title: Vocal cord palsy after anterior cervical spine surgery: a qualitative systematic review.
abstract: BACKGROUND
  Vocal cord palsy (VCP) is a known complication of anterior cervical spine surgery. However, the true incidence and interventions to minimize this complication are not well studied.
  
  
  OBJECTIVE
  To conduct a systematic review to identify the incidence, risk, and interventions for VCP after anterior cervical spine surgery.
  
  
  METHODS
  This is a qualitative systematic literature review.
  
  
  METHODS
  Prospective and retrospective trials of patients undergoing anterior cervical spine surgery that reported on postoperative VCP or recurrent laryngeal nerve palsy.
  
  
  METHODS
  Primary: incidence of VCP after anterior cervical spine surgery; secondary: risk factors and interventions for prevention of VCP after anterior cervical spine surgery.
  
  
  METHODS
  Electronic searches were conducted on Ovid Medline, EMBASE, Cochrane Central Register of Controlled Trials, and Cochrane Database of Systemic Reviews for clinical studies reporting VCP in anterior cervical spine surgery, limited to studies published between 1995 and June 2013 in English and French languages. After selection of studies independently by two review authors, data on incidence, risk, and interventions were extracted. Qualitative analysis was performed on three domains: quality of studies, strength of evidence, and impact of interventions.
  
  
  RESULTS
  Our search has identified 187 abstracts, and 34 studies met our inclusion criteria. The incidence of VCP ranges from 2.3% to 24.2%. Significant heterogeneity in study design and definition of VCP were used in the published studies. There is good evidence that reoperation increases the risk of VCP. One study of moderate strength suggests that operating from the right side may increase the risk of VCP. Among the interventions studied, endotracheal tube (ETT) cuff pressure monitoring with deflation during retraction has shown to reduce the incidence from 6% to 2%, but this result was not confirmed by randomized control trials. Limited evidence exists for other interventions of intraoperative electromyographic monitoring and methylprednisolone.
  
  
  CONCLUSIONS
  Vocal cord palsy is a significant morbidity after anterior cervical surgery with incidence up to 24.2% in the immediate postoperative period, with a higher risk in reoperation of the anterior cervical spine. Moderate evidence exists for ETT cuff pressure adjustment in preventing this complication.
authors.affiliation: Department of Anesthesia and Pain Management, Toronto Western Hospital, University Health Network, 399 Bathurst St, Toronto, Ontario, Canada M5T2S8. Electronic address: t_ping_tan@yahoo.com.
authors.forename: Tze P
authors.initials: TP
authors.lastname: Tan
authors.affiliation: Department of Anesthesia and Pain Management, Toronto Western Hospital, University Health Network, 399 Bathurst St, Toronto, Ontario, Canada M5T2S8.
authors.forename: Arun P
authors.initials: AP
authors.lastname: Govindarajulu
authors.affiliation: Division of Neurosurgery, Toronto Western Hospital, University Health Network, 399 Bathurst St, Toronto, Ontario, Canada M5T2S8.
authors.forename: Eric M
authors.initials: EM
authors.lastname: Massicotte
authors.affiliation: Department of Anesthesia and Pain Management, Toronto Western Hospital, University Health Network, 399 Bathurst St, Toronto, Ontario, Canada M5T2S8.
authors.forename: Lashmi
authors.initials: L
authors.lastname: Venkatraghavan
mesh_terms: D002574:Cervical Vertebrae / Q000601:surgery*; D006801:Humans; D015994:Incidence; D007442:Intubation, Intratracheal; D016343:Monitoring, Intraoperative / Q000379:methods; D011183:Postoperative Complications / Q000453:epidemiology* / Q000209:etiology / Q000517:prevention & control; D012307:Risk Factors; D014826:Vocal Cord Paralysis / Q000453:epidemiology* / Q000209:etiology / Q000517:prevention & control
keywords: Anterior cervical spine surgery; Dysphonia; Electromyography; Endotracheal tube; Laryngeal nerve; Vocal cord palsy