J Oral Maxillofac Surg 56:596602, 1998 The Influence of Craniofacial Structure on Obstructive Sleep Apnea in Young Adults Francis R. Johns, DMD, MD, * PatrickJ Strollo, Jr, MD, f Michael Buckley, DMD, MS,+ and Joseph Constantine, DrPHJ Purpose: This study compares craniofacial measurements of lateral cephalometric radiographs of young obstructive sleep apnea patients with those of nonapneic snorers and controls. Patients and Methods: Forty-eight patients (BMI = 28.0 -+ 3.8) with obstructive sleep apnea, 25 patients (BMI = 26.3 + 3.5) with nonapneic snoring, and 54 controls (BMI = 24.8 + 2.7) were evalu- ated. All subjects were between 18 and 40 years of age. Nineteen lateral cephalometric measurements were performed by a single investigator blinded to the results of the polysomnograms. Results: Univariate logistic regression analysis of the 19 variables showed significantly increased midfacial height (AN!+N), narrowed middle airway space (MAS), steep mandibular plane angle (IMA), elongated pharynx (PNS-Eb), and inferiorly positioned hyoid bone (PNS-H, MPH) in the obstructive sleep apnea group. The nonapneic snoring group showed only a tendency toward maxillary and mandibular retrognathia (SNA and SNB). No significant differences were found for cranial base angle (S-N-Ba), PAS, inferior airway space, maxillary unit length (ANS-PNS) mandibular unit length (Cd-Gn), tongue height (Trig-Ht), soft palate length (PNS-P), and palatal vault height (Ocl-Pa16). The OSA group was also found to have multiple sites of abnormality of both the upper and lower pharynx, with 58% of the patients having two or more abnormal values (1 standard deviation from the mean) asopposed to 40% of the nonapneic snoring group. Conclusions: Highly significant craniofacial abnormalities were found in the upper and lower pharynx in young obstructive sleep apnea patients. Most of these patients (58%) had abnormalities in both the upper and lower pharynx, suggesting that palatal surgery alone may be an inadequate treatment. This information may define future investigations needed to determine how to more effectively treat this subgroup of young obstructive sleep apnea patients. Obstructive sleep apnea (OSA) is a disorder in which recurrent closure of the upper airway occurs during sleep. Arousal from sleep is required to reopen the obstructed airway. These frequent arousals are the *Chief Resident, Department of Oral and Maxillofacial Surgery, University of Pittsburgh Medical Center. tAssociate Professor, Division of Pulmonary, Allergy, and Critical Care Medicine, University of Pittsburgh Medical Center. $Associate Professor, Department of Oral and Maxillofacial Sur- gery, University of Pittsburgh Medical Center. SAssociate Professor, Department of Biostatistics, University of Pittsburgh Graduate School of Public Health. The views expressed in this article are those of the authors and do not reflect the official policy of the Department of Defense or other Departments of the US Government. Address correspondence and reprint requests to Dr Strollo: Montefiore University Hospital, 3459 Fifth Ave, Suite S-643, Pitts- burgh, PA 15213. o 1998 American Association of Oral and Maxillofacial Surgeons 0278.2391/98/5605~010$3.00/0 primary cause of excessive daytime somnolence. Up- per airway closure primarily occurs either at the base of the tongue or posterior to the soft pa1ate.l Nonsurgi- cal therapy consisting of continuous positive airway pressure (CPAP) is the primary therapy. In patients who are intolerant of or noncompliant with CPAP, upper airway reconstruction can signiticantly im- prove, and in some cases cure, the obstructive sleep apnea.24z2” Multiple imaging techniques have been used to evaluate the upper airway in patients with obstructive sleep apnea.5 These techniques have included cepha- lometry, computed tomography, magnetic resonance imaging, fluoroscopy, and acoustic reflection stud- ies.5-7 Each has its own advantages and disadvantages in determining the anatomy of the airway and predict- ing the site of the upper airway occlusion. Cephalom- etry is the most commonly used imaging study to evaluate patients for obstructive sleep apnea. Cephalo- metric radiographs are easy and fast to perform, noninvasive, and of low cost. An obvious disadvantage to cephalometry is that it is a two-dimensional repre- 596