IONM assesses the motor function of the recurrent laryngeal nerve (RLN) while exposing the anatomical integrity, which does not always ensure the normal function. However, despite its advantages, IONM cannot always prevent injury to the nerve. Nevertheless, nerve monitoring can still play an important role in case of an inadvertent nerve injury. We present a case of an RLN injury in thyroid surgery performed under the guidance of IONM.
We planned for total thyroidectomy for the surgical treatment of papillary cancer under the guidance of IONM. We first dissected the right lobe harboring the malignant solid nodule. Pre-dissection sound signals (V1 and R1) after vagus nerve (VN) and RLN stimulations were obtained from the device while recording the wave amplitude. The right RLN was isolated and completely exposed. In the end, post-dissection stimulation (R2) of the anatomically intact RLN determined the loss of signal (LOS) without a recordable waveform amplitude. Post-dissection stimulation of the right VN confirmed the LOS, revealing the transient or permanent injury to the nerve. Electrophysiological monitoring of the RLN detected a segmental (type 1) injury. The resection of the left lobe was abandoned after right hemithyroidectomy. Postoperative laryngoscopy showed unilateral right VC palsy. The final pathological diagnosis was papillary thyroid cancer in the right lobe. The normal function of the right VC was recovered in the third postoperative month. Completion left lobe excision was performed under the guidance of IONM as a delayed procedure after 4 months of primary surgery. Postoperative laryngoscopy confirmed the normal function of both VCs.
IONM assesses and confirms the functional integrity of the laryngeal nerves. Intraoperative LOS indicates an injury to the nerve and the presence of palsy. In case of unfavorable complications, IONM detects the type of injury to the RLN. IONM establishes the outcome of the neural palsy, affects the surgical decision-making, and prevents the risk of bilateral palsy.
Yang S, Zhou L, Lu Z, Ma B, Ji Q, Wang Y. Systematic review with meta-analysis of intraoperative neuromonitoring during thyroidectomy. Int J Surg. 2017;39:104–13.CrossRefGoogle Scholar
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
Baek SK, Lee K, Oh D, Kang SH, Kwon SY, Woo JS, et al. Efficiency of intraoperative neuromonitoringon voice outcomes after thyroid surgery. Auris Nasus Larynx. 2017;44:583–9.CrossRefGoogle Scholar
Vasileiadis I, Karatzas T, Charitoudis G, Karakostas E, Tseleni-Balafouta S, Kouraklis G. Association of intraoperative neuromonitoring with reduced recurrent laryngeal nerve injury in patients undergoing total thyroidectomy. JAMA Otolaryngol Head Neck Surg. 2016;142:994–1001.CrossRefGoogle Scholar
Wojtczak B, Sutkowski K, Kaliszewski K, Głód M, Barczyński M. Experience with intraoperative neuromonitoring of the recurrent laryngeal nerve improves surgical skills and outcomes of non-monitored thyroidectomy. Langenbeck's Arch Surg. 2017;402:709–17.CrossRefGoogle Scholar
Calò PG, Medas F, Conzo G, Podda F, Canu GL, Gambardella C, et al. Intraoperative neuromonitoring in thyroid surgery: is the two-staged thyroidectomy justified? Int J Surg. 2017;41(Suppl 1):S13–20.CrossRefGoogle Scholar
Lombardi CP, Carnassale G, Damiani G, Acampora A, Raffaelli M, De Crea C, et al. “The final countdown”: is intraoperative, intermittent neuromonitoring really useful in preventing permanent nerve palsy? Evidence from a meta-analysis. Surgery. 2016;160:1693–706.CrossRefGoogle Scholar
Brajcich BC, McHenry CR. The utility of intraoperative nerve monitoring during thyroid surgery. J Surg Res. 2016;204:29–33.CrossRefGoogle Scholar
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
Anuwong A, Lavazza M, Kim HY, Wu CW, Rausei S, Pappalardo V, et al. Recurrent laryngeal nerve management in thyroid surgery: consequences of routine visualization, application of intermittent, standardized and continuous nerve monitoring. Updat Surg. 2016;68:331–41.CrossRefGoogle Scholar
Fontenot TE, Randolph GW, Setton TE, Alsaleh N, Kandil E. Does intraoperative nerve monitoring reliably aid in staging of total thyroidectomies? Laryngoscope. 2015;125:2232–5.CrossRefGoogle Scholar
Sitges-Serra A, Fontané J, Dueñas JP, Duque CS, Lorente L, Trillo L, et al. Prospective study on loss of signal on the first side during neuromonitoring of the recurrent laryngeal nerve in total thyroidectomy. Br J Surg. 2013;100:662–6.CrossRefGoogle Scholar
Hydman J, Björck G, Persson JK, Zedenius J, Mattsson P. Diagnosis and prognosis of iatrogenic injury of the recurrent laryngeal nerve. Ann Otol Rhinol Laryngol. 2009;118:506–11.CrossRefGoogle Scholar
Mattsson P, Hydman J, Svensson M. Recovery of laryngeal function after intraoperative injury to the recurrent laryngeal nerve. Gland Surg. 2015;4:27–35.PubMedPubMedCentralGoogle Scholar
Henry BM, Graves MJ, Vikse J, Sanna B, Pękala PA, Walocha JA, et al. The current state of intermittent intraoperative neural monitoring for prevention of recurrent laryngeal nerve injury during thyroidectomy: a PRISMA-compliant systematic review of overlapping meta-analyses. Langenbeck's Arch Surg. 2017;402:663–73.CrossRefGoogle Scholar
Bergenfelz A, Salem AF, Jacobsson H, Nordenström E, Almquist M, Steering Committee for the Scandinavian Quality Register for Thyroid, Parathyroid and Adrenal Surgery (SQRTPA). Risk of recurrent laryngeal nerve palsy in patients undergoing thyroidectomy with and without intraoperative nerve monitoring. Br J Surg. 2016;103:1828–38.CrossRefGoogle Scholar
Schneider R, Lorenz K, Sekulla C, Machens A, Nguyen-Thanh P, Dralle H. Surgical strategy during intended total thyroidectomy after loss of EMG signal on the first side of resection. Chirurg. 2015;86:154–63.CrossRefGoogle Scholar