Vocal palsy increases the risk of lower respiratory tract infection in low-risk, low-morbidity patients undergoing thyroidectomy for benign disease: A big data analysis

Safety of continuous intraoperative vagus nerve neuromonitoring during thyroid surgery

BACKGROUND

Continuous intraoperative neuromonitoring has successfully demonstrated to predict impending damage to the recurrent laryngeal nerve, by detecting changes in electromyographic recordings. Despite the apparent benefits associated with continuous intraoperative neuromonitoring, its safety is still a debate. The aim of this study was to investigate the electrophysiological impact of continuous intraoperative neuromonitoring on the vagus nerve.

METHODS

In this prospective study, the amplitude of the electromyographic wave of the vagus nerve-recurrent laryngeal nerve axis was measured both proximally and distally to the stimulation electrode placed upon the vagus nerve. Electromyographic signal amplitudes were collected at three distinct events during the operation: during the dissection of the vagus nerve, before application of the continuous stimulation electrode onto the vagus nerve and after its removal.

RESULTS

In total, 169 vagus nerves were analysed, among 108 included patients undergoing continuous intraoperative neuromonitoring-enhanced endocrine neck surgeries. Electrode application resulted in a significant overall decrease in measured proximo-distal amplitudes of -10.94 µV (95 per cent c.i. -17.06 to -4.82 µV) (P < 0.005), corresponding to a mean(s.d.) decrease of -1.4(5.4) per cent. Before the removal of the electrode, the measured proximo-distal difference in amplitudes was -18.58 µV (95 per cent c.i. -28.31 to -8.86 µV) (P < 0.005), corresponding to a mean(s.d.) decrease of -2.50(9.59) per cent. Seven nerves suffered a loss of amplitude greater than 20 per cent of the baseline measurement.

CONCLUSION

In addition to supporting claims that continuous intraoperative neuromonitoring exposes the vagus nerve to injury, this study shows a mild electrophysiological impact of continuous intraoperative neuromonitoring electrode placement on the vagus nerve-recurrent laryngeal nerve axis. However, the small observed differences are negligible and were not associated with a clinically relevant outcome, making continuous intraoperative neuromonitoring a safe adjunct in selected thyroid surgeries.

Ultrasound-Guided Radiofrequency and Microwave Ablation for the Management of Patients With Benign Thyroid Nodules: Systematic Review and Meta-Analysis

ABSTRACT

Ultrasound-guided thermal ablation has been shown to considerably reduce nodule-related discomfort and cosmetic problems. Hence, this review was done to determine the effectiveness of ultrasound-guided radiofrequency or microwave ablation in the management of benign thyroid nodules. Searches were done in EMBASE, SCOPUS, PubMed Central, Cochrane library, MEDLINE, Google Scholar, ScienceDirect, and Clinicaltrials.gov until August 2022. Meta-analysis was carried out using random-effects model. With 95% confidence intervals (CIs), pooled standardized mean differences, mean differences, and/or odds ratio reported. In total, we analyzed 16 studies, most of them had high risk of bias. The pooled standardized mean difference for symptom score was -1.01 (95% CI, -1.83 to -0.19; I2 = 94.2%), for cosmetic relief was -1.26 (95% CI, -2.27 to -0.24; I2 = 96%), for postoperative nodule volume was -1.77 (95% CI, -3.06 to -0.48; I2 = 94%), for hospital stay was -3.88 (95% CI, -4.58 to -3.18; I2 = 91.1%), for operation time was -3.30 (95% CI, -3.95 to -2.64; I2 = 93.4%). The pooled odds ratio for postoperative pain was 0.04 (95% CI, 0.00-0.35; I2 = 95.1%), for postoperative hypothyroidism was 0.04 (95% CI, 0.01-0.11; I2 = 0%), for postoperative hoarseness was 0.56 (95% CI, 0.22-1.47; I2 = 0%), for postoperative hematoma was 0.57 (95% CI, 0.15-2.22; I2 = 0%). Ultrasound-guided radiofrequency and microwave ablation had better efficacy and safety profile in terms of symptoms, cosmetic relief, complication rate, duration of stay, and operation time when compared with conventional surgery or observation without treatment for patients with benign thyroid nodules.

Lobo-isthmectomy in the management of differentiated thyroid cancer

We have recently witnessed a rapid increase in the incidence of differentiated thyroid carcinoma (DTC), particularly low and very low-risk papillary thyroid carcinoma. Simultaneously, the number of cancer-related deaths has remained stable for more than 30 years. Such an indolent nature and long-term survival prompted researchers and experts to an ongoing discussion on the adequacy of DTC management to avoid, on the one hand, the overtreatment of low-risk cases and, on the other hand, the undertreatment of highly aggressive ones.The most recent guidelines of the American Thyroid Association (ATA GL) moved primary thyroid surgery in DTC towards a less aggressive approach by making lobectomy an option for patients with intrathyroidal low-risk DTC tumors up to 4 cm in diameter without evidence of extrathyroidal extension or lymph node metastases. It was one of the key changes in DTC management proposed by the ATA in 2015.Following the introduction of the 2015 ATA GL, the role of thyroid lobectomy in DTC management has slowly become increasingly important. The data coming from analyses of the large databases and retrospective studies prove that a less extensive surgical approach, even if in some reports it was related to a slight increase of the risk of recurrence, did not show a negative impact on disease-specific and overall survival in T1T2N0M0 low-risk DTC. There is no doubt that making thyroid lobectomy an option for low-risk papillary and follicular carcinomas was an essential step toward the de-escalation of treatment in thyroid carcinoma.This review summarizes the current recommendations and evidence-based data supporting the necessity of de-escalation of primary thyroid surgery in low-risk DTC. It also discusses the controversies raised by introducing new ATA guidelines and tries to resolve some open questions.

Swallowing disorders after thyroidectomy: a systematic review and meta-analysis

PURPOSE

Swallowing disorders following thyroidectomy are common, even after surgery without confirmed complications. The purpose of the current systematic review is to investigate the prevalence of dysphagia at various time points after thyroidectomy, at the whole spectrum of it (total/partial, open/endoscopic, for benign/malignant disease).

METHODS

The literature available at PubMed, SciELO and Cochrane Library databases was reviewed, according to PRISMA guidelines, using the terms "dysphagia", "swallowing disorder", "deglutition disorder", "thyroidectomy" and "thyroid surgery" in the appropriate combinations. A quantitative synthesis of the results followed.

RESULTS

The systematic review of the literature resulted in 35 articles, which met the inclusion criteria and were analyzed regarding their type, sample, follow-up and results regarding post-thyroidectomy dysphagia in multiple follow-up times. A significant increase of swallowing impairment compared to baseline was recorded shortly after surgery. Dysphagia reverted to pre-operative levels 2-3 months later. Dysphagia continued to be reported in a significantly lower proportion of patients, even 1 year after surgery. No significant difference was noticed between open and endoscopic thyroid surgery at 2-3 months post-surgery.

CONCLUSIONS

The swallowing disorders reported after thyroidectomy should be expected, but are not always detectable through objective methods. This should not lead to underestimation of symptoms, since the patients' quality of life is negatively affected by the symptomatology.

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.

Continuous Intraoperative Recurrent Laryngeal Nerve Monitoring: Techniques, Applications, and Controversies

Purpose of Review

Purpose of the present review is to illustrate the current state of the art concerning continuous intraoperative recurrent laryngeal nerve monitoring (cIONM) for thyroid surgery.

Recent Findings

cIONM potentially leads to an improved postoperative vocal cord palsy rate, compared to the intermittent technique. There are currently two main approaches for cIONM: either conventional cIONM based on vagal nerve stimulation or experimental methods, which do not require the positioning of a vagal nerve electrode. One of these methods is the recently described technique “LAR-cIONM,” which utilizes the laryngeal adductor reflex.

Summary

cIONM represents an advancement of intermittent nerve monitoring, which allows for an immediate reaction to signal changes. Threshold values and guidelines to prevent recurrent laryngeal nerve palsy were validated for the direct stimulation of the vagal nerve and require verification for alterative cIONM methods, including LAR-cIONM.

Critical Review and Consensus Statement for Neural Monitoring in Otolaryngologic Head, Neck, and Endocrine Surgery

BACKGROUND

Enhancing patient outcomes in an array of surgical procedures in the head and neck requires the maintenance of complex regional functions through the protection of cranial nerve integrity. This review and consensus statement cover the scope of cranial nerve monitoring of all cranial nerves that are of practical importance in head, neck, and endocrine surgery except for cranial nerves VII and VIII within the temporal bone. Complete and applied understanding of neurophysiologic principles facilitates the surgeon's ability to monitor the at-risk nerve.

METHODS

The American Academy of Otolaryngology-Head and Neck Surgery (AAO-HNS) identified the need for a consensus statement on cranial nerve monitoring. An AAO-HNS task force was created through soliciting experts on the subject. Relevant domains were identified, including residency education, neurophysiology, application, and various techniques for monitoring pertinent cranial nerves. A document was generated to incorporate and consolidate these domains. The panel used a modified Delphi method for consensus generation.

RESULTS

Consensus was achieved in the domains of education needs and anesthesia considerations, as well as setup, troubleshooting, and documentation. Specific cranial nerve monitoring was evaluated and reached consensus for all cranial nerves in statement 4 with the exception of the spinal accessory nerve. Although the spinal accessory nerve's value can never be marginalized, the task force did not feel that the existing literature was as robust to support a recommendation of routine monitoring of this nerve. In contrast, there is robust supporting literature cited and consensus for routine monitoring in certain procedures, such as thyroid surgery, to optimize patient outcomes.

CONCLUSIONS

The AAO-HNS Cranial Nerve Monitoring Task Force has provided a state-of-the-art review in neural monitoring in otolaryngologic head, neck, and endocrine surgery. The evidence-based review was complemented by consensus statements utilizing a modified Delphi method to prioritize key statements to enhance patient outcomes in an array of surgical procedures in the head and neck. A precise definition of what actually constitutes intraoperative nerve monitoring and its benefits have been provided.

Prevalence of major structures injury in thyroid and neck surgeries: a national perspective

Background

The objectives of the study is to examine the prevalence and burden of major structures injury (pharynx, esophagus, trachea, larynx, lymphatic, vessels & nerves) in patients who underwent thyroid, parathyroid, and neck dissection surgeries in the United States.

Methods

The study is a retrospective cross-sectional analysis utilizing the Nationwide Readmissions Database, 2010-2015. The study population included adults (≥18 years) patients who underwent thyroid, parathyroid, and neck dissection surgeries.

Results

A total of 54,443 patients were included. Major structures injury was reported in 221 (0.48%) patients. The injured structures were vascular (0.22%), lymphatic (0.18%), pharynx/esophagus (0.06%), neural (0.03%), and trachea/larynx (0.002%). The risk of injury increased annually during the study period (OR: 1.29, 95% CI: 1.16, 1.44, P<0.001). The risk of injury was highest in patients who underwent thyroidectomy with neck dissection (1.01%) or neck dissection alone (1.81%) (P<0.001 each). The risk was also highest for patients with a head and neck cancer diagnosis (OR: 1.80, 95% CI: 1.24, 2.61, P=0.002). Patients with those injuries had a higher prevalence of blood transfusion (2.82% vs. 0.17%), postoperative fistula (3.10% vs. 0.03%), readmission (28.90% vs. 3.59%), and postoperative mortality (0.87% vs. 0.06%) (P<0.05 each). Management of patients with those injuries was associated with a longer hospital stay by 4.86±0.48 days (P<0.001), and a higher cost by $16,151.00±173.36 (P<0.001).

Conclusions

Injuries of major structures in thyroid and neck surgeries are more prevalent in cancer patients. There has been a recent increase in the risk of such injuries in the United States. Those injuries are associated with significant clinical and economic burden.

Comparison of ultrasound-guided thermal ablation and conventional thyroidectomy for benign thyroid nodules: a systematic review and meta-analysis

Objective: To compare the safety and efficacy of ultrasound-guided thermal ablation and conventional thyroidectomy for benign thyroid nodules (TNs) by performing a systematic review and meta-analysis.Methods: We searched PubMed, Embase, Web of Science and Cochrane Library databases for clinical trials from the date of their inception to 1 April 2019. Two investigators independently examined the trials to select qualified studies, extracted relevant information and assessed the risk of bias according to the Cochrane Collaboration checklist (Oxford, UK). The primary study outcomes were safety (hoarseness, hypothyroidism and postoperative pain) and efficacy (symptom improvement, postoperative cosmetic effects and hospitalization time). This study is registered with PROSPERO (CRD42019125643).Results: Seven studies involving 1289 patients were included. The results demonstrated that the incidences of hoarseness [odds ratio (OR) 0.33, 95% confidence interval (95% CI) (0.14, 0.79)], hypothyroidism [risk difference (RD) -0.31, 95% CI (-0.34, -0.28)] and postoperative pain [OR 0.35, 95% CI (0.25, 0.49)] were lower, and the hospitalization time was shorter [standard mean difference (SMD) -4.01, 95% CI (-4.22, -3.81)], in the thermal ablation group than in the conventional thyroidectomy group, and postoperative cosmetic effects were better [relative risk (RR) ratio 1.12, 95% CI (1.01, 1.24)] (p < 0.05). For symptom improvement, the difference was not statistically significant.Conclusions: This study shows that for benign TNs, ultrasound-guided thermal ablation may have potential advantages in terms of safety, cosmetic effects and shorter hospitalization time compared with conventional thyroidectomy, while symptom improvement is the same.

Medicolegal lessons learned from thyroidectomy-related lawsuits: an analysis of judicial precedents in South Korea from 1998 to 2019

Background

Thyroid cancer is one of the most common cancers in South Korea, and thyroidectomy is still frequently performed. As new diagnostic methods have led to a significant increase in the early detection of thyroid cancer worldwide, medical disputes related to thyroid surgery are also likely to increase. The purpose of this study was to investigate the causes of medical disputes related to thyroidectomy and to identify ways to prevent unnecessary disputes and malpractice.

Methods

We analyzed 35 judicial decisions involving thyroidectomy in South Korea from January 1998 to July 2019.

Results

The most common cause of lawsuits was "performance error during surgery" (n=19), especially "recurrent laryngeal nerve (RLN) injury" (n=7), of which five cases were ruled medical malpractice. For lawsuits involving misdiagnosis (n=14), five regarding fine needle aspiration cytology (FNAC) and frozen section examination were ruled malpractice. The most common malpractice related to informed consent was "lack of explanation about surgery complications" (n=10).

Conclusions

Surgeons should follow guidelines to protect themselves from diagnostic error dispute; performing FNAC more often might also prevent lawsuits. When the courts judge the surgeon's negligence in cases of RLN injuries, whether bilateral or unilateral, it is necessary to consider fully the surgeon's efforts to prevent RLN injuries. Providing information and building trust through sufficient patient-doctor communication is crucial.

Immediate Intraoperative Repair of the Recurrent Laryngeal Nerve in Thyroid Surgery

OBJECTIVES

Recurrent laryngeal nerve (RLN) injury is a recognized risk during thyroid and parathyroid surgery and can result in significant morbidity. The aim of this review paper is to consider the optimal approach to the immediate intraoperative repair of the RLN during thyroid surgery.

METHODS

A PubMed literature search was performed from inception to June 2020 using the following search strategy: immediate repair or repair recurrent laryngeal nerve, repair or reinnervation recurrent laryngeal nerve and immediate neurorraphy or neurorraphy recurrent laryngeal nerve.

RESULTS

Methods of immediate intraoperative repair of the RLN include direct end-to-end anastomosis, free nerve graft anastomosis, ansa cervicalis to RLN anastomosis, vagus to RLN anastomosis, and primary interposition graft. Techniques of nerve repair include micro-suturing, use of fibrin glue, and nerve grafting. Direct micro-suture is preferable when the defect can be repaired without tension. Fibrin glue has also been proposed for nerve repair but has been criticized for its toxicity, excessive slow reabsorption, and the risk of inflammatory reaction in the peripheral tissues. When the proximal stump of the RLN cannot be used, grafting could be done using transverse cervical nerve, supraclavicular nerve, vagus nerve, or ansa cervicalis.

CONCLUSIONS

Current evidence is low-level; however, it suggests that when the RLN has been severed, avulsed, or sacrificed during thyroid surgery it should be repaired intraoperatively. The immediate repair has on balance more advantages than disadvantages and should be considered whenever possible. This should enable the maintenance of vocal cord tone, better and prompter voice recovery and avoidance of aspiration. Laryngoscope, 131:1429-1435, 2021.

Recurrent laryngeal nerve monitoring during totally robot-assisted Ivor Lewis esophagectomy

Purpose

The robot-assisted approach for Ivor Lewis esophagectomy offers an enlarged, three-dimensional overview of the intraoperative situs. The vagal nerve (VN) can easily be detected, preserved, and intentionally resected below the separation point of the recurrent laryngeal nerve (RLN). However, postoperative vocal cord paresis can result from vagal or RLN injury during radical lymph node dissection, presenting a challenge to the operating surgeon.

Methods

From May to August 2019, 10 cases of robot-assisted minimally invasive esophagectomy (RAMIE) with extended 2-field lymphadenectomy, performed at the University Medical Center Mainz, were included in a prospective cohort study. Bilateral intermittent intraoperative nerve monitoring (IONM) of the RLN and VN was performed, including pre- and postoperative laryngoscopy assessment.

Results

Reliable mean signals of the right VN (2.57 mV/4.50 ms) and the RLN (left 1.24 mV/3.71 ms, right 0.85 mV/3.56 ms) were obtained. IONM facilitated the identification of the exact height of separation of the right RLN from the VN. There were no cases of permanent postoperative vocal paresis. Median lymph node count from the paratracheal stations was 5 lymph nodes.

Conclusion

IONM was feasible during RAMIE. The intraoperative identification of the RLN location contributed to the accuracy of lymph node dissection of the paratracheal lymph node stations. RLN damage and subsequent postoperative vocal cord paresis can potentially be prevented by IONM.

Immediate and partial neural dysfunction after thyroid and parathyroid surgery: Need for recognition, laryngeal exam, and early treatment

BACKGROUND

Laryngeal dysfunction after thyroid and parathyroid surgery requires early recognition and a standardized approach for patients that present with voice, swallowing, and breathing issues. The Endocrine Committee of the American Head and Neck Society (AHNS) convened a panel to define the terms "immediate vocal fold paralysis" and "partial neural dysfunction" and to provide clinical consensus statements based on review of the literature, integrated with expert opinion of the group.

METHODS

A multidisciplinary expert panel constructed the manuscript and recommendations for laryngeal dysfunction after thyroid and parathyroid surgery. A meta-analysis was performed using the literature and published guidelines. Consensus was achieved using polling and a modified Delphi approach.

RESULTS

Twenty-two panelists achieved consensus on five statements regarding the role of early identification and standardization of evaluation for patients with "immediate vocal fold paralysis" and "partial neural dysfunction" after thyroid and parathyroid surgery.

CONCLUSION

After endorsement by the AHNS Endocrine Section and Quality of Care Committee, it received final approval from the AHNS Council.

Transoral management of adult benign laryngeal stenosis

PURPOSE

Management of benign laryngeal stenosis (BLS) remains challenging even though transoral treatments in selected cases have shown satisfactory results, at least comparable to open-neck approaches, with reduced invasiveness. To date, no overall consensus has been reached on many issues. The aim of this study is to assess the effectiveness of a purely transoral treatment in a cohort of patients affected by BLS.

METHODS

We evaluated 40 patients affected by BLS, treated by transoral surgery between 2013 and 2017. The European Laryngological Society classification for laryngotracheal stenosis was applied for the staging. Improvement in airway patency and quality of life was assessed by decannulation rate, Airway-Dyspnea-Voice-Swallowing (ADVS) score, Voice handicap index (VHI)-30, and Eating assessment tool (EAT)-10 questionnaires.

RESULTS

Mean age was 61 years and M:F ratio was 1.4:1. Previous laryngeal surgery was the most common cause of stenosis (50%), followed by radiotherapy (20%), idiopathic etiology (12%), granulomatosis with polyangiitis (10%), and prolonged intubation (8%). Transoral treatment entailed an improvement in quality of life with a significant decrease in the VHI score (p < 0.0001) and improvement in Airway (p = 0.008), Dyspnea (p < 0.0001), and Voice (p < 0.0001) scores. No major perioperative complications were observed. The decannulation rate among patients with a tracheostomy in place (N = 16) was 63%.

CONCLUSIONS

Transoral treatment of selected BLS managed by a team with high-level expertise in surgery and anesthesiology is associated with significant improvement of quality of life, especially with regard to voice and breathing functions.

Effect of intraoperative nerve monitoring on postoperative vocal cord palsy rates after thyroidectomy: European multicentre registry-based study

Background

Intraoperative nerve monitoring (IONM) of the recurrent laryngeal nerve (RLN) predicts the risk of vocal cord palsy (VCP). IONM can be used to adapt the surgical strategy in order to prevent bilateral VCP and associated morbidity. Controversial results have been reported in the literature for the effect of IONM on rates of VCP, and large multicentre studies are required for elucidation.

Methods

Patients undergoing first‐time thyroidectomy for benign thyroid disease between May 2015 and January 2019, documented prospectively in the European registry EUROCRINE®, were included in a cohort study. The influence of IONM and other factors on the development of postoperative VCP was analysed using multivariable regression analysis.

Results

Of 4598 operations from 82 hospitals, 3542 (77·0 per cent) were performed in female patients. IONM was used in 4182 (91·0 per cent) of 4598 operations, independent of hospital volume. Postoperative VCP was diagnosed in 50 (1·1 per cent) of the 4598 patients. The use of IONM was associated with a lower risk of postoperative VCP in multivariable analysis (odds ratio (OR) 0·34, 95 per cent c.i. 0·16 to 0·73). Damage to the RLN noted during surgery (OR 24·77, 12·91 to 48·07) and thyroiditis (OR 2·03, 1·10 to 3·76) were associated with an increased risk of VCP. Higher hospital volume correlated with a lower rate of VCP (OR 0·05, 0·01 to 0·13).

Conclusion

Use of IONM was associated with a low rate of postoperative VCP.

Continuous vagal monitoring value in prevention of vocal cord paralysis following thyroid surgery

OBJECTIVES/HYPOTHESIS

Continuous intraoperative neuromonitoring (CIONM) of the vagus nerve was proposed to obtained frequent repetitive electromyography (EMG) data to recognize early change in intraoperative function of the recurrent laryngeal nerve. We examine our initial experience using this technology.

STUDY DESIGN

Retrospective review.

METHODS

Data for all patients who underwent neck surgery by a single surgeon at a North American institution over a 5-year period were reviewed. CIONM was used in cases with possible higher risk of traction injury and according to surgeon preference. In these cases, stretch injury was established by warning alarm with threshold of ≥50% reduction in amplitude and/or ≥ 10% increase in latency. Preoperative and postoperative direct laryngoscopy was performed for all patients.

RESULTS

A total of 879 endocrine neck surgeries were performed. CIONM was used to monitor 455 recurrent laryngeal nerves (RLNs) in 344 (39.1%) surgeries. An automatic periodic stimulation (APS) alarm detected impending nerve injury in 33 (9.6%) cases by 64.9% ± 12.7% decrease in amplitude and by 27.3% increase in latency in one case. A total loss of signal (LOS) was detected in 15 (4.36%) cases. The immediate release of causative retraction successfully preserved the nerves in all cases with impending injury; however, there was no improvement in the LOS cases. Other than the cases with LOS, postoperative laryngoscopy showed normal vocal cord function in all cases.

CONCLUSIONS

APS technology is safe, feasible, and helpful in approximately 10% of cases in our series, which developed nascent neurapraxia adverse EMG changes associated with intraoperative RLN stretch that could be reversed intraoperatively.

LEVEL OF EVIDENCE

4. Laryngoscope, 128:2429-2432, 2018.