Diagnosis, anatomy, and electromyography profiles of 73 nonrecurrent laryngeal nerves

Head Neck. 2018 Dec;40(12):2657-2663. doi: 10.1002/hed.25391. Epub 2018 Nov 22.


Background: The purpose of this work was to compare methods of detecting nonrecurrent laryngeal nerves (NRLNs).

Methods: Specificity and sensitivity were compared in three NRLN detection methods: CT, electromyography (EMG), and A-B point comparison.

Results: A total of 73 intraoperative pictures and 36 CT details of NRLNs are presented. Incidence of NRLN was 0.39%. Type I NRLN accounted for 50.7%, type IIA 45.2%, type IIB 4.1%. The NRLN median latency was 2.13 ms vs 3.00 ms median in an RLN control group (P < .001). When the threshold was set to 2.5 ms, EMG latency detection had 96.7% sensitivity and 91.6% specificity for detecting NRLN, and the A-B point comparison algrithm had 97.3% sensitivity and 92.5% specificity. Combining EMG latency detection with A-B point comparison achieved 100% sensitivity and specificity for detecting NRLN.

Conclusion: This is the largest series of NRLN presented in the literature. Latency shorter than 2.50 ms combined with the A-B point comparison method is the ideal algorithm procedure for early NRLN identification.

Keywords: amplitude; anatomy; embryology; identification; latency; neuromonitoring; nonrecurrent laryngeal nerve.

MeSH terms

  • Adult
  • Aged
  • Case-Control Studies
  • Electromyography
  • Electrophysiology
  • Female
  • Humans
  • Laryngeal Nerves / abnormalities
  • Laryngeal Nerves / anatomy & histology*
  • Laryngeal Nerves / diagnostic imaging
  • Laryngeal Nerves / physiology
  • Male
  • Middle Aged
  • ROC Curve
  • Retrospective Studies
  • Sensitivity and Specificity
  • Thyroidectomy / methods
  • Tomography, X-Ray Computed
  • Young Adult