Cost-effectiveness of recurrent laryngeal nerve monitoring in thyroid surgery

Patterns and indications of intraoperative nerve monitoring usage during thyroidectomy and parathyroidectomy in Spain: results of a national survey of endocrine surgeons

We investigated the use patterns and indications of intraoperative neural monitoring (IONM) among endocrine surgeons in Spain. We sent an anonymous web-based survey to endocrine surgeons' members of the Spanish Association of Surgery by email. We analysed 79/ 269 surveys. Respondents had a median age of 52 years and 13 years of surgical experience. Only 32% of respondents performed routinely preoperative laryngoscopy in all thyroidectomies and 19% in all parathyroidectomies. Seventy-five percent of respondents used the intermittent-IONM, and 9.7% used the continuous-IONM. All respondents identified recurrent laryngeal nerve during surgery, and 40% of surgeons routinely identified external branch superior laryngeal nerve (EBSLN) during thyroidectomy. Seventy-eight percent of respondents used IONM always for all thyroidectomies. Only 11% stimulated EBSLN in all cases. Forty-nine percent used IONM always for all parathyroidectomies. The most frequent reasons for not using IONM were the unavailability of IONM, the high cost, and the lack of adding value to their clinical practice. Almost 10% declared not having IONM. The IONM is a reality in Spain, especially the intermittent mode. Its use is superior in thyroid surgery than in parathyroid. Its standardized use is not yet fully established, and routine adherence to standardized guidelines should increase.

Vagus Nerve Stimulation in the Carotid Triangle: An Effective Method for Monitoring the Recurrent Laryngeal Nerve in Thyroid and Parathyroid Surgery

OBJECTIVE

Our objective is the description of the technique of vagus nerve stimulation in carotid triangle in order to monitor the recurrent laryngeal nerve (RLN) during thyroid and parathyroid surgery.

METHODS

We stimulated the vagus nerve in the carotid triangle during 150 thyroid or parathyroid surgeries using a monopolar electromyography electrode inserted under the mastoid process towards the jugular foramen as a cathode, and using another subdermal electrode in the mastoid as an anode. Another complementary method of vagus stimulation was achieved with a pair of subdermal electrodes, placing the cathode at the mandibular angle and the anode at the mastoid.

RESULTS

In all patients, compound muscle action potential (CMAP) was recorded in the vocal cords with both stimulation techniques, allowing semi-continuous monitoring to be carried out. Intraoperative lesions were detected in 16 of the cases; 9 of them were transient with CMAP recovery achieved when modifying surgical maneuvers.

CONCLUSIONS

Vagus nerve stimulation in the carotid triangle is a reliable technique for monitoring the RLN in thyroid surgery. Vagus nerve stimulation in the carotid triangle is effective and safe for RLN monitoring, and it is a clear alternative to direct continuous stimulation of the nerve that by contrast requires its dissection in the carotid sheath.

Intraoperative nerve monitoring in thyroid surgery-shifting current paradigms

Over the past two decades, intraoperative neural monitoring (IONM) has matured into a powerful risk minimization tool. Meta-analyses of studies, most of which were limited by poor study designs and the sole use of intermittent nerve stimulation, failed to demonstrate superiority of IONM over anatomic recurrent laryngeal nerve (RLN) dissection in the absence of IONM. With the advent of continuous IONM (CIONM), intraoperative nerve electromyographic tracings, registered almost in real time during the operation, accurately predict postoperative vocal fold function when International Neural Monitoring Study Group quality standards are adhered to. CIONM aids in avoiding permanent traction-related nerve injury by urging surgeons to reverse harmful surgical maneuvers. CIONM also forms an integral part in the surgical concept of staged thyroidectomy. Delaying completion surgery on the other side until nerve function has recovered mitigates the risk of bilateral vocal fold palsy. CIONM has greatly furthered our understanding of functional RLN injury, enabling conception of effective risk minimization strategies tailored to the individual patient. The review summarizes the advances of continuous IONM technology that caused a quantum leap in risk minimization for thyroid surgery, shifting current paradigms.