BACKGROUND
Surgery to remove all, or part, of the thyroid gland (thyroidectomy) is a common procedure for treating some types of benign and cancerous thyroid disease. As is true for every kind of surgery, complications (unexpected problems) can happen during thyroid surgery and these complications can result in unexpected problems after surgery. One of the most important complications that can happen during thyroid surgery is accidental injury to the recurrent laryngeal nerves. These 2 nerves come up from the chest, one on each side of the neck, and travel by the thyroid to insert into the voice box. They control the vocal cords and are very delicate. One of the surgeon’s jobs during thyroid surgery is to gently move these nerves away from the thyroid while removing the gland. If one of these nerves is injured during while doing this, the voice may be hoarse following surgery and this may be permanent. This may also cause coughing or choking when swallowing liquids. If both nerves are injured while removing the thyroid, a person may have difficulty breathing after surgery and may need to undergo emergency tracheostomy (placement of a tube through the skin into the windpipe) to allow breathing.

One tool a surgeon may use to try and avoid injuring the recurrent laryngeal nerves (and so avoid voice, swallowing and breathing problems after surgery) is called nerve monitoring. This technology allows a surgeon to verify (monitor) that these nerves are working throughout the operation and may also help the surgeon identify exactly where the nerves are located, relative to a person’s thyroid gland, while surgery is being performed. This information may help a surgeon avoid accidentally injuring one, or both, of these nerves. The research described here aims to determine if using nerve monitoring decreases the risk of recurrent laryngeal nerve injury during thyroid surgery.

THE FULL ARTICLE TITLE
Memeh K et al 2022 Effect of intraoperative neuromonitoring on the risks of recurrent laryngeal nerve injury during thyroidectomy: A doubly robust approach. Ann Surg. Epub 2022 Jul 15. PMID: 35837957.

SUMMARY OF THE STUDY
The authors of this study looked at a large database that includes information about people who undergo surgery in North America. The study identified 24,370 people who had undergone thyroid surgery between 2016 and 2019. In this group, 15,681 people had thyroid surgery that included use of nerve monitoring technology. The risk of injury to a recurrent laryngeal nerve during thyroid surgery was lower when nerve monitoring was used (5.9% risk of injury if monitoring was used compared to 6.8% without monitoring). This means that the risk of injury to a recurrent laryngeal nerve was lowered by 23% when nerve monitoring was used. One drawback of using nerve monitoring identified by the authors was that thyroid surgery took longer than if monitoring was not used. On the other hand, the authors found that the overall length of time a person was in the hospital after thyroid surgery was shorter when nerve monitoring was used.

WHAT ARE THE IMPLICATIONS OF THIS STUDY?
Minimizing the risk of recurrent laryngeal nerve injury during thyroid surgery, and thus the risk of associated voice, swallowing and/or breathing problems after surgery, is a critically important part of a thyroid surgeon’s job. Any technology that facilitates this risk reduction should be considered for use during thyroid surgery. This study indicates that using nerve monitoring technology during thyroid surgery helps thyroid surgeons avoid injuring the recurrent laryngeal nerves during surgery. Furthermore, the study authors did not identify any significant drawbacks associated with using nerve monitoring technology. Thyroid surgeons should thus strongly consider using nerve monitoring technology during thyroid surgery.

— Jason D. Prescott, MD PhD

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