title: Can a single cephalometric measurement predict obstructive sleep apnea severity?
abstract: OBJECTIVE
  To look for an association between the vertical position of the hyoid, as measured by the sella-hyoid (S-H) distance and the severity of obstructive sleep apnea (OSA). A previously published study on this subject showed a significant correlation between S-H distances more than 120 mm and severe OSA.
  
  
  METHODS
  A retrospective study of patients who were treated with a mandibular advancement splint (MAS) for sleep disordered breathing during June 2000 to May 2005 at the orthodontic department of Colchester University Hospital.
  
  
  METHODS
  One hundred and six consecutive patients who were treated with MAS during the period.
  
  
  RESULTS
  Lateral cephalograms were taken and traced prior to the provision of MAS therapy, and the distance S-H was measured. The mean S-H distance was 125.5 mm (103-148 mm) with a median of 126 mm. Four out of 8 patients (50%) with severe OSA had a S-H distance more than 120 mm, as did 38 out of 50 (76%) with mild to moderate OSA (AHI 5-30), and 17 out of 22 patients (77.27%) with an AHI of 0 to 4. No significant correlations between the S-H distance and the severity of OSA were found (Pearson correlation coefficient -0.034 and 95% confidence interval: -0.25, 0.18).
  
  
  CONCLUSIONS
  There was no correlation between patients' OSA severity and their cephalometric S-H distance. The utility of the latter as a screening test cannot therefore be recommended as a substitute for existing diagnostic tests.
authors.affiliation: Department of Sleep and Respiratory Medicine, Papworth Hospital, Papworth, UK. agulati47@gmail.com
authors.forename: Atul
authors.initials: A
authors.lastname: Gulati
authors.forename: Robert A C
authors.initials: RA
authors.lastname: Chate
authors.forename: Timothy Q
authors.initials: TQ
authors.lastname: Howes
mesh_terms: D000328:Adult; D000368:Aged; D002508:Cephalometry; D005260:Female; D006801:Humans; D006928:Hyoid Bone / Q000000981:diagnostic imaging* / Q000473:pathology; D008297:Male; D008875:Middle Aged; D009765:Obesity / Q000473:pathology; D011237:Predictive Value of Tests; D011859:Radiography; D012189:Retrospective Studies; D012720:Severity of Illness Index; D020181:Sleep Apnea, Obstructive / Q000000981:diagnostic imaging* / Q000473:pathology; D006113:United Kingdom; D044465:White People