title: Soft palate length and upper airway relationship in OSA and non-OSA subjects.
abstract: BACKGROUND
  The narrowest area of the airway between the posterior nasal opening and the epiglottis is usually located in the retro palatal area. Many consider this the most likely site of airway obstruction during an obstructive sleep apnea (OSA) event. The aim of this study was to investigate the differences in soft palate and airway length between OSA and non-OSA patients.
  
  
  METHODS
  In this study, we analyzed the ratio of the soft palate and the upper airway length in 45 consecutive patients. Twenty-five had an Apnea-Hypoapnea Index of more than five events per hour and were classified in the OSA group (male, 19; female, 6). These patients were compared with 20 normal controls (male, 12; female, 8). Controls who complained of snoring did have sleep studies (n=5). The other fifteen controls were clinically asymptomatic and did not have sleep studies. Medical computed tomography scans were taken to determine the length of the upper airway and the soft palate length measured in the midsagittal image.
  
  
  RESULTS
  Soft palate length was significantly larger in OSA patients compared to controls (p=0.009), and in men compared to women (p=0.002). However, there were no differences in airway length. The soft palate length, as a percent of oropharyngeal airway length, was significantly larger in OSA patients compared to controls (p= <0.0001) and in men compared to women (p=0.02). Soft palate length increases significantly with age by 0.3 mm per year in males (after adjustment for body mass index (BMI) and OSA). Soft palate length as a percent of airway length is larger in OSA patients and increases significantly with BMI in males only after adjusting for age.
  
  
  CONCLUSIONS
  In this study, OSA patients had a longer soft palate in proportion to their oropharyngeal airway compared to controls as well as men compared to women. This proportion could be used for identifying patients at risk for OSA in combination with age.
authors.affiliation: Orofacial Pain/Oral Medicine Center, Division of Diagnostic Sciences, School of Dentistry, University of Southern California, Los Angeles, CA, USA.
authors.forename: Yuko
authors.initials: Y
authors.lastname: Shigeta
authors.forename: Takumi
authors.initials: T
authors.lastname: Ogawa
authors.forename: Ikawa
authors.initials: I
authors.lastname: Tomoko
authors.forename: Glenn T
authors.initials: GT
authors.lastname: Clark
authors.forename: Reyes
authors.initials: R
authors.lastname: Enciso
mesh_terms: D000328:Adult; D000367:Age Factors; D000368:Aged; D000403:Airway Resistance / Q000502:physiology; D015992:Body Mass Index; D005260:Female; D006801:Humans; D007091:Image Processing, Computer-Assisted; D007564:Japan; D008297:Male; D008875:Middle Aged; D010160:Palate, Soft / Q000000981:diagnostic imaging* / Q000503:physiopathology; D017286:Polysomnography; D012016:Reference Values; D012891:Sleep Apnea Syndromes / Q000000981:diagnostic imaging* / Q000503:physiopathology; D012913:Snoring / Q000000981:diagnostic imaging* / Q000503:physiopathology; D036542:Tomography, Spiral Computed