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.

The Value of Paratracheal Lymphadenectomy in Esophagectomy for Adenocarcinoma of the Esophagus or Gastroesophageal Junction: A Systematic Review of the Literature

Background The role of upper mediastinal lymphadenectomy for distal esophageal or gastroesophageal junction (GEJ) adenocarcinomas remains a matter of debate. This systematic review aims to provide a comprehensive overview of evidence on the incidence of nodal metastases in the upper mediastinum following transthoracic esophagectomy for distal esophageal or GEJ adenocarcinoma. Methods A literature search was performed using Medline, Embase and Cochrane databases up to November 2020 to include studies on patients who underwent transthoracic esophagectomy with upper mediastinal lymphadenectomy for distal esophageal and/or GEJ adenocarcinoma. The primary endpoint was the incidence of metastatic nodes in the upper mediastinum based on pathological examination. Secondary endpoints were the definition of upper mediastinal lymphadenectomy, recurrent laryngeal nerve (RLN) palsy rate and survival. Results A total of 17 studies were included and the sample sizes ranged from 10-634 patients. Overall, the median incidence of upper mediastinal lymph node metastases was 10.0% (IQR 4.7-16.7). The incidences of upper mediastinal lymph node metastases were 8.3% in the 7 studies that included patients undergoing primary resection (IQR 2.0-16.6), 4,4% in the 1 study that provided neoadjuvant therapy to the full cohort, and 10.6% in the 9 studies that included patients undergoing esophagectomy either with or without neoadjuvant therapy (IQR 8.9-15.8%). Data on survival and RLN palsy rates were scarce and inconclusive. Conclusions The incidence of upper mediastinal lymph node metastases in distal esophageal adenocarcinoma is up to 10%. Morbidity should be weighed against potential impact on survival.

770 CONSIDERABLE EFFECT OF UPPER MEDIASTINAL LYMPHADENECTOMY UNDER LAPAROSCOPIC ASSISTED SINGLE-PORT INFLATABLE MEDIASTINOSCOPY THROUGH LEFT NECK APPROACH

Conventional minimally invasive esophagectomy requires transthoracic surgery, which could increase the risk of many perioperative complications. Mediastinoscopy-assisted transhiatal esophagectomy has been proposed for years, but the traditional methods have shortcomings, such as unclear vision, especially during the dissection of upper mediastinal lymph nodes. We proposed a novel approach of upper mediastinal lymphadenectomy with mediastinoscopy through a left-neck incision, and investigated the effect of lymphadenectomy and other perioperative outcomes. Methods This approach for upper mediastinal lymphadenectomy includes three parts. (I) Lymphadenectomy along the left recurrent laryngeal nerve (RLN) could be accomplished during esophagectomy under mediastinoscopy. (II) At the level of the lower edge of the right subclavian artery (RSA), between the trachea and the esophagus, instruments are used to access the right RLN. Lymphadenectomy of up to 2 cm could be accomplished at the upper edge of the RSA. (III) Between the trachea and esophagus, the left and right main bronchi are exposed along the trailing edge of the trachea down to the carina, and lymphadenectomy can be performed here. Results This lymphadenectomy had been completed successfully on 117 patients, and 1 was converted to thoracotomy due to intraoperative tracheal membrane damage. The average operation time was 181.4 ± 43.2 minutes, bleeding volume was 106.4 ± 87.9 mL. The number of dissected LNs of upper mediastinal, the left RLN, the right RLN and the subcarinal was 11.2 ± 6.3, 5.1 ± 2.8, 3.2 ± 1.3 and 3.8 ± 2.1 respectively. 10 cases of (8.5%) anastomotic fistula were resolved with proper drainage and nutritional support. There were 25 cases (21.2%) of anastomotic strictures, 10 cases (8.5%) of pleural effusion, 20 cases (16.9%) of hoarseness. The incidence of hoarseness was 2.5% in three months postoperation. Conclusion These results showed that the lymphadenectomy through the left neck approach was not inferior than other surgical approaches in the amount of upper mediastinal LNs resection and perioperative outcome. Further research is needed to discover its impact on the long-term prognosis of ESCC patients.

263 MEDIASTINAL LYMPHADENECTOMY UNDER LAPAROSCOPIC ASSISTED SINGLE-PORT INFLATABLE MEDIASTINOSCOPY THROUGH LEFT NECK APPROACH

Minimally invasive esophagectomy (MIE) has developed for decades. However, conventional MIE requires transthoracic operation, it could increase the risk of many perioperative cardiopulmonary complications. Therefore, mediastinoscopy-assisted transhiatal esophagectomy has been proposed, but the traditional surgical methods have shortcomings, such as unclear vision, especially during the dissection of mediastinal lymph nodes. A new approach of mediastinal lymphadenectomy under single-port inflatable mediastinoscopy through one left-neck incision was proposed. Methods With pneumomediastinum, esophagectomy was to be performed over the aortic arch to the level of lower edge of the left main bronchus, and the lymphadenectomy of 106recL has also accomplished during this process. At the level of lower edge of the right subclavian artery (RSA), between the trachea and the esophagus, the instruments could get accessed to the right RLN. The lymphadenectomy could get accomplished up to 2-cm at the upper edge of the RSA. Between the trachea and esophagus, the lymphadenectomy of 107 would be performed along the trailing edge of the trachea down to the carina. Results 56 patients with esophageal squamous cell carcinoma from March to September 2019 who underwent this operation. The mean age of 56 patients was 67.4 years, 46 were males, and 10 were females. Preoperative TNM staging: T1b, 10 cases; T2, 35 cases; and T3, 11 cases. The median number of mediastinal LNs removed was 17 (9 to 23); 6 (2 to 9) along the left RLN; 3 (1 to 6) along the right RLN. 7 patients (12.5%) developed RLN palsy. All of the 7 RLN palsy were left side, none of them appeared at 3-month postoperation. Conclusion This single-port inflatable mediastinoscopy technology could remove the upper mediastinal LNs on both sides with a single incision on the left neck, avoid trauma to the right neck. The bilateral RLN could be clearly exposed and protected under the mediastinoscopy. Compared with previous surgical techniques, this surgery is less invasive, and the bilateral RLN is more clearly revealed. The surgical procedure described here is the first mediastinal lymphadenectomy under mediastinoscopy through one single left-neck incision. Video https://www.jianguoyun.com/p/DUvIaIsQoPWPBhj1mt8C.

9 SURGICAL TECHNIQUES AND POTENTIAL OF MEDIASTINAL LYMPHADENECTOMY IN ROBOTIC SURGERY

Procedure of minimally invasive esophagectomy in prone position (Conventional prone-MIE) is standardized leading to feasible short outcomes. On the other hand, robot assisted MIE (Robotic MIE) was approved as Japanese health insurance treatment since 2018. Especially, reduction of recurrent laryngeal nerve (RLN) palsy leading to aspiration pneumonia is expected for Robotic MIE. The purpose of this study is to clarify the potential of Robotic MIE for improvement of short outcomes. Methods Twenty-four Robotic MIEs in introduction period since 2018 and 128 Conventional prone-MIEs in established period since 2015 from all of the 375 cases were compared using propensity score matching. Results Operative times in both entire and thoracic procedures were significantly longer in Robotic MIE. There were no significant differences between two groups in the number of harvested lymph nodes, amount of the blood loss, left RLN palsy rate (13% vs 14%, > Clavien-Dindo classification: C-D grade I), right RLN palsy rate (4% vs 8%, > C-D grade I), and pneumonia rate (7% vs 7%, > C-D grade II). Conclusion Short outcomes of Robotic MIE in introduction period were not inferior to those of Conventional prone-MIE in established period. More improvement is expected for Robotic MIE via learning curve. In conclusion, Robotic MIE has hidden potential to outstrip Conventional prone-MIE in outcomes. Video https://www.dropbox.com/s/7byc8nsqupgetsp/2020%20ISDE%20movie%20for%20submission.wmv?dl=0.

745 YIELD OF EXTENDED AND TOTAL MEDIASTINAL LYMPHADENECTOMY IN OESOPHAGEAL CANCER

The extent of lymphadenectomy in oesophageal cancer surgery is currently controversial, although current evidence shows that survival is directly related to the number of lymph nodes removed during surgery. Methods Descriptive study of patients with oesophageal cancer who underwent oesophagectomy with extended and total mediastinal lymphadenectomy using a minimally invasive approach (right prone thoracoscopy, laparoscopy and left cervicotomy) in our hospital for 2 years (2019 and 2020). Extended lymphadenectomy was indicated in patients with adenocarcinoma of the distal oesophagus, while total lymphadenectomy was indicated in patients with squamous tumours and adenocarcinoma of the middle oesophagus. The characteristics of the series studied and the results obtained in the 90 days postoperatively are described. Results 26 patients, mean age 65 ± 7.8 years, were operated. 21 with total mediastinal lymphadenectomy and 5 with extended lymphadenectomy. 80.7% received neoadjuvant treatment (CROSS scheme). The mean number of lymph nodes removed was 33.6 ± 14.3, with a 50% probability of being affected. As much in the lymphadenectomy of the right (106R) as in the left (106 L) recurrent groups, it was more frequently affected in the distal oesophagus adenocarcinomas. Postoperative morbidity was not negligible, with anastomotic leak rate of 7.7% (thoracic location) and 23.1% (cervical location) the majority mild, 23.1% of recurrent injury and 11.5% of chylothorax. Mortality at 90 days was 15.38%. Conclusion Based on our results, extended and total lymphadenectomy increases as much the global number of lymph nodes removed as the lymph nodes cancer-positive. In addition, it supports the performance of wide lymphadenectomies also in adenocarcinomas of the distal oesophagus. We cannot forget the greater radicalism is taxed with significant morbidity. We should remember the limitation of this study is the low number of cases, the extent of lymphadenectomy continues to be a matter of controversy.