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Intraoperative Nerve Monitorization

  • Günay Gürleyik
  • Emin Gürleyik
Chapter

Abstract

The anatomical integrity of the recurrent laryngeal nerve (RLN) is generally preserved by visual identification, and its exposure is mandatory during thyroid surgery. Intraoperative nerve monitoring (IONM) is used as an adjunct to visual identification to confirm the motor activity of both the RLN and the external branch of the superior laryngeal nerve (EBSLN).

We performed total thyroidectomy for the treatment of hyperthyroidism using IONM for both these nerves. The procedure was started from the dominant left lobe. Pre-dissection stimulation (V1) of the left vagus nerve showed normal function of the intrinsic laryngeal muscles. We could not visually, but could functionally, identify the left EBSLN by IONM. EBSLN stimulation generating cricothyroid muscle (CTM) contraction also induced vocal cord action recorded by nerve monitoring. We identified an extralaryngeal terminal bifurcation of the left RLN. Analysis of sound signal and wave amplitude after pre-dissection (R1) stimulation showed normal motor activity on the anterior branch and sensory function on the posterior branch. Stimulation of the left RLN also induced CTM twitches. At the end of the surgery, post-dissection (R2) and (V2) stimulations confirmed proper motor function of the RLN. EBSLN stimulation generated cricothyroid muscle (CTM) contraction revealing the normal function of this branch. The right lobe was also dissected under the guidance of IONM. All stages of monitoring were the same as on the left side, which showed proper function of the nerves at the end of the surgery.

IONM contributes to the identification of the EBSLN and establishes its proper motor function by observation of CTM contraction. It assesses the function of the RLN at the beginning, during, and the end of the surgery, with vocal cord mobility being received by surface electrodes creating a sound signal while recording the waveform amplitude. Based on recordable amplitudes after stimulation of EBSLN and induction of CTM twitches by stimulation of the left RLN, IONM establishes real-time motor interconnections between EBSLN and RLN via laryngeal anastomosis.

Keywords

Thyroid surgery RLN EBSLN IONM 

References

  1. 1.
    Tewari A, Samy RN, Castle J, Frye TM, Habeych ME, Mohamed M. Intraoperative neurophysiological monitoring of the laryngeal nerves during anterior neck surgery: a review. Ann Otol Rhinol Laryngol. 2017;126:67–72.CrossRefGoogle Scholar
  2. 2.
    Wojtczak B, Barczyński M. Intermittent neural monitoring of the recurrent laryngeal nerve in surgery for recurrent goiter. Gland Surg. 2016;5:481–9.CrossRefGoogle Scholar
  3. 3.
    Lee J, Fraser S, Glover A, et al. Prospective evaluation of the utility of routine neuromonitoring for an established thyroid surgical practice. ANZ J Surg. 2016;87:E138–42.  https://doi.org/10.1111/ans.13606.CrossRefPubMedGoogle Scholar
  4. 4.
    Wong KP, Mak KL, Wong CK, Lang BH. Systematic review and meta-analysis on intra-operative neuro-monitoring in high-risk thyroidectomy. Int J Surg. 2017;38:21–30.CrossRefGoogle Scholar
  5. 5.
    Randolph GW, Kamani D. Intraoperative electrophysiologic monitoring of the recurrent laryngeal nerve during thyroid and parathyroid surgery: experience with 1,381 nerves at risk. Laryngoscope. 2017;127:280–6.CrossRefGoogle Scholar
  6. 6.
    Stopa M, Barczyński M. Prognostic value of intraoperative neural monitoring of the recurrent laryngeal nerve in thyroid surgery. Langenbeck's Arch Surg. 2016;402:957–64.CrossRefGoogle Scholar
  7. 7.
    Gurleyik E, Gurleyik G. Nonrecurrent laryngeal nerve in the era of intraoperative nerve monitoring. Adv Med. 2016;2016:1606029.CrossRefGoogle Scholar
  8. 8.
    Lennquist S, Cahlin C, Smeds S. The superior laryngeal nerve in thyroid surgery. Surgery. 1987;102:999–1008.PubMedGoogle Scholar
  9. 9.
    Friedman M, LoSavio P, Ibrahim H. Superior laryngeal nerve identification and preservation in thyroidectomy. Arch Otolaryngol Head Neck Surg. 2002;128:296–303.CrossRefGoogle Scholar
  10. 10.
    Gurleyik E. Extralaryngeal terminal division of the inferior laryngeal nerve: anatomical classification by a surgical point of view. J Thyroid Res. 2013;2013:731250.  https://doi.org/10.1155/2013/731250.CrossRefPubMedPubMedCentralGoogle Scholar
  11. 11.
    Gurleyik E. Surgical anatomy of bilateral extralaryngeal bifurcation of the recurrent laryngeal nerve: similarities and differences between both sides. N Am J Med Sci. 2014;6:445–9.CrossRefGoogle Scholar
  12. 12.
    Gurleyik E. Location of motor fibers within branches of the recurrent laryngeal nerve with extralaryngeal terminal bifurcation; functional identification by intraoperative neuromonitoring. Surgery. 2015;158:1339–44.CrossRefGoogle Scholar
  13. 13.
    Gurleyik E, Gurleyik G. Incidence and surgical importance of Zuckerkandl’s tubercle of the thyroid and its relations with recurrent laryngeal nerve. ISRN Surg. 2012;2012:450589.  https://doi.org/10.5402/2012/450589.CrossRefPubMedPubMedCentralGoogle Scholar
  14. 14.
    Sanudo JR, Maranillo E, León X, et al. An anatomical study of anastomoses between the laryngeal nerves. Laryngoscope. 1999;109:983–7.CrossRefGoogle Scholar
  15. 15.
    Randolph GW. Surgical anatomy and monitoring of the recurrent laryngeal nerve, SLN monitoring. In: Randolph GW, editor. Surgery of the thyroid and parathyroid glands. 2nd ed. Philadelphia: Elsevier; 2013. p. 338–40.Google Scholar
  16. 16.
    Miyauchi A, Masuoka H, Nakayama A, Higashiyama T. Innervation of the cricothyroid muscle by extralaryngeal branches of the recurrent laryngeal nerve. Laryngoscope. 2016;126:1157–62.CrossRefGoogle Scholar
  17. 17.
    Martin-Oviedo C, Maranillo E, Lowy-Benoliel A, Pascual-Font A, et al. Functional role of human laryngeal nerve connections. Laryngoscope. 2011;121:2338–43.CrossRefGoogle Scholar
  18. 18.
    Liddy W, Barber SR, Cinquepalmi M, et al. The electrophysiology of thyroid surgery: electrophysiologic and muscular responses with stimulation of the vagus nerve, recurrent laryngeal nerve, and external branch of the superior laryngeal nerve. Laryngoscope. 2017;127:764–71.CrossRefGoogle Scholar

Copyright information

© Springer International Publishing AG, part of Springer Nature 2019

Authors and Affiliations

  • Günay Gürleyik
    • 1
  • Emin Gürleyik
    • 2
  1. 1.Department of SurgeryHaydarpaşa Numune Training and Research HospitalIstanbulTurkey
  2. 2.Department of SurgeryDüzce UniversityDüzceTurkey

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