title: Reduction in mouth opening with semi-rigid cervical collars.
abstract: BACKGROUND
  Reduced mouth opening may be a major contributing factor to the deterioration in the view obtained at laryngoscopy when a semi-rigid cervical collar is in place. We set out to assess the degree to which mouth opening is restricted by a cervical collar.
  
  
  METHODS
  We measured maximal inter-incisor distance in 52 volunteers. It was measured again after application of each of three appropriately sized semi-rigid cervical collars (Stifneck, Miami J, and Philadelphia).
  
  
  RESULTS
  Inter-incisor distance was significantly reduced by the application of a cervical collar [No collar 41 (7) mm-mean (SD); Stifneck 26 (8) P<0.0001; Miami J 29 (9) P<0.0001; Philadelphia 29 (9) P<0.0001]. There was a wide and unpredictable variation between subjects in the reduction in mouth opening and a significant proportion had an inter-incisor distance of 20 mm or less (Stifneck, 25%; Miami J, 21%; Philadelphia, 21%).
  
  
  CONCLUSIONS
  Application of a semi-rigid cervical collar can significantly reduce mouth opening. This could hinder definitive airway placement. Our results support removing the anterior portion of the collar before attempts at tracheal intubation.
authors: Department of Neuroanaesthesia, Institute of Neurological Sciences, Southern General Hospital, 1345 Govan Road, Glasgow G51 4TF, UK. c.goutcher@ntlworld.com
authors: C M
authors: CM
authors: Goutcher
authors: V
authors: V
authors: Lochhead
mesh_terms: D000886:Anthropometry; D002574:Cervical Vertebrae / Q000293:injuries; D004867:Equipment Design; D005260:Female; D006801:Humans; D007103:Immobilization; D007180:Incisor / Q000473:pathology; D007442:Intubation, Intratracheal; D008297:Male; D009055:Mouth / Q000503:physiopathology*; D009333:Neck; D009989:Orthotic Devices