Gastric cancer is one of the most common malignant tumors of the digestive system. Surgery is currently considered the only radical cure13. With the development of minimally invasive surgery, laparoscopic radical gastrectomy has been widely used in the treatment of gastric cancer and achieved good therapeutic effects14. However, preoperative enhanced CT cannot accurately judge the anatomy of important vessels, thus affecting lymph node dissection, which has always been an urgent problem to be solved in laparoscopic surgery. In this study, preoperative CTA was used to guide the operation by understanding perigastric arteries. The results showed that the operative time and estimated blood loss in The CTA group were significantly lower than those in the non-CTA group (251.88±55.91 min vs 268.34±30.78 min, 37.44±21.50 ml vs 50.47±24.49 ml, P < 0.05). There were no significant differences in the total number of lymph nodes, the number of positive lymph nodes, the incidence of complications, vascular injury, and other recent clinical outcomes between the two groups (P > 0.05)(Table 6). For decades, the classification of perigastric arteries has been a concern by gastrointestinal surgeons. Many studies 9,10,15reported the classification of gastric peripheral arteries and carried out detailed classification. Among them, Adachi classification and Hiatt classification are more classical. We conducted vascular classification according to Adachi classification and Hiatt classification and discussed vascular variation to avoid accidental injury caused by vascular variation, designed to make surgery safer
Some studies have divided the anatomical types of gastric peripheral arteries into 7 categories, among which LGA directly derived from AA accounted for 2.3%16. In this study, there were 3 cases of type II variation (2.4%): LGA was directly derived from AA, while CHA and SA were still derived from celiac trunk. Understanding the origin and course of LGA before surgery is helpful to ligation of LGA and dissection of No.7 lymph node.In addition, in one case of total gastrectomy, the trunk of the SA was mistakenly regarded as the LGA was severed because the LGA was thin and originated from the AA, while the SA from the celiac trunk was in an upward direction. The spleen turned black, and the SA was created to restore the spleen blood supply. If we anticipate the variation of the LGA with the help of preoperative CTA, the risk of dissevered vessels during surgery will be greatly reduced. In Marco's study17, a complete tetrafurcated trunk was detected in 4/596 CTs (0.7 %) Our study, there was one case of type IV variation (0.8%): CHA, SA, SMA, and LGA were all originated from CT. Since the dissection scope of D2 lymph node dissection does not include the SMA scope, it will not affect the dissection of lymph nodes. In this variation, attention should be paid to avoid misjudgment of blood vessels.
Keishi 18et al. research statistics showed that 28 of 714 cases(3.9%) CHA originated from SMA, and portal vein was directly exposed under 8a lymph node, without being covered by marker vessels.In our study, CHA originated from SMA in 3 patients (2.4%). If the CHA is damaged due to excessive separation without knowing vascular variation during intraoperative dissociation of the region, acute hepatic ischemia may be caused. Open abdomen to stop bleeding will not only prolong the operation time but also affect the recovery of patients after surgery, especially those patients with poor liver function.In addition, the portal vein is not covered by the CHA, which is a marker vessel, and will be directly exposed to the lymph nodes of Group 8a18. If it is not foreseen before surgery, the risk of lymph node dissection of Group 8a will be increased to some extent.In this study, CTA suggested this in the preoperative evaluation process, which helped the surgeon to remove lymph nodes without damaging the portal vein and hepatic artery.Hiatt typing: In this study, the total variation rate of the hepatic artery was 17.6%, which was similar to Hiatt's study.However, the variation of the hepatic artery is complex and diverse, and the Hiatt classification cannot cover all variations19.In this study, we found 2 types not described in Hiatt classification: in 1 case, the RHA originated from the celiac trunk; in 2 cases, RHA originated from AA.
According to relevant reports 20, 15-20%ALHA may originate from The LGA and reach the liver together with the hepatic branch of the left vagus nerve, which is sometimes the only arterial blood flow in the left hepatic lobe.ALHA can be divided into alternative LHA or accessory LHA. In 200 anatomical reports, the former accounted for 55% and the latter accounted for 45%21.In this study, there were 9 cases of type II variation: abnormal LHA from the LGA. it is uncertain whether the LHA is absent. To determine the blood supply source of the liver, the surgeon needs to carefully separate the blood vessels during the operation, continuing to separate tissue bare vessels from the root of the LGA upward until the LHA is exposed.If the accessory LHA is large or the LHA is lack, the LGA should be ligated from the root of the accessory LHA, otherwise the blood supply of the left liver will be cut off directly. The ischemia of the accessory left hepatic artery may cause transient liver dysfunction in the early postoperative period, which will undoubtedly have a serious impact on patients with poor liver function. In addition, studies have shown that the estimated amount of blood loss in patients with abnormal LHA variation is significantly higher than that in patients without such variation21.
According to reports, the incidence of ARHA ranged from 0.42% to 10.6%, and ARHA was mainly from SMA(546 cases, 5.6%)22. In this study, 6 type II variants (4.8%) of RHA were derived from SMA. In D2 lymph node dissection of gastric cancer, although the region of the RHA was not involved, Eshuis et al. believed that accidental injury or ligation of aRHA during pancreaticoduodenectomy might increase the risk of complications 23.In this study, the detection rate of the RGA was (82/125, 65.6%). We considered the RGA was thinner than other gastric peripheral arteries, and due to technical limitations, CTA could not display or could not display the specific RGA out of shape 21, so the detection rate was not high.But there is no denying the importance of identifying the RGA.In one case of total gastrectomy, we cut the RGA and the liver turned black at this time. The surgeon continued to separate the tissue along the RGA and found the PHA was also be clipped by mistake, which narrowed the RGA. Then we opened the vascular clip, and re-clipped the RGA without PHA, to make the blood flow to the liver again. We consider that due to the abnormal course of the PHA, the course moves upward and closely adheres to the RGA. Therefore, it is necessary for the surgeon to have predictive protection or avoidance of blood vessels, especially when dealing with blood vessels close to the blood supply of the liver such as RGA, try to avoid clamping the right RGA close to the root. And preoperative CTA provides clues to identify the special course of blood vessels.
In this study, the abnormal SA was classified according to three factors that affect the risk of surgery: the number of SA branches, whether there were spiral tortuous arteries and whether the upper splenic pole branches were generated in the middle part of the artery. Preoperative understanding of the bending degree of SA would be beneficial to complete intraoperative dissection of No.11 lymph node and reduce the risk of SA injury. In a case of distal radical gastrectomy, we found that the middle part of the splenic artery branched upward, mistakenly thinking that the branch is short gastric artery and cut this blood vessel. When we continue to separate tissues around the stomach, that branch was found to be the superior splenic branch, which not only affected the blood supply of the spleen, but also the blood supply of the remnant stomach, because the upper pole branch of the spleen sends out a small posterior gastric artery. In addition, we found that tortuous SA also bring a high risk of surgery. If the patient's SA is curved, if these arteries are not paid attention to before surgery and not completely exposed during surgery, it is easy to mistake them for lymph nodes, injury the SA, and lead to hemorrhage and even splenectomy.Therefore, preoperative evaluation of the tortuousness and bifurcation of the SA is a necessary part of the operation.In addition, 1 patient was found to have a giant splenic aneurysm by preoperative CTA examination, which was of high surgical risk.It has been reported that laparoscopic treatment of splenic aneurysms is a safe, effective, and minimally invasive option24.We made reasonable surgical strategies, ligation of lymph nodes in the region before dissection and excision of upper splenic branch vessels, avoiding the impact of emergencies and minimizing the damage to patients, thus safely and quickly performing surgery and giving patients the maximum benefit.
A large number of studies have shown5,16,25,26 that preoperative CTA examination can reduce the amount of blood loss, shorten the operation time and even improve the detection rate of lymph nodes in laparoscopic radical gastrectomy.In our study, there was no significant difference in the total number of lymph nodes and the number of positive lymph nodes between the CTA group and the non-CTA group (P > 0.05), which was believed to be related to the veteran experience of the surgeon and the result of careful dissection. Although in this study, postoperative liver function, three days of abdominal drainage after operation, postoperative hospital stay, postoperative exhaust time, postoperative try drinking time, first liquid diet time, postoperative first time to remove the drainage tube, postoperative complications, such as the recent clinical outcomes were no obvious difference (P > 0.05), but the estimated blood loss and operation time was lower than that in the group of CTA, Although the amount of blood loss and operation time are not direct indicators of clinical efficacy, we believe that they can be used to evaluate surgical quality to some extent.The lack of intraoperative bleeding may be related to the shortened time of intraoperative blood vessel identification and treatment by preoperative CTA assessment.We think the reason for the shorter operation time is that we can identify the blood vessels through CTA and perform the operation accurately. Literature on the LADG learning curve suggests that surgeons become proficient after 40 operations27. Based on this study, we further believe that preoperative CTA will play a significant role in safely and efficiently completing surgery for surgeons who are still overcoming the learning curve.
Notably, in the CTA group, the preoperative ICG staining group had less blood loss than the group without ICG staining (P < 0.05), but there was no significant statistical difference in the number of lymph node dissection and the injuries of large vessels. We found that preoperative CTA combined with ICG labeled was more effective in reducing blood loss, although it did not reduce large vessel injury incidence rate. We considered that preoperative CTA and ICG labeled could effectively distinguish lymphatic vessels from small blood vessels by fluorescence mode, effectively avoiding bleeding caused by small blood vessel injury and thus reducing the amount of blood loss. In this study, we considered that the time required to start the fluorescence pattern recognition process would prolong the total operation time. Even so, there was no significant difference in the operation time between the two groups, indicating that the combination of ICG markers did not prolong the operation time. There was no significant difference in the injury of important vessels in this study, and our data showed that there was only 1 case of SA injury caused by coagulation hook damage in the CTA group，not the wrong surgical procedure.
The sample size of this study is small, and this research is a retrospective analysis, not enough to explain the problem. So, It is necessary to conduct prospective studies and expand the sample size based on this study. Since the inferior pyloric artery, LGA and RGA are thin, 3d-CT reconstruction technology has a limited ability to develop them, so this study did not analyze them. In the future, more fine angiography technology can be used to develop them, and their moving characteristics and proportion can be analyzed. This study sample size is lesser, and this study is a retrospective analysis. In the future, we will further verify randomized controlled trials based on this research.
Studies have shown that preoperative CTA is helpful in other laparoscopic surgery fields such as liver transplantation28. With the development of functional laparoscopy, CTA may be widely used clinically as a reliable method for perigastric vessels identifying before surgery.Preoperative 3D angiography of the gastric peripheral artery can not only shorten the operation time but also make intraoperative blood loss lower. Moreover, ICG labeled fluorescent laparoscopic technology's precise positioning of lymph nodes can make our surgery safer. Finally, we believe that preoperative CTA can objectively evaluate the vascular course and variation of patients, shorten the operation time and reduce the amount of intraoperative blood loss to a certain extent, and can improve the perioperative recovery of patients. And through subgroup analysis, ICG labeled can further reduce the amount of blood loss and improve the quality of surgery without increasing the operation time.