Laryngeal Neural Monitoring during Pediatric Thyroid Cancer Surgery-Is Transcartilage Recording a Preferable Method?

The use of transcartilage (TC) intraoperative neuromonitoring (IONM) in a pediatric population has not been reported. This study evaluated the feasibility and the benefit of using TC-IONM for thyroid cancer surgery in a pediatric population. This retrospective single-center study enrolled 33 pediatric patients who had received an IONM-assisted thyroidectomy. Demographic characteristics, standardized IONM laryngeal examinations and stimulation information (L1-V1-R1-R2-V2-L2) were compared between endotracheal tube (ET) and TC methods. In the 15 cancer patients (30 nerves), TC-IONM provided significant higher electromyography (EMG) amplitude (p < 0.001), signal stability (lower V1/V2 signal correlation, r = 0.955 vs. r = 0.484, p = 0.004), signal quality (higher ratio of V1 or V2 amplitude <500 µV, 0.0% vs. 43.8%, p = 0.005) and lower R1-R2p change (7.1% vs. 37.5%, p = 0.049) compared to ET-IONM. In the 18 benign patients (28 nerves), TC-IONM provided significantly higher EMG amplitude (p < 0.001), signal stability (r = 0.945 vs. r = 0.746, p = 0.0324) and non-significant higher signal quality and R1-R2p change. This report is the first to discuss the use of TC-IONM in pediatric thyroid surgery. In contrast with ET-IONM, TC-IONM had superior amplitude, stability and quality of EMG signals, which greatly facilitates the meticulous recurrent laryngeal nerve dissection in pediatric thyroidectomies. The TC-IONM method can be considered a feasible, effective and preferable method of monitored thyroidectomy in pediatric thyroid cancer.

Prevention of transoral thyroidectomy complications: An analysis of surgical outcomes in 423 consecutive series.

BACKGROUND: Although there are several publications on the new transoral robotic thyroidectomy technique, few have thoroughly reviewed its associated complications. This study analyzed the causes and prevention of transoral robotic thyroidectomy-specific complications and presented preventive measures. METHODS: The medical records of patients who underwent transoral robotic thyroidectomy performed by a single surgeon between March 1, 2009 and April 30, 2019 were retrospectively analyzed. Patient demographic, clinical, and operative data were analyzed using descriptive statistics. We describe the transoral robotic thyroidectomy-related complications experienced at our institution and how to overcome them. RESULTS: This study included a total of 423 patients who underwent transoral robotic thyroidectomy. The general surgical complications included immediate postoperative bleeding (2 cases) and delayed hematoma (3 cases). Chyle leakage and localized wound infection were found in 1 case each. Transient vocal cord palsy occurred in 4 cases, and 1 case developed transient hypoparathyroidism. The transoral robotic thyroidectomy-specific complications included zygoma bruise (2 cases), flap bruise (3 cases), chin flap perforation (2 cases), and oral commissure tearing (2 cases). The complications occurring when creating the flap included flap burns (4 cases), skin dimpling in the midline of the lower chin (2 cases), and hematomas in the intraoral trocar insertion sites (3 cases). CONCLUSION: Surgeons familiar with thyroid surgery and experienced in robotic surgery can perform transoral robotic thyroidectomy without causing more complications than those seen with traditional surgery.

Transoral robotic thyroidectomy versus transoral endoscopic thyroidectomy: a propensity-score-matched analysis of surgical outcomes.

BACKGROUND: Transoral endoscopic thyroidectomy vestibular approach (TOETVA) has been shown to be safe and has similar outcomes as open thyroidectomy for selected patients. It is not clear if transoral robotic thyroidectomy (TORT) may extend transoral endoscopic thyroidectomy to more complex thyroid operations. The study aimed to compare the safety and outcomes of TORT with those of TOETVA. METHODS: We retrospectively reviewed all patients who had TORT and TOETVA performed by a single surgeon from June 2017 to May 2019. Intrathoracic goiter and combined operations were excluded. Surgical outcomes were compared after propensity score matching. Learning curves, as measured by operating time, were evaluated. RESULTS: A total of 150 patients underwent 154 transoral (55 TORT and 99 TOETVA) thyroidectomy. Of the 154 operations, 28 (18.2%) were bilateral total thyroidectomy and 126 (81.8%) were unilateral thyroid lobectomy. After propensity score matching, we found a longer operative time (median [interquartile range]) for TORT (n = 53) than for the TOETVA (308 [284-388] vs 228 [201-267] min, P < 0.001). Blood loss and visual analog scale scores for pain were not significantly different between the two groups. Central neck lymph node dissection was performed more frequent in the TORT group (28 of 53 [52.8%] vs 10 of 53 [18.9%], P = 0.001), and when performed, the numbers of total and positive lymph nodes did not differ significantly between the two groups. The rates of hypoparathyroidism and recurrent laryngeal nerve injury did not differ significantly between the two groups. There was no conversion to open thyroidectomy, mental nerve injury, or surgical site infection. The learning curve for TORT was 25 cases, but no obvious learning curve was observed for TOETVA. CONCLUSIONS: TORT requires a longer operative time, but is as safe as TOETVA and may be useful for more complex thyroid operations.

Safety of Ligasure exact dissector in thyroidectomy with continuous neuromonitoring: a porcine model.

BACKGROUND: The purpose of this study was to investigate and define safety parameters for using the Ligasure exact dissector (LED) for dissection close to the recurrent laryngeal nerve (RLN) during thyroidectomy. METHODS: Real-time electrophysiologic electromyographic (EMG) tracings were recorded in 16 RLNs (8 piglets) during various applications of LED under continuous intraoperative monitoring in this prospective porcine model study. In the activation study, LED was activated at varying distances from the RLN. In the cooling study, LED was activated with different cooling times or after touching the sternocleidomastoid muscle before application to the RLN. RESULTS: In the activation study, no adverse EMG events occurred at distances longer than 1 mm. In the cooling study, no adverse EMG events occurred after a 2-second cooling time. Additionally, no adverse EMG events occurred when a sternocleidomastoid muscle touch maneuver was used for cooling. CONCLUSIONS: The LED can be safely used at distance of 1 mm or longer, and it should be cooled for at least 2 seconds or by muscle touch maneuver. Thyroid surgeons can avoid RLN injury if standard procedures for LED use are observed.

Safety of energy based devices for hemostasis in thyroid surgery.

Energy based devices (EBD) have been developed, implemented and increasingly applied in thyroid surgery because they can provide a combined dissection and haemostatic effect. In particular, advantages of EBD have been described in terms of efficacious haemostasis, reduction of procedure-associated time, reduced incision length, less operative blood loss and transfusion need, decreased postoperative drain, pain and hospital stay. In addition, EBD are essential for endoscopic procedures. On the contrary, a potential drawback is the increased health care costs. This paper reviews relevant medical literature published on the safety of new devices for achieving hemostasis and dissection around the recurrent laryngeal nerve (RLN).

The anatomy of the external branch of the superior laryngeal nerve in Koreans.

BACKGROUND: Preservation of the external branch of the superior laryngeal nerve (EBSLN) during thyroidectomy is important because its injury may lead to frequent occurrence of vocal fatigue and the inability to perform superenergetic phonation. Most studies on the anatomy of EBSLN have been performed in Western countries and, thus, have some limitations in their application to Koreans. We explored the anatomy of EBSLNs using intraoperative neuromonitoring (IONM) in Korean adults. METHODS: Between August 2011 and December 2011, 50 patients underwent thyroidectomy at Korea University, Anam Hospital in Seoul, Korea. IONM was performed with the NIM response 3.0 system. RESULTS: Forty-two total thyroidectomies and eight lobectomies were performed with IONM and 92 EBSLNs were evaluated. Type I EBSLN was observed in 15 of the 92 nerves (16.3%), type IIa EBSLN was noted in 52 (56.5%) and type IIb EBSLN was noted in 25 (27.2%). Patients with types IIa and IIb were at higher risk of injuries and these types were more frequently observed (83.7%) compared with previous Western studies. We found that 35.9% of distal insertion sites of EBSLNs were located within 1cm of the center of the cricoid cartilage. CONCLUSION: Surgeons should pay close attention to preserving the EBSLN during thyroidectomy in Korean patients because their EBSLNs are more frequently located beneath the superior thyroid vessels.

Development of a canine model for recurrent laryngeal injury by harmonic scalpel.

Various energy devices had been used in thyroid surgery. Aim of study is to develop canine model for recurrent laryngeal nerve injury by harmonic scalpel and to evaluate feasibility of using this model for evaluating the safety use of harmonic scalpel during thyroid surgery. Nine dogs were divided into 3 groups according to distance between harmonic scalpel application and recurrent laryngeal nerve; group 1 (1 mm), 2 (2 mm), and 3 (3 mm). Vocal cord function was assessed pre- and postoperatively using video laryngoscopy. Harmonic scalpel was applied adjacent to left recurrent laryngeal nerve and, two weeks later, right recurrent laryngeal nerve at assigned distances. Recurrent laryngeal nerves were evaluated for subacute and acute morphologic changes. Laryngoscopy demonstrated 3 abnormal vocal cords in group 1, 1 in group 2, and no in group 3 (P=0.020). Subacute histologic changes were observed in nerves with abnormal function. Acute histologic changes were observed 5/8 (62.5%) in group 1, 1/7 (14.3%) in group 2, and not in group 3. We developed canine model for recurrent laryngeal injury. The functional outcomes matched with the histologic changes. These warrant further study to determine the safety margin for energy device in vicinity of recurrent laryngeal nerve.

Life-threatening acute hyponatremia with generalized seizure induced by low-dose cyclophosphamide in a patient with breast cancer.

Cyclophosphamide is commonly used in the treatment of malignant diseases. Symptomatic severe hyponatremia induced by low-dose cyclophosphamide is very uncommon worldwide. Recently we experienced a case of a 56-year-old woman with breast cancer who developed severe hyponatremia with generalized seizure after the first cycle of adjuvant chemotherapy with doxorubicin and cyclophosphamide. Her laboratory test showed a serum sodium of 116 mmol/L. Her hyponatremia was initially treated with hypertonic saline solution and furosemide. She completely recovered without neurological deficits after slow correction of the serum sodium concentration over two days. Clinicians must always keep in mind that life-threatening acute hyponatremia can be induced by intravenous cyclophosphamide during chemotherapy, even if the dosage is low.