Myer-Cotton Grade of Subglottic Stenosis Depends on Style of Endotracheal Tube Used.

OBJECTIVES: Determine percentage of subglottic stenosis using current endotracheal tube (ETT) cross-sectional areas as actual, compared with previously published ETT cross-sectional areas as expected, and determine if style of ETT could result in a change in percentage of stenosis or Myer-Cotton grade. STUDY TYPE: Cross-sectional study. DESIGN: Prospective analysis. METHODS: Eight styles of uncuffed pediatric ETT from four manufacturers ranging from 2.0 to 6.0 inner diameter (ID) were evaluated. ID and outer diameter (OD) measurements were obtained from each company's specification sheets. Cross-sectional area was calculated for each ETT using the formula (Area = πr2 ). The cross-sectional areas of each current ETT (actual) were compared with those of previously published ETTs (expected) based on age, and the degree of stenosis was calculated using the formula [1- (Area actual /Area expected )] × 100%. Ranges of percentage for each style of ETT were calculated. RESULTS: There was an increase in range of OD and area with increasing size of ETT ID, with the largest range in OD being 0.8 mm, and the largest range in area being 10.55 mm2 . The median interquartile range (IQR), range of percentage stenoses was 11 (5%), ranging from 0% to 21%. Seven of 28 (25%) ranges were found to span two Myer-Cotton grades. CONCLUSIONS: The Myer-Cotton grade of subglottic stenosis depends on the style of ETT used. Using updated values from currently available ETTs aims to keep this grading system valid with respect to surgical approach and outcomes following surgery. LEVEL OF EVIDENCE: NA Laryngoscope, 133:2808-2812, 2023.

Length of the Cricoid and Trachea in Children: Predicting Intubation Depth to Prevent Subglottic Stenosis.

OBJECTIVE: Define the length of the subglottis and trachea in children to predict a safe intubation depth. METHODS: Patients <18 years undergoing rigid bronchoscopy from 2013 to 2020 were included. The carina and inferior borders of the cricoid and true vocal folds were marked on a bronchoscope and distances were measured. Patient age, weight, height, and chest height were recorded. Four styles of cuffed pediatric endotracheal tubes (ETT) were measured and potential positions of each cuff and tip were calculated within each trachea using five depth of intubation scenarios. Multivariate linear regression was performed to identify predictors of subglottic and tracheal length. RESULTS: Measurements were obtained from 210 children (141 male, 69 female), mean (SD) age 3.21 (3.66) years. Patient height was the best predictor of subglottic length (R2 : 0.418): Lengthsg (mm) = 0.058 * height (cm) + 2.8, and tracheal length (R2 : 0.733): Lengtht (mm) = 0.485 * height (cm) + 21.3. None of the depth of intubation scenarios maintained a cuff-free subglottis for all ETT styles investigated. A formula for depth of intubation: Lengthdi (mm) = 0.06 * height (cm) + 8.8 found that no ETT cuffs would be in the subglottis and all tips would be above the carina. CONCLUSION: Current strategies for determining appropriate depth of intubation pose a high risk of subglottic ETT cuff placement. Placing the inferior border of the vocal cords 0.06 * height (cm) + 8.8 from the superior border of the inflated ETT cuff may prevent subglottic cuff placement and endobronchial intubation. LEVEL OF EVIDENCE: 4 Laryngoscope, 132:S1-S10, 2022.

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.