Recurrent laryngeal nerve monitoring during thoracoscopic esophagectomy

Short-term and long-term effects of recurrent laryngeal nerve injury after robotic esophagectomy

BACKGROUND

Robot-assisted minimally invasive esophagectomy (RAMIE) was reported to have superiority in upper mediastinal lymph nodes dissection than traditional approach, but related injuries to recurrent laryngeal nerve (RLNI) cannot be avoided. Considering that there is no study centering on RLNI during robotic manipulation, this study aimed to investigate the impact of RLNI on the short-term and long-term outcomes after RAMIE.

METHODS

Patients with esophageal cancer (EC) who underwent RAMIE from June 2015 to July 2019 were collated from a prospectively maintained database. Short-term and long-term outcomes of RLNI were analyzed.

RESULTS

A total of 409 patients were included with the incidence of RLNI being 18.6% (76/409). A higher rate of postoperative pulmonary complications including pneumonia (P < 0.001) and acute respiratory distress syndrome (ARDS) (P = 0.041) was associated with RLNI, requiring more interventions for bronchoscopy airway suction (P < 0.001), tracheal reintubation (P = 0.013) and tracheostomy (P < 0.001). Patients with RLNI had a prolonged length of hospitalization and intensive care unit (ICU) stay (P < 0.001). With the median follow-up time of 48.7 (interquartile range [IQR]:27.6-60.9) months, recurrence in regional lymph nodes at mediastinum did not differ between groups (P = 0.351). Similarly, the Kaplan-Meier curves revealed no significant divergency for overall survival after RLNI (P = 0.452).

CONCLUSIONS

RLNI after robotic esophagectomy is a serious morbidity associated with an increased rate of pulmonary complications, prolonged length of hospitalization with limited influence on long-term prognosis.

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.

Efficacy of Intraoperative Recurrent Laryngeal Nerve Monitoring During Thoracoscopic Esophagectomy for Esophageal Cancer: A Systematic Review and Meta-Analysis

Background: Recurrent laryngeal nerve paralysis (RLNP), a severe complication of mini-invasive esophagectomy, usually occurs during lymphadenectomy adjacent to recurrent laryngeal nerve. This systematic review and meta-analysis aimed to evaluate the efficacy of intraoperative nerve monitoring (IONM) in reducing RLNP incidence during mini-invasive esophagectomy. Methods: Systematic literature search of PubMed, EMBASE, EBSCO, Web of Knowledge, and Cochrane Library until June 4, 2021 was performed using the terms "(nerve monitoring) OR neuromonitoring OR neural monitoring OR recurrent laryngeal nerve AND (esophagectomy OR esophageal)." Primary outcome was postoperative RLNP incidence. Secondary outcomes were sensitivity, specificity, and positive and negative predictive values for IONM; complications after esophagectomy; number of dissected lymph nodes; operation time; and length of hospital stay. Results: Among 2,330 studies, five studies comprising 509 patients were eligible for final analysis. The RLNP incidence was significantly lower (odds ratio [OR] 0.33, 95% confidence interval [CI] 0.12-0.88, p < 0.05), the number of dissected mediastinal lymph nodes was significantly higher (mean difference 4.30, 95%CI 2.75-5.85, p < 0.001), and the rate of hoarseness was significantly lower (OR 0.14, 95%CI 0.03-0.63, p = 0.01) in the IONM group than in the non-IONM group. The rates of aspiration (OR 0.31, 95%CI 0.06-1.64, p = 0.17), pneumonia (OR 1.08, 95%CI 0.70-1.67, p = 0.71), and operation time (mean difference 7.68, 95%CI -23.60-38.95, p = 0.63) were not significantly different between the two groups. The mean sensitivity, specificity, and positive and negative predictive values for IONM were 53.2% (0-66.7%), 93.7% (54.8-100%), 71.4% (0-100%), and 87.1% (68.0-96.6%), respectively. Conclusion: IONM was a feasible and effective approach to minimize RLNP, improve lymphadenectomy, and reduce hoarseness after thoracoscopic esophagectomy for esophageal cancer, although IONM did not provide significant benefit in reducing aspiration, pneumonia, operation time, and length of hospital stay.

Intraoperative neuromonitoring during prone thoracoscopic esophagectomy for esophageal cancer reduces the incidence of recurrent laryngeal nerve palsy: a single-center study

The incidence of recurrent laryngeal nerve palsy (RLNP) following minimally invasive esophagectomy has yet to be satisfactorily reduced. Use of intraoperative neuromonitoring (IONM), specifically of the RLN, during thyroidectomy has been reported to reduce the incidence of RLN injury. We now apply IONM during curative prone thoracoscopic esophagectomy, and we conducted a retrospective study to evaluate the feasibility and efficacy of intermittent monitoring of the RLN during the surgery. The study involved 32 consecutive patients who underwent esophagectomy with radical lymph node dissection for esophageal cancer. The patients were of two groups: an IONM group (n = 17) and a non-IONM group (n = 15). We chiefly strip around the esophagus preserving the membranous structure, which contains the tracheoesophageal artery, lymph nodes, and RLN. In the IONM group patients, we stimulated the RLN and measured the electromyography (EMG) amplitude after dissection, at the dissection starting point and dissection end point on both sides. For the purpose of the study, we compared outcomes between the two groups of patients. IONM was carried out successfully in all 17 patients in the IONM group. The incidence of RLNP was significantly reduced in this group. We found that both RLNs can be identified by mean of IONM easily, immediately, and safely and that the EMG amplitude attenuation rate is particularly useful for predicting RLNP.

Efficacy of intraoperative recurrent laryngeal neuromonitoring during surgery for esophageal cancer

AIM

To evaluate the efficacy of intraoperative neuromonitoring in identifying recurrent laryngeal nerves and decreasing the incidence of nerve injury in minimally invasive esophagectomies for esophageal cancers.

METHODS

A total of 167 minimally invasive esophagectomy patients were retrospectively reviewed. They were divided into intraoperative neuromonitoring (n = 84) and no intraoperative neuromonitoring (n = 83) groups, based on whether or not intraoperative neuromonitoring was used during surgery. We compared short-term surgical outcomes and incidence of recurrent laryngeal nerve palsy between the two groups before and after propensity score matching. The association between the loss of signal and recurrent laryngeal nerve palsy was also evaluated.

RESULTS

The incidence of recurrent laryngeal nerve palsy (grade 2 and higher) was lower in the intraoperative neuromonitoring group than in the no intraoperative neuromonitoring group (6.0% vs 21.2%, P = 0.02). The rate of recurrent laryngeal nerve palsy recovery within 6 months was also significantly higher in the intraoperative neuromonitoring group (87.5% vs 20.0%, P < 0.01). The positive and negative predictive values of intraoperative neuromonitoring for recurrent laryngeal nerve palsy were 60% (9/15) and 86.9% (60/69), respectively. The duration from paralysis to recovery was shorter in recurrent laryngeal nerve palsy cases with negative loss of signal results than in cases with positive loss of signal results (median: 43 days vs 95 days).

CONCLUSION

Intraoperative neuromonitoring is useful in identifying recurrent laryngeal nerves and may aid in reducing the incidence of recurrent laryngeal nerve injury during esophageal surgery.

Recent advances in minimally invasive esophagectomy for squamous esophageal cancer

Over the past decade there has been tremendous development in the clinical application of minimally invasive esophagectomy (MIE) for the treatment of squamous esophageal carcinoma. The major challenges in the performance of MIE include limitations in visualization and manipulation within the confined, rigid thoracic cavity; the need for adequate patient positioning and anesthetic techniques to accommodate the surgical exposure; and changes in the surgical steps for achieving radical nodal dissection, especially for the superior mediastinum. The surgical procedure for MIE is more and more standardized, and there is an increasing practice of MIE worldwide. Randomized trials and meta-analyses have confirmed the advantages of MIE over open esophagectomy, including a significantly lower rate of complications and shorter hospital stays. The recent application of robotics technologies for MIE has further enhanced the quality and safety of the surgical dissection, while intraoperative nerve monitoring has contributed to a lower rate of recurrent laryngeal nerve palsy. With the application of new technologies, we expect further improvement in surgical outcomes for MIE in the treatment of squamous esophageal cancer.

Intraoperative Recurrent Laryngeal Nerve Monitoring During Pediatric Cardiac and Thoracic Surgery: A Mini Review

Objective: Review techniques for intraoperative recurrent laryngeal nerve (RLN) monitoring during pediatric surgery for esophageal atresia, tracheoesophageal fistula, tracheobronchomalacia, and cardiac surgery. Summary Background Data: Literature was reviewed for reports of intraoperative recurrent laryngeal nerve monitoring in cervical, thoracic, and cardiac surgical procedures which place the RLNs at risk for injury. Methods: Review paper. Results: The RLN is at risk during pediatric surgery for esophageal atresia, tracheoesophageal fistula, tracheobronchomalacia, and cardiac surgery. Intraoperative nerve monitoring has decreased rates of RLN injury in thyroid surgery. Intraoperative RLN monitoring techniques appropriate for pediatric surgery are discussed, including endotracheal tubes with integrated surface electrodes, adhesive surface electrodes for smaller endotracheal tubes, endolaryngeal electrodes, and automatic periodic continuous intra-operative stimulation. Conclusions: Multiple techniques exist to monitor the RLN in children undergoing cervical, cardiac, and thoracic surgery. Monitoring the RLN during procedures that place the RLNs at risk may help decrease the rate of RLN injury.

Effects of bronchial blockers on one-lung ventilation in general anesthesia: A randomized controlled trail

BACKGROUND

Double-lumen bronchial tubes (DLBT) and bronchial blockers (BB) are commonly used in the anesthesia for clinical thoracic surgery. But there are few systematic clinical comparisons between them. In this study, the effects of BB and DLBT on one-lung ventilation (OLV) are studied.

METHODS

The 200 patients with thoracic tuberculosis undergoing thoracic surgery, were randomly assigned to group A (DLBT) and group B (BB). Intubation time, hemodynamic changes (mean arterial pressure [MAP], heart rate [HR]), and arterial blood gas indicators (arterial partial pressure of carbon dioxide [PaCO2], arterial partial pressure of oxygen [PaO2], airway plateau pressure [Pplat], and airway peak pressure [Ppeak]) at 4 time points were recorded. Complications such as hoarseness, pulmonary infection, pharyngalgia, and surgical success rate were also evaluated postoperatively.

RESULTS

Intubation times were shorter in group B. Both MAP and HR in group A were significantly higher 1 minute after intubation than before, but also higher than those in group B. PaO2 levels were lower in both groups during (OLV) than immediately after anesthesia and after two-lung ventilation (TLV), with PaO2 being lower after 60 minutes of OLV than after 20 minutes of OLV. Furthermore, at both points during OLV, PaO2 was lower in group A than in group B. No significant differences in PaCO2 were found between the 2 groups. Ppeak and Pplat were increased in both groups during OLV, with both being higher in group A than in group B. The incidence of postoperative hoarseness, pulmonary infection, and pharyngalgia were lower in group B. There was no significant difference in the success rate of operation between the 2 groups.

CONCLUSIONS

Compare with using DLBT, implementation of BB in general anesthesia has less impact on hemodynamics, PaO2 and airway pressures, and achieves lower incidence of postoperative complication.

Combined recurrent laryngeal nerve monitoring and one-lung ventilation using the EZ-Blocker and an electromyographic endotracheal tube

Background

Intraoperative neuromuscular monitoring (IONM) is a widespread procedure to identify and protect the recurrent laryngeal nerve (RLN) during thyroid surgery. However, for left thoracic surgery with high risk of RLN injury, both reliable recurrent laryngeal nerve monitoring and one-lung ventilation could interfere.

Methods

In this prospective study, a new method for IONM during one-lung ventilation combining RLN monitoring with an electromyographic (EMG) endotracheal tube (ETT) and lung separation using the EZ-Blocker (EZB) is described and its clinical feasibility and effectiveness were assessed.

Results

A total of 14 patients undergoing left upper lobe surgery and left upper mediastinal lymph node dissection were enrolled. The EZB was introduced and positioned without any problems and sufficient lung collapse was achieved in all patients. No tracheobronchial injuries or immediate complications occurred. A stable EMG signal was present in all patients and no RLN palsy and no negative side effects of the NIM EMG ETT or the EZB were observed postoperatively.

Conclusions

The described method is technically feasible, easy to apply and save. It provides both reliable IONM and independent lung separation for optimal surgical exposure. The combined use of the EZB and the NIM EMG ETT might reduce the risk for RLN palsy and impaired lung separation during left thoracic surgery with high risk for RLN injury.

Resection of a Superior Mediastinal Mature Teratoma Using Intraoperative Neural Monitoring

A 33-year-old woman presented with a right cervical mass. Contrast computed tomography showed a multilocular tumor with a clear border and heterogeneous contents including fat and calcification. The tumor was located adjacent to the vagus and recurrent nerves. To avoid injury of these nerves, we resected the tumor through a median sternotomy and right cervical lateral incision. Intraoperative neural monitoring was performed using an NIM TriVantage EMG tube (Medtronic, Minneapolis, MN). After the surgery, no neuropathy such as hoarseness was recognized. Pathological diagnosis showed a benign mature teratoma. Intraoperative neural monitoring is useful for superior mediastinal surgery around the vagus and recurrent nerves.

Usefulness of intraoperative nerve monitoring in esophageal cancer surgery in predicting recurrent laryngeal nerve palsy and its severity

BACKGROUND

Recurrent laryngeal nerve (RLN) palsy is a critical postoperative complication in esophageal cancer surgery. However, intraoperative prediction of its occurrence and severity is difficult. In this prospective study, we evaluated the usefulness of intraoperative nerve monitoring (IONM) in predicting RLN palsy and its severity.

METHODS

Twenty patients who underwent subtotal esophagectomy with 3-field lymph node dissection were enrolled. Intraoperative electromyography (EMG) amplitudes of the vocal cords were measured by IONM at RLN and vagus nerve (VN) stimulation. Comparison was made between the vocal cords with RLN palsy and those without palsy and additionally between the vocal cords with transient RLN palsy and those with persistent palsy.

RESULTS

Among 40 vocal cords in 20 patients, 26 were intact and 14 were paralyzed. Seven had transient, six had permanent palsy. The mean EMG amplitude of intact vocal cords was significantly larger than that of paralyzed ones at VN (506 ± 498 µV vs. 258 ± 226 µV, p = 0.022) and RLN stimulation (642 ± 530 µV vs. 400 ± 308 µV, p = 0.038). The cut-off value for postoperative palsy were 419 µV [positive predictive value (PPV): 48.0%, negative predictive value (NPV): 84.6%] at VN and 673 µV (PPV: 44.8%, NPV: 90.9%) at RLN stimulation. The mean EMG amplitude of persistently paralyzed vocal cords tended to be small, compared with that of recovered ones at both VN (168 ± 173 µV vs. 336 ± 266 µV, p = 0.11) and RLN (244 ± 223 µV vs. 536 ± 344 µV, p = 0.051) stimulation.

CONCLUSION

The absolute EMG amplitude of IONM might be helpful to predict the occurrence and severity of RLN palsy after esophageal surgery although the predictive value is low.

Technique and surgical outcomes of mesenterization and intra-operative neural monitoring to reduce recurrent laryngeal nerve paralysis after thoracoscopic esophagectomy: A cohort study

BACKGROUND

Because the thoracic esophageal carcinoma has a high metastatic rate to the upper mediastinal lymph nodes, especially along the recurrent laryngeal nerves (RLN), it is crucial to perform a complete lymphadenectomy along the RLN without complications. Although intraoperative neural monitoring (IONM) during thyroid surgery has gained widespread acceptance as a useful tool for visual nerve identification, utilization of IONM during esophageal surgery has not become common. Here, we describe our procedures, focusing on a lymphadenectomy along the RLN utilizing the IONM.

METHODS

Eighty-seven patients who underwent prone esophagectomy between December 2009 and September 2017 were included in this study. We divided patients into two groups: neural monitoring group (Nm, n = 31) and conventional method group without IONM (Cm, n = 56). We first dissect around the esophagus, preserving the membranous structure; mesoesophagus, which contains tracheoesophageal artery; RLN; and lymph nodes (mesenterization). In Nm group, we next identify the location of the RLN, which runs in the mesoesophagus using IONM before visual contact. Next, we perform lymphadenectomy around the RLN, preserving the nerve itself. Early surgical outcomes were retrospectively compared between two groups.

RESULTS

In all 31 cases in the Nm group, we detected the location of the RLN before the visual contact. The sensitivity and specificity of the IONM to detect the RLN paralysis were 67% and 96%, respectively. Postoperative RLN paralysis was observed in 3 cases in the Nm group (9.7%), which was lower than that in the Cm group (32.1%, p = 0.03). Clavien-Dindo grade 2 and over aspiration were seen in 2 (Nm, 6.5%) and 16 (Cm, 28.6%) cases (p = 0.01), respectively. The postoperative hospital stay was shorter in the Nm group (22 days, median) than in the Cm group (39 days, median, p = 0.0002). The number of dissected mediastinal lymph nodes was similar in both groups (25 vs. 20, median, p = 0.12).

CONCLUSIONS

The combination of IONM and the concept of the mesoesophagus have substantial advantages in allowing accurate and safe mediastinal lymphadenectomy during prone esophagectomy.

Recurrent laryngeal nerve injury after esophagectomy for esophageal cancer: incidence, management, and impact on short- and long-term outcomes

BACKGROUND

Recurrent laryngeal nerve (RLN) injury caused by esophagectomy may lead to postoperative morbidity, however data on long-term recovery are scarce. The aim of this study was to evaluate the consequences of RLN palsy (RLNP) in terms of pulmonary morbidity and long-term functional recovery.

METHODS

Patients who underwent a 3-stage transthoracic (McKeown) or a transhiatal esophagectomy for esophageal carcinoma in the University Medical Center Utrecht (UMCU) between January 2004 and March 2016 were included from a prospective database. Multivariable analyses were conducted to assess the association between RLNP and pulmonary complications and hospital stay. Data regarding long-term recovery were summarized using descriptive statistics.

RESULTS

Out of the 451 included patients, 47 (10%) were diagnosed with RLNP. Of the patients with RLNP, 34 (7%) had a unilateral lesion, 8 (2%) had a bilateral lesion, and in 5 (1%) the location of the lesion was unknown. The incidence of RLNP was 3/127 (2%) in the transhiatal group, and 44/324 (14%) in the McKeown group. RLNP after McKeown esophagectomy was associated with a higher incidence of pulmonary complications (OR 2.391; 95% CI 1.222-4.679; P=0.011), as well as a longer hospital stay (+4 days) (P=0.001). Of the RLNP patients with more than 6 months follow up almost half recovered fully {median follow-up of 17.5 [7-135] months}. Of the remainder, six required a surgical intervention and the others had residual symptoms.

CONCLUSIONS

RLNP after McKeown esophagectomy is associated with an increased pulmonary complication rate, longer hospital stay, and a moderate long-term recovery. Further studies are necessary that examine technologies, which may reduce RLNP incidence and contribute to the early detection and treatment of RLNP.

Continuous Intraoperative Neuromonitoring Study Using Pigs for the Prevention of Mechanical Recurrent Laryngeal Nerve Injury in Esophageal Surgery

PURPOSES

During esophageal surgery, clamping injury and injury associated with the use of energy devices are common mechanisms underlying intraoperative recurrent laryngeal nerve (RLN) damage. Recently, intraoperative neuromonitoring (IONM) has been applied to prevent RLN injury. This study was aimed at investigating the changes in the EMG signals associated with clamping injury of the RLN caused by picking up of the nerve with tweezers in domestic pigs.

METHODS

Six domestic pigs (12 RLNs) underwent continuous IONM (CIONM) by our original automated periodic vagal nerve stimulation method.

RESULTS

Our system can be used safely and accurately. The signals showed a decrease of the amplitude when the RLN was picked up and closed slowly by the double-action Maryland with jaw covers. If the clamp was released before the signal amplitude decreased to 50% of the baseline, the signal showed gradual recovery to the baseline in 12 ± 3 minutes.

CONCLUSION

Although there were limitations in our study using domestic pig, including the small sample size, our results are expected to contribute to a decrease in the incidence of RLN damage during esophageal surgery.

Impact of routine recurrent laryngeal nerve monitoring in prone esophagectomy with mediastinal lymph node dissection

BACKGROUND

The problem of recurrent laryngeal nerve (RLN) paralysis (RLNP) after radical esophagectomy remains unresolved. Several studies have confirmed that intraoperative nerve monitoring (IONM) of the RLN during thyroid surgery substantially decreases the incidence of RLN damage. This study tried to determine the feasibility and effectiveness of IONM of the RLN during thoracoscopic esophagectomy in the prone position for esophageal cancer.

METHODS

All 108 patients who underwent prone esophagectomy at Tohoku University Hospital between July 2012 and March 2015 were included in this study. We divided patients into two groups: a control group (No-Monitoring group, surgery without IONM; n = 54) and a study group (Monitoring group, surgery with IONM; n = 54). In Monitoring group, neural stimulation was performed for both RLNs before and after dissection in the thoracic procedure, then for RLNs and vagus nerves (VNs) in the cervical procedure. The feasibility of IONM in Monitoring group and early surgical outcomes were retrospectively compared with those in No-Monitoring group.

RESULTS

IONM could be performed for 47 cases (87.0%) in Monitoring group. Reasons for discontinuation were use of muscle relaxants (3 patients), change in thoracotomy procedure (2 patients), past rib bone fracture (1 patient), and allergic shock by transfusion (1 patient). Right RLNPs were identified postoperatively in 4 patients, and left RLNPs in 23 patients. IONM sensitivities were 92.7 and 88.0% for the right and left VNs, respectively. Incidences of postoperative RLNP, aspiration, and primary pneumonia did not differ significantly between groups.

CONCLUSIONS

This study confirmed the feasibility and safety of IONM of the RLN for thoracoscopic esophagectomy in the prone position. No significant differences in postoperative outcomes were seen between esophagectomy with and without IONM.