Velopharyngeal anatomy in patients with obstructive sleep apnea versus normal subjects.
OBJECTIVE
Obesity can cause disturbed breathing and is one of the most significant risk factors for obstructive sleep apnea (OSA). However, the anatomic basis of OSA and, specifically, the anatomic mechanisms leading from obesity to OSA are still unclear. We examined the anatomic features of the velopharynx in patients with OSA versus those without in correlation with the body mass index (BMI), age, history of snoring, and OSA severity and re-evaluated the contribution of adding a frontal view to the cephalometric analysis of patients with OSA.


METHODS
Lateral and frontal cephalometric measurements were taken to assess the velopharyngeal anatomic features of 306 men with various degrees of OSA and 64 men without OSA and without a history of snoring. The demographic, polysomnographic, and cephalometric features were compared.


RESULTS
The patients with OSA had an increased pharyngeal length, thicker velum, a thicker posterior pharyngeal wall, a reduced pharyngeal width, and a consequent narrowing of the pharyngeal lumen. As the BMI increased, the OSA severity increased. Also, in parallel, the velum and posterior pharyngeal wall thickness increased and the pharyngeal width decreased. Three types of velopharyngeal narrowing, with an increased occurrence in severe degrees of OSA, were identified: bottle shape, hourglass shape, and tube shape. These aerodynamically unfavorable changes might cause increased upper airway resistance, explaining the development of both OSA and hypoventilation syndrome in obese patients.


CONCLUSIONS
Velopharyngeal thickening and lumen narrowing were shown to be features of obese men with OSA. However, these features developed only above a threshold BMI value. The combination of frontal and lateral cephalometry is important for comprehensive evaluation of patients with OSA.
Palate Surgery Unit, Department of Otolaryngology-Head and Neck Surgery, Center of Cleft Palate and Craniofacial Anomalies, Meir Medical Center, Kfar Saba, Israel, and Tel Aviv University Sackler Faculty of Medicine, Tel Aviv, Israel.
Yehuda
Y
Finkelstein
Tel Aviv University School of Computer Science, Tel Aviv, Israel. Electronic address: liorwolf@gmail.com.
Lior
L
Wolf
Center of Cleft Palate and Craniofacial Anomalies, Meir Medical Center, Kfar Saba, Israel, and Communication Disorders Faculty, Hadassah Academic College, Jerusalem, Israel.
Ariela
A
Nachmani
Tel Aviv University School of Computer Science, Tel Aviv, Israel.
Uri
U
Lipowezky
Palate Surgery Unit, Meir Medical Center, Kfar Saba, Israel.
Mordechai
M
Rub
Palate Surgery Unit, Meir Medical Center, Kfar Saba, Israel.
Sa'ar
S
Shemer
Ear, Nose, and Throat Histopathological Laboratory, Department of Otolaryngology-Head and Neck Surgery, Meir Medical Center, Kfar Saba, Israel, and Tel Aviv University Sackler Faculty of Medicine, Tel Aviv, Israel.
Gilead
G
Berger
D015992:Body Mass Index; D016022:Case-Control Studies; D002508:Cephalometry; D006801:Humans; D010160:Palate, Soft / Q000000981:diagnostic imaging / Q000473:pathology*; D010614:Pharynx / Q000000981:diagnostic imaging / Q000473:pathology*; D017286:Polysomnography; D011859:Radiography; D020181:Sleep Apnea, Obstructive / Q000000981:diagnostic imaging / Q000503:physiopathology*