Residency · Residency · Oral Maxillofacial Surgery

Obstructive Sleep Apnea: Evaluation and the Role of OMFS

Introduction

Obstructive sleep apnea (OSA) is a prevalent sleep-disordered breathing condition characterized by repetitive upper airway collapse during sleep. Affecting approximately 15 to 30% of males and 10 to 15% of females, OSA has significant cardiovascular, metabolic, and neurocognitive consequences. The OMFS surgeon contributes expertise in craniofacial anatomy, airway evaluation, and surgical intervention that is integral to the multidisciplinary management of this disease.

Pathophysiology

OSA results from dynamic upper airway collapse during sleep due to loss of pharyngeal muscle tone. Anatomic factors that reduce the pharyngeal cross-sectional area include retrognathia, macroglossia, enlarged tonsils, redundant soft tissue, and obesity. The Bernoulli effect causes increased airflow velocity through a narrowed airway to generate negative intraluminal pressure, promoting collapse. Sites of obstruction include the retropalatal, retroglossal, and hypopharyngeal regions, and obstruction may be multilevel. The balance between anatomic compromise and neuromuscular compensation determines disease severity.

Clinical Presentation

Symptoms

The cardinal symptom is excessive daytime sleepiness, assessed by the Epworth Sleepiness Scale (ESS). Other symptoms include witnessed apneas and loud snoring, morning headaches, dry mouth, sore throat, nocturia, insomnia, nocturnal gasping or choking, cognitive impairment, irritability, and decreased libido. In children, OSA may present with behavioral problems, poor school performance, enuresis, and failure to thrive.

Systemic Consequences

Cardiovascular consequences include hypertension (present in 50% of OSA patients), atrial fibrillation, heart failure, stroke, and pulmonary hypertension. Metabolic consequences include insulin resistance, metabolic syndrome, and type 2 diabetes. Neurocognitive effects include memory impairment, depression, and a 2 to 7-fold increased risk of motor vehicle accidents. Perioperative risk is elevated due to increased sensitivity to sedation and analgesia and higher postoperative complication rates.

Diagnosis

Polysomnography (PSG)

Polysomnography is the gold standard for OSA diagnosis. It is an overnight in-laboratory study measuring EEG, EMG, EOG, airflow, respiratory effort, SpO2, and body position. The Apnea-Hypopnea Index (AHI) quantifies the number of apneas and hypopneas per hour of sleep.

The study also reports oxygen desaturation index (ODI), lowest SpO2, sleep architecture, and arousal index.

Home Sleep Apnea Testing (HSAT)

HSAT is a portable monitoring option for uncomplicated adult patients with high pretest probability. It measures airflow, respiratory effort, and oxygen saturation. It may underestimate severity, and negative results should be confirmed with in-lab PSG.

Drug-Induced Sleep Endoscopy (DISE)

DISE involves flexible nasopharyngoscopy during pharmacologically induced sleep using propofol or midazolam. It identifies specific sites and patterns of obstruction (retropalatal, retrolingual, epiglottic, lateral wall). The VOTE classification describes obstruction at the Velum, Oropharynx (tonsils), Tongue base, and Epiglottis. DISE guides surgical planning and is increasingly used before OMFS interventions.

OMFS Evaluation of the OSA Patient

Craniofacial Assessment

Skeletal analysis using a lateral cephalogram assesses SNA, SNB, posterior airway space (PAS), and hyoid position. Retrognathia (SNB less than 78 degrees) is strongly associated with OSA. A posterior airway space less than 11 mm at the tongue base level suggests retroglossal obstruction. A low hyoid position (greater than 15 mm below the mandibular plane) correlates with OSA severity.

Clinical Examination

The examination includes BMI and neck circumference (greater than 40 cm increases risk), Mallampati classification (Class III-IV correlates with OSA), tonsil size (Friedman scale 0-4), macroglossia, lateral pharyngeal wall thickness, nasal obstruction (septal deviation, turbinate hypertrophy), and assessment of maxillary and mandibular position, dental occlusion, and facial skeletal pattern.

Imaging

A lateral cephalogram is the standard screening tool for skeletal contribution to airway narrowing. CBCT provides 3D airway volumetric analysis and identifies the minimum cross-sectional area. MRI offers soft tissue detail of pharyngeal structures and has research applications.

Treatment Overview

Conservative Management

CPAP (Continuous Positive Airway Pressure) is the first-line therapy and works by pneumatic splinting of the airway. Adherence rates are 40 to 60%, and poor tolerance drives the need for surgical alternatives. Weight loss of 10% can improve AHI by 26 to 50%. Positional therapy is used for position-dependent (supine-predominant) OSA. Oral appliances (mandibular advancement devices) are effective for mild to moderate OSA, and the OMFS surgeon plays a role in fabrication and titration.

Surgical Options (OMFS)

Maxillomandibular advancement (MMA) is the most effective surgical treatment. Genioglossus advancement advances the genial tubercle to increase tongue base airway space. Hyoid suspension anteriorly repositions the hyoid bone (thyrohyoid or mandibulohyoid). Transpalatal advancement pharyngoplasty addresses retropalatal narrowing. Distraction osteogenesis is used for pediatric or severe retrognathia-related OSA.

Otolaryngologic Procedures

Uvulopalatopharyngoplasty (UPPP) addresses retropalatal obstruction with 40 to 50% success as a standalone procedure. Tonsillectomy is first-line for pediatric OSA and effective in adults with tonsillar hypertrophy. Tongue base procedures include radiofrequency ablation, midline glossectomy, and transoral robotic surgery (TORS). Epiglottoplasty addresses epiglottic collapse. Hypoglossal nerve stimulation is an emerging device-based therapy.

Multidisciplinary Team

The sleep medicine physician manages diagnosis, CPAP, and medical optimization. The OMFS surgeon provides skeletal surgery (MMA, distraction) and oral appliance therapy. The otolaryngologist performs soft tissue surgery, DISE, and HNS implantation. The pulmonologist manages comorbid pulmonary disease. The bariatric surgeon offers weight loss surgery for morbidly obese OSA patients. The dentist and orthodontist fabricate oral appliances and manage dental issues.

Clinical Pearls

OSA is highly prevalent and underdiagnosed, and OMFS surgeons should screen patients with suggestive craniofacial features. Cephalometric analysis revealing retrognathia and a narrow posterior airway space identifies patients who may benefit from skeletal surgery. DISE has become an essential tool for identifying the specific site(s) of obstruction and tailoring surgical intervention. CPAP remains first-line, but poor adherence drives the need for effective surgical alternatives. MMA is the most efficacious surgical treatment for moderate to severe OSA with skeletal deficiency.

References

1. Zaghi S, et al. "Obstructive Sleep Apnea and the Role of Oral and Maxillofacial Surgery." Oral and Maxillofacial Surgery Clinics of North America. 2020;32(3):347-362.
2. Epstein LJ, et al. "Clinical Guideline for the Evaluation, Management, and Long-Term Care of Obstructive Sleep Apnea in Adults." Journal of Clinical Sleep Medicine. 2009;5(3):263-276.
3. Kezirian EJ, et al. "Drug-Induced Sleep Endoscopy." Otolaryngology--Head and Neck Surgery. 2011;145(1):126-130.
4. Camacho M, et al. "Maxillomandibular Advancement and Tracheostomy for Morbidly Obese Obstructive Sleep Apnea." Otolaryngology--Head and Neck Surgery. 2015;152(4):619-630.

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