Ankara, Turkey; 2 Beytepe Military Hospital, Chief of Dental Service, Cankaya, Ankara, Turkey; 3 Gulhane Military Medical Academy, Sleep Disorders Center, Department of Psychiatry, Etlik, Ankara, Turkey; 4 Gulhane Military Medical Academy, Department of Chest Diseases, Etlik, Ankara, Turkey Abstract. Bimaxillary orthognathic surgery (BOS) is commonly used in the correction of severe Class III deformities (mandibular prognathism with maxillary retrognathism). The postural response of the pharyngeal airway after mandibular setback and maxillary advancement procedures is clinically crucial for maintaining optimum respiration. Patients might suffer from obstructive sleep apnoea, postoperatively. The aim of this study was to determine the effects of BOS on pharyngeal airway space, respiratory function during sleep and pulmonary functions. 21 male patients were analysed using cephalometry, spirometry for pulmonary function tests, and a 1 night sleep study for full polysomnography before and 17  5 months after BOS. The data show that the hyoid bone repositioned to the inferior, the tongue and soft palate displaced to the posterior, narrowed at the oropharynx and hypopharynx and widened at the nasopharynx and velopharynx levels significantly (p < 0.05). The alterations indicated decreased airway resistance and better airflow. As a consequence of polysomnography evaluation, the sleep quality and efficiency of the patients improved significantly after BOS. Patients who undergo BOS should be monitored with pulmonary function tests and polysomnography pre- and postoperatively to detect any airway obstruction. Keywords: mandibular prognathism; orthog- nathic surgery; pharyngeal airway space; ce- phalometry; polysomnography; pulmonary function tests; OSA. Accepted for publication 5 January 2012 Available online 3 April 2012 Class III malocclusions usually present with skeletal discrepancies such as a prog- nathic mandible with or without a retru- sive maxilla. A severe Class III skeletal relationship poses aesthetic and func- tional problems. Its correction involves orthodontic and orthognathic surgical treatments. Bimaxillary orthognathic sur- gery (BOS) (mandibular setback (MS) and maxillary advancement (MA) proce- dures) are commonly used to correct this deformity 1 . Orthognathic surgery (OS) procedures, reposition the orofacial skeletal together with their soft tissue components, such as the soft palate, the tongue and, relatively, the hyoid bone (HB). The tension of these, directly or indirectly, attached soft tissue Int. J. Oral Maxillofac. Surg. 2012; 41: 820–829 doi:10.1016/j.ijom.2012.01.003, available online at http://www.sciencedirect.com 0901-5027/070820 + 10 $36.00/0 # 2012 International Association of Oral and Maxillofacial Surgeons. Published by Elsevier Ltd. All rights reserved.