title: Clinical predictors in obstructive sleep apnoea patients with calibrated cephalometric analysis--a new approach.
abstract: OBJECTIVE
  Utilization of a new method to accurately quantify differences in cephalometric parameters between obstructive sleep apnoea (OSA) and normal patients, and to identify good predictors for OSA. To illustrate the ethnic differences in cephalometry.
  
  
  METHODS
  This prospective study involves 106 South-east Asians. A calibrated catheter is inserted into the upper airway during standard cephalometry to obtain the precise magnification and allow exact measurement of anatomical parameters of cephalometry in both erect and supine positions.
  
  
  RESULTS
  The OSA patients have longer lower-facial length, narrower skull base, shorter and receding mandible, smaller posterior airway space (PAS), narrower retropalatal space, longer and thicker soft palate, smaller hard and soft palate angles longer tongue length and more inferiorly displaced hyoid. For the palatal level, retropalatal distance of 11.2 mm cut-off/predictive value for male (receiver operating characteristics (ROC) = 0.8414 with PPV = 77.46, NPV = 90.00) and 5.5 mm for female (ROC = 0.9180 with PPV = 100.00, NPV = 84.21) at erect position were selected. For retrolingual level, erect PAS of 10.1 mm cut-off/predictive value for male (ROC = 0.7000 with PPV = 78.38, NPV = 37.78), 5.3 mm for female (ROC = 0.7227 with PPV = 75.00, NPV = 75.00) were selected. Our study showed that South-east Asians have different cephalometric values compared with White people, Black people and Hispanics.
  
  
  CONCLUSIONS
  This new method of cephalometry using a calibrated catheter provides an accurate and simple method of obtaining precise cephalometric measurements. There is no cephalometric data on OSA from South-east Asia available. These results suggested that surgeons managing OSA patients and using cephalometry as a diagnostic method should have a set of normative and OSA cephalometric values that apply to their local populations.
authors.affiliation: Division of Otolaryngology, Changi General Hospital, Singapore. hsuponpoh@yahoo.com
authors.forename: P P
authors.initials: PP
authors.lastname: Hsu
authors.forename: A K L
authors.initials: AK
authors.lastname: Tan
authors.forename: Y H
authors.initials: YH
authors.lastname: Chan
authors.forename: P K S
authors.initials: PK
authors.lastname: Lu
authors.forename: R L
authors.initials: RL
authors.lastname: Blair
mesh_terms: D000328:Adult; D044466:Asian People; D016022:Case-Control Studies; D002508:Cephalometry / Q000379:methods*; D005147:Facial Bones / Q000000981:diagnostic imaging / Q000473:pathology*; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D011237:Predictive Value of Tests; D011446:Prospective Studies; D012372:ROC Curve; D011859:Radiography; D012137:Respiratory System / Q000000981:diagnostic imaging / Q000473:pathology*; D020181:Sleep Apnea, Obstructive / Q000000981:diagnostic imaging / Q000473:pathology*; D016683:Supine Position