Conventional VAMIE remains the most prevalent for esophageal cancer surgery. As RAMIE has been studied clinically in multiple international research centers and has shown to have excellent minimally invasive surgical outcomes, such as less trauma, faster recovery, and better postoperative pain tolerance for patients, the RAMIE technique is theoretically more advantageous valuable than VAMIE22–24. However, it has been discovered that the clinical benefit of the robotic-assisted technique after its use in the upper abdomen is not as anticipated, making it doubtful that total thoracoabdominal RAMIE can achieve better perioperative outcomes than VAMIE. Therefore, we compared the perioperative outcomes of single-thorax McKeown-RAMIE and McKeown-VAMIE in people matched by propensity scores in this study, to determine whether single-thorax McKeown-RAMIE performed differently than McKeown-VAMIE in the perioperative period.
In this study, we discovered that the operation time of the single-thorax McKeown-RAMIE group was significantly shorter than that of the McKeown-VAMIE group, with the difference mainly reflected in the chest surgery time. The primary causes may include the following: Firstly, compared to McKeown-VAMIE, the single-thorax McKeown-RAMIE, with the help of robotic imaging systems, can amplify the imaging field during thoracic esophageal free and mediastinal lymph node clearance, especially when tumor tissue extensively invades surrounding tissues; Second, the multi-angle operation of the robotic arm can reduce normal tissue damage while removing as much diseased tissue as possible25, significantly reducing the difficulty and duration of surgery26; In addition, compared with McKeown-VAMIE, Shirakawa and Deng et al confirmed the single-thorax McKeown-RAMIE has less trauma, faster recovery, less postoperative pain, less postoperative pleural effusion drainage, and shorter hospitalization days27–29.
Disease-free survival and tumor recurrence rates after esophagectomy depend primarily on complete removal of lymph nodes in the surgical area30,31. Therefore, it is important to ensure that the lymph nodes are cleared during esophagectomy. In their respective studies, Deng, Li, and Oshikiri et al highlight the benefits of robot-assisted lymph node dissection compared to conventional VAMIE27,32,33. Robotic-assisted techniques can reduce vascular damage during surgical procedures while effectively exposing and removing lymph nodes from the operative area. In this study, the numbers of chest lymph node removal in the single-thorax McKeown-RAMIE group were comparable to those in the McKeown-VAMIE group. We consider that the number of lymph nodes dissected is related to the patient's disease status and physical characteristics. Whether robotic-assisted technology can improve surgical efficiency and increase the number of lymph node dissections needs to be confirmed by more RCT studies.
Postoperative complications have been shown to be the main cause of poor postoperative recovery and prolonged hospitalization days in patients34,35. In this study, the incidence of postoperative cardiopulmonary or digestive complications was not significantly higher in the single-thorax McKeown-RAMIE group than in the McKeown-VAMIE group. Interestingly, the incidence of postoperative anastomotic leak was significantly lower in the single-thorax McKeown-RAMIE group than in the McKeown-VAMIE group. In general, insufficient blood supply to the tubular stomach and anastomosis site is the main reason for the increase in the incidence of anastomotic leak36, but it has also been suggested that intraoperative blood loss and duration of surgery are factors that increase the rate of esophageal anastomosis leak20. Kamarajah37 also suggested in Saunders’s study38 to consider the influence of different surgical methods on postoperative anastomotic leak. This confirms that these factors (intraoperative blood loss, surgery time, surgical method, etc.) also increase the incidence of postoperative anastomotic leak.
Therefore, we suspect that any factor affecting blood supply to the anastomosis site may contribute to an increased incidence of anastomotic leak. For example, the surgery time and the amount of intraoperative blood loss can reflect the degree of surgical trauma, and if the degree of injury is greater, the more inflammatory factors that may be produced after surgery39,40. An increase in systemic inflammatory factors postoperatively causes an inflammatory response and vasoconstriction at the surgical site, which affects the blood supply to the gastric tube and anastomosis site41. In our study, although laparoscopy was used in both surgical methods, when the gastric tube was sucked back into the mediastinum and anastomosed with the severed end of the neck, it was exactly where the original esophageal bed was. A large number of inflammatory mediators produced by surgical trauma of the esophageal bed promote the contraction of the right gastroepiploic artery, affecting the repair of damaged tissue42,43. Under these assumptions, we suggest that the degree of injury to the thoracoesophageal bed affects the postoperative blood supply to the gastric tube and anastomosis, thus explaining the difference in the incidence of anastomotic leak. This is also consistent with differences in perioperative outcomes between the two groups.
The study had several limitations. First, this was a single-centre retrospective study with limited sample data for analysis and comparison, and although attempts were made to eliminate the influence of confounding factors with PSM, bias could not be avoided; Secondly, as neoadjuvant therapy is recommended in patients with intermediate and advanced esophageal cancer, the difficulty of lymph node dissection will also increase, which is also the advantage of robotics. However, the number of patients receiving neoadjuvant therapy in this study was so small that it could not be included as a study variable compared to Western countries, so this study cannot fully reflect the advantages of robotics44. Third, the long-term survival benefit of patients should be considered when evaluating the efficacy and benefits of surgery45. Therefore, analyses should include long-term outcomes such as tumour recurrence and disease-free survival. Due to medical history limitations, this study can only analyze perioperative outcomes, and there is no survival analysis.
In conclusion, we compared the intraoperative and postoperative outcomes of single-thorax McKeown-RAMIE and McKeown-VAMIE in the propensity score matching population, and found that the surgery time, intraoperative blood loss/rehydration, postoperative pain, and anastomotic leak incidence of single-thorax McKeown-RAMIE were lower than those of McKeown-VAMIE. However, due to limitations of our study, larger sample sizes and randomised controlled trials are needed to confirm these findings.