Objective To investigate the clinical value of laparoscopic evaluation of anato-mical position of inferior mesenteric artery (IMA), inferior mesenteric vein (IMV) and left colic artery (LCA).

Methods The prospective one-arm study was conducted. The clinical data of 229 pati-ents who underwent laparoscopic left hemicolectomy for left colon or laparoscopic radical resection of rectal cancer in The Second Affiliated Hospital of Air Force Medical University from December 2022 to December 2023 were selected. The distance between the origin point of IMA and the origin point of the first branch (L1) as well as the distance from the origin point of LCA root to the junction of LCA and IMV (L2) were measured during the operation. IMA classification, the location relation-ship of LCA and IMV junction were recorded. Observation indicators: (1) situations of enrolled patients; (2) difference analysis between L1, L2 and clinical features; (3) distribution characteristics of the location relationship between LCA and IMV in different types of IMA. Mann-Whitney U test was used for comparison of measurement data with skewed distribution between groups, Kruskal-Wallis H test was used for comparison between multiple groups, and Dunn-Bonferroni test was used for pairwise comparison. Comparison of count data between groups was performed by chi-square test. Pearson or Spearman correlation analysis was conducted for correlation of continuous variables.

Results (1) Situations of enrolled patients. A total of 229 eligible patients were screened out, including 146 males and 83 females, aged 64(range, 55-71)years. The height of 229 patients was 168(range, 160-172)cm, the weight was 65.0(55.5,71.5)kg, the body surface area was (1.68±0.17)m², the tumor maximum diameter was 3.0(2.5,4.0)cm. The total number of lymph nodes dissected was 19(17,21), and the number of No.253 lymph node dissected was 4(3,5). The L1 was 3.50(1.20,8.00)cm, and the L2 was 2.20(0.50,7.30)cm. There were 58, 31, 32, 71, 22, 90, 26 and 212 patients with smoking, alcohol drinking, diabetes, hypertension, coronary heart disease, neoadjuvant chemo-therapy, neoadjuvant radiotherapy and preservation of the LCA, respectively. Among 229 patients, cases with BMI <18.5 kg/m², 18.5-23.9 kg/m² and >23.9 kg/m² were 11, 133 and 85, respectively. There were 153 cases in pathological stage Ⅰ-Ⅱ and 76 cases in stage Ⅲ. There were 168 cases of Dixon operation, 6 cases of Miles operation and 55 cases of sigmoid colon resection. There were 135 cases of IMA type 1, 44 cases of IMA type 2, 23 cases of IMA type 3, 2 cases of IMA type 4, and 25 cases of IMA type unable to judge. (2) Difference analysis between L1, L2 and clinical features.Correlation analysis showed negative correlation between the height, body surface area and L1 (r=-0.17, -0.15, P<0.05). The L1 was 3.20(2.68,4.00)cm for male patients and 3.60(3.00,4.20)cm for female patients, respectively, showing a significant difference between the two groups (Z=-2.37, P<0.05). The L1 of patients with IMA type 1, 2, and 3 was 3.20(2.80,4.00)cm, 3.85(3.00,4.48)cm, and 3.20(2.50,4.30)cm, respectively, showing a significant difference among them (H=7.54, P<0.05). Further pairwise com-parison showed that there was a significant difference in L1 between patients with IMA type 2 and those with IMA type 1 (P<0.05). The L2 of smokers and non-smokers were 2.50(1.95,3.20)cm and 2.20(1.60,2.80)cm, respectively, showing a significant difference between the two groups (Z=-2.24, P<0.05). (3)Distribution characteristics of the location relationship between LCA and IMV in different types of IMA. There was no significant difference in LCA distribution between the anterior and posterior positions of IMV among the three IMA types (type 1, 2, 3) (χ²=1.63, P>0.05).

Conclusions Patients with greater height have larger body surface area and shorter L1. L1 is significantly longer in female patients than in male patients. L1 is significantly longer in patients with IMA type 2 than in those with type 1. L2 is significantly longer in smokers than in non-smokers. There was no significant difference in the distribution location between LCA and IMV among patients of IMA type 1, 2 and 3.