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

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.

Patient-reported swallowing outcomes after transoral robotic thyroidectomy: Comparison with conventional transcervical thyroidectomy

BACKGROUND

This study aimed to evaluate the swallowing outcomes after transoral robotic thyroidectomy (TORT) and compare them with those of conventional transcervical thyroidectomy.

METHOD

We enrolled 146 patients who underwent thyroidectomy (73 TORT; 73 conventional approach). We prospectively analyzed swallowing outcomes using the Swallowing Impairment Index-6 (SIS-6) questionnaire, a patient-reported measure, before and 1, 3, and 6 days; 1, 3, and 6 months; and 1 year after surgery. Propensity score-matched analysis was performed using three covariates: age, sex, and extent of thyroidectomy.

RESULTS

SIS-6 scores worsened significantly immediately after surgery and progressively recovered 1 year postoperatively in both groups. Propensity score matching generated two matched groups of 22 patients each. In the propensity score-matched samples, the SIS-6 scores did not differ between the TORT and conventional groups, except at 1 day postoperatively.

CONCLUSION

Patient-reported swallowing outcomes of TORT were comparable to those of the conventional transcervical procedure.

Complication and conversion outcomes in transoral endoscopic thyroidectomy vestibular approach (TOETVA): a retrospective multicenter propensity score-matched cohort study

Transoral endoscopic thyroidectomy with vestibular approach (TOETVA) is a scarless thyroid surgery used as an alternative to open conventional surgery. Our aim was to investigate possible risk factors for complications and conversion during TOETVA. The study was conducted internationally by centres from Turkiye, the Republic of Korea, Italy, and Peru. A total of 406 patients who underwent TOETVA and were ≥ 18 years of age were included in the study. Demographic, pre-, intra-, and postoperative data were collected and compared between the groups with/without complication/conversion to identify possible predictors of complication/conversion. Subsequently, patients with complication/conversion were matched by the hospital, age, sex, and American Society of Anesthesiologists classification score using a propensity score (PSM) of 1:3 to eliminate confounding differences. Results were reported for the un-matched and matched groups. Complications occurred in 11 (2.7%) patients. High body mass index (26.4 ± 3.4 vs. 23.3 ± 3.7, p = 0.007), larger tumor size (1.7 ± 1.3 cm. vs. 1.1 ± 1.0 cm, p = 0.012), larger thyroid volume (20.0 ± 9.2 vs. 12.8 ± 8.5, p = 0.007) and long operation time (127.8 ± 45.0 min. vs. 97.7 ± 38.5 min., p = 0.008) were significantly associated with complications in un-matched analyses. Older age (42.7 ± 8.0 vs. 34.9 ± 9.2, p = 0.023), high BMI (26.7 ± 3.2 vs. 23.3 ± 3.7, p = 0.012), and longer operation time (160.1 ± 54.1 min. vs. 97.4 ± 37.8, p = 0.001) were significantly related to conversion in un-matched analyses. However, significance was lost after PSM for both complication and conversion. The data from this study conducted on TOETVA cases do not suggest a risk factor for complications and conversion with PSM.

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.

Initial Clinical Application of Enhanced Recovery After Transoral Robotic Thyroidectomy

Background: The enhanced recovery after surgery (ERAS) protocol has been widely adopted across various surgical subspecialties. Transoral robotic thyroidectomy (TORT) has grown in popularity in the past decade. Therefore, this study aimed to discuss the initial application of ERAS in TORT. Methods: We retrospectively analyzed the clinical data of 95 patients who had undergone TORT in our department from April 2020 to March 2022. All patients were treated using the ERAS protocol. Results: TORT was successfully performed in all 95 patients. Postoperative histopathological examination revealed papillary carcinoma. The average operative time, hemorrhage volume, length of postoperative stay, and pain score (24 hours after surgery) were 227.32 ± 44.37 minutes, 35.81 ± 23.45 mL, 1.37 ± 0.62 days, and 2.11 ± 0.54, respectively. Sixty patients received an analgesia pump, with no significant difference in pain scores between the patients with and without the pump (P > .05). Eight patients experienced transient mandibular numbness, and two experienced transient hoarseness postoperatively. Of the 24 cases of total thyroidectomy/bilateral subtotal thyroidectomy (ST) or lobectomy with isthmusectomy plus contralateral ST patients, 8 developed transient hypoparathyroidism. No common complications, such as incision infection, hematoma/effusion formation, coughing while drinking, or permanent hoarseness/hypocalcemia, were reported. Conclusion: Our initial outcomes demonstrate that implementing an ERAS protocol in TORT is safe and feasible.

Comparison of Different Mandibular Jawlines Classifications on Transoral Endoscopic Thyroidectomy for Papillary Thyroid Carcinoma: Experiences of 690 Cases

BACKGROUND

The influences of patients' different mandibular jawlines on transoral endoscopic thyroidectomy via vestibular approach (TOETVA) have not been described before. The objective of this study was to introduce a new classification to assess different mandibular jawlines, and to evaluate the effects on TOETVA in terms of safety, feasibility, and postoperative feelings in the treatment of papillary thyroid carcinoma (PTC).

METHODS

The crossing angle of esthetic plane and mandibular plane was defined as Wang Angle, used to assess patients' different mandibular jawlines. Mandibular classifications of A (angle: 80° ~ 110°), B (angle > 110°), and C (angle < 80°) types were compared to evaluate the surgical outcomes of TOETVA by a retrospective study. 690 patients of PTC who received TOETVA were included in this study, which were divided into three groups according to mandibular classifications.

RESULTS

Clinicopathological characteristics of the patients including age, gender, body mass index, tumor size, Hashimoto thyroiditis were similar in the three groups. Patients' length of jay in group C was significantly longer than group A and group B (P < 0.01). The ratios of using suspension system in group C were significantly higher than group A and group B (P < 0.01). The scores of postoperative visual analogue scale (VAS) and ratios of mandibular swell in group C were significantly higher than group A and group B (P < 0.01). There was no significant difference in the three groups regarding surgical outcomes, including postoperative vocal cord paralysis, hypocalcemia, serum white blood cells and C-reactive protein levels.

CONCLUSIONS

The Wang angle and mandibular jawline classifications were firstly introduced in TOETVA. All the patients of class A, B, and C mandibular jawline can achieve safe and effective surgical outcomes in the treatment of PTC with TOETVA. Patients of class C need more assistance of suspension system, would experience higher scores of VAS, and higher ratios of mandibular swell compared with class A and B.

Success rate and learning curve of intraoperative neural monitoring of the external branch of the superior laryngeal nerve in thyroidectomy

BACKGROUND

This study aimed to evaluate the success rate and learning curve of intraoperative neural monitoring (IONM) of the external branch of the superior laryngeal nerve (EBSLN) in thyroidectomy.

METHODS

We studied 130 consecutive patients (200 nerves at risk [NARs]) who had undergone conventional thyroidectomy with IONM of the recurrent laryngeal nerve (RLN) and EBSLN from January 2017 to March 2020. The learning curve was defined as the number of NARs required to achieve an effective and reliable neuromonitoring rate.

RESULTS

IONM of the EBSLN was successful in 136/200 (68%) NARs. The cutoff point of the learning curve was 45 NARs (28 patients). The neural identification rate of EBSLN was significantly higher in the post-learning 155 NARs group than the pre-learning group (82.6% vs. 17.8%, p < 0.001).

CONCLUSIONS

Approximately 45 NAR neuromonitoring attempts were required to reach a significant increase in the EBSLN identification rate and overcome the learning curve.

Informed Consent for Intraoperative Neural Monitoring in Thyroid and Parathyroid Surgery - Consensus Statement of the International Neural Monitoring Study Group

In the past decade, the use of intraoperative neural monitoring (IONM) in thyroid and parathyroid surgery has been widely accepted by surgeons as a useful technology for improving laryngeal nerve identification and voice outcomes, facilitating neurophysiological research, educating and training surgeons, and reducing surgical complications and malpractice litigation. Informing patients about IONM is not only good practice and helpful in promoting the efficient use of IONM resources but is indispensable for effective shared decision making between the patient and surgeon. The International Neural Monitoring Study Group (INMSG) feels complete discussion of IONM in the preoperative planning and patient consent process is important in all patients undergoing thyroid and parathyroid surgery. The purpose of this publication is to evaluate the impact of IONM on the informed consent process before thyroid and parathyroid surgery and to review the current INMSG consensus on evidence-based consent. The objective of this consensus statement, which outlines general and specific considerations as well as recommended criteria for informed consent for the use of IONM, is to assist surgeons and patients in the processes of informed consent and shared decision making before thyroid and parathyroid surgery.

Complications of Transoral Thyroidectomy: Overview and Update

Transoral thyroidectomy via the vestibular approach has become popular worldwide, with advantages including less surgical morbidity, excellent postoperative cosmesis, and superior functional voice outcomes. Several studies have reported that the surgical outcomes of the transoral approach were comparable to those of the conventional transcervical approach in selected patients. However, unusual complications, such as CO2 embolism, mental nerve injury, surgical space infection, skin perforation, burns, and trauma have been noted in transoral thyroidectomy. This paper aims to review and provide updated information on these complications and their management. Routine intraoperative neural monitoring is required to avoid laryngeal nerve palsy in the transoral approach. To prevent CO2 embolism, surgeons need to be careful not to injure the anterior jugular vein, and the CO2 insufflation pressure should be set as low as 4-6 mmHg. To avoid mental nerve injury, vestibular incisions should be placed in the safety zone, and dissection of the vestibular area and chin should be minimized. In conclusion, recognizing the possibility of complications and understanding their prevention and management are important for patient safety and the success of the transoral approach.

Transoral Thyroidectomy: Advantages and Disadvantages

To date, many remote-access thyroid surgery techniques using endoscopic or robotic instruments have been developed. Transoral thyroidectomy has attracted great attention as a scarless thyroidectomy and is performed worldwide. Each surgical method has its advantages and disadvantages: selecting the optimal surgical method according to each patient's condition and preferences will possibly result in obtaining the best results and achieving patient satisfaction while minimizing complications after surgery.