title: Bilateral recurrent laryngeal nerve injury in total thyroidectomy with or without intraoperative neuromonitoring. Systematic review and meta-analysis.
abstract: OBJECTIVE
  The risk of producing bilateral laryngeal paralysis (BLP) in total thyroidectomy (TT) is low, but it is a concern for the surgeon and a serious safety incident that may compromise the airway, require reintubation or tracheostomy and cause serious sequelae or death. Neuromonitoring (NM), as an early diagnostic tool for the existence of injury to the recurrent laryngeal nerve (RLN), has not been shown to have reduced the risk, even though published series show lower incidences. Our objective was to estimate the risk of bilateral RLN paralysis with and without NM TT by systematic review and meta-analysis.
  
  
  METHODS
  We performed a systematic review of clinical trials, cohort studies and case series with total thyroidectomy without NM published in the period 2000-2014. A database search was performed using PubMed, Scopus (EMBASE) and the Cochrane Library. Heterogeneity between studies was explored and weighted risks grouped according to random effects models were estimated.
  
  
  RESULTS
  We selected 40 articles and estimates of risk were identified in 54 case series (without NM, 25; with NM, 29) with 30,922 patients. The prevalence of BLP in the series with NM was lower compared to that without NM (2.43‰, [1.55 to 3.5‰] versus 5.18‰ [2.53 to 8.7‰]). This difference is equivalent to an absolute risk reduction of 2.75‰ with a number needed to treat of 364.13. The NM group was more homogeneous (I2=7.52%) than those without NM (I2=79.32%). The observed differences in the subgroup analysis were very imprecise because the number of observed paralysis was very low.
  
  
  CONCLUSIONS
  The risk of bilateral paralysis is lower in studies with neuromonitoring.
authors.affiliation: Servicio de Otorrinolaringología, Complejo Asistencial de Zamora, SACYL, Zamora, España. Electronic address: jlpardal@saludcastillayleon.es.
authors.forename: José Luis
authors.initials: JL
authors.lastname: Pardal-Refoyo
authors.affiliation: Unidad de Apoyo a la Investigación, Complejo Asistencial de Zamora, SACYL, Zamora, España.
authors.forename: Carlos
authors.initials: C
authors.lastname: Ochoa-Sangrador
mesh_terms: D006801:Humans; D007442:Intubation, Intratracheal / Q000009:adverse effects; D016343:Monitoring, Intraoperative / Q000009:adverse effects; D012008:Recurrence; D061226:Recurrent Laryngeal Nerve Injuries; D013965:Thyroidectomy / Q000009:adverse effects; D014826:Vocal Cord Paralysis / Q000453:epidemiology
keywords: Airway extubation; Extubación; Meta-analysis; Metaanálisis; Monitoring, intraoperative; Monitorización intraoperatoria; Nervio laríngeo recurrente; Parálisis de cuerda vocal; Patient safety; Recurrent laryngeal nerve; Review; Revisión; Seguridad del paciente; Thyroidectomy; Tiroidectomía; Vocal cord paralysis