Re-Exploration Of Local Anatomy Of Inferior Mesenteric Vessels Based On Axial Enhanced CT

BackgroundAs a common malignant tumor of the digestive tract in our country,the incidence of rectal cancer is increasing year by year.With the increase of the incidence of young people,rectal cancer has become an important problem threatensing human life and health.Laparoscopic anterior resection of rectal cancer is currently the most commonly used treatment for rectal cancer,and its advantages are relatively small surgical trauma and fast postoperative recovery.With the improvement of the medical technology,the surgical indications for Laparoscopic anterior resection of rectal cancer include rectal malignant tumors 5 cm from the anal verge,which greatly increases the chance of anal preservation.The blood supply of the lesion is one of the difficulties in the operation.Complex vascular anatomical variations will affect the overall surgical effect.The issues we are concerned about are as follows:①The root of the inferior mesenteric artery may be located behind or even above the duodenum,which increases the difficulty of surgical dissection and may even damage the duodenum and cause related complications;②There are many types of branches of the inferior mesenteric artery,and there is no unified classification method;③The course of the left colic artery is quite different,and there is no unified description method.Whether to preserve the left colic artery may be related to the blood supply of the anastomotic stoma and postoperative anastomotic leakage.Therefore,preoperative assessment of vascular anatomy is very important.Preoperative three-dimensional vascular reconstruction can clearly and intuitively display the peritoneal vascular structure,but this examination increases the financial burden of patients,and some areas may not have the conditions for CT three-dimensional reconstruction.We find that by reading the axial enhanced CT,the anatomical relationship between the inferior mesenteric artery and its branches can also be clearly displayed,and the intraoperative operation can be guided.In addition,whether to preserve the left colic artery during the operation will affect the postoperative recovery of patients is also a current hot topic,and there is no clear conclusion yet.Part Ⅰ:Re-explore the local anatomy of inferior mesenteric vessels based on axial enhanced CTObjectiveBased on preoperative axial enhanced CT,the relationship between the starting point of inferior mesenteric artery and the inferior margin of duodenum,the type of branches of inferior mesenteric artery and the relative position of left colonic artery and inferior mesenteric vein were explored to provide guidance for vascular anatomy during Laparoscopic anterior resection of rectal cancer.MethodsThe clinical data of 316 patients who underwent Laparoscopic anterior resection of rectal cancer in the Department of Gastrointestinal and Colorectal surgery,Qilu Hospital of Shandong University from January 2019 to August 2020 were retrospectively analyzed.The preoperative axial enhanced CT was analyzed one by one,and the distance between the inferior margin of duodenum and the starting point of inferior mesenteric artery was measured.The branch type was determined according to the branch structure of inferior mesenteric artery.The position relationship between the left colonic artery and the inferior mesenteric vein was judged at the initial level of the inferior mesenteric artery.ResultsThe enhanced CT data of 316 clinical patients were analyzed and measured.1.According to the relationship between the origin of inferior mesenteric artery and the lower edge of duodenum,those above the lower edge of duodenum were defined as high-level origin,and those below the lower edge of duodenum were defined as low-level origin,among which 89 patients(27.93%)had high-level origin of inferior mesenteric artery and 227 patients(72.07%)had low-level origin.It was found that the starting position of inferior mesenteric artery in male patients was(3.014±0.2)cm away from the lower edge of duodenum,and that in female patients was(3.3±0.188)cm.There was no significant difference(P>0.05).2.The branching types of inferior mesenteric artery were as follows:type Ⅰ:the starting point of LCA and SA was independent of IMA;type Ⅱ:IMA and SA had a common trunk,which was more than 5mm from the starting point;type Ⅲ:LCA and SA originated from the same point of IMA,or had a common trunk,less than 5mm from the starting point;type Ⅳ:absence of LCA.There were 171 cases of type I(54.1%),58 cases of type Ⅱ(18.4%),82 cases of type Ⅲ(26.6%)and 5 cases of typeⅣ(1.6%).The analysis showed that type Ⅱ was more rare in female patients(P<0.05).3.At the level of the starting point of the inferior mesenteric artery,the positional relationship between the left colic artery and the inferior mesenteric vein was judged,and according to the position of the left colic artery in the inferior mesenteric artery,it was divided into the inner proximal type(42 case,13.3%),the inner distal type(1 case,0.3%),and the lateral proximal type.type(116 cases,36.7%),lateral distal type(65 cases,20.6%),anterior type(75 cases,23.7%),posterior type(12 cases,3.8%),LCA absence(5 cases,1.6%).The positional relationship between the left colic artery and the inferior mesenteric artery showed that the lateral proximal type was dominant in male patients,and the lateral proximal type was similar to the distal type in female patients(P>0.05).ConclusionIn laparoscopic anterior resection of rectal cancer,preoperative axial contrast-enhanced CT can accurately display the local anatomy of the inferior mesenteric vessels(the positional relationship between the starting point of the inferior mesenteric artery and the lower edge of the duodenum,the classification of the branches of the inferior mesenteric artery and the left colon The positional relationship between the artery and the inferior mesenteric vein),which has guiding significance for intraoperative operations.Part Ⅱ:the effect of preservation of left colonic artery on short-term postoperative complications in Laparoscopic anterior resection of rectal cancer.ObjectiveTo compare whether to preserve the left colic artery during operation and the short-term treatment effect after operation,to provide guidance for the choice of whether to preserve the left colic artery in rectal surgery.MethodsThe clinical data of 316 patients who underwent Laparoscopic anterior resection of rectal cancer in the Department of Gastrointestinal and Colorectal surgery,Qilu Hospital of Shandong University from January 2019 to August 2020 were retrospectively analyzed.The patients were then divided into two groups according to whether the left colonic artery was preserved or not.177 cases in the observation group retained the left colonic artery and 139 cases in the control group did not retain the left colonic artery.The differences of operative use,intraoperative bleeding,lymph node dissection and postoperative complications between the two groups were compared and analyzed.ResultsThere were no significant differences in gender,age,tumor stage,and tumor location between the two groups of patients(P>0.05),and the data were comparable.The operation time of the observation group was(175±42)min,and the operation time of the control group was(164±42)min(P<0.05);the average number of lymph nodes dissected in the observation group was(17±5)and that of the control group was The number was(18±5)(P>0.05);the average decrease in hemoglobin in the observation group was(13±8)g/L on the first day after operation,and the average decrease in hemoglobin in the control group was(14±8)on the first day after operation There was no significant difference in/L(P>0.05);there was no significant difference in the incidence of complications such as postoperative anastomotic leakage,abdominal hemorrhage,incision infection and postoperative intestinal obstruction(P>0.05);There was no statistical difference in postoperative recovery indicators such as the average first exhaust time and the average length of hospital stay(P>0.05).ConclusionPreserving the left colic artery in Laparoscopic anterior resection of rectal cancer increases the difficulty of the operation and prolongs the operation time to a certain extent,but has no obvious advantage for the short-term recovery of patients after surgery.The long-term effect of preserving the left colic artery on patients needs further study.