scholarly journals The New Concept of Physiological “Riolan’s Arch” and the Reconstruction Mechanism of Pathological Riolan’s Arch After High Ligation of the Inferior Mesenteric Artery by CT Angiography-Based Small Vessel Imaging

2021 ◽  
Vol 12 ◽  
Author(s):  
Ying Wang ◽  
Weibin Shu ◽  
Aimie Ouyang ◽  
Lei Wang ◽  
Yuping Sun ◽  
...  

BackgroundDue to the complexity of anatomical relationship between superior mesenteric artery (SMA) and left colic artery (LCA), there is no unified anatomical concept of “Riolan’s arch.” There is no consensus as to tie off the inferior mesenteric artery (IMA) at its origin or just below the origin of the left colic artery during radical surgery of sigmoid colon and rectal cancers. The aim of the study is to investigate the anatomy of shortcut anastomotic branches (adjacent branches) of SMA at splenic flexure and to explore how the shortcut pathway (Riolan’s arch) was formed, as the compensation of anastomotic branches between MCA and LCA under pathological conditions and the reconstruction and the mechanism of pathological Riolan’s arch after high ligation of the inferior mesenteric artery.MethodsBetween January 2018 and May 2020, patients with colorectal cancer who underwent CTA before surgery were enrolled in the study. The anatomy of shortcut anastomotic branch of SMA and LCA was investigated by volume rendering technique (VR) and maximum-intensity projection (MIP). GE’s small vessel extraction technology (selected VR) was used to directly display these shortcut anastomotic branches on a map and to establish their three-dimensional anatomical classification. Then, we used the axonometric drawing to make the model more exact. Next, combining with some cases of pathological Riolan’s arch and basing on hydrodynamic principle, we speculate the mechanism of collateral circulation. Finally, based on the retrospective study of high ligation cases and combined principles of fluid mechanics, we show how these shortcut anastomotic branches evolved into Riolan’s arch.ResultsWe report the classification of the ascending branch of LCA (which approaches the splenic flexure) and the left branch of MCA, display these shortcut anastomotic branches on a map, and establish their three-dimensional anatomical classification. We found that Riolan’s arch is a shortcut pathway for the compensation of anastomotic branches, between MCA and LCA under pathological conditions, and that the formation mechanism of shortcut path accords with the principle of hydrodynamics.ConclusionsOur results show the mechanism of pathological Riolan’s arch formation and provide new anatomic thinking for the battle between high and low ligation of IMA in colorectal cancer surgery.

2020 ◽  
Vol 42 (12) ◽  
pp. 1509-1515
Author(s):  
Mitsuhiro Yano ◽  
Shinji Okazaki ◽  
Ichiro Kawamura ◽  
Shunichiro Ito ◽  
Shintaro Nozu ◽  
...  

Abstract Purpose In the present study, we focused on the accessory middle colic artery and aimed to increase the safety and curative value of colorectal cancer surgery by investigating the artery course and branching patterns. Methods We included 143 cases (mean age, 70.4 ± 11.2 years; 86 males) that had undergone surgery for neoplastic large intestinal lesions at the First Department of Surgery at Yamagata University Hospital between August 2015 and July 2018. We constructed three-dimensional (3D) computed tomography (CT) angiograms and fused them with reconstructions of the large intestines. We investigated the prevalence of the accessory middle colic artery, the variability of its origin, and the prevalence and anatomy of the arteries accompanying the inferior mesenteric vein at the same level as the origin of the inferior mesenteric artery. Results Accessory middle colic artery was observed in 48.9% (70/143) cases. This arose from the superior mesenteric artery in 47, from the inferior mesenteric artery in 21, and from the celiac artery in two cases. In 78.2% (112/143) cases, an artery accompanying the inferior mesenteric vein was present at the same level as the origin of the inferior mesenteric artery; this artery was the left colic artery in 92, the accessory middle colic artery in 11, and it divided and became the left colic artery and the accessory middle colic artery in 10 cases. Conclusion 3D CT angiograms are useful for preoperative evaluation. Accessory middle colic arteries exist and were observed in 14.9% of cases.


2021 ◽  
Author(s):  
Pavan Kumar Jonnada ◽  
Monish Karunakaran ◽  
Dayakar Rao

The level of ligation of the inferior mesenteric artery (IMA) is a critical factor that can influence outcomes. The aim of this meta-analysis was to compare outcomes following high or low ligation of IMA. A systematic search was performed for relevant articles published between 2000 and 2020. Meta-analysis was performed using fixed-effects or random-effects models; 31 studies were included. Results show significantly lower rates of anastomotic leak, postoperative morbidity and urinary dysfunction with low ligation compared with high ligation. Though recurrence rates were similar, 5-year overall survival was longer in the low ligation group. Low ligation of IMA decreases anastomotic leak rates and overall morbidity. Addition of IMA nodal clearance to low ligation appears to improve overall survival in colorectal cancer.


2016 ◽  
Vol 33 (04) ◽  
pp. 193-196 ◽  
Author(s):  
R. Singh

Abstract Introduction: Inferior mesenteric artery arises from abdominal aorta just below the third part of duodenum at the level of L3-L4 vertebra. It supplies left colon and rectosigmoid colon through its branches namely- left colic artery, two-three sigmoid arteries and superior rectal artery. The branching pattern of inferior mesenteric artery is of immense use in colon surgery. Material and Methods: The study was carried out in the department of anatomy by dissecting seven embalmed cadavers. The inferior mesenteric artery and its branches were identified; its vertebral level was analysed. The length and diameter of inferior mesenteric artery were measured by vernier callipers. Results: In first case, bifurcation of inferior mesentric artery into common trunk and main artery then trifitrcation of main artery and bifurcation of common trunk belong to anomalous configuration. In second case, this artery gave a tetrafitrcated common trunk and main artery which continued as superior rectal artery. In third case, the same artery trifurcated into left colic, superior rectal artery and bifurcated common trunk. In fourth case, the artery bifurcated into common trunk further dividing into left colic and sigmoid arteries and main artery into superior rectal and sigmoid arteries. In fifth case, this artery trifitrcated into three branches namely, sigmoid, rectosigmoid, and superior rectal arteries. Left colic artery arose from superior mesenteric artery. Conclusion: The knowledge of branching pattern of inferior mesenteric artery will be of paramount importance to colon surgeons during colectomy, to radiologists in avoiding misinterpretation of radiographs and anatomists for new variants.


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