Continuous Intraoperative Nerve Monitoring Research Articles

Continuous Intraoperative Nerve Monitoring for Thyroid and Parathyroid Surgery

Continuous Intraoperative Nerve Monitoring for Thyroid and Parathyroid Surgery

Continuous Intraoperative Nerve Monitoring of a Non-Recurrent Laryngeal Nerve: Real-Life Data of a High-Volume Thyroid Surgery Center.

Thyroid surgery is associated with a risk of injury to the recurrent laryngeal nerve, especially in the presence of anatomical variants such as a non-recurrent laryngeal nerve (NRLN). Injury to the nerve leads to transient or permanent vocal cord palsy (VCP). A novel method to prevent VCP is continuous intraoperative nerve monitoring (cIONM), but less is known about the applicability of this method in patients with NRLN. The aim of this study was to evaluate our own data regarding feasibility and detailed characteristics of cIONM in NRLN patients. We performed a monocentric retrospective cohort analysis including clinical data and intraoperative nerve monitoring data (measured by Inomed Medizintechnik GmbH, Emmendingen, 'C2' and 'C2 Xplore' device) of all thyroid surgery patients, showing NRLN between 2014 and 2022. Of 1406 patients who underwent thyroid surgery with cIONM between 2014 and 2022, 12 patients (0.9%) showed NRLN intraoperatively. Notably, cIONM was feasible in eight patients (67%). In all cases the onset latency of the right vagus nerve was shorter (<3.0 ms) than usually expected, suggesting that a short latency might be suitable to distinguish NRLN. None of the patients had a post-operative VCP. Overall, cIONM appears to be feasible and safe in NRLN patients and provides helpful information to prevent VCP.

Preserving vocal cord function: Continuous intraoperative vagus nerve monitoring in total thyroidectomy

A 42-year-old female patient who underwent left hemithyroidectomy for a benign thyroid nodule, was referred for further management, as histology revealed a minimally invasive follicular carcinoma requiring completion thyroidectomy as recommended by Oncologists. She had developed unilateral vocal card palsy following the initial hemithyroidectomy. Pre operatively vocal cord function was evaluated by fibre optic laryngoscopy, which confirmed a left vocal cord palsy. During the completion thyroidectomy, continuous intraoperative nerve monitoring was done using an electrode attached to endotracheal tube. A delta electrode was attached to the Vagus nerve and continuous monitoring of the Vagus nerve was done while performing intermittent monitoring of the Recurrent Laryngeal nerve. Stimulation was performed using a current of 1–2 mA. According to the International Nerve monitoring Study Group (INMSG) guidelines initial amplitude value of at least 500 μV was considered as the normal value.According to INMSG guide lines, change of EMG signal curve amplitude below 100 μV was considered as loss of signal during the operation. Post-operative period of the patient was uneventful and the right vocal cord function was confirmed as normal by fibre optic endoscopic examination. Even though intraoperative nerve monitoring is a useful procedure for all the thyroidectomy surgeries it is documented to be more beneficial during revision surgeries, thyroid malignancies and pre-operative unilateral nerve palsy patients.

A Case of Zenker’s Diverticulum That Was Resected Under Continuous Intraoperative Nerve Monitoring

A Case of Zenker’s Diverticulum That Was Resected Under Continuous Intraoperative Nerve Monitoring

436. USEFULNESS OF INTRAOPERATIVE CONTINUOUS NERVE MONITORING IN TRANSMEDIASTINAL MINIMALLY INVASIVE ESOPHAGECTOMY

Abstract Introduction We have previously reported that continuous intraoperative nerve monitoring (CIONM) is useful in reducing postoperative left recurrent laryngeal nerve paralysis (RLNP) in transmediastinal esophagectomy (TME). In this study, we investigated the relationship between the paralysis risk types on CIONM and postoperative RLNP. Methods A total of 161 patients who underwent TME for esophageal malignancies and esophagogastric junctional cancer with CIONM between October 2017 and July 2022. The relationship between clinical background factors, changes in amplitude during surgery, and left RLNP (endoscopic vocal cord findings on postoperative day 7) was retrospectively investigated. Furthermore, the relationship between LOS types (segmental or diffuse) and left RLNP was examined. Results The median age was 70 years, with 127 male and 34 female patients. At the end of transcervical procedure, 46 patients had amplitude less than 100 μV (LOS: loss of signal) and 78 patients had amplitude ≤50% of baseline. Postoperatively, 76.1% of LOS cases and 46.2% of cases with amplitudes ≤50% of baseline had left RLNP. The amplitude reduction types (LOS, baseline≤50%), primary tumor in the cervical/upper thoracic/middle thoracic esophagus, and males were significantly associated with left RLNP (p &amp;lt; 0.001). When examined by LOS type, RLNP was more common in segmental LOS than in diffuse LOS. Conclusion The pattern of amplitude reduction on CIONM is useful in predicting postoperative left RLNP. We will continue to increase the number of cases and verify the further effectiveness of CIONM for TME.

Effects of Intraoperative Nerve Monitoring Techniques on Voice and Swallowing Disorders after Uncomplicated Thyroidectomy: Preliminary Report of a Bi-Institutional Prospective Study.

Background: Voice and swallowing problems are frequently associated with thyroidectomy. Intermittent nerve monitoring (i-IONM) seems to provide a positive effect in reducing its prevalence. The aim of this study was to test the hypothesis that continuous intraoperative nerve monitoring (c-IONM) may reduce the prevalence of these disorders even further than i-IONM. Methods: This 3-arm prospective bi-institutional study compared 179 consecutive patients that underwent thyroidectomy: 56 without IONM, 55 with i-IONM and 67 with c-IONM. Neck dissections and laryngeal nerve palsies were excluded. Two questionnaires (VHI-10 for voice disorders and EAT-10 for swallowing disorders; both validated for Italian language use) were administered before and 1 month after surgery. Statistical significance was analyzed by the chi-squared test. Results: After thyroidectomy, no statistically significant differences were found in the three groups concerning EAT-10. although these symptoms seemed to be influenced by gastro-esophageal reflux. VHI-10 worsened in the “no-IONM” group compared with both i-IONM (p < 0.09, not quite statistically significant) and c-IONM (p < 0.04). Conclusion: Both i- and c-IONM improve voice quality independently of laryngeal nerve integrity. Reduced dissection and particularly restrained manipulation could explain these results, being particularly favorable for c-IONM.

180. SINGLE-PORT MEDIASTINOSCOPIC LYMPHADENECTOMY IN THE UPPER AND MIDDLE MEDIASTINUM USING CONTINUOUS INTRAOPERATIVE NERVE MONITORING

Abstract The left cervical approach with single-port mediastinoscopy is essential for radical esophagectomy without thoracotomy for esophageal cancer, which provides excellent visibility and handling along the esophagus to achieve radical lymph nodes (LNs) dissection in the upper and middle mediastinum. However, the transcervical procedure dissecting along the recurrent laryngeal nerve (RLN) requires careful use of both energy device for dissection and forceps for surgical field expansion to minimize the risk of RLN palsy. Using the left cervical approach, the LNs along the left RLN and tracheal bifurcation (subcarinal and bilateral main bronchial LNs) were dissected en bloc with the esophagus. The LNs along the right RLN were basically dissected through a right cervical incision under direct vision or dissected with the left cervical approach if visible. Intraoperative nerve monitoring (IONM) with NIM Response 3.0 was introduced to minimize the risk of RLN palsy. Continuous and intermittent IONMswere used for the left and right cervical procedures, respectively. Until March 2019, 175 patients underwent transmediastinal esophagectomy. Squamous cell carcinoma was predominant (93.7%). The upper and middle thoracic tumors were the most frequent (65.7%). Since IONM introduction, RLN palsy (grade I or more, CD classification) was significantly reduced. Without IONM (n = 106), the left RLN palsy was observed in 35.9%, while was in 13.6% with IONM (n = 66). In addition, the bilateral RLNs palsy was 14.2% without IONM, while was reduced to 3.0% with IONM. IONM is useful to reduce RLN palsy in transmediastinal esophagectomy. Especially, continuous IONM, which provides a real-time information on the risk procedure of RLN injury, is effective in preventing RLN palsy. The left cervical procedure with continuous IONM will be shown in movie.

AB130. SOH22ABS114. Intra-operative nerve monitoring and recurrent laryngeal nerve injury during thyroid surgery: a Bayesian network meta-analysis of prospective studies

Background: Recurrent laryngeal nerve (RLN) injury leading to vocal cord palsy is a dreaded complication of thyroid surgery occurring in 1–5% of cases. The main approaches to RLN preservation are: RLN visualization without nerve monitoring (No-NM), intermittent intraoperative nerve monitoring (I-IONM) and continuous intraoperative nerve monitoring (C-IONM). At present it is unclear which of these strategies should be the preferred method of RLN preservation. We performed a systematic review and network meta-analysis (NMA) to define the optimal method of RLN preservation during thyroid surgery using only the highest levels of available evidence.

Feasibility of Continuous Intraoperative Nerve Monitoring System for Esophageal Cancer during Transmediastinal Esophagectomy

Feasibility of Continuous Intraoperative Nerve Monitoring System for Esophageal Cancer during Transmediastinal Esophagectomy

Intraoperative Neuromonitoring: Evaluating the Role of Continuous IONM and IONM Techniques for Emerging Surgical and Percutaneous Procedures.

Intraoperative nerve monitoring (IONM) is a tool used during thyroid surgery to assist in the identification of the recurrent laryngeal nerve (RLN). Multiple IONM systems that exist for thyroidectomy require intubation with an endotracheal tube. Given that one of the advantages of thermal ablation procedures, such as radiofrequency ablation, is that they can be done safely without the use of general anesthesia, nerve monitoring systems that utilize cutaneous surface electrodes have been developed, though are not widely available in the United States. This article will review the use of IONM for RFA including the cutaneous surface electrode system.

Intraoperative Neuromonitoring: Evaluating the Role of Continuous IONM and IONM Techniques for Emerging Surgical and Percutaneous Procedures.

Continuous and intermittent intraoperative nerve monitoring (IONM) has become an important asset for endocrine surgeons over the past few decades. The ability to determine neurophysiologic integrity of the recurrent laryngeal nerve (RLN) and external branch of the superior laryngeal nerve (EBSLN) on top of identification and meticulous dissection of the nerve in the surgical field, has allowed for advances in technology and improved outcomes when it comes to prevention of vocal fold immobility. This article aims to compare in review continuous and intermittent nerve monitoring (CIONM, IIONM), as well as review the current paradigms of their use. This article will also discuss the future of intraoperative nerve monitoring technologies in scarless thyroid surgery and percutaneous approaches to thyroid pathology in form of radiofrequency ablation (RFA).

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

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. 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. 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. 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.

The Year in Surgical Thyroidology: Recent Technological Developments and Future Challenges.

Background: The field of surgical and interventional thyroidology is rapidly evolving. In the past few years, we have seen the introduction and establishment of many novel surgical adjuncts, techniques, and disruptive ablative technologies that have impacted the field. Methods: We identified the most influential articles on technological developments in surgical and interventional thyroidology that were published from September 1, 2020, to August 1, 2021. We searched three electronic databases and consulted experts. Results: Major findings are summarized. Continuous intraoperative nerve monitoring (cIONM) lowered the risk of early postoperative vocal cord palsy 1.8-fold and permanent palsy 29 · 4-fold compared with intermittent intraoperative nerve monitoring. Parathyroid autofluorescence yielded a diagnostic odds ratio (OR) of 228.9 for detection of parathyroid glands over visualization, with 96% sensitivity and 92% specificity. There was no significant difference in the incidence of major complications between the transoral endoscopic thyroidectomy vestibular approach (TOETVA) and transcervical thyroidectomy (1.5% vs. 2.1%, p = 0.75), and a higher body mass index did not lead to a significant increase in the odds of cumulative complication with TOETVA for the overweight (OR = 0.52 [95% confidence interval {CI} 0.17-1.58]) and obese groups (OR = 1.69 [CI 0.74-3.88]). Radiofrequency ablation (RFA) for benign thyroid nodules typically resulted in a 50-85% volume reduction with faster recovery times, less pain levels, and higher social and psychological well-being compared with conventional thyroidectomy at 15 months post-treatment, although physical well-being levels were higher in the conventional thyroidectomy group at this time. RFA for papillary thyroid microcarcinoma showed no significant difference in local tumor progression (1.8% vs. 3.3%, p = 0.209), lymph node metastasis (0.6% vs. 0.6%, p = 1.000), recurrence (1.2% vs. 2.4%, p = 0.244), and 4-year recurrence-free survival rates (98.2% vs. 97.0%, p = 0.223) when compared with transcervical lobectomy. Conclusions: cIONM, parathyroid autofluorescence, transoral vestibular approach thyroid surgery, and RFA for benign and malignant thyroid nodules are some of the latest additions to the surgeon's and interventionalist's armamentarium to manage thyroid disease. These technological advancements demonstrate promise to improve outcomes, decrease complications, and enhance a patient's quality of life, but further rigorous studies are needed to define their utility and value.

Is craniocaudal dissection of recurrent laryngeal nerve safer than lateral approach: a prospective randomized study comparing both techniques by using continuous intraoperative nerve monitoring.

PurposeThis study was performed to compare the real-time electromyographic (EMG) changes and the rate of recurrent laryngeal nerve (RLN) injury in craniocaudal and lateral approaches for RLN during thyroidectomy.MethodsOne hundred twelve and 86 patients were prospectively randomized to receive lateral (group 1) or craniocaudal (group 2) approach to RLN, respectively, under continuous intraoperative nerve monitoring.ResultsLoss of signal (LOS) occurred in 7 (2.0%) of 356 nerves at risk (NAR). LOS was significantly associated with repeated adverse EMG changes and presence of RLN entrapment at the ligament of Berry (LOB), which was accompanied by other clinicopathological or anatomical features, such as tubercle of Zuckerkandl (TZ), extralaryngeal branching, hyperthyroidism, autoimmune thyroid disease (ATD), or thyroid lobe volume of >29 cm3 (P = 0.001 and P = 0.030, respectively). The rate of repeated adverse EMG changes and LOS in the NARs with LOB entrapment accompanied by other clinicopathological and anatomical features was higher in group 1 vs. group 2 (11.1% vs. 2.2%, respectively and 9.7% vs. 0%, respectively; P = 0.070). The total rate of vocal cord palsy (VCP) was significantly higher in group 1 than in group 2 (P = 0.005). The rate of permanent VCP showed no significant difference between the 2 groups.ConclusionThe craniocaudal approach to the RLN is safer than the lateral approach in the RLNs with entrapment at the LOB accompanied by other features, such as TZ, extralaryngeal branching, hyperthyroidism, ATD, or high thyroid lobe volume.

Clinical Benefits of Facial Nerve Monitoring during Cerebellopontine Angle Surgery

Background: The surgery of cerebellopontine angle tumours has remarkably progressed over the last 2 decades due to improved microsurgical techniques. The primary operative goals are microscopic total removal of the tumour while securing the adjacent cranial nerves. Facial Nerve plays a critical role in facial muscles function and one’s cosmetic appearance, and its weakness can have profound implications on a patient’s quality of life. Aim of the Study: To assess the impact of monitoring techniques on the preservation of facial nerve function during cerebellopontine angle tumours surgery. Patients and Methods: This is a prospective study. This study was conducted on 30 cases (2 groups, each had 15 patients) with CPA lesions that had undergone surgical excision of these lesions performed by retrosigmoid approach (Group A: the patients were operated under continuous intraoperative facial nerve monitoring (IOFNM) and Group B: the patients were operated without IOFNM). They were operated upon in neurosurgery departments at Al-Azhar university hospitals between August 2019 and August 2021. Results: This study showed that excellent facial nerve function (HB Grade I and II) was higher in group A than group B, immediately and at 6-month post op (80% and 93% VS 53.3% and 66.7%). Intermediate (HB Grade III and VI) and Poor (HB Grade V and VI) facial nerve function was higher in group B than group A; both immediately and 6-month postop (46.7% and 33.3% VS 20% and 6.6%). However, no statistically significant P-Value between both groups. Conclusion: We concluded that IOFNM can help, but cannot guarantee, the preservation of facial nerve. Furthermore, it is merely a technical adjunct and does not replace surgical skills, knowledge of anatomy and experience.

Vagus Nerve Injury during Continuous Intraoperative Neuromonitoring (cIONM) for Thyroid Surgery: Assessment of Severity

Introduction: Vocal cord palsy is one of the biggest concern in thyroid surgery especially among the professional voice user. Continuous intra-operative nerve monitoring allows real time of the nerve function during surgery that will reduce risk of injury. The procedure involve is not without complication but meticulous usage and following standard operating procedure is utmost important. This study was aimed looking at the potential morbidity of the procedure.&#x0D; Methodology: A prospective observational study was conducted on 20 patients who underwent routine thyroid surgery using c-IONM. The procedure of c-IONM follows the standard guidelines. Measurements of vagal stimulation were taken proximal(V3) and distal(V2) to APS electrode to document any injury to the vagus nerve. The blood pressure and pulse rate were also documented through-out surgery, looking at the physiological effect of the stimulation. The function of the vocal cord was assessed by pre and post-operative laryngoscopy&#x0D; Result: 18 patients with 29 nerves at risk were included as in two patients, the vagal stimulation did not achieve the acceptable amplitude (400 µV). There were drops of amplitude between V3 and V2 in 14 nerve at risks but there was clinical evidence of palsy on laryngoscopy. There were also fluctuation of mean arterial pressure and pulse rate but not significant enough to warrant intervention.&#x0D; Conclusion: The use of c-IONM during thyroidectomy do exert minimal effect on the vagus nerve and its function but not significant enough to abandoned the procedure. It is safe and able to help the surgeon to identify and preserve the nerve function especially in difficult thyroidectomy

Open Total Thyroidectomy with Continuous Intraoperative Nerve Monitoring

Introduction: Continuous intraoperative nerve monitoring (C-IONM) during thyroid surgery can be used to assess the recurrent laryngeal nerve (RLN) function and preventing unilateral and bilateral palsy. The main advantage of C-IONM using temporary implantable vagus electrode compared with the intermittent format (I-IONM) is the real-time monitoring of RLN integrity during thyroid mobilization and RLN dissection.1 Indeed, the I-IONM format using the handheld stimulation probe exposes the RLN to the risk of injury in between two stimulations. Therefore, the injury of the nerve can only be detected after the damage has already occurred, allowing to set to zero only bilateral RLN palsy by means of avoiding contralateral procedure (two-step surgery).2 In contrast, C-IONM provides the opportunity to perform the critical surgical actions necessary to avoid the impending RLN injury and enables to recover the RLN function after loss of signal, allowing to avoid even unilateral RLN palsy. Hereby we presented a video of a total thyroidectomy for a huge multinodular goiter performed with the help of C-IONM. Materials and Methods: A 54-year-old woman presented with a huge multinodular goiter. A total thyroidectomy performed with the help of C-IONM was planned. The surgical steps were illustrated and the anatomical structures identified. Results and Conclusions: C-IONM is a safe additional tool for thyroidectomy, which enables to perform the corrective maneuvers to avoid permanent nerve injury. If adequately used, it could prevent bilateral and unilateral RLN palsy. It results of great help in difficult cases, such as huge or recurrent multinodular goiter. No competing financial interests exist. Runtime of video: 7 mins 13 secs

Experience with the use of intraoperative continuous nerve monitoring in video-assisted neck surgery and external cervical incisions.

ObjectivesRecurrent laryngeal nerve (RLN) injury is one of the severe complications in thyroid surgery. Therefore, intraoperative nerve monitoring (IONM) has been widely used to identify the RLN and confirm its integrity. Recently, the usefulness of continuous IONM (CIONM) with automatic, periodic stimulation to the vagus nerve during thyroid surgery was reported. This study aimed to report our experience with minimally invasive video‐assisted endoscopic endocrine neck surgery (VANS), during which, CIONM was successfully applied for the first time.MethodsConsecutive patients who underwent thyroid surgery with CIONM, performed in our department using either external neck incision surgery or VANS between July 2017 and June 2019, were retrospectively analyzed.ResultsA total of 22 patients who underwent thyroid surgery with neck incision (14 cases; 7 men and 7 women; age, 21‐75 years [mean, 52 years]) or VANS (8 cases; 8 women, age, 20‐61 years [mean, 41 years]) were enrolled in this study. The addition of CIONM in VANS prolonged the operation's duration by approximately 30 minutes as the endoscopic surgery was technically more difficult. No intra‐ and postoperative incidence of transient or permanent RLN palsy was observed in any patient, except for three patients who underwent external neck incision surgery in whom combined resection was unavoidable due to tumor invasion of the RLN.ConclusionWe reported the first successful application of CIONM during thyroidectomy using VANS. Future clinical trials should clarify the benefits of CIONM when compared to intermittent IONM in VANS.Level of Evidence5.

Continuous Intraoperative Nerve Monitoring in Thyroidectomies: A Systematic Review and Meta-Analysis

Branchial clefts are most often associated with the pediatric population but can also affect adults. The adult population undergoing branchial cleft excision is poorly described. This study sought to describe the population and outcomes of those undergoing branchial cleft excision.

Intraoperative monitoring of the recurrent laryngeal nerve in surgeries for thyroid cancer: a review

Intraoperative nerve monitoring (IONM) has evolved into an objective tool not only for the identification but also for the preservation and prognostication of function of the recurrent laryngeal nerve in thyroid surgeries. Technical improvements have resulted in the increasing incorporation of IONM into operating rooms around the world. The importance of adherence to recommended standards is also recognized as being vital in optimizing the efficacy of IONM. The advent of continuous IONM has made real-time nerve monitoring possible, thus providing the surgeon with an ally in difficult surgeries. Additionally, as thyroid surgeries are evolving into remote access and minimally invasive procedures, so also is the applicability of IONM. This review focuses on the use of IONM for nerve monitoring in thyroidectomies for neoplastic conditions while discussing the rationale, technique, and interpretation of findings and their implications.