Improving Outcome of Superior Mediastinal Lymph Node Dissection During Esophagectomy: A Novel Approach Combining Continuous and Intermittent Recurrent Laryngeal Nerve Monitoring

Impact of intraoperative recurrent laryngeal nerve monitoring on minimally invasive esophagectomy outcomes for esophageal cancer: a meta-analysis of case-control studies

Esophagectomy and lymphadenectomy for esophageal cancer carry an inherent risk of recurrent laryngeal nerve (RLN) injury. Intraoperative nerve monitoring (IONM) may help prevent RLN damage, though evidence on its effectiveness is still limited. This systematic review and meta-analysis (SRMA) evaluate the feasibility and efficacy of IONM during minimally invasive esophagectomy (MIE) for esophageal cancer. This SRMA followed Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) and Meta-Analysis of Observational Studies in Epidemiology (MOOSE) guidelines, with a registered protocol on PROSPERO (CRD42022367916). Two independent authors conducted a comprehensive literature search across multiple databases, screening studies on MIE for esophageal cancer using IONM. Case-control studies were included, focusing on the RLN palsy (RLNP) rate as the primary outcome. A total of 11 studies involving 1907 patients (IONM group: 752 patients; non-IONM group: 1155 patients) were included in the SRMA. IONM significantly reduced the incidence of RLNP (OR = 0.47, P < 0.001). Length of hospital stay (LOHS) and lower respiratory tract infection (LRTI) rates were significantly reduced with IONM use. No significant differences were observed in anastomotic leak, chylothorax, total number of lymph nodes dissected, operation time, aspiration rates, or intraoperative blood loss. The pooled sensitivity and specificity of IONM for detecting RLN injury were 83.3% and 81%, respectively. IONM during MIE significantly reduces the incidence of RLNP, postoperative LRTI, and shortens the LOHS, without adding operative risks. Further research is needed to evaluate its long-term survival benefits and cost-effectiveness.

Intraoperative Recurrent Laryngeal Nerve Monitoring for Esophagectomy: A National Cohort Study

BACKGROUND

Lymphadenectomy around the recurrent laryngeal nerve (RLN) is an essential part of curative surgery for esophageal cancer. Although several single-center studies have shown that intraoperative nerve monitoring (IONM) can avoid RLN palsy, this has not been confirmed in a large-scale multicenter study. This study used a national database to evaluate whether IONM can reduce postoperative RLN palsy during minimally invasive esophagectomy (MIE) for esophageal cancer.

METHODS

We retrieved data of patients with esophageal cancer who underwent 3-field thoracoscopic or robotic MIE with cervical anastomosis with IONM(+) (502 patients) and without IONM(-) (4353 patients) from April 2020 to March 2022 from the Diagnosis Procedure Combination database in Japan. We used propensity score-matching analysis to compare the frequency of postoperative RLN palsy and respiratory complications between the IONM(+) group and IONM(-) group.

RESULTS

The postoperative RLN palsy rate was significantly lower in the IONM(+) than IONM(-) group (odds ratio, 0.24; 95% CI, 0.13-0.46). The respiratory complication rate was also significantly lower in the IONM(+) than in the IONM(-) group (odds ratio, 0.66; 95% CI, 0.45-0.97). The anesthesia time was significantly longer in the IONM(+) group (regression coefficient, 60.1 minutes; 95% CI, 44.2-76.9 minutes). The length of postoperative hospitalization tended to be shorter in the IONM(+) than in the IONM(-) group (regression coefficient, -1.39 days; 95% CI, -3.91 to 1.14).

CONCLUSIONS

This national cohort study showed that IONM during 3-field MIE for esophageal cancer was associated with a reduction of postoperative RLN palsy and respiratory complications.

Lymph Node Metastasis for pN+ Superficial Esophageal Squamous Cell Carcinoma

OBJECTIVES

This study aimed to analyze lymph node metastasis (LNM) distribution in superficial esophageal squamous cell carcinoma (ESCC) and its impact factors on survival.

METHODS

We reviewed 241 pT1N+ ESCC cases between February 2012 and April 2022 from 10 Chinese hospitals with a high volume of esophageal cancer (EC). We analyzed clinicopathological data to identify overall survival (OS) risk factors and LNM distribution in relation to tumor invasion depth.

RESULTS

Of the 241 patients, 26 (10.8%) had pT1a cancer and 215 (89.2%) had pT1b cancer. We showed that N3 stage, ≤ 28 lymphadenectomies, and nerve infiltration (NI) were negative factors for OS in superficial pN+ ESCC, whereas the OS was not definitively affected by the tumor depth and the choice of adjuvant therapy. In general, the LNM rates of the 193 pT1N+ ESCC cases can be ranked in the following order: station 106recR > station 106recL > station 1 > station 7 > station 2. With deeper tumor invasion, the higher LNM rate was observed near the bilateral recurrent laryngeal nerves (RLN), but there was no statistically significant difference.

CONCLUSIONS

In superficial ESCC, LNM was frequently observed along the 106recR (35.8%) and 106recL (25.6%) stations. Advanced N-staging (N3) was a major negative impact factor in prognosis, and adequate lymph nodes dissected (LND) (N > 28) improved OS of pT1N+ ESCC. However, in superficial ESCC, tumor infiltration depth did not affect patients' OS or the distribution of positive LNs. The optimal adjuvant treatment that favors survival for these patients required further investigation.

Usefulness of an Artificial Intelligence Model in Recognizing Recurrent Laryngeal Nerves During Robot-Assisted Minimally Invasive Esophagectomy

BACKGROUND

Recurrent laryngeal nerve (RLN) palsy is a common complication in esophagectomy and its main risk factor is reportedly intraoperative procedure associated with surgeons' experience. We aimed to improve surgeons' recognition of the RLN during robot-assisted minimally invasive esophagectomy (RAMIE) by developing an artificial intelligence (AI) model.

METHODS

We used 120 RAMIE videos from four institutions to develop an AI model and eight other surgical videos from another institution for AI model evaluation. AI performance was measured using the Intersection over Union (IoU). Furthermore, to verify the AI's clinical validity, we conducted the two experiments on the early identification of RLN and recognition of its location by eight trainee surgeons with or without AI.

RESULTS

The IoUs for AI recognition of the right and left RLNs were 0.40 ± 0.26 and 0.34 ± 0.27, respectively. The recognition of the right RLN presence in the beginning of right RLN lymph node dissection (LND) by surgeons with AI (81.3%) was significantly more accurate (p = 0.004) than that by surgeons without AI (46.9%). The IoU of right RLN during right RLN LND recognized by surgeons with AI (0.59 ± 0.18) was significantly higher (p = 0.010) than that by surgeons without AI (0.40 ± 0.29).

CONCLUSIONS

Surgeons' recognition of anatomical structures in RAMIE was improved by our AI system with high accuracy. Especially in right RLN LND, surgeons could recognize the RLN more quickly and accurately by using the AI model.

Occurrence and recovery of vocal cord paralysis after minimally invasive McKeown esophagectomy, risk factors, and clinical outcome

BACKGROUND

This study aimed to observe the occurrence of recurrent laryngeal nerve injury after McKeown esophagectomy for esophageal squamous cell carcinoma, as well as its recovery and influencing factors within 7 months after surgery.

METHODS

From July 2020 to July 2021, among all patients who underwent minimally invasive McKeown esophagectomy, 90 patients who developed vocal cord paralysis after surgery were included in the study. These patients underwent endoscopic vocal cord function assessment every 1 to 2 months and continued until 7 months postoperatively.

RESULTS

Among all 388 patients undergoing esophagectomy, 23.2% (90/388) of patients suffered postoperative vocal cord paralysis. Left, right, and bilateral injuries were confirmed in 73 (81.1%), 12 (13.3%), and 5 patients (5.6%), respectively. With a median recovery time being 183 days, the cumulative overall recovery rate was 65.4% at 7 months, 68.6% for the left side, 55.6% for the right, and 20.0% for bilateral injuries. In multivariable analysis, cervical paraoesophageal lymph node dissection and conventional thoracoscopic-assisted esophagectomy were demonstrated to be independent risk factors associated with non-recovery of vocal cord paralysis.

CONCLUSIONS

After intensive endoscopic follow-up, a cumulative vocal cord paralysis recovery rate of 65.4% within 7 months was observed in patients after minimally invasive McKeown esophagectomy. Cervical paraoesophageal lymph node dissection and conventional thoracoscopic-assisted esophagectomy were demonstrated to be risk factors hindering vocal cord paralysis recovery.

Recurrent Laryngeal Nerve Intraoperative Neuromonitoring Indications in Non-Thyroid and Non-Parathyroid Surgery

Introperative nerve monitoring (IONM) of the recurrent laryngeal nerve (RLN) is a well-established technique to aid in thyroid/parathyroid surgery. However, there is little evidence to support its use in non-thyroid or non-parathyroid surgery. The aim of this paper was to review the current evidence regarding the use of IONM in non-thyroid/non-parathyroid surgery in the head and neck and thorax. A literature search was performed from their inception up to January 2024, including the term "recurrent laryngeal nerve monitoring". IONM in non-thyroid/non-parathyroid surgery has mainly been previously described in oesophageal surgery and in tracheal resections. However, there is little published evidence on the role of IONM with other resections in the vicinity of the RLN. Current evidence is low-level for the use of RLN IONM in non-thyroid/non-parathyroid surgery. However, clinicians should consider its use in surgery for pathologies where the RLN is exposed and could be injured.

Robotic esophagectomy with outermost layer-oriented dissection for esophageal cancer: technical aspects and a retrospective review of a single-institution database

BACKGROUND

Systematic lymph node dissection in patients with gastric cancer could be sufficiently and reproducibly achieved along the outermost layer of the autonomic nerves and similar concept has been extensively used for robotic esophagectomy (RE) since 2018. This study aimed to determine the surgical and oncological safety of RE using the outermost layer-oriented approach for esophageal cancer (EC).

METHODS

Sixty-six patients who underwent RE with total mediastinal lymphadenectomy for primary EC between April 2018 and December 2021 were retrospectively reviewed. All underwent the outermost layer-oriented approach with intraoperative nerve monitoring (IONM). Postoperative complications within 30 days were analyzed.

RESULTS

Among the patients, 51 (77.3%) were male. The median age was 64 years, and the body mass index was 21.8 kg/m2. Furthermore, 58 (87.9%) patients had squamous cell carcinoma and eight (12.1%) patients had adenocarcinoma. Clinical stages I, II, and III were seen in 23 (34.8%), 23 (34.8%), and 16 (24.2%) patients, respectively. Thirty-four (51.5%) patients received preoperative treatment. No patient shifted to conventional thoracoscopic or open procedure intraoperatively. The median operative time was 716 min with 119 mL of blood loss. Additionally, 64 (97%) patients underwent R0 resection. The morbidity rates based on Clavien-Dindo grades ≥ II and ≥ IIIa were 30.3% and 10.6%, respectively, within 30 postoperative days. None died within 90 days postoperatively. Three (4.5%) patients exhibited recurrent laryngeal nerve (RLN) palsy (CD grade ≥ II). The sensitivity and specificity of IONM for RLN palsy were 50% and 98.3% at the right RLN and 33.3% and 98.0% at the left RLN, respectively.

CONCLUSION

RE with the outermost layer-oriented approach can provide safe short-term outcomes.

The TOFr of 0.75 to 0.85 is the optimal timing for IONM during thyroid surgery: a prospective observational cohort study

BACKGROUD

Recurrent laryngeal nerve (RLN) injury is one of the serious complications of thyroid tumour surgery, surgical treatment of thyroid cancer requires careful consideration of the RLN and its impact on glottis function. There has been no unified standard for precise neuromuscular block monitoring to guide the monitoring of RLN in thyroid surgery. This study aimed to investigate the correlation between Train-of-four stabilization ratio (TOFr) and neural signal values of intraoperative neurophysiological monitoring (INOM) during thyroid operation, and further to determine the optimal timing for INOM during thyroid operation.

METHODS

Patients scheduled for thyroid tumour resection with INOM and RLN monitoring from April 2018 to July 2018 in our center were recruited. Electromyography (EMG) signals and corresponding TOFr were collected. All nerve stimulation data were included in group VR. Vagus nerve stimulation data were included in Subgroup V. RLN stimulation data were included in Subgroup R. The timing of recording was as follows: Vagus nerve EMG amplitude after opening the lateral space between the thyroid and carotid sheath and before the initiation of thyroid dissection, RLN EMG amplitude at first recognition, RLN EMG amplitude after complete thyroid dissection (Repeat three times), and Vagus nerve EMG amplitude after resection of the thyroid (Repeat three times). Correlation analysis of continuous variables was described by a scatter diagram. Pearson correlation analysis or Spearman correlation analysis was used for the two groups of variables.

RESULTS

Finally, 134 vagus nerve signals and 143 RLN signals were analysed after matching with TOFr. The EMG amplitude in the VR group and subgroups after nerve stimulation was positively correlated with TOFr (p < 0.05). In the VR, V and R group, the incidence of EMG ≥ 500 µV in the 0.75 < TOFr ≤ 0.85 interval was significantly higher than the 0 < TOFr ≤ 0.75 interval (P = 0.002, P = 0.013 and P = 0.029), and has no statistical difference compared to 0.85 < TOFr ≤ 0.95 interval (P > 0.05).

CONCLUSIONS

The EMG signals of the RLN and vagus nerve stimulation during thyroid surgery were positively correlated with TOFr. TOFr > 0.75 could reflect more than 50% of the effective nerve electrophysiological signals, 0.75 < TOFr ≤ 0.85 interval was the optimal timing for IONM during thyroid surgery.

TRIAL REGISTRATION

Chinese Clinical Trial Registry (ChiCTR1800015797) Registered on 20/04/2018. https://www.chictr.org.cn .

Application of Intraoperative Neuromonitoring (IONM) of the Recurrent Laryngeal Nerve during Esophagectomy: A Systematic Review and Meta-Analysis

BACKGROUND

recurrent laryngeal nerve palsy (RLNP) is a common and severe complication of esophagectomy in esophageal cancer (EC). Several studies explored the application of intraoperative neuromonitoring (IONM) in esophagectomy to prevent RLNP. The purpose of this study was to conduct a systematic review and meta-analysis to evaluate the value of IONM in esophagectomy for EC.

METHODS

an electronic of the literature using Google Scholar, PubMed, Embase, and Web of Science (data up to October 2022) was conducted and screened to compare IONM-assisted and conventional non-IONM-assisted esophagectomy. RLNP, the number of mediastinal lymph nodes (LN) dissected, aspiration, pneumonia, chylothorax, anastomotic leakage, the number of total LN dissected, postoperative hospital stay and total operation time were evaluated using Review Manager 5.4.1.

RESULT

ten studies were ultimately included, with a total of 949 patients from one randomized controlled trial and nine retrospective case-control studies in the meta-analysis. The present study demonstrated that IONM reduced the incidence of RLNP(Odds Ratio (OR) 0.37, 95% Confidence Interval (CI) 0.26-0.52) and pneumonia (OR 0.58, 95%CI 0.41-0.82) and was associated with more mediastinal LN dissected (Weighted Mean Difference (WMD) 4.75, 95%CI 3.02-6.48) and total mediastinal LN dissected (WMD 5.47, 95%CI 0.39-10.56). In addition, IONM does not increase the incidence of aspiration (OR 0.4, 95%CI 0.07-2.51), chylothorax (OR 0.55, 95%CI 0.17-1.76), and anastomotic leakage (OR 0.78, 95%CI 0.48-1.27) and does not increase the total operative time (WMD -12.33, 95%CI -33.94-9.28) or postoperative hospital stay (WMD -2.07 95%CI -6.61-2.46) after esophagectomy.

CONCLUSION

IONM showed advantages for preventing RLNP and pneumonia and was associated with more mediastinal and total LN dissected in esophagectomy. IONM should be recommended for esophagectomy.

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.

A survey of the clinical outcomes of cervical esophageal carcinoma surgery focusing on the presence or absence of laryngectomy using the National Clinical Database in Japan

BACKGROUND

One upside of cervical esophageal carcinoma is that radical surgery can be performed by laryngectomy, even for tumors with tracheal invasion. However, this approach drastically reduces the quality of life, such as by losing the vocal function. Cervical esophageal carcinoma is rare, and no comprehensive reports have described the current state of surgery. Using a Japanese nationwide web-based database, we analyzed the surgical outcomes of cervical esophageal carcinoma to evaluate the impact of larynx-preserving surgery.

METHODS

Based on the Japan National Clinical Database, 215 surgically treated cases of cervical esophageal carcinoma between January 1, 2018, and December 31, 2019, were enrolled. Clinical outcomes were compared between the larynx-preserved group and the laryngectomy group.

RESULTS

Ninety-four (43.7%) patients underwent larynx-preserving surgery. A total of 177 (82.3%) patients underwent free jejunum reconstruction. More T4b patients and more patients who underwent preoperative radiotherapy were in the laryngectomy group. There were no significant differences in the frequency and the severity of morbidities between the two groups. However, in the laryngectomy group, in-hospital death within 30 days after surgery was observed in 1 patient, and the postoperative hospital stay was significantly longer (P = 0.030). In the larynx-preserved group, recurrent nerve paralysis was observed in 24.5%. Re-operation (35.3%, P = 0.016), re-intubation (17.6%, P = 0.019) and tracheal necrosis (17.6%, P = 0.028) were significantly more frequent in patients who underwent pharyngolaryngectomy with total esophagectomy and gastric tube reconstruction than in others.

CONCLUSION

Larynx-preserving surgery was therefore considered to be feasible because it was equivalent to laryngectomy regarding the short-term surgical outcomes.