According to traditional Chinese medicine, Qi and Blood circulate through the human body via pathways known as 'channels and collaterals'. This process supports the normal function of internal organs and the whole body. Pathological conditions can be attributed to abnormal circulation of Qi and Blood, which results in excess or deficiency of organs and channels. Therapeutic methods used in traditional Chinese medicine restore the balance of Qi and Blood.Since acupuncture was introduced in Europe, discussion and debate about the nature of 'acupoints,' 'channels,' and 'collaterals' has continued. Currently, opposing views exist on this subject, ranging from complete denial of the existence of the channels to uncovering the previously unknown system of intra-tissue gaps and microscopic vessels. The author offers an original hypothesis that regards the theory of channels and collaterals as the description of the physiology and pathology of intercellular space and the theory of organs as a description of the physiology and pathology of cells.

Introduction. “Vein definition” for locally advanced pancreatic ductal adenocarcinoma (LA PDAC) assumes portal-to-superior mesenteric vein (PV/SMV) unreconstructability due to tumor involvement or occlusion. Radical pancreatectomies with SMV resection without PV/SMV reconstruction are scarcely discussed in the literature. Retrospective analysis of 19 radical pancreatectomies for “low” LA PDAC with SMV and all its tributaries resection without PV/SMV reconstruction has shown zero mortality, overall morbidity – 56%, Dindo-Clavien – 3-10,5%, R0- rate – 82%, mean operative procedure time – 355±154 min, mean blood loss – 330±170 ml, delayed gastric emptying– 25%, clinically relevant postoperative pancreatic fistula – 8%. In three cases surgery was associated with superior mesenteric (n2) and common hepatic artery (n1) resection. Surgery was completed without vein reconstruction (n13) and with inferior mesenteric-to-splenic anastomosis (n6). There were no cases of liver, gastric, or intestinal ischemia. A specific complication of the SMV resection without reconstruction was 2-3 days-long intestinal edema (48%). Median overall survival – 25 months, median progression-free survival – 18 months. All the relapses, except two, were distant. The possibility of successful SMV resection without PV/SMV reconstruction can be predicted before surgery by CT-based reconstructions. The mandatory anatomical conditions for the procedure were: 1) preserved SMV-SV confluence; 2) occluded SMV for any reason (tumor or thrombus); 3) well-developed inferior mesenteric vein collaterals with dilated intestinal veins; 4) no right-sided vein collaterals, and 5) no varices in the upper abdomen. Conclusion: “Low” LA PDACs involving SMV with all its tributaries can be radically and safely resected in highly and specifically selected cases without PV/SMV reconstruction with an acceptable survival rate.