title: The O-C2 angle established at occipito-cervical fusion dictates the patient's destiny in terms of postoperative dyspnea and/or dysphagia.
abstract: OBJECTIVE
  We have revealed that the cause of postoperative dyspnea and/or dysphagia after occipito-cervical (O-C) fusion is mechanical stenosis of the oropharyngeal space and the O-C2 alignment, rather than total or subaxial alignment, is the key to the development of dyspnea and/or dysphagia. The purpose of this study was to confirm the impact of occipito-C2 angle (O-C2A) on the oropharyngeal space and to investigate the chronological impact of a fixed O-C2A on the oropharyngeal space and dyspnea and/or dysphagia after O-C fusion.
  
  
  METHODS
  We reviewed 13 patients who had undergone O-C2 fusion, while retaining subaxial segmental motion (OC2 group) and 20 who had subaxial fusion without O-C2 fusion (SA group). The O-C2A, C2-C6 angle and the narrowest oropharyngeal airway space were measured on lateral dynamic X-rays preoperatively, when dynamic X-rays were taken for the first time postoperatively, and at the final follow-up. We also recorded the current dyspnea and/or dysphagia status at the final follow-up of patients who presented with it immediately after the O-C2 fusion.
  
  
  RESULTS
  There was no significant difference in the mean preoperative values of the O-C2A (13.0 ± 7.5 in group OC2 and 20.1 ± 10.5 in group SA, Unpaired t test, P = 0.051) and the narrowest oropharyngeal airway space (17.8 ± 6.0 in group OC2 and 14.9 ± 3.9 in group SA, Unpaired t test, P = 0.105). In the OC2 group, the narrowest oropharyngeal airway space changed according to the cervical position preoperatively, but became constant postoperatively. In contrast, in the SA group, the narrowest oropharyngeal airway space changed according to the cervical position at any time point. Three patients who presented with dyspnea and/or dysphagia immediately after O-C2 fusion had not resolved completely at the final follow-up. The narrowest oropharyngeal airway space and postoperative dyspnea and/or dysphagia did not change with time once the O-C2A had been established at O-C fusion.
  
  
  CONCLUSIONS
  The O-C2A established at O-C fusion dictates the patient's destiny in terms of postoperative dyspnea and/or dysphagia. Surgeons should pay maximal attention when establishing the O-C2A during surgery, because their careless decision for the O-C2A may cause persistent dysphagia or a life-threatening consequence. We recommend that the O-C2A in O-C fusion should be kept at least at more than the preoperative O-C2A in the neutral position.
authors: Department of Orthopaedic Surgery, Graduate School of Medicine, Kyoto University, Kyoto, Japan.
authors: Masanori
authors: M
authors: Izeki
authors: Masashi
authors: M
authors: Neo
authors: Mitsuru
authors: M
authors: Takemoto
authors: Shunsuke
authors: S
authors: Fujibayashi
authors: Hiromu
authors: H
authors: Ito
authors: Koutatsu
authors: K
authors: Nagai
authors: Shuichi
authors: S
authors: Matsuda
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D003251:Constriction, Pathologic / Q000209:etiology; D003680:Deglutition Disorders / Q000209:etiology*; D004417:Dyspnea / Q000209:etiology*; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D011183:Postoperative Complications / Q000209:etiology; D011184:Postoperative Period; D011187:Posture / Q000502:physiology*; D013123:Spinal Fusion / Q000009:adverse effects* / Q000379:methods
references: Anesthesiology. 1990 Oct;73(4):775-6
references: 2221446
references: Acta Anaesthesiol Taiwan. 2008 Sep;46(3):134-7
references: 18809525
references: J Anesth. 2011 Feb;25(1):120-2
references: 21188427
references: Spine (Phila Pa 1976). 2001 Jan 15;26(2):161-5
references: 11154536
references: Spine (Phila Pa 1976). 2011 Dec 1;36(25):2116-21
references: 21343858
references: Spine (Phila Pa 1976). 2010 Sep 1;35(19):E971-5
references: 20436381
references: Spine (Phila Pa 1976). 2011 May 15;36(11):E720-6
references: 21270693
references: Spine (Phila Pa 1976). 2012 May 15;37(11):996-1002
references: 22037524
references: J Bone Joint Surg Br. 2007 Mar;89(3):342-5
references: 17356146
references: Anesthesiology. 1983 May;58(5):441-9
references: 6837996
references: Spine (Phila Pa 1976). 2004 May 15;29(10):E204-8
references: 15131455
references: Scand J Rheumatol. 1988;17(4):273-9
references: 3187458
references: Spine (Phila Pa 1976). 2009 Jan 15;34(2):184-8
references: 19139669
references: Spine (Phila Pa 1976). 2005 Nov 15;30(22):2564-9
references: 16284596
references: Spine (Phila Pa 1976). 2013 Apr 20;38(9):E513-20
references: 23392412
references: Spine (Phila Pa 1976). 2002 Nov 15;27(22):2453-8
references: 12435974
references: J Spinal Disord Tech. 2005 Feb;18 Suppl:S101-6
references: 15699794
references: Masui. 2002 May;51(5):513-5
references: 12058436
references: Spine (Phila Pa 1976). 2010 Apr 20;35(9 Suppl):S76-85
references: 20407354
references: Br J Anaesth. 1999 Apr;82(4):644-6
references: 10472239
references: J Bone Joint Surg Am. 2004 Feb;86(2):251-6
references: 14960668
references: Spine (Phila Pa 1976). 2007 Apr 15;32(8):E267-70
references: 17426623
references: Spine J. 2007 Mar-Apr;7(2):141-7
references: 17321961
references: AJNR Am J Neuroradiol. 2005 Apr;26(4):970-2
references: 15814955