Pediatric intraoperative nerve monitoring during thyroid surgery: A review from the American Head and Neck Society Endocrine Surgery Section and the International Neural Monitoring Study Group

Effectiveness of intraoperative nerve monitoring in reducing rates of recurrent laryngeal nerve injury in aerodigestive and cardiovascular pediatric surgery

OBJECTIVE

To investigate the effectiveness of intraoperative nerve monitoring at decreasing vocal fold movement impairment in children undergoing at-risk procedures.

BACKGROUND

Children undergoing aerodigestive or cardiovascular procedures are at risk for recurrent laryngeal nerve injury, leading to vocal fold movement impairment. Although intraoperative nerve monitoring has been shown to decrease recurrent laryngeal nerve injury in adults, there is paucity of data in children.

METHODS

This was a retrospective, single-center cohort study of children who underwent airway, esophageal, or great vessel surgery between 2018 and 2023. Vocal fold movement impairment was evaluated with pre- and postoperative awake flexible fiberoptic laryngoscopy. Vocal fold movement impairment rates and associated characteristics were compared between those with and without intraoperative nerve monitoring.

RESULTS

Among 387 children undergoing 426 at-risk procedures, intraoperative nerve monitoring was used in 72.1% (n = 307) of procedures. Intraoperative nerve monitoring significantly reduced postoperative vocal fold movement impairment compared with those without (11.4% vs 20.2%, P = .019, 43.6% relative risk reduction, number needed to treat: 12). In children with a pre-existing vocal fold movement impairment (n = 79, 18.5%), intraoperative nerve monitoring provided enhanced protection (vocal fold movement impairment 7.8% with intraoperative nerve monitoring compared with 25% without, P = .046, 68.6% relative risk reduction, number needed to treat: 3). Bilateral vocal fold movement impairment was 14 times more likely without intraoperative nerve monitoring (1.8% overall, 0.3% with intraoperative nerve monitoring, 5.6% without; 95% confidence interval 1.6-123.2; P = .006). Increasing intraoperative nerve monitoring use correlated with decreasing vocal fold movement impairment rates year over year (P = .046). Multivariable logistic regression demonstrated intraoperative nerve monitoring to remain significantly associated with reduced risk of vocal fold movement impairment (odds ratio, 0.48; 95% confidence interval, 0.26-0.85; P = .013).

CONCLUSION

Intraoperative nerve monitoring in children seems effective at decreasing recurrent laryngeal nerve injury and consequently vocal fold movement impairment. Intraoperative nerve monitoring should be considered in children undergoing cervicothoracic or cardiothoracic procedures, especially in those with preoperative vocal fold movement impairment.

Paradigms of intraoperative neuromonitoring in paediatric thyroid surgery

The larynx of children and adolescents is still in the developmental phase and the anatomical structure is still very small and sensitive. The higher malignancy and faster progression of some paediatric thyroid cancers make surgery more difficult. Intraoperative neuromonitoring (IONM) is frequently used in thyroid surgery as an effective means of securing the recurrent laryngeal nerve (RLN). Little information is available on the clinical efficacy of IONM in paediatric surgery. In addition, classic IONM techniques such as reinforced tracheal tube models with integrated surface electrodes are not standardised for children and adolescents. The use of innovative devices such as laryngeal masks with surface electrodes and thyroid cartilage receiving electrodes could replace monitoring tubes as a new form of IONM. Tracheal intubation in children needs to be performed by a highly experienced anaesthetist. The continued maturation of AI technology could be attempted in the future in conjunction with IONM to further reduce RLN injuries in children and adolescents. This article describes the anatomical features of the paediatric larynx, which differ from those of adults, and the advantages and shortcomings of IONM techniques for thyroid surgery in this population. The use of IONM in paediatric surgery is a complex technique and should be performed by experienced thyroid surgeons with in-depth IONM training. The use of IONM should be standardised within the clinical parameters of children.

Effectiveness and feasibility of nerve real-time monitoring and intermittent monitoring in endoscopic thyroidectomy: a multicenter retrospective cohort study of 1621 patients

BACKGROUND

Protecting recurrent laryngeal nerve (RLN) and external branch of the superior laryngeal nerve (EBSLN), a crucial indicator for assessing the quality of thyroid surgery, poses a challenge in endoscopic thyroidectomy. The aim of this study was to investigate the effectiveness and feasibility of nerve real-time monitoring and intermittent monitoring in endoscopic thyroidectomy.

METHODS

In this retrospective cohort study, patients underwent endoscopic thyroidectomy were included, and the characteristics and outcomes of real-time monitoring and intermittent monitoring groups were compared. Thereafter, the outcomes of four surgical types (unilateral lobectomy, total thyroidectomy, unilateral lobectomy + lymph node dissection (LND), and total thyroidectomy + LND) were compared in both groups.

RESULTS

A total of 1621 patients were enrolled. Compared to intermittent monitoring group, real-time monitoring group significantly shortened operation durations in the four surgical types (30.8±6.1 min vs. 35.7±5.7 min, 54.7±4.4 min vs. 59.1±5.2 min, 39.3±4.6 min vs. 42.0±4.7 min, 59.1±4.9 min vs. 66.0±5.8 min, respectively). As for surgical complications, compared to intermittent monitoring group, real-time monitoring group had lower rates of transient vocal cord paralysis among the four surgical types (0.0 vs. 3.3%, 0.0% vs. 4.0%, 0.8 vs. 3.2%, 2.8 vs. 6.7%, respectively), and lower rates of EBSLN injury (1.1 vs. 4.4%, 0.0 vs. 12.0%, 0.8 vs. 3.8%, 0.9 vs. 4.8%, respectively). Clinicopathologic characteristics and postoperative inflammatory reactions were similarly paralleled in both groups.

CONCLUSION

Implementation of real-time monitoring in endoscopic thyroidectomy effectively protects the RLN and EBSLN while shortening operation duration, demonstrating its feasibility and efficacy in enhancing nerve protection and surgical efficiency.

Management of pediatric thyroid carcinoma

PURPOSE OF REVIEW

The incidence of thyroid carcinoma is increasing among children and adolescents, particularly in female individuals. Children and adolescents require special considerations in management as the molecular genetics of pediatric thyroid tumors are inherently different from their adult counterparts. The increased risk of malignancy, nodal metastases, and pulmonary metastases in pediatric patients warrants pediatric-specific management recommendations and pediatric-specific multidisciplinary teams.

RECENT FINDINGS

This article highlights the molecular origins of pediatric thyroid carcinoma and the implications of tumor genetics for the course of disease and treatment considerations. We highlight specific surgical considerations to optimize outcomes while minimizing lifelong risks of vocal paralysis and hypoparathyroidism. The landscape of treatment options is rapidly evolving with development of sophisticated molecular approaches to understand the genetic landscape, and this review features updated recommendations and systemic treatment options for the management of pediatric thyroid malignancy.

SUMMARY

Pediatric thyroid carcinoma is a lifelong burden and the treatment tailored to optimize outcomes minimizes long-term risks of treatments, surgery, radiation and targeted systemic therapies. Multidisciplinary teams that treat pediatric thyroid carcinoma should focus surgical experience and use the most updated guidelines and treatments available, particularly considering the landscape of molecular genetics in pediatric thyroid carcinoma.

The INMSG Survey on the Loss of Signal Management on the First Side During Planned Bilateral Thyroid Surgery

BACKGROUND

The aim of this study is to describe the management and associated follow-up strategies adopted by thyroid surgeons with different surgical volumes when loss of signal (LOS) occurred on the first side of planned bilateral thyroid surgery, and to further define the consensus on intraoperative neuromonitoring (IONM) applications.

METHODS

The International Neural Monitoring Study Group (INMSG) web-based survey was sent to 950 thyroid surgeons worldwide. The survey included information on the participants, IONM team/equipment/procedure, intraoperative/postoperative management of LOS, and management of LOS on the first side of thyroidectomy for benign and malignant disease.

RESULTS

Out of 950, 318 (33.5%) respondents completed the survey. Subgroup analyses were performed based on thyroid surgery volume: <50 cases/year (n = 108, 34%); 50 to 100 cases/year (n = 69, 22%); and >100 cases/year (n = 141, 44.3%). High-volume surgeons were significantly (P < .05) more likely to perform the standard procedures (L1-V1-R1-S1-S2-R2-V2-L2), to differentiate true/false LOS, and to verify the LOS lesion/injury type. When LOS occurs, most surgeons arrange otolaryngologists or speech consultation. When first-side LOS occurs, not all respondents decided to perform stage contralateral surgery, especially for malignant patients with severe disease (eg, extrathyroid invasion and poorly differentiated thyroid cancer).

CONCLUSIONS

Respondents felt that IONM was optimized when conducted under a collaborative team-based approach, and completed IONM standard procedures and management algorithm for LOS, especially those with high volume. In cases of first-site LOS, surgeons can determine the optimal management of disease-related, patient-related, and surgical factors. Surgeons need additional education on LOS management standards and guidelines to master their decision-making process involving the application of IONM.

Complications of Thyroid Cancer Surgery in Pediatric Patients at a Tertiary Cancer Center

BACKGROUND

The incidence of complications and risk factors for hypocalcemia after pediatric thyroid cancer surgery has not been clearly defined in the literature because most reports fail to distinguish between benign and malignant disease. The trend away from total thyroidectomy (TT) to thyroid lobectomy in low-risk disease means there is a need to clearly define the complication profile of malignant disease.

METHODS

After institutional review board (IRB) approval, a retrospective chart review was undertaken at Memorial Sloan Kettering Cancer Center for pediatric patients undergoing surgery for well-differentiated thyroid cancer from 1986 to 2021. Clinicopathologic characteristics and complications were evaluated. Multivariable analysis was performed to identify factors independently associated with postoperative hypocalcemia.

RESULTS

The study identified 307 pediatric patients with well-differentiated thyroid carcinoma (median follow-up period, 61 months). Of these patients, 69% underwent TT and 31% received a partial thyroidectomy. Among them, 40% had N0 disease, 28% had N1a disease, and 33% had N1b disease. Postoperatively, no patients experienced a neck hematoma, 1.6% had temporary unilateral vocal cord palsy (VCP), and 0.7% had permanent VCP due to recurrent laryngeal nerve (RLN) invasion. Temporary and permanent hypocalcemia occurred in respectively 32.6 % and 5.2 % of the patients. Multivariable analysis identified central neck dissection (CND) (odds ratio [OR] 3.30; p < 0.001) and N1 disease (OR 2.51; p = 0.036) as independent risk factors for temporary hypocalcemia and N stage (OR 3.64; p = 0.018) as a risk factor for permanent hypocalcemia.

CONCLUSION

Pediatric thyroid cancer surgery results in low complication rates despite nodal metastases. Vocal cord paralysis is rare unless disease is found to be invading the RLN intraoperatively. Both N stage and CND are independent risk factors for hypocalcemia, helping to identify high-risk patients.

The Utility of Intraoperative Neuromonitoring in Pediatric Surgical Oncology

BACKGROUND

Intraoperative nerve monitoring (IONM) is a technique used to decrease the possibility of nerve-associated morbidity and damage to nearby neural structures during complex surgical procedures. The use and potential benefits of IONM in pediatric surgical oncology are not well-described.

METHODS

An overview of the current literature was performed to elucidate the various techniques that may be useful to pediatric surgeons for resection of solid tumors in children.

RESULTS

The physiology and common types of IONM relevant to the pediatric surgeon are described. Important anesthetic considerations are reviewed. Specific applications for IONM that may be useful in pediatric surgical oncology are then summarized, including its use for monitoring the recurrent laryngeal nerve, the facial nerve, the brachial plexus, spinal nerves, and lower extremity nerves. Troubleshooting techniques regarding common pitfalls are then proposed.

CONCLUSION

IONM is a technique that may be beneficial in pediatric surgical oncology to minimize nerve injury during extensive tumor resections. This review aimed to elucidate the various techniques available. IONM should be considered as an adjunct for the safe resection of solid tumors in children in the proper setting with the appropriate level of expertise. A multidisciplinary approach is advised. Additional studies are necessary to further clarify the optimal use and outcomes in this patient population.

LEVELS OF EVIDENCE

Level III.

Application of Intraoperative Neuromonitoring (IONM) of the Recurrent Laryngeal Nerve during Esophagectomy: A Systematic Review and Meta-Analysis

BACKGROUND

recurrent laryngeal nerve palsy (RLNP) is a common and severe complication of esophagectomy in esophageal cancer (EC). Several studies explored the application of intraoperative neuromonitoring (IONM) in esophagectomy to prevent RLNP. The purpose of this study was to conduct a systematic review and meta-analysis to evaluate the value of IONM in esophagectomy for EC.

METHODS

an electronic of the literature using Google Scholar, PubMed, Embase, and Web of Science (data up to October 2022) was conducted and screened to compare IONM-assisted and conventional non-IONM-assisted esophagectomy. RLNP, the number of mediastinal lymph nodes (LN) dissected, aspiration, pneumonia, chylothorax, anastomotic leakage, the number of total LN dissected, postoperative hospital stay and total operation time were evaluated using Review Manager 5.4.1.

RESULT

ten studies were ultimately included, with a total of 949 patients from one randomized controlled trial and nine retrospective case-control studies in the meta-analysis. The present study demonstrated that IONM reduced the incidence of RLNP(Odds Ratio (OR) 0.37, 95% Confidence Interval (CI) 0.26-0.52) and pneumonia (OR 0.58, 95%CI 0.41-0.82) and was associated with more mediastinal LN dissected (Weighted Mean Difference (WMD) 4.75, 95%CI 3.02-6.48) and total mediastinal LN dissected (WMD 5.47, 95%CI 0.39-10.56). In addition, IONM does not increase the incidence of aspiration (OR 0.4, 95%CI 0.07-2.51), chylothorax (OR 0.55, 95%CI 0.17-1.76), and anastomotic leakage (OR 0.78, 95%CI 0.48-1.27) and does not increase the total operative time (WMD -12.33, 95%CI -33.94-9.28) or postoperative hospital stay (WMD -2.07 95%CI -6.61-2.46) after esophagectomy.

CONCLUSION

IONM showed advantages for preventing RLNP and pneumonia and was associated with more mediastinal and total LN dissected in esophagectomy. IONM should be recommended for esophagectomy.

Optimal Monitoring Technology for Pediatric Thyroidectomy

This retrospective study aimed to describe, firstly, characteristics and outcomes of the intraoperative neural monitoring technology in the pediatric population, and secondarily the recurrent laryngeal nerve complication rate. Thirty-seven patients (age <18 years) operated on from 2015 to 2021 by conventional open thyroid surgery were included. Twenty-four (64.9%) total thyroidectomies and 13 (35.1%) lobectomies were performed. Seven central and six lateral lymph node dissections completed 13 bilateral procedures. Histology showed malignancy in 45.9% of the cases. The differences between the electromyographic profiles of endotracheal tubes or electrodes for continuous monitoring were not statistically significant. In our series of young patients, both adhesive (even in 4- or 5-year-olds) and embedded endotracheal tubes were used, while in patients 3 years old or younger, the use of a more invasive detection method with transcartilage placement recording electrodes was required. Overall, out of 61 total at-risk nerves, 5 (8.2%) recurrent laryngeal nerves were injured with consequent intraoperative loss of the signal; however, all these lesions were transient, restoring their normal functionality within 4 months from surgical procedure. To our knowledge, this is the first study of intraoperative neural monitoring management in a cohort of Italian pediatric patients.