OP80 -A Novel Continuous Intra-operative Neuromonitoring Technique for the Recurrent Laryngeal Nerve: Initial experience with 100 nerves-at-risk

     

    Sinclair, Catherine F.1, Téllez, Maria J.2, Ulkatan, Sedat2
    1 Department of Otolaryngology Head and Neck Surgery, Mount Sinai West Hospital, New York, NY, USA
    2 Department of Intraoperative Neurophysiology, Mount Sinai West Hospital, New York, NY, USA 1

     

    Background / Purpose: Intra-operative neuromonitoring(IONM) of the recurrent laryngeal nerve(RLN) is commonly performed using endotracheal tube(ETT) based surface electrodes to record vocal fold electromyographic activity with a continuous(CIONM) or intermittent(IIONM) technique depending on the mechanism of nerve stimulation. The only currently available CIONM technique requires placement of a separate vagus nerve electrode which can be difficult in some patients. We present our initial experience for 100 nerves-at-risk with a non-invasive CIONM technique that relies solely on ETT electrodes to stimulate and record the laryngeal adductor reflex(LAR).

    Methods: The LAR was elicited by electrical stimulation of laryngeal mucosa on the side contralateral to the operative field using ETT electrode(s). ETT electrodes ipsilateral to the surgical field recorded contralateral R1(cR1) and R2(cR2) responses. Changes in LAR amplitude and latency were correlated with changes in IIONM EMG amplitude elicited by direct stimulation of RLN/vagus nerves. All patients completed pre- and post-operative flexible transnasal laryngoscopies (FNL) and vocal handicap index-10 questionnaires.

    Results: Mean opening R1 amplitude/latency were 251.1(+/-193.4)uV/22.9 (+/-2.8)msec. Mean closing R1 amplitude/latency were 173.6(+/-151.9)uV/24.1(+/-3.5)msec. Surgical maneuvers that potentially stretched or compressed the nerve caused reflex amplitude decline, generally reversible on release of tissue and correlating with concomitant changes in vagal and RLN EMG traces. Loss of reflex correlated with postoperative vocal fold paralysis on FNL but not with VHI-10 scores.

    Discussion & Conclusion: The LAR is a novel method for CIONM that appears robust and reproducible, requiring no equipment other than the ETT. It monitors both sensory and motor vagal pathways with multiple potential applications.

     

    References:

    1. Sasaki CT, Suzuki M. Laryngeal reflexes in cat, dog, and man. Arch Otolaryngol. 1976;102: 400-2
    2. Ludlow CL, Van Pelt F, Koda J. Characteristics of late responses to superior laryngeal nerve stimulation in humans. Ann Otol Rhinol Laryngol 1992;101:127-34
    3. Yamashita T, Nash EA, Tanaka Y, Ludlow CL. Effects of stimulus intensity on laryngeal long latency responses in awake humans. Otolaryngol Head Neck Surg 1997;117: 521–529.
    4. Aviv JE, Martin JH, Kim T, et al. Laryngopharyngeal sensory discrimination testing and the laryngeal adductor reflex. Ann Otol Rhinol Laryngol 1999;108:725-30.
    5. Bhabu P, Poletto C, Mann E, Bielamowica S, Ludlow CL. Thyroarytenoid muscle responses to air pressure stimulation of the laryngeal mucosa in humans Ann Otol Rhinol Laryngol 2003;112:834-40
    6. Kearney, Poletto, Ludlow et al. suppression of thyroarytenoid muscle responses during repeated air-pressure stimulation of the laryngeal mucosa in awake humans. Ann Otol Rhinol Laryngol 2005; 114:264-70.
    7. Carey B, Sulica L, Wu A, Branski R. A Novel Means of Clinical Assessment of Laryngeal Nerve Conduction. Muscle Nerve 2013;47(3):432-36.
    8. Sasaki CT, Jassin B, Kim YH, Hundal J, Rosenblatt W, Ross DA. Central facilitation of the glottic closure reflex in humans. Ann Otol Rhinol Laryngol. 2003;112:293-7.
    9. Randolph GW, Dralle H, Abdullah H, Barczynski M, Bellantone R, et al. ?Electrophysiologic recurrent laryngeal nerve monitoring during thyroid and parathyroid surgery: International standards guidelines statement. Head Neck 2011; 121:S1–S16
    10. Goding GS, Richardson MA, Trachy RE. Laryngeal chemoreflex: anatomic and ?physiologic study by use of the superior laryngeal nerve in the piglet. Otolaryngol Head ?Neck Surg 1987;97:28-38
    11. Sasaki CT, Yu Z, Xu J, Hundal J, Rosenblatt W. Effects of Altered Consciousness on the ?Protective Glottic Closure Reflex. Ann Otol Rhinol Laryngol 2006; 10:759-763.
    12. Lotto ML, Banoub M, Schubert A. Effects of anesthetic agents and physiologic changes ?on intraopeative motor evoked potentials. J Neurosurg Anesthesiol 2004. 16:32-42.
    13. Lee HY, Cho YG, You JY, Choi BH, Kim Jy, Wu CW, Chiang FY, Kim HY. Traction ?injury of the recurrent laryngeal nerve: Results of continuous intraoperative ?neuromonitoring in a swine model. Head Neck 2016;38(4):582-88
    14. Barber SR, Liddy W, Kyriazidis N, Cinquepalmi M, Lin BM, Modi R, et al. Changes in electromyographic amplitudes but not latencies occur with endotracheal tube malpositioning during intraoperative monitoring for thyroid surgery: Implications for guidelines. Laryngoscope. 2016. doi: 10.1002/lary.26392
    15. Phelan E, Potenza A, Slough C, Zurakowski D, Kamani D. Recurrent Laryngeal Nerve Monitoring during Thyroid Surgery. Normative Vagal and Recurrent Laryngeal Nerve Electrophysiological Data. Otolaryngol Head Neck Surg 2012;147(4):640-46.
    16. Sinclair CF, Tellez MJ, Tapia OR, Ulkatan S, Deletis V. A novel methodology for assessing laryngeal and vagus nerve integrity in patients under general anesthesia. Clinical Neurophyl, 2017 (in print).

 

Leave a Reply

  • Upcoming Events

     

    World Congress on Thyroid Cancer 3.5
    Rome, Italy | 2019

    World Congress on Thyroid Cancer 4.0
    July 29 – August 1, 2021
    Boston, Massachusetts

     

  • WCTC3.5 Steering Committee:

     

    Rocco Bellatone, Co-Chair
    Celestino Lombardi, Co-Chair
    Gregory W. Randolph, MD
    Bryan McIver, MD
    Jeremy Freeman, MD
    Ian J. Witterick, MD
    Ashok R. Shaha, MD
    Jatin P. Shah, MD