[Five-step maneuver of transthoracic single-port assisted laparoscopic lower mediastinal lymph node dissection for Siewert type Ⅱ adenocarcinoma of the esophagogastric junction].

Surgical operation is the main treatment for advanced adenocarcinoma of esophagogastric junction (AEG). Due to its special anatomic location and unique lymph node reflux mode, the surgical treatment of Siewert II AEG is controversial. Lower mediastinal lymph node dissection is one of the most controversial points and a standard technique has not yet been established. This study is aim to explore the safety and feasibility of five-step maneuver of transthoracic single-port assisted laparoscopic lower mediastinal lymph node dissection for Siewert type II AEG. A descriptive case series study was conducted. The intraoperative and postoperative data of 25 patients with Siewert type II AEG who underwent five-step maneuver of transthoracic single-port assisted laparoscopic lower mediastinal lymph node dissection in Guangdong Provincial Hospital of Traditional Chinese Medicine from January 2019 to April 2021 were retrospectively analyzed. Five-step maneuver was as follows: In the first step, the subcardiac sac was exposed; the right pulmonary ligament lymph nodes and the anterior thoracic paraaortic lymph nodes were dissected cranial to inferior pericardium, left to left edge of thoracic aorta. In the second step, the left diaphragm was opened, and a 12 mm trocar was placed through the 6-7 rib in the left anterior axillary line. The supra-diaphragmatic nodes were dissected through the thoracic operation hole. In the third step, the left inferior pulmonary ligament was severed. The anterior fascia of thoracic aorta was incised to join the anterior space of thoracic aorta formed in the first step and then the lymphatic tissue was dissected upward until the exposure of left inferior pulmonary vein. In the fourth step, the posterior pericardium was denuded retrogradely from ventral side to oral side to the level of left inferior pulmonary vein, right to right pleura, and then the right pulmonary ligament lymph nodes were completely removed. In the fifth step, the esophagus was denuded, and the esophagus was transected 5 cm above the tumor using a linear stapler to complete the dissection of lower thoracic paraesophageal lymph nodes. Operations were successfully completed in 25 patients without conversion, intra-operative complication and perioperative death. Total gastrectomy was performed in 19 cases and proximal gastrectomy in 6 cases. The mean operative time was (268.7±85.6) minutes, the mean estimated blood loss was (90.4±44.2) ml, the mean time of lower mediastinal lymph node dissection was (38.6±10.3) minutes, and the mean harvested number of lower mediastinal lymph node was 5.9±2.9. The length of esophageal invasion was >2 cm in 7 cases and ≤ 2 cm in 18 cases. Eight patients (33.0%) had lower mediastinal lymph node metastasis, including 3 cases with esophageal invasion >2 cm and 5 cases with esophageal invasion ≤ 2 cm. The mean time to postoperative first flatus was (5.5±3.1) days. The average time of postoperative thoracic drainage was (5.9±2.9) days. The mean hospital stay was (9.7±3.1) days. Two patients (8.0%) developed postoperative grade IIIa complications according to the Clavien-Dindo classification, including 1 case of pancreatic fistula and 1 case of pleural effusion, both of whom were cured by puncture drainage. Five-step maneuver of transthoracic single-port assisted laparoscopic lower mediastinal lymph nodes dissection for Siewert type II AEG is safe and feasible. Which can ensure sufficient lower mediastinal lymph node dissection to the level of left inferior pulmonary vein.