Factors of postoperative recurrent laryngeal nerve paralysis and recovery of vocal cord movement in thyroid surgery.

OBJECTIVE: Postoperative recurrent laryngeal nerve paralysis is one of the complications of thyroid surgery, and the prevention and management of paralysis is an important issue for surgeons. In this study, in order to gain further understanding of recurrent laryngeal nerve paralysis after thyroid surgery, we analyzed and examined the usefulness of nerve stimulators for recurrent laryngeal nerve paralysis and the factors that may cause recurrent laryngeal nerve paralysis. Furthermore, in cases where transient recurrent laryngeal nerve paralysis occurred, we analyzed and examined the timing of improvement in vocal cord movement for each intraoperative finding and intraoperative operation that caused the paralysis. METHODS: At the Department of Otorhinolaryngology Head and Neck Surgery, Sapporo Medical University Hospital, between January 2012 and December 2021, the subjects were 543 thyroid surgery cases (692 nerves) without preoperative paralysis or cancer nerve invasion performed. The relationship between postoperative transient and permanent paralysis of the recurrent laryngeal nerve was evaluated using univariate and multivariate analysis. The factors evaluated were gender, age, BMI, total thyroidectomy, benignity, malignancy, Graves' disease, using IIONM (intermittent intraoperative nerve monitoring), using CIONM (continuous intraoperative nerve monitoring), malignant tumor T3b or higher, with lateral neck dissection, and years of experience of the surgeon. Furthermore, by targeting 87 nerves with transient paralysis, surgical operations were divided into three groups: minor injury, major injury, and adhesion, and their relationship with the timing of postoperative vocal fold movement improvement was evaluated. RESULTS: Permanent paralysis of the recurrent laryngeal nerve occurred in 12 nerves (1.7 %), and transient paralysis occurred in 100 nerves (14.5 %). Univariate analysis showed no association with each factor, but multivariate analysis showed that transient paralysis was significantly lower in men and in patients using IIONM. The improvement time for vocal cord paralysis was 2.8 months in the minor injury group, 4.5 months in the major injury group, and 3.2 months in the adhesion group, indicating a statistically significant difference between the minor injury group and the major injury group. CONCLUSION: This study suggests that the use of IIONM and gentle manipulation of women may prevent recurrent laryngeal nerve paralysis during thyroid surgery. In addition, understanding the period of nerve recovery for each operation for postoperative transient recurrent laryngeal nerve paralysis may contribute to patient explanations and determining the timing of therapeutic intervention for speech improvement surgery.

Outcomes of Immediate Total Thyroidectomy in First-Side Loss of Neuromonitoring Signal.

Importance: Use of intraoperative neuromonitoring (IONM) during thyroidectomy can nearly eliminate the risk of postoperative bilateral vocal cord palsy (VCP) by indicating staged surgery in cases of loss of signal (LOS) on the first side of planned total thyroidectomy. However, aborting planned total thyroidectomy may lead to persistence of symptoms, delay in adjuvant treatment, and patient inconvenience and distress. There are few data to guide a selective approach to total thyroidectomy in patients with first-side LOS. Objective: To investigate outcomes of immediate bilateral surgery in patients undergoing total thyroidectomy with first-side LOS. Design, Setting, and Participants: This cohort study was a retrospective review of outcomes for patients undergoing thyroidectomy between January 2016 and July 2023 at an academic tertiary referral center for thyroid surgery. Consecutive patients scheduled for total thyroidectomy using IONM were included. Exclusion criteria were preoperative VCP, deliberate sacrifice of recurrent laryngeal nerve (RLN), inadvertent RLN resection, and surgery performed without IONM. Exposures: Total thyroidectomy performed using IONM. Main Outcome Measures: Vocal mobility on first postoperative day as assessed by flexible laryngoscopy; secondary outcome measures included subjective voice assessment, other postoperative complications, and long-term vocal mobility. Results: Among 400 patients undergoing planned total thyroidectomy (mean age, 50.5 years [range, 4-88 years]; 318 female [79.5%]), 51 (12.8%) had first-side LOS, of whom 37 (9.3%) had persistent LOS. Twenty-nine patients (56% of procedures with first-side LOS, including 18 with persistent LOS) proceeded to immediate total thyroidectomy. Postoperatively, 16 patients (55% of patients undergoing total thyroidectomy following first-side LOS, including 14 of 18 with persistent LOS) had impaired vocal mobility. One patient had bilateral VCP that did not require tracheostomy, and 2 had postoperative hypoparathyroidism. Of those whose surgery was aborted after first-side LOS, 8 of 22 (36%) underwent completion thyroidectomy at a later stage. In those undergoing completion thyroidectomy, 2 of 8 (25%) had temporary VCP after the second surgery, 2 (25%) had permanent hypoparathyroidism, and 1 (12.5%) developed inoperable cancer. Postoperative VCP was fully reversible in all but 1 patient. Conclusion and Relevance: Among patients planned for total thyroidectomy who develop first-side LOS, immediate total thyroidectomy may be considered among those who have pressing reasons for same, and where surgical difficulties might be anticipated in a secondary surgery.

Routine use of intraoperative nerve monitoring is associated with a reduced risk of vocal cord dysfunction after thyroid cancer surgery.

BACKGROUND: The aim of this study was to investigate the associations between individual surgeon's intraoperative nerve monitoring (IONM) practice and factors associated with vocal cord (VC) dysfunction in patients with thyroid cancer undergoing thyroidectomy. METHODS: Using Collaborative Endocrine Surgery Quality Improvement Program (CESQIP) 2014-21 data, multivariable logistic regression analyses investigated variables associated with short- and long-term VC-dysfunction, associations of routine use of IONM with postoperative outcomes, and patient characteristics associated with IONM use. RESULTS: Among 5,446 patients (76.7% female, mean age 49 years), 68.5% had surgery by surgeons using IONM in ≥ 90% of cases (63% of surgeons, n = 73). Post-operative VC-dysfunction was diagnosed by laryngoscopy in 3.0% of patients in the short-term and 2.7% in the long-term. When surgeons routinely used IONM, the incidence of VC-dysfunction was 2.4% in the short-term and 2.2% in the long-term, compared to 4.4% and 3.7%, respectively, when surgeons did not routinely use IONM (p < 0.01). After adjustment, routine use of IONM was independently associated with reduced risk of short- (OR 0.48, p < 0.01) and long-term (OR 0.52, p < 0.01) VC-dysfunction, a lower risk of postoperative hypoparathyroidism in the short- (OR 0.67, p < 0.01) and long-term (OR 0.54, p < 0.01), and higher likelihood of same-day discharge (OR 2.03, p < 0.01). Extrathyroidal tumor extension and N1-stage were factors associated with postoperative VC-dysfunction in the short- (OR 3.12, p < 0.01; OR 1.92, p = 0.01, respectively) and long-term (OR 3.11, p < 0.01; OR 2.32, p < 0.01, respectively). CONCLUSION: Routine use of IONM was independently associated with a lower risk of endocrine surgery-specific complications and greater likelihood of same-day discharge.

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.

Effectiveness of the recurrent laryngeal nerve monitoring during endoscopic thyroid surgery: systematic review and meta-analysis.

BACKGROUND: Thyroid disease is a common endocrine disorder, and thyroid surgeries and postoperative complications have increased recently. This study aimed to explore the effectiveness of intraoperative nerve monitoring (IONM) in endoscopic thyroid surgery using subgroup analysis and determine confounding factors. MATERIALS AND METHODS: Two researchers individually searched for relevant studies published till November 2022 in the PubMed, Embase, Web of Science and Cochrane Library databases. Eventually, eight studies met the inclusion criteria. Heterogeneity was assessed using the Cochran's Q test, and a funnel plot was implemented to evaluate publication bias. The odds ratio or risk difference were calculated using fixed-effects models. The weighted mean difference of continuous variables was calculated. Subgroup analysis was performed according to the disease type. RESULTS: Eight eligible papers included 915 patients and 1242 exposed nerves. The frequencies of transient, permanent and total recurrent laryngeal nerve (RLN) palsy were 2.64, 0.19 and 2.83%, respectively, in the IONM group and 6.15, 0.75 and 6.90%, respectively, in the conventional exposure group. In addition, analysis of the secondary outcome indicators for the average total length of surgery, localisation time of the RLN, recognition rate of the superior laryngeal nerve and length of incision revealed that IONM reduced the localisation time of the RLN and increased the identification rate of the superior laryngeal nerve. Subgroup analysis showed that IONM significantly reduced the incidence of RLN palsy in patients with malignancies. CONCLUSIONS: The use of IONM significantly reduced the incidence of transient RLN palsy during endoscopic thyroid surgery, but it did not significantly reduce the incidence of permanent RLN palsy. However, the reduction in the total RLN palsy was statistically significant. In addition, IONM can effectively reduce the location time of the RLN and increase the recognition rate of the superior laryngeal nerve. Therefore, the application of IONM for malignant tumours is recommended.

Utility of the continuous intraoperative neuromonitoring in the prevention of the recurrent laryngeal nerve paralysis during thyroid surgery. A prospective observational study / Utilidad de la neuromonitorización continua intraoperatoria en la prevención de la parálisis del nervio laríngeo recurrente durante la cirugía tiroidea. Un estudio observacional prospectivo

Background: The continuous intraoperative neuromonitoring (C-IONM) of the recurrent laryngeal nerve (RLN) could help reducing the incidence of nerve paralysis after thyroid surgery, in comparison with the mere anatomical visualization of the RLN. The objective is to assess the efficacy and utility of C-IONM as a predictive test for recurrent laryngeal nerve paralysis after thyroidectomy. Methods: A prospective observational study was performed in 248 patients who underwent thyroid surgery where C-IONM was applied, between September 2018 and December 2019, in a high-volume center. A previous and later laryngoscopy was performed, which allowed to evaluate the reliability of the C-IONM as a predictive test for recurrent paralysis. Sensitivity (SE), specificity (SP), positive predictive value (PPV), negative predictive value (NPV) were studied. Results: A total number of 171 thyroidectomies, 62 hemithyroidectomies, 15 totalization thyroidectomies and 27 thyroidectomy with cervical dissections were performed. Postoperative laryngoscopy was altered in 40 patients (16.12%). The SE, SP, PPV and NPV values ​​were 65%, 94.7%, 70.2% and 93.4% respectively. Conclusions: C-IONM is a safe technique that provides real-time information about anatomical and functional integrity of the RLN and can improve the results of thyroid surgery. (AU)

Introducción: La neuromonitorización continua intraoperatoria (C-IONM) del nervio laríngeo recurrente (RLN) puede contribuir a la reducción de la incidencia de parálisis nerviosa tras una cirugía tiroidea, en comparación con la mera visualización anatómica del RLN. El objetivo de este estudio es evaluar la fiabilidad de la NCIO de los nervios laríngeos recurrentes como prueba predictora de parálisis vocal postoperatoria. Material y métodos: Se trata de un estudio observacional prospectivo realizado en 248 pacientes intervenidos de patología tiroidea en los que se aplicó la C-IONM, entre Septiembre de 2018 y Diciembre de 2019 en un único centro de alto volumen. Se realizó una laringoscopia pre y post operatoria a todos los pacientes, lo que pudo determinar la fiabilidad de la C-IONM como test predictivo de la parálisis recurrencial tras cirugía tiroidea. Se hallaron los valores de sensibilidad (SE), especificidad (SP), valor predictivo positivo (PPV) y valor predictivo negativo (NPV) de dicha técnica. Resultados: Se realizaron un total de 171 tiroidectomías totales, 62 hemitiroidectomías, 15 tiroidectomías de totalización y 27 tiroidectomías con disección cervical. Se hallaron alteraciones en la laringoscopia postoperatoria en 40 pacientes (16,12%). Los valores de SE, SP, PPV y NPV fueron 65%, 94.7%, 70.2% y 93.4% respectivamente. Conclusiones: La C-IONM es una técnica segura que ofrece información anatómica y funcional del NLR en tiempo real y puede contribuir a mejorar los resultados de la cirugía tiroidea. (AU)

Utility of the continuous intraoperative neuromonitoring in the prevention of the recurrent laryngeal nerve paralysis during thyroid surgery. A prospective observational study.

BACKGROUND: The continuous intraoperative neuromonitoring (C-IONM) of the recurrent laryngeal nerve (RLN) could help reducing the incidence of nerve paralysis after thyroid surgery, in comparison with the mere anatomical visualization of the RLN. The objective is to assess the efficacy and utility of C-IONM as a predictive test for recurrent laryngeal nerve paralysis after thyroidectomy. METHODS: A prospective observational study was performed in 248 patients who underwent thyroid surgery where C-IONM was applied, between September 2018 and December 2019, in a high-volume center. A previous and later laryngoscopy was performed, which allowed to evaluate the reliability of the C-IONM as a predictive test for recurrent paralysis. Sensitivity (SE), specificity (SP), positive predictive value (PPV), negative predictive value (NPV) were studied. RESULTS: A total number of 171 thyroidectomies, 62 hemithyroidectomies, 15 totalization thyroidectomies and 27 thyroidectomy with cervical dissections were performed. Postoperative laryngoscopy was altered in 40 patients (16.12%). The SE, SP, PPV and NPV values ​​were 65%, 94.7%, 70.2% and 93.4% respectively. CONCLUSIONS: C-IONM is a safe technique that provides real-time information about anatomical and functional integrity of the RLN and can improve the results of thyroid surgery.

Intraoperative Neuromonitoring and Optical Magnification in the Prevention of Recurrent Laryngeal Nerve Injuries during Total Thyroidectomy.

Background and Objectives: Recurrent laryngeal nerve (RLN) paralysis is a fearful complication during thyroidectomy. Intraoperative neuromonitoring (IONM) and optical magnification (OM) facilitate RLN identification and dissection. The purpose of our study was to evaluate the influence of the two techniques on the incidence of RLN paralysis and determine correlations regarding common outcomes in thyroid surgery. Materials and Methods: Two equally sized groups of 50 patients who underwent total thyroidectomies were examined. In the first group (OM), only surgical binocular loupes (2.5×−4.5×) were used during surgery, while in the second group (IONM), the intermittent NIM was applied. Results: Both the operative time and the length of hospitalization were shorter in the OM group than in the IONM group (median 80 versus 100 min and median 2 versus 4 days, respectively) (p < 0.05). The male patients were found to have a five-fold higher risk of developing transient dysphonia than the females (adjusted OR 5.19, 95% IC 0.99−27.18, p = 0.05). The OM group reported a four-fold higher risk of developing transient hypocalcemia than the IONM group (OR 3.78, adjusted OR 4.11, p = 0.01). Despite two cases of temporary bilateral RLN paralysis in the IONM group versus none in the OM group, no statistically significant difference was found (p > 0.05). No permanent RLN paralysis or hypoparathyroidism have been reported. Conclusions: Despite some limitations, our study is the first to compare the use of IONM with OM alone in the prevention of RLN injuries. The risk of recurrent complications remains comparable and both techniques can be considered valid instruments, especially if applied simultaneously by surgeons.

Continuous vagal intraoperative neuromonitoring during video-assisted thoracoscopic surgery for left lung cancer: its efficacy in preventing permanent vocal cord paralysis.

OBJECTIVES: We investigated the safety and efficacy of continuous intraoperative neuromonitoring (CIONM) during video-assisted thoracoscopic lobectomy for left lung cancer in preventing recurrent laryngeal nerve injury. METHODS: From August 2015 to March 2020, 22 patients with left lung cancer without CIONM (unmonitored) and 20 patients with left lung cancer with CIONM underwent thoracoscopic lobectomy with complete mediastinal lymph node dissection including 4L dissection. Clinical outcomes from these 2 groups were compared. RESULTS: The incidence of 4L metastasis was 7.14% (3 patients). There was no significant difference in the total number of dissected 4L lymph nodes between the 2 groups (3.23 ± 2.2 in the unmonitored group, 3.95 ± 2.0 in the CIONM group). CIONM was successful in all of the cases. There was no significant difference in the incidence of postoperative vocal cord palsy (22.7% in the unmonitored group, 20% in the CIONM group, P = 1.000). All of the 5 patients (100%) had permanent vocal cord palsy in the unmonitored group. Although statistically insignificant, 75% (3 patients) had total recovery of the vocal cord function, with only 1 patient remaining in permanent vocal cord palsy in the CIONM group. CONCLUSIONS: CIONM was safe and efficient. CIONM might be helpful to avoid permanent vocal cord palsy by immediately warning the surgeon about impending nerve injury, so the surgeon can stop delivering further injury to the recurrent laryngeal nerve.

Continuous Recurrent Laryngeal Nerve Monitoring During Single-Port Mediastinoscopic Radical Esophagectomy for Esophageal Cancer.

BACKGROUND: Although single-port mediastinoscopic radical esophagectomy is ultimate minimally invasive surgery for esophageal cancer without thoracotomy or the thoracoscopic approach, the high incidence of recurrent laryngeal nerve (RLN) palsy remains a pivotal clinical issue. METHODS: This study included 41 patients who underwent single-port mediastinoscopic radical esophagectomy with mediastinal lymphadenectomy between September 2014 and March 2022. Among these, continuous nerve monitoring (CNM) for RLN was done in 25 patients (CNM group), while the remaining 16 patients underwent without CNM (non-CNM group). Clinical benefits of CNM for RLN were evaluated. RESULTS: The overall incidence of postoperative RLN palsy was 14.6% (6/41). The CNM group showed a significantly lower incidence of postoperative RLN palsy as compared to the non-CNM group (P = 0.026: CNM vs. non-CRNM: 4.0% (1/25) vs. 31.2% (5/16)). The CNM group had a lower incidence of postoperative pneumoniae (CNM vs. non-CNM: 4.0% (1/25) vs. 18.8% (3/16)) and shorter days of postoperative hospital stay (CNM vs. non-CNM: 13 days vs. 41 days). Multivariate analysis revealed that the CNM use (odds ratio 0.07; 95% CI 0.05-0.98) was an independent factor avoiding postoperative RLN palsy. CONCLUSION: The CNM for RLN contributes to a remarkable reduction in the risk of postoperative RLN palsy and improvement in outcomes in single-port mediastinoscopic radical esophagectomy.

Recurrent Laryngeal Nerve with Loss of Signal During Monitored Thyroidectomy: Percentage Reduction in Sum of the Amplitude of Left and Right Channel.

PURPOSE: The prognostication for the injured recurrent laryngeal nerve (RLN) with incomplete loss of signal (LOS) and its function outcome have not been well unified. A warning criterion was proposed to predict RLN injury during monitored thyroidectomy. METHODS: A retrospective review of prospectively collected data from consecutive 357 patients with 560 nerves at risk was conducted. Vocal cords mobility with laryngoscope was performed preoperatively, on the second day, and once a month postoperatively until complete recovery. Different cutoff values of the percentage reduction in sum of the amplitude of left and right channel at the end of the surgery, for postoperative vocal cord paralysis (VCP) prediction were compared. RESULTS: Percentage reduction in sum of the amplitude of left and right channel at the end of operation ranged from 30.2 to 63.6% in 27 nerves with incomplete LOS (absolute amplitude value of final R2 > 100 µV with reduction > 50% of R1). Seven (1.25%) nerves experienced transient postoperative VCP, in which one nerve with postoperative VCP showed no amplitude reduction. The positive predictive value of VCP for the sum amplitude reduction exceeding 30, 40, 50, and 60% was 22.2, 40, 85.7, and 100%, respectively. Accuracy was 96.1, 98.2, 99.6, 99.4%, respectively. CONCLUSION: Percentage reduction in sum of the amplitude of left and right channel is a meaningful method to improve the accuracy of VCP prediction. When the sum amplitude reduction ≥ 50%, surgeons should consider the possibility of postoperative VCP and correct some surgical maneuvers.

An atypical bilateral trifurcation of recurrent laryngeal nerve.

BACKGROUND: Thyroidectomy is a frequently performed surgery for benign and malignant conditions. Nevertheless, one of the most critical complications of thyroidectomy is recurrent laryngeal nerve (RLN) injury leading to vocal cord paralysis. A thorough knowledge of the anatomical variations of RLN and ligation of the related vessels close to their distal branches is critical to avoid injury. CASE PRESENTATION: Here, we report the first case of bilateral trifurcation of recurrent laryngeal nerve (RLN) in a 40-year old woman with multinodular goitre. Total thyroidectomy was performed and RLN was preserved bilaterally. Followed by a precise dissection, fine branches were traced penetrating the larynx. We did not observe any further post-operative complications and patient was discharged with desired outcomes. CONCLUSIONS: Anatomical variations of the RLN include-bifurcations, trifurcations, relation of RLN with inferior thyroid artery (ITA) and presence of non-recurrent laryngeal nerve. Only RLN dividing at a distance greater than 5 mm (branching point distance) before its entry into the larynx beneath the cricothyroid are said to bifurcate or trifurcate. Approximately 25% of nerves show branching [71%-unilateral and 18%-bilateral bifurcation]. Incidence of unilateral trifurcations have been noted be 0.9% and the rates of bilateral trifurcation and the divisions of the branches is yet to be ascertained. This is the first report of a bilateral trifurcation of RLN, detected in patient with multinodular goitre and hence warrants a precise analysis of variations of the RLN in patients undergoing thyroidectomy, which is critical to prevent RLN injury.

Selective laryngoscopy before thyroidectomy: a risk assessment.

BACKGROUND: Patients presenting for thyroidectomy may have an unrecognized pre-existing vocal cord palsy (VCP). This raises the danger of bilateral VCP if a patient sustains an injury to the RLN on the sole functioning side. Part of the rationale for routine preoperative laryngoscopy is to eliminate such a risk. This paper endeavours to quantify the relevant potential risk. METHODS: Patients who underwent laryngoscopy prior to thyroid or parathyroid surgery in an endocrine surgical unit over a 5 year period were identified. Literature review revealed four papers in which VCP prevalence in patients without risk factors was reported. Using our data, combined with that of these other authors, the background rate of pre-existing VCP was ascertained, and the subsequent risk of bilateral VCP estimated. RESULTS: Of our 632 patients who underwent preoperative laryngoscopy, there were four patients (0.63%) who were found to have a unilateral VCP, but all had voice symptoms or previous neck surgery. When patients with these risk factors are excluded, our data combined with the published data provides a pre-existing VCP rate of 0.2%. Calculations estimate that if preoperative laryngoscopy is omitted in patients with no risk factors, the risk of bilateral VCP, due to the nerve on the sole functioning side being injured, would be between 1/50000 and 1/150000, depending on an individual surgeon's level of experience. CONCLUSION: Selective use of laryngoscopy prior to thyroidectomy would result in an acceptably low statistical risk of bilateral VCP. Routine laryngoscopy for all patients is not necessary.

The learning curve and safety of continuous intraoperative vagus nerve monitoring in thyroid surgery.

INTRODUCTION: Continuous intraoperative nerve monitoring allows for continuous feedback on the integrity of the recurrent laryngeal nerve (RLN) and the quality of its induced myogenic potential. The aims of this study were to assess the time requirements and risks associated with vagus nerve electrode placement when learning the technique. METHODS: This is a prospective observational study carried out in a single otolaryngology department at the start of a trainee's placement. A total of 40 vagus nerve dissections in 31 consecutive operations (22 hemithyroidectomies, 9 total thyroidectomies) using automatic periodic stimulation (APS, Medtronic) are included. Of the electrode placements, 10 were performed by the trainer and 30 by the trainee. The time required for each surgical step and complications relating to vagus nerve dissection were recorded. RESULTS: The average (median+IQR) total additional time attributable to vagus nerve dissection, electrode placement and baseline electromyogenic assessment was 3.1mins (2.5-3.3) for the trainer and 4.8mins (4.1-5.3) for the trainee (p<0.0001). There was a downward trend in time requirement for the trainee (not statistically significant, p=0.080). Total operative time was 38min (35-45) for hemithyroidectomy and 56min (53-62) for total thyroidectomy. There was a mix of benign (74%) and malignant (26%) histology, no intraoperative complications relating to autonomic dysfunction and one (2.5%) transient nerve palsy. CONCLUSIONS: Operative time attributable to vagus nerve electrode placement is short and the procedure is easy to learn. Appropriate surgical technique and careful anaesthetic considerations allow monitoring to be performed safely, and may reduce the rate of RLN palsy.

Transcutaneous Laryngeal Ultrasonography for Assessing Vocal Cord Twitch Response in Thyroid Operation during Predissection Vagus Nerve Stimulation.

BACKGROUND: In this study, we aimed to report our experience with the use of intraoperative transcutaneous laryngeal ultrasonography (TLUSG) to evaluate the vocal cord twitch response during predissection vagus nerve stimulation in thyroid surgeries and examine the reliability of this technique when compared with that of laryngeal twitch palpation (LTP). STUDY DESIGN: The prospective data collection of consecutive patients who underwent open thyroidectomy with intraoperative neuromonitoring (IONM) was reviewed retrospectively. We recorded the electromyographic activity and assessed the vocal cord twitch response on LTP, TLUSG. We compared the accessibility, sensitivity, and specificity of the techniques. RESULTS: A total of 110 patients (38 men and 72 women) with 134 nerves at risk were enrolled. The vocal cord was assessable by TLUSG in 103 (93.6%) patients and by LTP in 64 (59.1%) patients. Two patients showed negative predissection IONM signal but positive on TLUSG and the presence of laryngeal twitch response confirmed by laryngoscopy. Fourteen patients showed positive IONM signals and presence of the vocal cord twitch response on TLUSG but not on LTP. The sensitivity and specificity were 70.21% and 100%, respectively, for LTP, and those both were 100% for TLUSG. For patients who could be assessed using both techniques, TLUSG had better accuracy than LTP (100% vs 80.33%, p = 0.0005). CONCLUSIONS: The innovative intraoperative application of TLUSG is better for evaluating the laryngeal twitch response than LTP. This technique provides practical troubleshooting guidance for patients with no IONM signals during predissection vagus nerve stimulation.

Intraoperative nerve monitoring during esophagectomy reduces the risk of recurrent laryngeal nerve palsy.

BACKGROUND: Despite the risk of recurrent laryngeal nerve (RLN) palsy during esophagectomy, no established method of monitoring RLN injury is currently available. METHODS: This study included 187 patients who underwent esophagectomy between 2011 and 2018. Among these, intraoperative nerve monitoring (IONM) was done in 142 patients (IONM group), while the remaining 45 patients underwent conventional surgery without IONM (control group). We investigated the incidence of postoperative complications with regard to the use of IONM. RESULTS: The overall incidence of postoperative RLN palsy was 28% (52/187). The IONM group showed a significantly lower incidence of postoperative RLN palsy as compared to that in the control group (p = 0.004). The overall incidence of postoperative pneumonia was 22% (41/187) in those with Clavien-Dindo (CD) classification beyond grade 2. There were no significant differences between the incidence of any grade of postoperative pneumonia and the use of IONM (p = 0.195 and 0.333; CD > 2 and > 3, respectively). Multivariate analysis demonstrated that tumors in the upper third [odds ratio (OR) 3.12; 95% confidence interval (CI) 1.04-9.29] and lack of IONM use (OR 2.51; 95% CI 1.17-5.38) were independent factors causing postoperative RLN palsy after esophagectomy. CONCLUSION: IONM helps to reduce the risk of postoperative RLN palsy after esophageal cancer surgery.

The effectiveness and safety of prophylactic central neck dissection in clinically node-negative papillary thyroid carcinoma patients: A meta-analysis.

Objective: This meta-analysis was performed to evaluate the effectiveness and safety of prophylactic central neck dissection (PCND) in patients with clinically node-negative (cN0) papillary thyroid carcinoma. Materials and methods: A meta-analysis of the literature was performed using the key words "papillary thyroid carcinomas" and "lymph node ecisions" for searches of electronic databases. Complications such as transient hypocalcemia, permanent hypocalcemia, transient and permanent hypoparathyroidism, transient and permanent vocal cord paralysis, transient recurrent and permanent recurrent laryngeal nerve injury, and local recurrence were pooled by meta-analysis. Stata17.0 was used to carry out the meta-analysis. Results: Data were extracted from 15 studies. In the present review, the group of patients who had total thyroidectomy (TT) with PCND had a lower local recurrence than the group with TT alone (OR 0.22, 95% CI 0.10-0.45, P = 0.000), whereas the incidence of permanent hypocalcemia (OR 4.24, 95% CI 1.05-17.22, P = 0.043) and transient hypoparathyroidism (OR 2.14, 95% CI 1.34-3.42, P =0.001) were higher. No significant differences were recorded in the incidence of other complications: transient hypocalcemia (OR 2.24, 95% CI 0.77-6.51, P = 0.138), permanent hypoparathyroidism (OR 1.70, 95% CI 0.89-3.27, P = 0.111), transient vocal cord paralysis (OR 1.48, 95% CI 0.78-2.83, P = 0.231), permanent vocal cord paralysis (OR 1.44, 95% CI 0.53-3.94, P = 0.477), transient recurrent laryngeal nerve injury (OR 1.47, 95% CI 0.93-2.32, P = 0.102) and permanent recurrent laryngeal nerve injury (OR 1.24, 95% CI 0.56-2.74, P = 0.587) between the two groups. Conclusion: Compared with TT alone, TT with PCND was more effective in reducing local recurrence without increasing the risk of recurrent laryngeal nerve, thyroid and vocal cord, except for hypocalcemia and transient hypoparathyroidism. Therefore, we believe that TT with PCND should be recommended for patients with cN0 PTC. Systematic review registration: https://www.crd.york.ac.uk/prospero/, identifier CRD4202 2355078.

Application of intraoperative nerve monitoring for recurrent laryngeal nerves in minimally invasive McKeown esophagectomy.

BACKGROUND: Mediastinal lymphadenectomy is of great importance during esophagectomy for esophageal squamous cell carcinoma. However, recurrent laryngeal nerve (RLN) injury is a severe complication caused by lymphadenectomy along the RLN. Intraoperative nerve monitoring (IONM) can effectively identify the RLN and reduce the incidence of postoperative vocal cord paralysis (VCP). Here, we describe the feasibility and effectiveness of IONM in minimally invasive McKeown esophagectomy. METHODS: A total of 150 patients who underwent minimally invasive McKeown esophagectomy from 2016 to 2020 were enrolled in this study. We divided the patients into two groups: a neuromonitoring group (IONM, n = 70) and a control group (control, n = 80). Clinical data, surgical variables, and postoperative complications were retrospectively analyzed and compared. RESULTS: There was no significant difference in baseline data between the two groups. Postoperative VCP occurred in six cases (8.6%) in the IONM group, which was lower than that in the control group (21.3%, P = 0.032). Postoperative pulmonary complications were found in five cases (7.1%) and 14 in the control group (18.8%, P = 0.037). The postoperative hospital stay in the IONM group was significantly shorter than that in the control group (8 vs. 12, median, P < 0.001). The number of RLN lymph nodes harvested in the IONM group was higher than that in the control group (13.74 ± 5.77 vs. 11.03 ± 5.78, P = 0.005). The sensitivity and specificity of IONM monitoring VCP were 83.8% and 100%, respectively. A total of 66.7% of patients with a reduction in signal showed transient VCP, whereas 100% with a loss of signal showed permanent VCP. CONCLUSION: IONM is feasible in minimally invasive McKeown esophagectomy. It showed advantages for distinguishing RLN and achieving thorough mediastinal lymphadenectomy with less RLN injury. Abnormal IONM signals can provide an accurate prediction of postoperative VCP incidence.

How blue lining the recurrent laryngeal nerve can aid in re-operative surgery?

The recurrent laryngeal nerve (RLN), is one of the main structures at risk of injury causing vocal cord paralysis during head and neck surgery, especially during thyroid or parathyroid surgery, central neck dissection and upper oesophageal sphincter surgery. We describe the systematic use of marking of the RLN using non-resorbable blue polypropylene suture after its localisation, just inside its penetration below the cricopharyngeal muscle, to help identify the nerve for cases of re-operative surgery in this area. This specific marking technique could facilitate subsequent preservation of the nerve and reduce nerve injury risk in cases of planned or unexpected future operations, as well as emergency surgery due to postoperative complications. We apply this technique simultaneously with intra-operative laryngeal neuromonitoring. This method is safe and easy to perform.