title: Systematic review with meta-analysis of intraoperative neuromonitoring during thyroidectomy.
abstract: BACKGROUND
  Intraoperative neuromonitoring (IONM) has been a commonly used technology during thyroid surgery aimed at reducing the incidence of recurrent laryngeal nerve palsy (RLNP), which is a severe complication and leads to significant impacts on a patient's life. In order to give a comprehensive assessment for potential benefits and disadvantage of IONM, this meta-analysis and systematic review discusses RLNP rate, predictive power, continuous intraoperative neuromonitoring (CIONM), and emphasises application during thyroid cancer surgeries.
  
  
  METHODS
  A literature search was performed in the following electronic databases: PubMed, Embase, and the Cochrane library from January 1, 2004 to July 30, 2016. After applying inclusion and exclusion criteria, 24 studies, including four prospective randomised trials, were selected. Heterogeneity of studies was checked by the Cochran Q test. Publication bias was assessed by funnel plots with Egger's linear regression test of asymmetry. Odds ratio (OR) was calculated by random effects model.
  
  
  RESULTS
  Overall, 9203 patients and 17,203 nerves at risk (NAR) were included. Incidence of overall, transient, and persistent RLNP in IONM group were, respectively, 3.15%, 1.82%, and 0.67%, whereas for the ID group, they were 4.37%, 2.58%, and 1.07%. The summary OR of overall, transient, and persistent RLNP compared using IONM and ID were, respectively, 0.81 (95%CI 0.66-0.99), 0.76 (95%CI 0.61-0.94), and 0.78 (95%CI 0.55-1.09).
  
  
  CONCLUSIONS
  The presented data showed benefits of reducing RLNP rate by using IONM, but without statistical significance for persistent RLNP rate. For patients with thyroid cancer who undergo total thyroidectomy, using IONM may improve the outcome by reducing amount of residual thyroid tissue. However, no benefits were found for thyroid reoperation; visual identification and careful dissection remain standard for this challenging procedure. In addition, the relative low positive predictive power indicated intermittent intraoperative neuromonitoring (IIONM) may not be reliable; but CIONM was showed to be a more promising method, with prudent approach.
authors.affiliation: Department of Head & Neck Surgery, Fudan University Shanghai Cancer Center, Shanghai, 200032, China; Department of Oncology, Shanghai Medical College, Fudan University, Shanghai, 200032, China; Cancer Research Institute, Fudan University Shanghai Cancer Center, Shanghai, 200032, China.
authors.forename: Shuwen
authors.initials: S
authors.lastname: Yang
authors.affiliation: Department of Head & Neck Surgery, Fudan University Shanghai Cancer Center, Shanghai, 200032, China; Department of Oncology, Shanghai Medical College, Fudan University, Shanghai, 200032, China; Cancer Research Institute, Fudan University Shanghai Cancer Center, Shanghai, 200032, China.
authors.forename: Li
authors.initials: L
authors.lastname: Zhou
authors.affiliation: Department of Head & Neck Surgery, Fudan University Shanghai Cancer Center, Shanghai, 200032, China; Department of Oncology, Shanghai Medical College, Fudan University, Shanghai, 200032, China.
authors.forename: Zhongwu
authors.initials: Z
authors.lastname: Lu
authors.affiliation: Department of Head & Neck Surgery, Fudan University Shanghai Cancer Center, Shanghai, 200032, China; Department of Oncology, Shanghai Medical College, Fudan University, Shanghai, 200032, China; Cancer Research Institute, Fudan University Shanghai Cancer Center, Shanghai, 200032, China.
authors.forename: Ben
authors.initials: B
authors.lastname: Ma
authors.affiliation: Department of Head & Neck Surgery, Fudan University Shanghai Cancer Center, Shanghai, 200032, China; Department of Oncology, Shanghai Medical College, Fudan University, Shanghai, 200032, China; Cancer Research Institute, Fudan University Shanghai Cancer Center, Shanghai, 200032, China.
authors.forename: Qinghai
authors.initials: Q
authors.lastname: Ji
authors.affiliation: Department of Head & Neck Surgery, Fudan University Shanghai Cancer Center, Shanghai, 200032, China; Department of Oncology, Shanghai Medical College, Fudan University, Shanghai, 200032, China; Cancer Research Institute, Fudan University Shanghai Cancer Center, Shanghai, 200032, China. Electronic address: neck130@hotmail.com.
authors.forename: Yu
authors.initials: Y
authors.lastname: Wang
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D005260:Female; D006801:Humans; D015994:Incidence; D008297:Male; D008875:Middle Aged; D016343:Monitoring, Intraoperative / Q000379:methods*; D011183:Postoperative Complications / Q000453:epidemiology / Q000209:etiology / Q000517:prevention & control*; D011446:Prospective Studies; D016032:Randomized Controlled Trials as Topic; D013964:Thyroid Neoplasms / Q000601:surgery*; D013965:Thyroidectomy / Q000009:adverse effects* / Q000379:methods; D014826:Vocal Cord Paralysis / Q000453:epidemiology / Q000209:etiology / Q000517:prevention & control*; D055815:Young Adult
keywords: Continuous intraoperative neuromonitoring; Intraoperative neuromonitoring; Recurrent laryngeal nerve palsy; Thyroid cancer; Thyroidectomy