Patients and specimens
This study was conducted at the Sixth Medical Center of PLA General Hospital. From February 2018 to January 2019, 60 consecutive patients suffering from AEG type II were chosen for this study. Endoscopy and computed tomography (CT) were included in the preoperative diagnostic evaluation. All the tumors covered in this study were histologically proven as AEG and defined as Siewert type II AEG. Tumor stage was classified based on the 8th edition of the TNM staging system of the International Union Against Cancer (UICC) for GC. Furthermore, the lymph node stations were numbered based on the definitions of the Japanese Gastric Cancer Association[8].
More than 200 laparoscopic gastrectomy procedures have been performed by the same surgical group each year. This group obtained professional training for laparoscopic surgery beforehand. The possible risks and complications were known to the patients. All patients provided written informed consent before the operation, and this study was approved by the ethics committee of our hospital (Number of ethics approval: 2017011). The clinicopathological features of the patients are summarized in Table 1.
Surgical procedure
Typically, under general anesthesia, the patients were placed in a reverse Trendelenburg position with their legs apart. The umbilicus was chosen for the camera port, which can permit a flexible laparoscope to be introduced with a 10-mm trocar. Altogether, four other trocars were inserted into the upper abdomen, which is demonstrated in Figure 1. During this process, the assistant stood on the right side of the patient, while the surgeon usually stood on the left side of the patient. The video laparoscope operator filmed from a distal position and stood between the patients’ legs.
The abdominal cavity was explored and revealed no metastases in the greater omentum, peritoneum, free fluid or liver. During the process of mobilizing the stomach, the left gastroepiploic artery (No. 4sb), the short gastric artery (No. 4sa) and other lymph nodes were removed. Subsequently, the suprapancreatic lymph nodes were excised. This led to the removal of the lymph nodes around the left gastric artery (No. 7), common hepatic artery (No. 8a, No. 8p), celiac artery (No. 9), and proximal splenic artery (No. 11p). The lower perigastric lymph nodes (No. 5, No. 6) were removed during routine D2 lymphadenectomy.
The left gastric artery was classified and ligatured. Afterwards, the abdominal esophagus was exposed circumferentially by the phrenoesophageal ligament. Both sides of the crus were cut open to release the cardia esophagus. During the operation, the right pericardial (No. 1), left pericardial (No. 2), and lesser curvature (No. 3) lymph nodes were thoroughly removed. The laparoscopic dissection of the mediastinal lymph nodes was obstructed by the diaphragm around the lower esophagus. A 10 cm anterior incision was made routinely in the diaphragmatic crus via a coagulating device (Figure 2), and an abundant working space was created to enhance the view of the mediastinal space. After dissection of the muscle fibers of the esophageal hiatus cross-section, the thoracic aorta was exposed. The esophageal artery was classified and confirmed during dissection of the posterior layer of the esophagus. The dissection of the left side of the distal esophagus and anterior esophagus was conducted down to the level of the tracheal bifurcation. The surgeon incised the left parietal pleura close to the pericardium. Afterwards, the surgeon opened the left thoracic cavity to the mediastinal space. The incision was extended to the left pulmonary aortic arch and hilum, leading to a large surgical field. In this manner, the lower thoracic esophageal (No. 110), supradiaphragmatic (No. 111), and posterior mediastinal (No. 112) nodes were dissected. The transection plane of the esophagus was determined through intraoperative endoscopy. A 60-mm articulating endoscopic linear stapler was used to transect the esophagus 5 cm above the proximal margin (Figure 3). Intraoperative frozen pathology studies were routinely conducted.
At the stump of the esophagus, a 25-mm circular stapler anvil head was placed, with hand-sewn purse-string sutures or a suture made with a needle through an esophagotomy. A circular stapler was used to perform the intracorporeal end-to-side esophagojejunostomy. The anastomosis could be made in the functional end-to-end anastomosis manner or the side-to-side fashion, which is known as the “overlap method”, in which one prongs of a linear stapler were inserted into the anterior wall of jejunum via a small hole made 5-10 cm from the edge. Another prongs of a linear stapler were inserted the posterior wall of esophageal stump, another hole was made. Meanwhile, side-to-side anastomosis was performed (Figure 4). Subsequently, a hand-sewn technique was used to close the common entry hole with a continuous suture (Figure 5). Repairing the hiatus of the diaphragm through a continuous suture is important to avoiding hiatal hernia (Figure 6).Two abdominal drainage tubes were placed in either side of the esophageal anastomosis (Figure 7) (Supplementary video showed the type of anastomosis with circular stapler. The video did not be uploaded due to the limited size. We have uploaded it in a shared network location: http://u.163.com/nnnnnMAb, password: Di1sVwnV).
Statistical analysis
Statistical analyses were performed by using SPSS 21.0. Categorical data were compared by Fisher’s exact test or χ2 test. Consecutive data are presented as the mean ± standard deviation (SD). T-tests or rank-sum tests were used to compare the means of two groups. P<0.05 was considered statistically significant.