Unveiling the hidden: identification and management of overlooked blood vessels in laparoscopic left hemicolectomy for splenic flexure cancer.

BACKGROUND: During laparoscopic left hemicolectomy procedures, a previously overlooked consistently thick blood vessel within the gastrocolic ligament near the splenic hilum may contribute to post-operative bleeding complications. The purpose of this study was to investigate the identification and management of the previously overlooked blood vessel. METHODS: This is a retrospective descriptive study of patients undergoing laparoscopic left colectomy for splenic fexure cancer conducted at a national gastrointestinal surgery centre in China. Consecutive patients with splenic fexure cancer who underwent laparoscopic left colectomy using our"five-step process"(n = 34) between January 2021 and July 2023 were included. RESULTS: The vessels can be effectively exposed using the aforementioned "five-step process." It was observed that the overlooked vessels consistently present in all patients were identified as the omental branch of the left gastroepiploic artery and vein. CONCLUSION: We have identified the origin of previously overlooked blood vessels and recommended a safe method for their management. This may offer advantages to colorectal surgeons performing laparoscopic left colectomy for splenic flexure cancer.

Usefulness of 3D-CT Angiography to Determine the Extent of Lymphadenectomy in Colon Cancer of the Splenic Flexure.

BACKGROUND/AIM: This study aimed to evaluate the extent of lymph node dissection (LND) determined using preoperative Three-dimensional computed tomographic angiography (3D-CTA), in the management of splenic flexure colon cancer (SFC). PATIENTS AND METHODS: In this retrospective, observational study, 61 patients who underwent preoperative 3D-CTA and laparoscopic complete mesocolic excision for SFC between December 2011 and December 2021 were identified at a tertiary care center in Japan. Preoperative 3D-CTA was used to confirm the feeding arteries, following which the extent of LND was determined. Left hemicolectomy was performed in cases requiring LND in the domains of the middle colic artery and left colic artery. In other cases, a partial colectomy (PC) that was defined as a segmental resection of the splenic flexure with LND in the domains of the feeding arteries was performed. Surgical and oncological outcomes were compared between PC and left hemicolectomy. RESULTS: Preoperative 3D-CTA enabled the evaluation of the feeding artery in all patients. PC was performed in 51 patients (83.6%). Patients who underwent PC had a shorter operative time (p=0.03) and less blood loss (p=0.01). There was no difference in complications between the two groups. There was also no significant difference in 5-year overall survival, nor 3-year disease free survival. CONCLUSION: Preoperative simulation using 3D-CTA has the potential to be useful in the identification of feeding arteries and determination of the oncologically adequate extent of LND for each patient.

Clinical outcomes and radiological assessment of vascular anatomy in patients who underwent D3 left hemicolectomy.

Background: Adequate blood supply is one of the key factors for colorectal anastomosis healing. Various variants of vascular anatomy often come as a surprise to surgeons during operations. Objectives: The aims of this study were to carry out a comparative analysis of three-dimensional-computed tomography (3D-CT) angiography data with intraoperative data and a detailed analysis of variants of the anatomy of splenic flexure. Material and methods: In this study, we included 103 patients (56 males and 47 females; mean age 64.2 ± 11.6) with the left-sided colon and rectal cancer who underwent preoperative 3D-CT angiography at Ternopil University Hospital between 2016 and 2022. Results: According to the recently proposed classification, there are four types of blood supply to the splenic flexure of the colon: Our analysis showed that type 1 was found in 83 (80.6%) patients, type 2 in 9 (8.7%), type 3 in 10 (9.7%), and type 4 in 1 (1%). All patients underwent local left radical hemicolectomy with resection of complete mesocolic excision (CME), central vascular ligation (CVL) and resección (R0). Seven cases were operated laparoscopically; and the median quantity of removal lymph nodes was 21.54 ± 7.32. Positive lymph nodes were revealed in 24.3% cases. AL was diagnosed in one patient. Conclusions: Careful pre-operative analysis of vascular anatomy on 3D-CT angiography will assess the vascularization of the splenic flexure of the colon, reduce intraoperative time to identify structures, and develop a personalized strategy for surgery which potentially can reduce the risk of anastomotic leakage.

Antecedentes: El suministro de sangre adecuado es uno de los factores clave para la curación de la anastomosis colorrectal. Varias variantes de la anatomía vascular a menudo sorprenden a los cirujanos durante las operaciones. Objetivo: Realizar un análisis comparativo de los datos de la angiografía tridimensional por tomografía computarizada (3D-TC) con los datos intraoperatorios y un análisis detallado de las variantes de la anatomía del ángulo esplénico. Método: Se incluyeron en el estudio 103 pacientes con cáncer de colon y recto del lado izquierdo que se sometieron a una angiografía 3D-TC preoperatoria en el Hospital Universitario de Ternopil. Resultados: De acuerdo con la clasificación propuesta recientemente, existen cuatro tipos de irrigación del ángulo esplénico del colon. Nuestro análisis mostró que el tipo 1 se encontró en 83 (80.6%) pacientes, el tipo 2 en 9 (8.7%), el tipo 3 en 10 (9.7%) y el tipo 4 en 1 (1%). Todos los pacientes fueron sometidos a hemicolectomía radical izquierda local con resección de escisión mesocólica completa (CME), ligadura vascular central (CVL) y resección (R0). Siete pacientes fueron operados por vía laparoscópica. La mediana de ganglios extirpados fue de 21.54 ± 7.32. Se revelaron ganglios linfáticos positivos en el 24.3% de los casos. Se diagnosticó fuga anastomótica en un paciente. Conclusiones: El análisis preoperatorio cuidadoso de la anatomía vascular en la angiografía 3D-TC evaluará la vascularización del ángulo esplénico del colon, reducirá el tiempo intraoperatorio para identificar estructuras y desarrollará una estrategia personalizada para la cirugía.

Drainage pattern of the splenic flexure vein and its accompanying arteries using three-dimensional computed tomography angiography: a single-centre study of 600 patients.

AIM: The splenic flexure has variable vascular anatomy, and the details of the venous forms are not known. In this study, we report the flow pattern of the splenic flexure vein (SFV) and the positional relationship between the SFV and arteries such as the accessory middle colic artery (AMCA). METHODS: This was a single-centre study using preoperative enhanced CT colonography images of 600 colorectal surgery patients. CT images were reconstructed into 3D angiography. SFV was defined as a vein flowing centrally from the marginal vein of the splenic flexure visible on CT. AMCA was defined as the artery feeding the left side of the transverse colon, separate from the left branch of the middle colic artery. RESULTS: The SFV returned to the inferior mesenteric vein (IMV) in 494 cases (82.3%), the superior mesenteric vein in 51 cases (8.5%) and the splenic vein in seven cases (1.2%). The AMCA was present in 244 cases (40.7%). The AMCA branched from the superior mesenteric artery or its branches in 227 cases (93.0% of cases with existing AMCA). In the 552 cases in which the SFV returned to the IMV, superior mesenteric vein or splenic vein, the left colic artery was the most frequent artery accompanying the SFV (42.2%), followed by the AMCA (38.1%) and the left branch of the middle colic artery (14.3%). CONCLUSIONS: The most common flow pattern of the vein in the splenic flexure is from the SFV to IMV. The SFV is frequently accompanied by the left colic artery or AMCA.

Re-interpreting mesenteric vascular anatomy on 3D virtual and/or physical models, part II: anatomy of relevance to surgeons operating splenic flexure cancer.

BACKGROUND: The splenic flexure is irrigated from two vascular areas, both from the middle colic and the left colic artery. The challenge for the surgeon is to connect these two vascular areas in an oncological safe procedure. MATERIALS AND METHODS: The vascular anatomy, manually 3D reconstructed from 32 preoperative high-resolution CT datasets using Osirix MD, Mimics Medical and 3-matic Medical Datasets, were exported as STL-files, video clips, stills and supplemented with 3D printed models. RESULTS: Our first major finding was the difference in level between the middle colic and the inferior mesenteric artery origins. We have named this relationship a mesenteric inter-arterial stair. The middle colic artery origin could be found cranial (median 3.38 cm) or caudal (median 0.58 cm) to the inferior mesenteric artery. The lateral distance between the two origins was 2.63 cm (median), and the straight distance 4.23 cm (median). The second finding was the different trajectories and confluence pattern of the inferior mesenteric vein. This vein ended in the superior mesenteric/jejunal vein (21 patients) or in the splenic vein (11 patients). The inferior mesenteric vein confluence could be infrapancreatic (17 patients), infrapancreatic with retropancreatic arch (7 patients) or retropancreatic (8 patients). Lastly, the accessory middle colic artery was present in ten patients presenting another pathway for lymphatic dissemination. CONCLUSION: The IMV trajectory when accessible, is the solution to the mesenteric inter-arterial stair. The surgeon could safely follow the IMV to its confluence. When the IMV trajectory is not accessible, the surgeon could follow the caudal border of the pancreas.

Vascular variations encountered during laparoscopic surgery for transverse colon, splenic flexure, and descending colon cancer: a retrospective cohort study.

BACKGROUND: Laparoscopic surgery for cancer located in the transverse colon or splenic flexure is difficult because of vascular variability in this region and adjacent vital organs such as the pancreas, spleen, and duodenum. METHODS: This retrospective cohort study involved 51 patients who underwent laparoscopic surgery for colon cancer at Tokushima University Hospital from July 2015 to December 2020. Variations of the middle colic artery (MCA), left colic artery (LCA), middle colic vein (MCV), and first jejunal vein (FJV) and short-term outcomes of laparoscopic surgery in patients with each vascular variation were evaluated. RESULTS: Variations of the MCA, LCA, MCV, and FJV were classified into four, three, five, and three patterns, respectively. The short-term outcomes of laparoscopic surgery for transverse colon cancer in patients with MCA variations and those with FJV variations were evaluated, and no significant difference was found in the operation time, blood loss, postoperative complication rate, time from surgery to start of dietary intake, or time from surgery to discharge among the different variations. Additionally, no significant differences were found in the short-term outcomes of laparoscopic surgery for descending colon cancer in patients with LCA variations. CONCLUSION: Preoperative assessment of vascular variations may contribute to the stability of short-term outcomes of laparoscopic surgery for transverse colon, splenic flexure, and descending colon cancer.

Laparoscopic middle colic artery-preserved right hemicolectomy with true D3 lymph node dissection for right-sided colon cancer: modified complete mesocolic excision.

BACKGROUND: Complete mesocolic excision (CME) has been demonstrated to be a useful surgical procedure for advanced colon cancer. We previously reported on laparoscopic (Lap) CME with true central vascular ligation (CVL) for advanced right-sided colon cancer. Lap CME with true CVL is highly plausible from the perspective of surgical oncology. However, true CVL of the middle colic artery (MCA) may require extensive resection of the transverse colon. The Japanese Classification of Colorectal Cancer defines D3 as main lymph node dissection around the superior mesenteric artery (SMA), and true CVL is not listed as a required condition. Our institution has been performing a Lap procedure (Lap D3/modified CME) that consists of the dissection of main lymph nodes around the root of the MCA (#223LNs) while preserving the left branch of the MCA. Two videos of a Lap D3/modified CME are presented, and the short-term outcome is reported. METHODS: Lap D3/modified CME was defined as Lap ligation surgery at the root of the right branch of the MCA that preserves the MCA with #223LNs on the resection side. The present study retrospectively examined 11 cases of Lap D3/modified CME performed at the Tokyo Medical University Hospital between 2015 and 2020. When the SMA is difficult to visualize in Type V/A cases, the SMV is pulled using some silicone string, and the surrounding lymph nodes are dissected while visualizing the SMA. RESULTS: The median operating time was 289 min, and the median blood loss was 57 ml. The median total number of dissected lymph nodes was 38, and the median number of dissected #223LNs was three. No metastasis was found in the dissected #223LNs. CONCLUSION: Although this surgery can be performed safely, we believe that this surgery needs to be performed for suitable cases by a highly experienced and skilled surgical team.

How to do a laparoscopic high left colectomy with complete mesocolic excision and central vascular ligation for splenic flexure cancer.

Due to a lack of a standardized surgical approach in splenic flexure cancer, we consider useful to present a how to do it material on laparoscopic high left colectomy with complete mesocolic excision and central vascular ligation for this type of tumours.

Arterial anatomy of the splenic flexure using preoperative three-dimensional computed tomography.

BACKGROUND: To perform a safe and precise laparoscopic surgery for the splenic flexure cancer, it is important for surgeons to gain a preoperative understanding of the running of the feeding artery of the splenic flexure. We evaluated the blood supply to the splenic flexure by using preoperative three-dimensional computed tomography (3D-CT). METHOD: We retrospectively analyzed a total of 88 patients with colorectal cancer who underwent preoperative 3D-CT at our institutions between April 2016 and June 2017. RESULTS: The arterial blood supply to the splenic flexure was divided into four patterns as follows: type 1, the left branch of the middle colic artery (MCA) with common trunk and the left colic artery (LCA) (n = 48, 54.5%); type 2, the left branch of the MCA with independent origin and the LCA (n = 8, 9.1%); type3, the accessory-MCA (A-MCA) and the LCA (n = 27, 30.7%); and type4, the LCA alone (n = 5, 5.7%). The MCA had the common trunk of the right and left branches in the majority of cases (85.2%). The right and left branches of the MCA arose separately from the superior mesenteric artery (SMA) in 8 of 88 patients (9.1%). CONCLUSIONS: The arterial patterns of the splenic flexure were classified into four patterns by using preoperative 3D-CT. The A-MCA existed in 30% of the patients in this study. These information should be helpful to perform the optimal surgery for the splenic flexure cancer.

Non-anatomical colonic resections: splenic flexure and transverse colectomy. Central vascular ligation is crucial for survival.

BACKGROUND: Cancers of the transverse colon (TC) and of the splenic flexure (SF) are rather uncommon and their prognosis has been reported significantly poorer as compared to right- and left-sided colon cancers. Several studies tried to investigate which is the optimal surgery for oncological and survival outcomes reporting extended colectomies as more effective than limited resections. METHODS: All consecutive patients with diagnosis of colorectal cancer submitted to surgical resection with anastomosis between January 2005 and December 2016 at the Division of Surgical Oncology and Digestive Surgery, Department of Oncology, at the University of Turin, were included. Based on tumor location, patients were enrolled in arm A (cancer of the ascending colon, right (hepatic) flexure, left and sigmoid colon) or arm B (cancer of the transverse colon and of the left (splenic) flexure). RESULTS: Out of 1433 patients registered, 500 patients fulfilled all inclusion and exclusion criteria and were allocated in arm A (N.=425) or in arm B (N.=75). Central vascular ligation and the achievement of at least 5 cm of healthy margin were always performed in all procedures of both arms. Patients' population of the two arms was homogeneous as concerns demographic characteristics and stage of the disease. In arm A, resections were performed more frequently by mini-invasive approach as compared to arm B. Operative time was statistically longer in arm B. Postoperative complications rate was extremely low and comparable in both arms (13.4 and 8.0 in arms A and B, respectively). No postoperative mortality was observed. Overall 5-year survival rates were similar in arm A and B (82.3% and 73.05%, respectively; P=0.29). Arm B patients were treated either with more limited resections (resection of the TC and of the SF) or with extended colectomies (right- and left-sided, standard or enlarged, hemicolectomies), both associated with central vascular ligation. Despite a shorter length of surgical specimen after limited resections, postoperative complications, lymph node yield, and survival were absolutely comparable in both types of surgical treatments. CONCLUSIONS: Limited resections for TC and SF cancers can be performed with the same clinical, oncological and survival outcomes as compared to more extended colectomies if an adequate size of the specimen for the achievement of at least 5 cm of health margin is associated to Central Vascular Ligation.

Vascular anatomy of the transverse mesocolon and bidirectional laparoscopic D3 lymph node dissection for patients with advanced transverse colon cancer.

Laparoscopic D3 lymph node dissection for transverse colon cancer is technically demanding because of complicated anatomy. Here, we reviewed the vascular structure of the transverse mesocolon, explored the extent of the base of the transverse mesocolon, and evaluated the feasibility and oncological safety of D3 lymph node dissection. We retrospectively reviewed the clinical records of 42 patients with advanced transverse colon cancer who underwent curative surgery and D3 dissection at Kyushu University Hospital between January 2008 and December 2015. We examined the venous and arterial anatomy of the transverse mesocolon of each resection and compared surgical outcomes between patients who underwent laparoscopic D3 (Lap D3) and open D3 (Open D3) dissection. Patients included two with Stage I, 18 with Stage II, 20 with Stage III, and two with Stage IVA. Thirty-six (85.7%) and six (14.3%) patients underwent Lap D3 or Open D3, respectively. The tumor sizes of the Open D3 and Lap D3 groups were 7.8 and 3.7 cm, respectively (P < 0.001). The Lap D3 group had significantly less blood loss (26 mL vs 272 mL, P = 0.002). The other outcomes of the two groups were not significantly different, including 3-year overall survival (87.7% vs 83.3%, P = 0.385). We observed four patterns of the middle colic artery (MCA) arising from the superior mesenteric artery (SMA), and the frequency of occurrence of a single MCA was 64.3%. The right-middle colic vein (MCV) was present in 92.9% of resections and served as a tributary of the gastrocolic trunk, and 90.5% of the left MCVs drained into the superior mesenteric vein (SMV). The root of the transverse mesocolon was broadly attached to the head of the pancreas and to the surfaces of the SMV and SMA. Laparoscopic D3 lymph node dissection may be tolerated by patients with advanced transverse colon cancer.

Evaluation of the venous drainage pattern of the splenic flexure by preoperative three-dimensional computed tomography.

INTRODUCTION: Anatomical evaluation of the splenic flexure vein is essential for complete mesocolic excision with central vascular ligation when treating patients with splenic flexure cancer. Although there have been several studies relating to the arterial branches of the splenic flexure, very limited data are available regarding the variation in venous anatomy in this region. METHODS: Sixty-six patients with colorectal cancer who underwent preoperative 3-D CT between April 2016 and April 2017 were included in this retrospective study. The pattern of the venous drainage of the splenic flexure and its association with the inferior border of the pancreas were evaluated. RESULTS: The inferior mesenteric vein flowed into the splenic vein in 32 patients (48.5%), into the superior mesenteric vein in 27 patients (40.9%), and into the confluence of splenic vein and superior mesenteric vein in 7 patients (10.6%). The splenic flexure vein joined the inferior mesenteric vein in 62 patients (93.9%), the splenic vein in 2 patients (3.0%), and the middle colic vein in 2 patients (3.0%). The splenic flexure vein flowed into the inferior mesenteric vein below the level of the inferior border of the pancreas in 58 patients (90.6%) and above it in 4 patients (6.3%). CONCLUSION: Preoperative evaluation of the venous pattern of the splenic flexure on 3-D CT is useful before complete mesocolic excision with central vascular ligation to avoid intraoperative bleeding during splenic flexure cancer surgery.

Standardize the Surgical Technique and Clarify the Relevant Anatomic Concept for Complete Mobilization of Colonic Splenic Flexure Using da Vinci Xi® Robotic System.

BACKGROUND: The present study is to set up a standardized approach for complete mobilization of colonic splenic flexure using da Vinci Xi® robotic system, based on clarification of the mesenteric structures of distal transverse colon. METHODS: The surgical outcomes and relevant anatomic structures of 104 consecutive patients undergoing robotic resection of primary colorectal cancer with the intent of complete mobilization of colonic splenic flexure using da Vinci Xi® robotic system were retrospectively reviewed. RESULTS: Complete mobilization of colonic splenic flexure can be efficiently performed by the Xi® robotic system, as demonstrated by short operation time, minimal intra-operative blood loss, and few surgical complications. Xi® robotic system has overcome the drawbacks of Si® robotic system for the mobilization of colonic splenic flexure. The present study defined the following anatomic hallmarks for the colonic splenic flexure: (1) The transverse mesocolon distal to the inferior mesenteric vein adheres to the low border of pancreas by the avascular fibrous connective tissues, which have been inappropriately named as "mesenteric root"; (2) The colonic splenic flexure abuts closely to spleen with an acute angle in 78.85% (n = 82/104); (3) Only a minority of patients presented with the Riolan branch (15.38%, n = 16/104) or the Moskowitz artery (8.65%, n = 9/104). CONCLUSION: With increased maneuverability of Xi® robotic arms and the clarification of relevant anatomic concept, the surgical technique for the complete mobilization of colonic splenic flexure can be standardized; and the standardization of surgical technique is the first step toward the enhanced automation in the rapidly evolving robotic systems.

A Rare Branching Pattern of a Middle Mesenteric Artery Supplying the Head of the Pancreas and the Transverse Colon.

OBJECTIVE: The appearance of a middle mesenteric artery is a rare branching variation, with an incidence lower than 0.1%. Our case reports such an anatomical artery pattern which was discovered in a male Caucasian cadaver during routine educational dissection. This alternation is seldom encountered and may trouble diagnostic and surgical interventions. CASE REPORT: The case of a Middle Mesenteric Artery is described, as a vessel originating from the Abdominal Aorta 3.3 cm below the origin of the Superior Mesenteric and 3.8 cm above the origin of the Inferior Mesenteric Artery. The middle mesenteric artery, directed upwards, gives two branches for supplying blood to the head of the pancreas. We first mention the thinner branch, corresponding to the posterior one of the inferior pancreaticoduodenal artery, and second the thicker branch corresponding to the anterior branch of the Inferior Pancreaticoduodenal Artery. The main artery continues its course between the two sheets of the mesocolon to supply the transverse colon, thus substituting the normal colic artery. CONCLUSION: The occurrence of a Middle Mesenteric Artery constitutes a very rare anatomic variation. We present, to our knowledge, the first case described where the Middle Mesenteric Artery provides blood to the pancreas.

Evaluation of the vascular anatomy of the left-sided colon focused on the accessory middle colic artery: a single-centre study of 734 patients.

AIM: Surgery for colorectal cancer located in the splenic flexure is difficult to perform because of the complex anatomy. Recently, in addition to the middle colic artery and left colic artery (LCA), the accessory middle colic artery (AMCA) has been recognized as a feeding artery for the left-sided colon. This study aimed to evaluate the vascular anatomy of the splenic flexure focusing on the AMCA in a large number of patients. METHOD: A total of 734 patients who underwent CT before surgery for colorectal cancer were enrolled. We retrospectively evaluated the vascular anatomy using both two- and three-dimensional CT angiography. RESULTS: The AMCA existed in 36.4% of the cases (n = 267). In many cases, it originated from the superior mesenteric artery (n = 228, 85.4%). The AMCA had a common trunk with the transverse pancreatic artery in 54 patients (20.2%). The frequency of the presence of the AMCA was associated with the branching pattern of the LCA, and was more frequent when the LCA was absent (P < 0.001). CONCLUSION: The presence of the AMCA is not rare and the AMCA has some branching patterns; therefore, recognizing it preoperatively and intra-operatively is important, being especially careful when the LCA is absent.

Analysis of the Vascular Interrelationships Among the First Jejunal Vein, the Superior Mesenteric Artery, and the Middle Colic Artery.

BACKGROUND: The technical difficulty of laparoscopic surgery for transverse colon cancer is partly due to the vascular variability around the middle colic vessels. Although individual variations in the arteries or veins in this area were previously investigated, the vascular interrelationships between these vessels remain unknown. This study was designed to investigate the vascular interrelationships between the arteries and veins around the middle colic vessels and to provide practically useful classifications. METHODS: This study included 105 consecutive patients who underwent colorectal surgery for colorectal tumors in our institution in 2016. Patients with a history of colectomy were excluded. Vascular anatomical classifications were analyzed by evaluating thin-slice images of preoperative contrast-enhanced computed tomography. RESULTS: Vascular anatomical patterns were classified according to whether the first jejunal vein ran behind (type A) or in front (type B) of the superior mesenteric artery. Type B was subclassified into two subtypes, depending on whether the middle colic artery originated cephalad (type B1) or caudad (type B2) to the first jejunal vein. We identified 83 (79.0%) cases of type A, 11 (10.5%) of type B1, and 11 (10.5%) of type B2. In 17 cases, the middle colic vein drained into the inferior mesenteric vein, and all of these were type A (P = 0.0202). Furthermore, in eight cases, the middle colic vein drained into the first jejunal vein, and all of these were type B (P < 0.0001). CONCLUSIONS: This study elucidated the vascular interrelationships around the middle colic vessels. Our findings provided important knowledge for laparoscopic surgery in treating transverse colon cancer.

Anomalous inferior mesenteric artery supplying the ascending, transverse, descending, and sigmoid colons.

We have encountered in our anatomical practice the first case and an extremely rare second case in which the ascending, transverse, descending, and sigmoid colons were supplied by the inferior mesenteric artery. The causes of colic artery anomalies are generally explained in conjunction with the development of the superior mesenteric artery, which is intimately related to embryonic elongation and midgut rotation. However, this embryological model was inapplicable to both cases. This difficulty motivated us to seek possible relationships with reported anomalous inferior mesenteric arteries in adults as well as their embryological causes. We consider that the aberrant right colic artery found in 2009 is an "intermesenteric artery" which anastomoses the superior (or its middle colic branch) and inferior mesenteric artery, but secondarily lost its origin from the superior mesenteric artery. The aberrant colic artery found in 2010 is a "middle-inferior mesenteric artery" in which the inferior mesenteric artery formed a common trunk with remnant middle mesenteric artery.