The Value Of Preserving Left Colic Artery During Radical Resection Of Rectal Cancer And The Study Of Inferior Mesenteric Artery Types

Background and objective:The treatment of rectal cancer is more and more diversified,and surgical treatment is still the main method.The inferior mesenteric artery?IMA?needs to be exposed and ligated during radical resection of rectal cancer.There are two ways for ligation of the IMA:1)high ligation,the IMA was ligated at 1cm from its origin,with non-preservation left colic artery?LCA?,and 2)low ligation,the IMA was ligated at below the origin of LCA,with preservation LCA.The high ligation of IMA made the blood supply of the proximal colon of the anastomotic only supplied by the marginal arch artery,leading to the insufficiency of blood perfusion at the anastomotic in some patients,which may affect the normal healing of the anastomotic.It has been reported that the blood supply at the proximal colon of the anastomotic is derived from the dual supply of LCA and the marginal artery due to the preservation of LCA in the radical resection of rectal cancer,which is conducive to the increase of blood supply of anastomotic and ensure the normal healing of anastomotic.Therefore,preservation of the LCA in the radical resection of rectal cancer has attracted increasing attention in recent years.However,whether or not to preserving LCA in radical resection of rectal cancer and its effect on anastomotic leakage are remains controversial.Moreover,rectal cancer surgery guidelines do not reach clear consensus on this issue.We designed a clinical cohort study based on real world study principles to compare the intraoperative parameters,short-term efficacy,postoperative pathological indicators,and oncology efficacy of LCA preservation and non-preservation during radical resection of rectal cancer.It provides guidance for surgeons to choose whether to preserving LCA during radical resection of rectal cancer and provide evidence of evidence-based medicine for the development of surgical guidelines for rectal cancer in the future.Practice has proved that preoperative evaluation of IMA types is of important reference value for deciding whether to preserving LCA and intraoperative anatomy.Therefore,IMA types and its characteristics were retrospectively analyzed based on the three-dimensional Computed Tomography?CT?reconstruction images of rectal cancer patients,so as to provide guidance for safe,accurate and effective implementation of preserving LCA during radical resection of rectal cancer.Method:Part ?:A single-center cohort study was conducted.All patients were confirmed to be rectal adenocarcinoma by preoperative pathological biopsy,and the tumor was within 15cm from the anal margin.Patients were divided into two groups based on whether or not LCA was preserved:preservation LCA group and non-preservation group.The intraoperative indicators,postoperative pathological indicators,postoperative complications and postoperative short-term efficacy were compared between the two groups.Follow-up of 2years,compared two groups of local recurrence?LRR?,distant metastasis rate?DMS?,disease-free survival?DFS?and overall survival?OS?.To explore the safety,feasibility,short-term efficacy and long-term prognosis of preserving LCA in rectal cancer surgery,to provide evidence for clinical practice.Part ?:The clinical data and preoperative three-dimensional CT reconstruction images of patients with rectal cancer were retrospectively analyzed.Evaluation indicators included IMA types,the vertical distance from IMA root to the origin of the first branch of IMA(L_IMA),and the vertical distance from IMA root to the bifurcation of abdominal aorta(D_IMA),etc.The characteristics and differences of different IMA types were compared and analyzed.To evaluate the value of IMA types based on three-dimensional CT reconstruction in the radical resection of rectal cancer with LCA preservation.Result:1.Comparison of preservation LCA group and non-preservation LCA groupBetween January 2017 and October 2019,a total of 160 patients were enrolled in this study,56 patients were arranged to the preservation LCA and 104 to non-preservation LCA.There were no statistically differences in age,sex,Body Mass Index?BMI?,tumor location,American Society of Anesthesiologsts?ASA?classification,neoadjuvant therapy rate and other baseline data between the two groups?P>0.05?,suggesting comparability.The surgical type,surgical method,preventive ileostomy,intraoperative blood loss,and intraoperative complications showed no significant difference between preservation LCA group and non-preservation LCA group?P>0.05?.The operative time in preservation LCA group were significantly longer than in non-preservation LCA group,with statistically significant differences?P<0.05?.Patients undergoing preserving LCA surgery had a lower anastomotic leakage rate?3.6%vs 13.5%;P<0.05?.The overall early complications rate in the preservation LCA group and the non-preservation LCA group,was 8.9%and 26.0%,respectively,with significant differences?P<0.05?.The reoperation rate of the preservation LCA group?1.8%?was lower than that of the non-preservation LCA group?10.6%?,but the significant difference was not found?P>0.05?.There were no significant difference in ileus,anastomotic bleeding,urinary tract infection,urinary dysfunction,postoperative hospital stay,and postoperative diarrhea between the two groups?P>0.05?.No significant difference in postoperative pathological stage,total number of harvested lymph nodes,number of positive lymph nodes,and degree of tumor differentiation between these two groups?P>0.05?.Postoperative follow-up:the number of effective follow-up cases was 53 and 94 in the preservation LCA group and non-preservation LCA group,respectively.The LRR,DMS,OS,and DFS were similar in the two groups?P>0.05?.2.Evaluation of IMA types and characteristics of different types based on three-dimensional CT reconstructionBetween January 2017 and November 2018,a total of 108 patients were enrolled in this study.According to the three-dimensional CT reconstruction image,the IMA of 108patients was divided into four types,of which 53?49.1%?were type I,24?22.2%?were type II,18?16.7%?were type III,and 13?12%?were type IV.There were no significant differences in age,BMI,L_IMA,D_IMA,total number of harvested lymph nodes,number of positive lymph nodes,operation time and postoperative hospital stay among patients with different IMA subtypes?P>0.05?.The L_IMA of 108 patients was?5.7±2.0?cm and D_IMA was?6.3±2.3?cm.Conclusion:The preservation of LCA in radical resection of rectal cancer could help reducing the anastomotic leakage,overall early complications rate,and reoperation rate and without increasing intraoperative complications and blood loss.Preservation of LCA during radical resection of rectal cancer does not affect lymph node dissection and postoperative oncology efficacy.The type of IMA can be accurately evaluated by three-dimensional CT reconstruction,which has guiding value in making surgical decisions and preserving LCA during radical resection of rectal cancer.