Patterns and Predictors of Metastatic Spread to the Neck in Pediatric Thyroid Carcinoma.

OBJECTIVE: Evaluate patterns and predictors of spread to the neck in pediatric metastatic differentiated thyroid carcinoma (DTC). METHODS: Patients <18 years old undergoing thyroidectomy by a single surgeon from January 2015 to December 2019 were included. Neck sublevels were removed separately according to AJCC boundaries. Clinical outcomes included nerve injury, hypocalcemia, hematoma, and residual tumor. RESULTS: Forty-eight children underwent thyroid surgery. Thirty (63%) were for malignancy, 27 (90%) of which were DTC. Nineteen (70%) patients with DTC underwent 24 neck dissections; 19 central plus lateral and 5 central alone. The female to male ratio increased from 1:1 to 3:1 with age. Two children with lateral neck involvement had sub-centimeter primaries. Patients requiring neck dissection were more likely to have 1) diffuse sclerosing or tall cell variant, 2) T3 or T4 disease, 3) genetic mutation, 4) lymphatic invasion, 5) extracapsular extension, 6) positive resection margin. Levels IIA (79%), III (89%), IV (84%), VI (100%) were most commonly involved. Levels IB (16%), IIB (16%), VB (16%) were also involved, often without involvement of adjacent levels. Permanent injuries included one unilateral recurrent laryngeal nerve, one mild marginal mandibular nerve and one mild accessory nerve. Hypocalcemia was highest following neck dissection for malignant disease. One patient was re-operated for a mediastinal node. Most patients with N1 disease received radioactive iodine. Most patients have no evidence or indeterminate disease on long-term follow-up. CONCLUSION: Children with lateral nodal spread from DTC should be considered for neck dissection including Levels IB, IIA, IIB, III, IV, VB, bilateral VI. LEVEL OF EVIDENCE: 4 Laryngoscope, 131:E1002-E1009, 2021.

Recurrent laryngeal nerve monitoring with surface electrodes in pediatric thyroid surgery.

OBJECTIVE: To prospectively evaluate 1) use of endotracheal tube (ETT) surface electrodes for recurrent laryngeal nerve (RLN) monitoring in thyroid surgery in children, and 2) effects of thyroid surgery on the RLN in children. METHODS: Patients <18 years old undergoing thyroidectomy were included. Vocal cord mobility was assessed pre- and postoperatively. RLNs were monitored using adhesive or integrated electrodes. Recordings were made before and after dissection, and area under the curve and latency were compared using mixed models. RESULTS: Twenty-five children (44 nerves at risk), mean (standard deviation) age 13.1 (3.4) years (range 4.5-17.4 years), underwent thyroidectomy. Twelve (46%) monitors were adhesive. One nerve had unobtainable responses. Nerveäna Power Index (NPI) (Neurovision Medical Products, Ventura, CA) decreased, and latency increased pre- versus postdissection at all amplitudes (P < 0.0001), with change in slope of NPI affected by tumor size (P < 0.05). Postdissection, the NPI was lower, and the latency was longer when stimulating low in the neck versus near the cricothyroid joint at all stimulating amplitudes (P < 0.0001), with change in NPI related to tumor size (P < 0.0001). Changes were not associated with decreased vocal cord mobility, aspiration, or voice change. One patient had a temporary unilateral paresis that resolved by 7 weeks, and another had normal movement 3 weeks postoperatively and developed a paresis 2 months postoperatively. CONCLUSION: ETT surface electrodes are reliable for RLN monitoring in thyroid surgery in children. Thyroid surgery is associated with a decrease in RLN stimulability that is related to tumor size. The site of RLN stimulation matters when evaluating the nerve. LEVEL OF EVIDENCE: 4 Laryngoscope, 130:1583-1589, 2020.