Comparison of intraoperative neural monitoring between endoscopic transoral and bilateral axillo-breast approach thyroidectomy.

BACKGROUND: The use of intraoperative neuromonitoring (IONM) during endoscopic thyroidectomy has not been fully explored, with limited studies focusing solely on the recurrent laryngeal nerve (RLN) and neglecting the external branch of the superior laryngeal nerve (EBSLN). This study aimed to compare the effectiveness of IONM in two endoscopic thyroidectomy techniques, namely the transoral and bilateral axillo-breast approach (BABA). METHODS: We retrospectively reviewed patients who underwent endoscopic thyroidectomy with IONM and compared the outcomes between those who underwent different surgical techniques (transoral or BABA). We recorded the detection method and identification rate of the EBSLN and RLN, along with the amplitude and latency of the evoked potential. RESULTS: We monitored 98 nerves at risk (NAR) from 74 patients (60 and 38 in the transoral and BABA groups, respectively). Almost all EBSLNs were identified using electromyography (EMG) signals and/or cricothyroid muscle twitches, except for one patient in the transoral group who developed EBSLN palsy. Patients in the transoral group were more likely to have the sternothyroid muscle divided (75.0% vs. 15.8%, p < 0.001) and had a lower rate of visual recognition of the EBSLN fibers (10.0% vs. 31.6%, p = 0.007) than did those in the BABA group. All RLNs were identified in both groups; however, patients in the BABA group had a relatively higher rate of post-dissection amplitude reduction > 50% (15.8% vs. 5.0%, p = 0.072), and one patient had transient RLN palsy. CONCLUSIONS: Both the EBSLN and RLN could be adequately identified and monitored during endoscopic transoral and BABA thyroidectomies using IONM.

Optimization of Intraoperative Neural Monitoring of the Recurrent Laryngeal Nerve in Thyroid Surgery.

The application of intraoperative neural monitoring (IONM) has been widely accepted to improve surgical outcomes after thyroid surgery. The malfunction of an IONM system might interfere with surgical procedures. Thus, the development of anesthesia modalities aimed at ensuring functional neuromonitoring is essential. Two key issues should be taken into consideration for anesthetic management. Firstly, most patients undergo recurrent laryngeal nerve monitoring via surface electrodes embedded in an endotracheal tube. Thus, advanced video-assisted devices might optimize surface electrode positioning for improved neuromonitoring signaling accuracy. Secondly, neuromuscular blocking agents are routinely used during thyroid surgery. The ideal neuromuscular block should be deep enough for surgical relaxation at excision and recovered enough for an adequate signal f nerve stimulation. Proper neuromuscular block management could be achieved by titration doses of muscle relaxants and reversal agents.

Prevention of non-recurrent laryngeal nerve injury in robotic thyroidectomy: imaging and technique.

INTRODUCTION: The aim of this report was to summarize observations, evaluate the feasibility, provide detailed information concerning proper techniques, and address limitations for non-recurrent laryngeal nerve (NRLN) dissection and release during the robotic bilateral axillo-breast approach (BABA) for thyroidectomy. MATERIALS AND METHODS: The BABA approach was used in two cases of thyroidectomy in the setting of NRLN. Preoperative CT imaging findings suggesting the aberrant anatomy are reviewed and technical planning, inclusive of intraoperative nerve monitoring, was employed. Intraoperative videos with narrative discussion of technique for safe dissection are provided, along with supplementary video of additional technical guidance. RESULTS: In both cases, the NRLNs were identified, dissected, and preserved. We dissected the proximal segment of each NRLN to its origin. We determined that the use of only the NRLN proximal to distal robotic dissection jeopardized the nerve. The BABA approach with the Type I NRLN is similar to the dissection of the recurrent laryngeal nerve (RLN) in transoral thyroidectomy. Due to interference with endoscopic viewing caused by the thyroid cartilage, the Type I NRLN is more challenging to manage both at the laryngeal entry point and its origin from the vagus nerve (VN). For the Type II NRLN, it is essential to identify its point of origin and the reflection of the nerve from the VN. Therefore, modification of nerve dissection to mirror open surgery with bidirectional nerve dissection assisted in avoidance of traction injury to the nerve. CONCLUSIONS: We presented a video, a detailed description of methods, and discussed limits for NRLN management in robotic BABA. This report included (i) a description of the aberrant anatomy and CT scans to inform surgeons of the possible NRLN locations, (ii) a description of a technique for using the nerve monitor in the robotic surgeries, and (iii) a description of the techniques used to isolate and protect the NRLN during the robotic surgery. In robotic BABA, our NRLN-sparing technique and degree included mainly a multi-directional nerve dissection (i.e., medial-grade, later-grade approach together with proximal to/from distal) using athermal technique. The NRLN-sparing technique is predominantly carried out in an anterior dissection plane.

Clinical validation of NerveTrend versus conventional i-IONM mode of NIM Vital in prevention of recurrent laryngeal nerve events during bilateral thyroid surgery: A randomized controlled trial.

BACKGROUND: The aim of this study was to test the hypothesis that use of NerveTrend™ mode of intermittent neuromonitoring (i-IONM) during thyroidectomy may identify and prevent impending recurrent laryngeal nerve (RLN) injury. METHODS: A randomized clinical trial. The primary outcome was prevalence of RLN injury on postoperative day 1. In NerveTrend™ group the i-IONM stimulator was used for trending of amplitude and latency changes from initial vagal electromyographic baseline to tailor surgical strategy. RESULTS: Some 264 patients were randomized into the intervention versus the control group, 132 patients each. RLN injury was found on postoperative day 1 in 5/264 (1.89%) nerves at risk (NAR) versus 12/258 (4.65%) NAR whereas staged thyroidectomy was used in 0/132 (0.00%) versus 6/132 (4.54%) patients (p = 0.067 and p = 0.029, respectively). CONCLUSION: The use of NerveTrend™ mode resulted in tendency towards reduced RLN injury on postoperative day 1 and significant decrease of need for a staged thyroidectomy.

Feasibility of the enhanced neuromuscular blockade recovery protocol with selective use of sugammadex in thyroid surgery with intraoperative neuromonitoring.

BACKGROUND: To investigate feasibility of utilizing enhanced neuromuscular blocking agents with selective recovery protocol during thyroid surgery with intraoperative neuromonitoring (IONM). METHODS: Two-hundred and ninety patients were randomized into two groups: group A 0.3 mg/kg rocuronium and group B 0.6 mg/kg. Sugammadex 2 mg/kg was injected if needed followed initial vagal stimulation (V0). Electromyography signals from vagus and recurrent laryngeal nerves before and after resection were recorded as V1, V2, R1, and R2. RESULTS: In group B, 30 patients (20.7%) had V0 signals <100 µV, compared to 9 (6.2%) in group A. After sugammadex administration, 144 patients (99.3%) in both groups achieved positive V1 signals. Group B demonstrated a shorter surgical time from rocuronium injection to V2 stimulation compared to group A, accompanied by a significantly lower incidence of intraoperative body movement (0 vs. 16 patients). CONCLUSIONS: 0.6 mg/kg rocuronium with selective use 2 mg/kg sugammadex for IONM in thyroid surgery can meet both anesthesia and surgery demands.

Cost-effectiveness of intraoperative neural monitoring of recurrent laryngeal nerves in thyroid lobectomy for papillary thyroid carcinoma.

Purpose: Recurrent laryngeal nerve injury after thyroid surgery may cause vocal cord palsy (VCP), which leads to unexpected additional costs. In recent years, intraoperative neural monitoring (IONM) has been used to lower the incidence rate of VCP. This study aimed to analyze postoperative management costs for patients with papillary thyroid carcinoma (PTC). Methods: We analyzed the medical records of patients who underwent lobectomy for PTC from September 2018 to August 2019 at The Catholic University of Korea, Seoul St. Mary's Hospital. A total of 411 patients were enrolled and all the patients had voice examinations. We investigated the total costs in the IONM and non-IONM groups during a maximum 1-year follow-up and calculated the additional costs due to VCP by subtraction of the mean values in each group. Results: The incidence rate of VCP was 3.9% (16 of 411). Extrathyroidal extension was related to VCP in Cox regression tests and accounted for 3.2% (13 of 411). VCP rate did not show a significant difference between the IONM and non-IONM groups (4.1% vs. 3.8%, P = 0.883). Total costs for postoperative management were higher in the IONM group than in the non-IONM group (US $328.2 ± $220.1 vs. $278.7 ± $141.4, P < 0.05). However, the additional costs due to VCP were significantly lower in the IONM group than in the non-IONM group ($474.1 ± $150.3 vs. $568.9 ± $367.6, P < 0.005). Conclusion: The use of IONM can mitigate the increase in costs by saving additional expenses associated with VCP.

Evaluation of Intraoperative Neural Monitoring During Thoracoscopic Surgery for Esophageal Cancer.

BACKGROUND/AIM: Recurrent laryngeal nerve paralysis (RLNP) induces aspiration pneumonia and reduces the patient's quality of life. To decrease the incidence of RLNP, we performed intraoperative neural monitoring (IONM) during thoracoscopic surgery for esophageal cancer and evaluated its usefulness. PATIENTS AND METHODS: A total of 737 consecutive patients who underwent thoracoscopic surgery for esophageal cancer were enrolled in this study. Between May 1995 and March 2016, thoracoscopic esophagectomies were performed using video-assisted thoracoscopic surgery (VATS) with a small incision, whereas from April to June 2023, we used positive pressure pneumothorax with port placement only [minimum invasive esophagectomy (MIE)]. A total of 110 consecutive patients who underwent thoracoscopic surgery with IONM (IONM group) were retrospectively compared with those who underwent VATS or MIE without IONM (No-IONM group). RESULTS: The incidence of RLNP [Clavien-Dindo (CD) classification of ≥1] on postoperative day (POD) 5 was 13.9% in the IONM group, which was significantly lower than that of the no-IONM group (31.2%, p<0.001). Even when comparing only patients who underwent MIE, the incidence of RLNP on POD5 was 13.9% in the IONM group, which was significantly lower than that in the no-IONM group (26.2%, p=0.035). The incidence of postoperative pneumonia (CD ≥2) was 10.9% in the IONM group, which was significantly lower than that in the no-IONM group (26.1%, p=0.005). Bilateral RLNP did not occur in any of the IONM groups. CONCLUSION: IONM is a useful tool for reducing RLNP incidence and postoperative pneumonia after thoracoscopic surgery for esophageal cancer.

Outcomes of Surgical Treatment for Graves' Disease: A Single-Center Experience of 216 Cases.

BACKGROUND: The role of surgery in the treatment of Graves' disease (GD) needs to be revisited. The aims of the present retrospective study were to evaluate the outcomes of the current surgical strategy as a definitive treatment of GD at our center and to explore the clinical association between GD and thyroid cancer. METHODS: A patient cohort of 216 cases from 2013 to 2020 was involved in this retrospective study. The data of the clinical characteristics and follow-up results were collected and analyzed. RESULTS: There were 182 female and 34 male patients. The mean age was 43.9 ± 15.0 years old. The mean duration of GD reached 72.2 ± 92.7 months. Of the 216 cases, 211 had been treated with antithyroid drugs (ATDs) and hyperthyroidism had been completely controlled in 198 cases. A total (75%) or near-total (23.6%) thyroidectomy was performed. Intraoperative neural monitoring (IONM) was applied to 37 patients. The failure of ATD therapy (52.3%) was the most common surgical indication, followed by suspicion of a malignant nodule (45.8%). A total of 24 (11.1%) patients had hoarseness after the operation and 15 (6.9%) patients had transient vocal cord paralysis; 3 (1.4%) had this problem permanently. No bilateral RLN paralysis occurred. A total of 45 patients had hypoparathyroidism and 42 of them recovered within 6 months. Sex showed a correlation with hypoparathyroidism through a univariate analysis. A total of 2 (0.9%) patients underwent a reoperation because of hematomas. A total of 104 (48.1%) cases were diagnosed as thyroid cancer. In most cases (72.1%), the malignant nodules were microcarcinomas. A total of 38 patients had a central compartment node metastasis. A lateral lymph node metastasis occurred in 10 patients. Thyroid carcinomas were incidentally discovered in the specimens of 7 cases. The patients with concomitant thyroid cancer had a significant difference in body mass index, duration of GD, gland size, thyrotropin receptor antibodies and nodule(s) detected. CONCLUSION: Surgical treatments for GD were effective, with a relatively low incidence of complications at this high-volume center. Concomitant thyroid cancer is one of the most important surgical indications for GD patients. Careful ultrasonic screening is necessary to exclude the presence of malignancies and to determine the therapeutic plan.

Effects of Endotracheal Tube with Adhesive Superficial Laryngeal Electrodes for Intraoperative Nerve Monitoring on Laryngopharyngeal Complications during Thyroidectomy.

The endotracheal tube (ETT) with laryngeal adhesive electrodes for intraoperative neural monitoring (IONM) may be related to laryngopharyngeal complications, such as postoperative sore throat (POST), hoarseness, and coughing. We aimed to evaluate the effects of the ETT with laryngeal adhesive electrodes for IONM on the occurrence of laryngopharyngeal complications during thyroidectomy. In this retrospective study, we included 176 patients who underwent thyroidectomy for thyroid cancer between September 2020 and February 2021. The patients were categorized into control (n = 108) and IONM (n = 68) groups. Patients in the IONM group were intubated with the ETT with surface electrodes. Characteristics of the patients and surgery, perioperative variables, and laryngopharyngeal complications, including POST, hoarseness, and cough, were evaluated. The severity and incidence of POST were comparable between the two groups on postoperative days 0, 1, and 2 (p = 0.103, 0.386, and 0.056, respectively). Furthermore, no significant differences were observed in the occurrence of postoperative hoarseness and cough between the groups. The ETT with laryngeal adhesive electrodes for IONM during thyroidectomy did not affect the incidence and severity of postoperative laryngopharyngeal complications, including POST, hoarseness, and cough. Further prospective, double-blinded, randomized clinical trials are required to gain a clearer understanding.

Recurrent laryngeal never monitoring versus non-monitoring in parathyroid surgery.

Background: Although intraoperative neural monitoring (IONM) is well established in thyroid surgery, it is less commonly analyzed in parathyroid operations. This study presents the results of IONM for primary and secondary hyperparathyroidism surgery. Methods: We retrospectively assessed 270 patients with primary hyperparathyroidism (PHPT), 53 patients with secondary hyperparathyroidism (SHPT), and 300 patients with thyroid cancer from June 2010 to June 2022 in one hospital in China. The follow-up was 12 months. Demographic, electromyography data from IONM, laboratory, and clinical information were collected. Laryngoscopy was collected from 109 patients with PHPT in whom IONM was not used. All groups were assessed by Pearson's chi-square test and Fisher's exact probability method to verify the relationship between parathyroid size and location, duration of surgery, preoperative concordant localization, laryngeal pain, IONM outcomes, cure rate, and RLN injury. Visual analog scale (VAS) assessed laryngeal pain. RLN outcomes were measured according to nerves at risk (NAR). Results: The study comprehended 918 NAR, that is 272, 105, 109, and 432 NAR for PHPT, SHPT with IONM, PHPT without IONM, and thyroid surgery control group, respectively. IONM successfully prevented RLN injury (P<0.001, P=0.012): Fifteen (5.51%) RLNs experienced altered nerve EMG profiles during surgery, and five (1.84%) experienced transient RLN injury in PHPT patients. Five (4.76%) RLNs were found to have altered EMG profiles during surgery, and one (0.95%) RLN had a transient RLN injury in SHPT patients. There was no permanent nerve injury (0.00%) in this series. There was no association between location, gland size, preoperative concordant localization, cure rate, duration of surgery, and IONM (P >0.05). Duration of surgery was associated with postoperative pharyngeal discomfort (P=0.026, P=0.024). Transient RLN injury was significantly lower in patients with PHPT who underwent IONM than in those who did not. Intraoperative neuromonitoring played an effective role in protecting the recurrent laryngeal nerve (P=0.035). Compared with parathyroidectomy, thyroidectomy had a higher rate of RLN injury (5.32%, P<0.001). Conclusion: IONM for SHPT and PHPT offers rapid anatomical gland identification and RLN functional results for effective RLN protection and reduced RLN damage rates.

Facial nerve monitoring in parotid gland surgery: Design and feasibility assessment of a potential standardized technique.

Background: Even though the use of nerve monitoring during parotid gland surgery is not the gold standard to prevent damage to the nerve, it surely offers some advantages over the traditional approach. Different from thyroid surgery, where a series of steps in intraoperative nerve monitoring have been described to confirm not only the integrity but-most importantly-the function of the recurrent laryngeal nerve, in parotid gland surgery, a formal guideline to follow while dissecting the facial nerve has yet to be described. Methods: A five-year retrospective study was done reviewing the intraoperative records of patients who underwent parotid gland surgery under neural monitoring. The operative findings regarding the neuromonitoring process, particularly in regard to the amplitude of two main branches, were revised. A literature search was done to search for guidelines to follow when a facial nerve loss of signal is encountered. Results: Fifty-five patients were operated on using the Nim 3 Nerve Monitoring System (Medtronic); 31 were female patients, and 47 patients had benign lesions. Minimum changes were observed in the amplitude records after a comparison was made between the first and the last stimulation. There were only three articles discussing the term loss of signal during parotid gland surgery. Conclusion: Today, no sufficient attention has been given to the facial nerve monitoring process during parotidectomy. This study proposes a formal guideline to follow during this procedure as well as an instruction to consider when a loss of signal is observed to develop a uniform technique of facial nerve stimulation.

Intraoperative cricothyroid muscle electromyography may contribute to the monitorization of the external branch of the superior laryngeal nerve during thyroidectomy.

Background: In thyroid surgery, both the recurrent laryngeal nerve (RLN) and external branch of the superior laryngeal nerve (EBSLN) should be preserved for maintaining the vocal cord functions. We aimed to evaluate whether EMG of the CTM applied after the superior pole dissection provided additional informative data to the IONM via ETT or not, regarding the EBSLN function. Methods: The prospectively collected data of the patients, who have undergone thyroidectomy with the use of IONM for the exploration of both the RLN and EBSLN between October 2016 and March 2017, were evaluated retrospectively. Patients over 18 years of age with primary thyroid surgery for malignant or benign thyroid disease, and whom were applied CTM EMG with a needle electrode after the completion of thyroidectomy were included in the study. In the study, each neck side was evaluated as a separate entity considering the EBSLN at risk. Results: The data of 41 patients (32 female, 9 male) (mean age, 46.7 + 9.1; range, 22-71) were evaluated. Sixty seven EBSLNs out of 26 bilateral and 15 unilateral interventions were evaluated. With EBSLN stimulation after the superior pole dissection, positive glottic EMG waveforms via ETT were obtained in 45 (67.2%) out of 67, and the mean glottic amplitude value was 261 + 191 µV (min-max: 116-1086 µV). Positive EMG responses via the CTM EMG were achieved from all of the 67 EBSLNs (100%) with stimulation using a monopolar probe at the most cranial portion above the area of divided superior pole vessels. The mean value of CTM amplitudes via CTM EMG obtained with EBSLN stimulation was 5268 + 3916 µV (min-max:1215 -19726 µV). With EBSLN stimulation, the mean CTM EMG amplitude was detected significantly higher than the mean vocal cord amplitude (p<0.0001). The CTM EMG provided more objective quantifiable data regarding the EBSLN function (100% vs 67,2%, p<0.001). Conclusion: In addition to the IONM via ETT, intraoperative post-dissection CTM EMG via needle electrode is a safe, simple and applicable method that may provide significant additional informative data to IONM with ETT by obtaining and recording objective quantitative data related to the EBSLN function.

Perspective: Triple intraoperative neurophysiological monitoring (IONM) should be considered the standard of care (SOC) for performing cervical surgery for ossification of the posterior longitudinal ligament (OPLL).

Background: Triple Intraoperative Neurophysiological Monitoring (IONM) should be considered the standard of care (SOC) for performing cervical surgery for Ossification of the Posterior Longitudinal Ligament (OPLL). IONM's three modalities and their alerts include; Somatosensory Evoked Potentials (SEP: =/> 50% amplitude loss; =/>10% latency loss), Motor Evoked Potentials (MEP: =/> 70% amplitude loss; =/>10-15% latency loss), and Electromyography (loss of EMG, including active triggered EMG (t-EMG)). Methods: During cervical OPLL operations, the 3 IONM alerts together better detect intraoperative surgical errors, enabling spine surgeons to immediately institute appropriate resuscitative measures and minimize/avoid permanent neurological deficits/injuries. Results: This focused review of the literature regarding cervical OPLL surgery showed that SEP, MEP, and EMG monitoring used together better reduced the incidence of new nerve root (e.g., mostly C5 but including other root palsies), brachial plexus injuries (i.e., usually occurring during operative positioning), and/or spinal cord injuries (i.e., one study of OPLL patients documented a reduced 3.79% incidence of cord deficits utilizing triple IONM vs. a higher 14.06% frequency of neurological injuries occurring without IONM). Conclusions: Triple IONM (i.e., SEP, MEP, and EMG) should be considered the standard of care (SOC) for performing cervical OPLL surgery. However, the positive impact of IONM on OPLL surgical outcomes critically relies on spinal surgeons' immediate response to SEP, MEP, and/or EMG alerts/significant deterioration with appropriate resuscitative measures to limit/avert permanent neurological deficits.

Lymph Node Dissection for Esophageal Squamous Cell Carcinoma.

Lymph node metastasis is one of the most important prognostic factors in esophageal squamous cell carcinoma. However, the optimal extent of lymph node dissection is still under debate. We specifically address several controversies regarding lymph node dissection, for example, recurrent laryngeal node lymphadenectomy, cervical lymphadenectomy, and thoracic duct resection, in esophageal squamous cell carcinoma. We also describe new concepts in surgical anatomy of the upper mediastinum and technologies, for example, near-infrared image-guided lymphatic mapping and intraoperative neural monitoring that facilitate recurrent laryngeal node lymphadenectomy.

Intraoperative Management of the Recurrent Laryngeal Nerve Transected or Invaded by Thyroid Cancer.

Thyroid cancer often invades the recurrent laryngeal nerve (RLN), causing vocal cord paralysis. In such patients, the invaded portion of the RLN usually needs to be resected through curative surgery. We attempt to preserve the nerve by performing sharp dissection in such cases. During nerve dissection, an intraoperative nerve monitoring system helps identify the course of the RLN in the fibrous tissue around the tumor or even within the tumor, and also helps evaluate the nerve integrity. Because of extensive dissection, the preserved RLN may become much thinner than its original thickness. We refer to this procedure as "partial layer resection" of the RLN. In our cases, although the dissected RLNs became thinner, we found that vocal cord function recovered in most patients. If the RLN is fully involved by thyroid cancer or response of the vocal cord against electric stimulation to the RLN is lost, we resect the portion of the RLN together with the tumor and repair it using one of the reconstruction techniques. When a unilateral RLN is resected, the vocal cord on that side is paralyzed. Symptoms include hoarseness, mis-swallowing, and short phonation. RLN reconstruction using one of the reconstruction techniques leads to the recovery of phonatory and swallowing function, although the normal motion of the vocal cord on the side of the anastomosis is not restored. We used direct anastomosis, free nerve grafting, ansa cervicalis-RLN anastomosis, and vagus-RLN anastomosis to reconstruct the RLN. Thyroid cancer often invades the RLN near the Berry's ligament. In such patients, surgeons might assume that reconstruction of the RLN may not be possible because the peripheral stump of the RLN cannot be observed. However, if we divide the inferior pharyngeal constrictor muscles along the lateral edge of the thyroid cartilage, the peripheral RLN can be identified, and nerve reconstruction can be performed. We refer to this procedure as "laryngeal approach".In summary, of the patients with thyroid cancer who required resection of the RLN, RLN reconstruction led to the recovery of phonatory function. We suggest that all thyroid surgeons familiarize themselves with these reconstruction techniques.

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.

Intraoperative recurrent laryngeal nerve monitoring using endotracheal electromyography during parathyroidectomy for secondary hyperparathyroidism.

OBJECTIVE: To investigate the factors associated with adherence of an enlarged parathyroid gland to the recurrent laryngeal nerve (RLN) and the effectiveness of intraoperative neural monitoring (IONM). METHODS: This single-center retrospective study involved samples from 197 consecutive patients (394 RLNs; 733 parathyroid glands) who underwent parathyroidectomy and transcervical thymectomy between September 2010 and December 2014. The presence of parathyroid gland adhesion to the RLN and the clinical characteristics of patients with and without nerve adhesion were recorded. All patients underwent intraoperative monitoring of the electromyographic responses of the vocal cords using the endotracheal NIM-Response 3.0 system. The patients' postoperative clinical outcomes were recorded. RESULTS: Parathyroid gland adhesion to the RLN was significantly associated with maximum gland diameter (>15 mm), weight (>500 mg), and the presence of nodular hyperplasia. IONM demonstrated a sensitivity of 97.8%, specificity of 43.5%, and accuracy of 94.7% for detecting nerve damage. Parathyroid gland adhesion to 17 RLNs occurred in 3 cases (17.6%) of vocal cord paralysis, whereas the 377 glands without nerve adhesion resulted in vocal cord paralysis in 20 cases (5.3%). CONCLUSION: Our findings demonstrated the effectiveness of IONM using endotracheal electromyography in patients who underwent parathyroidectomy for secondary hyperparathyroidism.

Varied Recurrent Laryngeal Nerve Course Is Associated with Increased Risk of Nerve Dysfunction During Thyroidectomy: Results of the Surgical Anatomy of the Recurrent Laryngeal Nerve in Thyroid Surgery Study, an International Multicenter Prospective Anatomic and Electrophysiologic Study of 1000 Monitored Nerves at Risk from the International Neural Monitoring Study Group.

Background: The recurrent laryngeal nerve (RLN) can be injured during thyroid surgery, which can negatively affect a patient's quality of life. The impact of intraoperative anatomic variations of the RLN on nerve injury remains unclear. Objectives of this study were to (1) better understand the detailed surgical anatomic variability of the RLN with a worldwide perspective; (2) establish potential correlates between intraoperative RLN anatomy and electrophysiologic responses; and (3) use the information to minimize complications and assure accurate and safe intraoperative neuromonitoring (IONM). Methods: A large international registry database study with prospectively collected data was conducted through the International Neural Monitoring Study Group (INMSG) evaluating 1000 RLNs at risk during thyroid surgery using a specially designed online data repository. Monitored thyroid surgeries following standardized IONM guidelines were included. Cases with bulky lymphadenopathy, IONM failure, and failed RLN visualization were excluded. Systematic evaluation of the surgical anatomy of the RLN was performed using the International RLN Anatomic Classification System. In cases of loss of signal (LOS), the mechanism of neural injury was identified, and functional evaluation of the vocal cord was performed. Results: A total of 1000 nerves at risk (NARs) were evaluated from 574 patients undergoing thyroid surgery at 17 centers from 12 countries and 5 continents. A higher than expected percentage of nerves followed an abnormal intraoperative trajectory (23%). LOS was identified in 3.5% of NARs, with 34% of LOS nerves following an abnormal intraoperative trajectory. LOS was more likely in cases of abnormal nerve trajectory, fixed splayed or entrapped nerves (including at the ligament of Berry), extensive neural dissection, cases of cancer invasion, or when lateral lymph node dissection was needed. Traction injury was found to be the most common form of RLN injury and to be less recoverable than previous reports. Conclusions: Multicenter international studies enrolling diverse patient populations can help reshape our understanding of surgical anatomy during thyroid surgery. There can be significant variability in the anatomic and intraoperative characteristics of the RLN, which can impact the risk of neural injury.

Optimization of electromyographic endotracheal tube electrode position by UEScope for monitored thyroidectomy.

OBJECTIVE: Proper position of an electromyographic (EMG) endotracheal tube within the larynx plays a key role in functional electrophysiologic intraoperative neural monitoring (IONM) in thyroid surgery. The purpose of this study was to determine the feasibility of a portable video-assisted intubation device (UEScope) to verify the optimal placement of an EMG tube. METHODS: A retrospective study enrolled 40 consecutive patients who underwent monitored thyroidectomies. After positioning the patient for surgery, an anesthesiologist performed tracheal intubation with UEScope and checked the position of the tube at the proper depth without rotation to the vocal cords. The main outcome measured was the proper EMG tube position, free from further adjustment. The secondary outcomes assessed were the percentage of available initial vagal stimulation (V1) signals. RESULTS: All tracheal intubations were successful at first attempt. Proper EMG tube placement without position adjustment was found in 97.5% of the patients. Tube withdrawal was required in a male patient. All patients obtained detectable V1 signals; the lowest and median V1 amplitude was 485 and 767 µV as a reference value, respectively. CONCLUSION: The UEScope is a valuable and reliable tool for placing an EMG tube and confirming its position during monitored thyroidectomy. In addition, further tube adjustment might be waived in most cases when the anesthesiologist placed the EMG tube after patient positioning for surgery. Routine use of video-assisted intubation devices is highly recommended. LEVEL OF EVIDENCE: 4.

Neural Monitoring of the External Branch of the Superior Laryngeal Nerve During Transoral Thyroidectomy.

OBJECTIVES/HYPOTHESIS: There is no study regarding intraoperative neural monitoring (IONM) of the external branch of the superior laryngeal nerve (EBSLN) during transoral thyroidectomy. The objective of this study was to evaluate the feasibility and success rate of electrical identification of the EBSLN during transoral robotic or endoscopic thyroidectomy. STUDY DESIGN: Case series study. METHODS: We studied a cohort of 76 patients (87 nerves at risk, (NARs)) who underwent transoral robotic or endoscopic thyroidectomy and simultaneous intermittent IONM between July 2017 and May 2019. We performed the standard IONM procedure plus routine neural monitoring of the EBSLN. IONM and surgical outcome data were prospectively collected. RESULTS: Sixty-one patients underwent the robotic procedure, and 15 patients underwent the endoscopic procedure. Thirty-seven external branches of the superior laryngeal nerves at risk (42.5%) were electrically identified using electromyography signals (31 NARs, 35.6%) or cricothyroid muscle twitches (6 NARs, 6.9%). The mean pre-(S1) and post-dissection (S2) amplitudes of the EBSLN were 372 ± 147 and 351 ± 159 µV, respectively. The identification rates were not different between the robotic and endoscopic procedures. In comparing the early 20 NARs (18 patients) and the later 67 NARs (58 patients), the identification rate was higher in the later cases, although the difference was not statistically significant (25.0% vs. 47.8%, P = .079). CONCLUSION: IONM of the EBSLN is feasible and useful in identifying and preserving the nerve during transoral thyroidectomy, although the identification rate of the nerve is relatively low. LEVEL OF EVIDENCE: 4 Laryngoscope, 131:E671-E676, 2021.