3/8/2018 AIRWAY ASSESSMENT UPPER AIRWAY ANATOMY AND PATHOLOGY SMALL AIRWAY What Happened? David C. Hatcher, DDS, MSc, MRCD ( C ) Oral and Maxillofacial Radiologist Airway Anatomy & Pathology Sleep Disordered Breathing (SDB) Increasing Upper Airway Collapsibility Polysomnography (PSG) . Abnormal Respiratory Pattern During Sleep . Apnea Hypopnea Index (AHI) . Snoring Apnea = Cessation of Airflow > 10 seconds . Upper Airway Resistance Syndrome Hypopnea = Decrease in Airflow by > 30% for > 10 . Obstructive Sleep Apnea Syndrome Seconds . Obesity‐Hypoventilation Syndrome Associated with Drop SaO2 by > 3 % AHI = A+ H / Hour Sleep > 5 Abnormal UOP Ortho Alumni Hatcher UOP Ortho Alumni Hatcher UOP Ortho Alumni Hatcher Obstructive Sleep Apnea Pathophysiology of OSA Role of Anatomy Awake: Small Airway + Neuromuscular Compensation Sleep Onset . Recurrent Collapse of Airway During Sleep Loss of Hyperventilate: Abnormal Upper Airway Anatomy Neuromuscualar Correct Hypoxia & Compensation Hypercapnia . Abnormal AHI with Symptoms Pharyngeal Muscle . Increase Resistance Activity Mild OSA‐ 5‐15 AHI Events/ Hour Airway Opens Mod. OSA‐ 16‐30 AHI Events/ Hour Airway Collapse Pharyngeal Muscle . Turbulent Air Flow Activity Restored Sev. OSA‐ > 30 AHI Events/ Hour Apnea Hypoxia & Arousal From Sleep Hypercapnia . Increases Collapsibility Ventilatory Effort UOP Ortho Alumni Hatcher UOP Ortho Alumni Hatcher UOP Ortho Alumni Hatcher 1 3/8/2018 OSA Airway Metric Analysis . Related to Abnormal Timing of Upper Airway . Volume Dilator Muscle Contraction . Cross Sectional Area . Normally Dilator Muscles Contract BEFORE . Linear Distances Diaphragm & Accessory Inspiratory Muscles Move OR it will Create a Negative Pressure Leading to Airway Collapse . Requires Good Neurological System UOP Ortho Alumni Hatcher UOP Ortho Alumni Hatcher UOP Ortho Alumni Hatcher Measurement Error Source Effect of Tongue Position on Airway Map Region of Interest (ROI) . Soft Ware Accuracy . Head Position . Tongue Position . Tongue Motion UOP Ortho Alumni Hatcher UOP Ortho Alumni Hatcher UOP Ortho Alumni Hatcher Cross Sectional Area UOP Ortho Alumni Hatcher UOP Ortho Alumni Hatcher UOP Ortho Alumni Hatcher 2 3/8/2018 CSA v. Age Airway: Role of Imaging Upright Imaging 180 . Airway Imaging Can Not Confirm Or Exclude 160 (mm2) OSA 140 Area 120 . Imaging Can Help Understand Airway 100 Sectional Anatomy (Phenotype) 80 Medium OSA Risk Identify Potential Obstruction Sites Cross 50 Evaluate Airway Support Structures High OSA Risk 8 1012 14 16 20 40 >50 Age UOP Ortho Alumni Hatcher UOP Ortho Alumni Hatcher UOP Ortho Alumni Hatcher Airway Resistance and Flow Airway Dimensions and OSA 3d CBCT Trends . Poiseuille’s Law . Ohm’s Law 4 OSA Control (R = 8nl / π r ) (V = Pmouth –Palveoli / R) . Retroglossal and Retropalatal Space R = Reistance V = Flow Predictive of RDI BMI 29.5 23.1 N = Viscosity P = Pressure 3 3 Π = phi R = Resistance Cross Sectional Area OSA Probability Volume 4868 mm 6051 mm R = Radius 2 < 52 mm High Smallest Area 46 mm2 147 mm2 52 ‐ 110 mm2 Medium > 110 mm2 Low AP 4.6 mm 7.8 mm Radius = Resistance = Pressure Gradient Lateral 11.6 mm 16.2 mm •Li HY, Chen NH, Wang CR, Shu YH, Wang PC. “ Use of 3-dimensional computed tomography scan to evaluate upper airway patency for patients undergoing sleep-disordered breathing surgery.” Otolaryngol Respiratory Effort Head Neck Surg 2003;1294):336-42 Ogawa, T, Reyes Enciso, W Shintaku Glenn Clark, OOOOE Jan 2007 UOP Ortho Alumni Hatcher UOP Ortho Alumni Hatcher UOP Ortho Alumni Hatcher Nasal Valves . External Nasal Valve . Internal Nasal Valve UOP Ortho Alumni Hatcher UOP Ortho Alumni Hatcher UOP Ortho Alumni Hatcher 3 3/8/2018 External Nasal Valve Internal Nasal valve . Major Alar Cartilage: Lateral Crus Medial Crus . Septal nasal cartilage . (Quadriangular cartilage) Netter’s Head and Neck Anatomy for Dentistry UOP Ortho Alumni Hatcher UOP Ortho Alumni Hatcher UOP Ortho Alumni Hatcher Pyriform aperture UOP Ortho Alumni Hatcher UOP Ortho Alumni Hatcher UOP Ortho Alumni Hatcher Nasal Septum Nasal Cavity boundaries . Cribriform plate of the Ethmoid . Ethmoid air cells . Maxillary sinuses . Nasal septum UOP Ortho Alumni Hatcher UOP Ortho Alumni Hatcher UOP Ortho Alumni Hatcher 4 3/8/2018 Concha Bullosa Polyposis . Pneumatized Middle Turbinate . Etiology Allergy + Inflammation ‐> Unstable Mucosa ‐> Epithelial Proliferation ‐> Morphological Changes UOP Ortho Alumni Hatcher UOP Ortho Alumni Hatcher UOP Ortho Alumni Hatcher UOP Ortho Alumni Hatcher UOP Ortho Alumni Hatcher UOP Ortho Alumni Hatcher Chronic RhinoSinusitis (CRS) . Group of Disorders Characterized by Inflammation of Nose & Sinuses >/= 12 Consecutive Weeks Duration UOP Ortho Alumni Hatcher UOP Ortho Alumni Hatcher UOP Ortho Alumni Hatcher 5 3/8/2018 Rhinolith Foreign Body UOP Ortho Alumni Hatcher UOP Ortho Alumni Hatcher UOP Ortho Alumni Hatcher UOP Ortho Alumni Hatcher UOP Ortho Alumni Hatcher UOP Ortho Alumni Hatcher Sinonasal Tumor Courtesy of Dr. Shikha Rathi UOP Ortho Alumni Hatcher UOP Ortho Alumni Hatcher UOP Ortho Alumni Hatcher 6 3/8/2018 Oral & Nasopharynx Nasal Resistance Boundaries . Mouth Breathing Inferior Tongue posture . Narrowing of Dental Arches . Clockwise Facial Growth Pattern . Increase Anterior Face Height UOP Ortho Alumni Hatcher UOP Ortho Alumni Hatcher UOP Ortho Alumni Hatcher UOP Ortho Alumni Hatcher UOP Ortho Alumni Hatcher UOP Ortho Alumni Hatcher UOP Ortho Alumni Hatcher UOP Ortho Alumni Hatcher UOP Ortho Alumni Hatcher 7 3/8/2018 UOP Ortho Alumni Hatcher UOP Ortho Alumni Hatcher UOP Ortho Alumni Hatcher UOP Ortho Alumni Hatcher UOP Ortho Alumni Hatcher UOP Ortho Alumni Hatcher SCC of Palatine tonsils UOP Ortho Alumni Hatcher UOP Ortho Alumni Hatcher UOP Ortho Alumni Hatcher 8 3/8/2018 UOP Ortho Alumni Hatcher UOP Ortho Alumni Hatcher UOP Ortho Alumni Hatcher UOP Ortho Alumni Hatcher UOP Ortho Alumni Hatcher UOP Ortho Alumni Hatcher 2 UOP Ortho Alumni Hatcher UOP Ortho Alumni Hatcher 11.88 mm UOP Ortho Alumni Hatcher 9 3/8/2018 Support Structures for Airway . Cervical Spine . Jaws UOP Ortho Alumni Hatcher UOP Ortho Alumni Hatcher UOP Ortho Alumni Hatcher UOP Ortho Alumni Hatcher UOP Ortho Alumni Hatcher UOP Ortho Alumni Hatcher •Local Insult Facial Growth Patterns •Regional Adaptation UOP Ortho Alumni Hatcher UOP Ortho Alumni Hatcher UOP Ortho Alumni Hatcher 10 3/8/2018 UOP Ortho Alumni Hatcher UOP Ortho Alumni Hatcher UOP Ortho Alumni Hatcher UOP Ortho Alumni Hatcher UOP Ortho Alumni Hatcher UOP Ortho Alumni Hatcher UOP Ortho Alumni Hatcher UOP Ortho Alumni Hatcher UOP Ortho Alumni Hatcher 11 3/8/2018 Conclusions . Imaging provides a Support Role in SDB . Granular Dx. Leads to a Tailored Treatment . Accurate Dx. Leads to the Best Treatment Outcomes . Consider Airway from External Nasal Valves to Trachea . Consider Support Structures for Airway Jaws Spine Tongue Soft Palate UOP Ortho Alumni Hatcher UOP Ortho Alumni Hatcher UOP Ortho Alumni Hatcher 12.