Assessing anatomical variations of the inferior mesenteric artery via three-dimensional CT angiography and laparoscopic colorectal surgery: a retrospective observational study.

To assess the anatomy of the inferior mesenteric artery (IMA) and its branches by reviewing laparoscopic left-sided colorectal cancer surgery videos and comparing them with preoperative three-dimensional computed tomography (3D-CT) angiography, to verify the accuracy of 3D-CT vascular reconstruction techniques. High-definition surgical videos and preoperative imaging data of 200 patients who underwent laparoscopic left-sided colorectal cancer surgery were analysed, and the alignment of the IMA and its branches in relation to the inferior mesenteric vein (IMV) was observed and summarized. The above two methods were used to measure the length of the IMA and its branches. Of 200 patients, 47.0% had the sigmoid arteries (SAs) arise from the common trunk with the superior rectal artery (SRA), and 30.5% had the SAs arise from the common trunk with the left colic artery (LCA). In 3.5% of patients, the SAs arising from both the LCA and SRA. The LCA, SA, and SRA emanated from the same point in 13.5% of patients, and the LCA was absent in 5.5% of patients. The range of D cm (IMA length measured by intraoperative silk thread) and d cm (IMA length measured by 3D-CT vascular reconstruction) in all cases was 1.84-6.62 cm and 1.85-6.52 cm, respectively, and there was a significant difference between them. (p < 0.001). The lengths between the intersection of the LCA and IMV measured intraoperatively were 0.64-4.29 cm, 0.87-4.35 cm, 1.32-4.28 cm and 1.65-3.69 cm in types 1A, 1B, 1C, and 2, respectively, and there was no significant difference between the groups (p = 0.994). There was only a significant difference in the length of the IMA between the 3D-CT vascular reconstruction and intraoperative observation data, which can provide guidance to surgeons in preoperative preparation.

Reducing aneurysm sac growth and secondary interventions following endovascular abdominal aortic aneurysm repair by preemptive coil embolization of the inferior mesenteric artery and lumbar arteries.

OBJECTIVE: Type II endoleak (EL-2) is the most common complication following endovascular aneurysm repair (EVAR), leading to continued sac growth and potential rupture. In this study, we examined the association between patency of the inferior mesenteric artery (IMA) and lumbar arteries (LAs) with respect to sac growth. The effect of preemptive embolization of the IMA and/or LAs on the need for secondary interventions for sac growth post-EVAR was also evaluated. METHODS: A retrospective cohort study was performed on consecutive patients who underwent EVAR for non-ruptured, infrarenal abdominal aortic aneurysms (AAAs) from January 2012 to December 2020. A select group of patients underwent preemptive embolization of the IMA and/or LA. Patients with any types I, III, or IV endoleaks were excluded. Patency of the IMA and LA on preoperative computed tomography angiogram (CTA) was evaluated on TeraRecon workstation. All secondary interventions to treat EL-2 were recorded. Sac growth was defined as centerline axial diameter increase of ≥5 mm on follow-up CTA. RESULTS: A total of 300 patients (mean age, 74 ± 8.5 years; 83.7% male) underwent EVAR. Ninety-nine patients had preemptive embolization of the IMA and/or LA. Mean follow-up of the cohort was 59.3 ± 30.5 months. Thirty-six patients (12%) demonstrated sac growth on follow-up; 12 of these (33.3%) had preemptive embolization. The median time until detection of sac growth was 28.8 months (interquartile range, 15.2-46.5 months), with a mean growth of 10.1 ± 6.4 mm. Sac growth was significantly associated with presence of EL-2: 27 of 36 (75%) with EL-2 vs 9 of 36 (25%) without EL-2 (P < .001). Patients with sac growth had a higher mean total number (2.6 ± 1.5) of patent lower LAs (L3, L4) compared with those without (2.0 ± 1.4; P = .03). Patency of L1, L2, and L3 LAs were not associated with sac growth. However, patency of at least one L4 LA was significantly associated with sac growth (14.8% vs 7.7%; P = .04). The highest incidence of sac growth (17.6%) was seen when both IMA and L4 LA were patent; significantly different from the lowest incidence (5.3%) when both were occluded preoperatively (P = .018). Preemptive coiling of the IMA and/or LA significantly reduced the need for post-EVAR secondary intervention for sac growth. Freedom from post-EVAR secondary intervention was achieved in 92 of 99 (92.9%) pre-EVAR coiled patients vs 163 of 201 (81.5%) patients who did not undergo pre-EVAR coiling (P = .009). CONCLUSIONS: Preemptive coil embolization of the IMA and LAs, especially L4 LA, reduces the need for secondary interventions for sac growth, potentially improving the long-term durability of EVAR.

High Ligation of the Inferior Mesenteric Artery in Left-Sided Colon and Rectal Cancer Resection: Rates of Success and Outcomes.

BACKGROUND: High ligation of the inferior mesenteric artery, defined as ligation before the takeoff of the left colic artery, is often described as the gold standard in low left-sided colon and rectal cancer surgery. The aim of this study is to quantify the rate of ligation at the described level at a single academic center. Additionally, we examined the relationship between level of ligation and cancer-related outcomes. METHODS: This retrospective cohort study included patients ages 18 and over with low left-sided colon, rectal, and anal cancers undergoing surgical resection. Radiographic evidence of high ligation was defined as ligation of the inferior mesenteric artery before the takeoff of the left colic artery. Patients with and without radiographic evidence of high ligation on CT were compared. Secondary outcomes include lymph node yield and positivity, need for adjuvant therapy, and time from surgery to adjuvant therapy. RESULTS: 169 patients (54% male) were included in the study. 61.5% of operative reports described high ligation of the IMA. There was radiographic evidence of high ligation in 55.6% of total patients and in 70.2% of patients where high ligation was intended. There was no significant difference in surgeon experience, surgical procedure, or surgical approach. There was no difference in lymph node yield, time to adjuvant chemotherapy, or recurrence rates. CONCLUSION: This study demonstrates good technical success rate of high ligation of the inferior mesenteric artery but shows no difference in short-term patient-measured outcomes between high and low ligation (or successful and unsuccessful high ligation).

Laparoscopic surgery for rectal cancer with a coexisting Retzius shunt and inferior mesenteric arteriovenous malformation: A case report.

A coexisting short-circuit from the inferior mesenteric vein (IMV) to the inferior vena cava, known as a Retzius shunt, and arteriovenous malformation (AVM) of the inferior mesentery are extremely rare conditions. We encountered a case of rectal cancer with coexisting Retzius shunt and inferior mesenteric AVM successfully treated with laparoscopic surgery. Contrast computed tomography (CT) in a 62-year-old man with rectal cancer showed multiple dilated veins at the mesenterium of the descending sigmoid colon. These dilated veins were connected between the IMV and the left renal vein. A diagnosis of Retzius shunt was made, and laparoscopic low anterior resection with lymph node dissection was performed. A pathological examination of the colonic mesenterium revealed AVM communicating with the dilated IMV and Retzius shunt. The preoperative evaluation of aberrant vessels by three-dimensional CT is particularly useful for patients with vascular malformations to ensure safe laparoscopic surgery.

A rare case of unconnection between the celiac trunk and the abdominal aorta and a large anastomosis with the inferior mesenteric artery with a literature review.

PURPOSE: Direct connection between the celiac trunk (CT) and inferior mesenteric artery (IMA) is very rare, knowledge of this anomaly is of great importance to surgeons and anatomists. INTRODUCTION: Splanchnic arteries arise from the abdominal aorta (AA). Unusual development of these arteries can lead to considerable variations. Historically there were a lot of classification of the variation in the CT and IMA, none of the classifications describes a direct connection from IMA to CT. MATERIALS AND METHODS: We report a rare case in which the connection between the CT and AA was lost and replaced by a direct anastomosis with IMA. RESULTS: 60 year old male presented to the hospital to undergo a computed tomography scan. Which showed that there was no CT arising from the AA, but there was a large anastomosis arises from the IMA and ended with a short axis and Left gastric artery (LGA), Splenic artery (SA), Common hepatic artery (CHA) arise from this axis, these arteries continued to the stomach and spleen and liver normally. The anastomosis provides the total supply to the CT. The CT branches are normal. CONCLUSION: Knowledge of the arterial anomalies provides an important help in clinical surgical implications especially in organs transplant.

Inferior mesenteric artery arteriovenous malformation, a rare cause of ischemic colitis: A case report.

RATIONALE: An arteriovenous malformation (AVM) is an abnormal tangle of blood vessels that connects the arteries and the veins. Because normal capillary bed is partially or completely absented in the AVM, the blood passes quickly from the arteries to the veins, which disrupts normal blood flow and oxygen supply to the surrounding tissues. This is called "steal phenomenon," and in the inferior mesenteric artery (IMA) territory, this may lead to abdominal pain, gastrointestinal bleeding, portal hypertension, and even ischemic colitis. PATIENT CONCERNS: A 67-year-old man presented to our emergency department because of left side abdominal pain. DIAGNOSES: The abdominal computed tomography with contrast enhancement revealed a cluster of abnormal vascular lesions abutting the IMA with early opacification of the left colonic marginal vein. In addition, poor enhancement of segmental colonic wall was found from proximal descending colon to middle rectum. The diagnosis of AVM of the IMA and ischemic colitis was made. INTERVENTIONS: The patient underwent left hemicolectomy as well as the AVM resection. OUTCOMES: He was discharged uneventfully after the surgery without complications. LESSONS: IMA AVM carries the risk of ischemic colitis. computed tomography scan is helpful not only to the diagnosis of AVMs but also to exclude other lesions as well. Treatment options include endovascular embolization, surgical intervention, and a combination of both. Due to the complexity of this disease, treatment requires a case-specific multidisciplinary approach and a coordination of medical, radiological, and surgical staffs.

Verification of blood flow path reconstruction mechanism in distal sigmoid colon and rectal cancer after high IMA ligation through preoperative and postoperative comparison by manual subtraction CTA.

INTRODUCTION: We aimed to investigate manual subtraction computed tomography angiography (MS-CTA) to further confirm the distribution and classification of LCA (left colic artery) ascending/descending branches, then observe the postoperative blood flow path to illustrate how the above branches evolved to postoperative blood path. MATERIAL AND METHODS: 89 patients with distal sigmoid and rectal cancer were referred in our observation and underwent MS-CTA between June 2020 and March 2022. We classified the distribution of LCA and confirmed whether there exists AMCA (accessory middle colic artery). Then we planned blood flow path based on the classification of LCA branches before operation. High ligation was applied in regular radical surgery. During operation, we carefully protect the bifurcation of ascending and descending LCA. Then we compared the planned blood flow path with the actual postoperative blood flow path to verify the mechanism we proposed previously. RESULTS: Of 89 patients, 82 cases met our criteria, we summarized 6 distribution pattens of LCA ascending and descending branches. These preoperative pattens are consistent with the inspection during operation. The postoperative blood flow path of 6 pattens is evolved from the above adjacent anastomotic branches and is consistent with the planned blood flow path. We also found 2 cases with IMA stenosis and 1 case with SMA stenosis under pathological condition, and their compensatory blood flow path is in accordance with our theory. The rate of the anastomotic leakage in our study group is relatively low (7.3%). CONCLUSION: MS-CTA could confirm the distribution of LCA and AMCA, display accurate postoperative blood reconstruction path after IMA high ligation, and it further verified the mechanism we proposed previously, which is the proximal anastomotic branches forming new blood flow path from high-pressure area to the low-pressure area. This mechanism might be helpful for performing accurate laparoscopic sigmoid and rectal cancer surgery.

Routine Inferior Mesenteric Artery Embolisation is Unnecessary Before Endovascular Aneurysm Repair.

OBJECTIVE: A type II endoleak is the most common complication during surveillance after endovascular aneurysm repair (EVAR), and a patent inferior mesenteric artery (IMA) is a known risk factor for an endoleak. The effect of routine IMA embolisation prior to EVAR on overall outcome is unknown. The aim of the study was to compare two strategies: routine attempted IMA embolisation prior to EVAR (strategy in centre A) and leaving the IMA untouched (strategy in centre B). METHODS: Patients were treated with EVAR in two centres during the period 2005 - 2015, and the data were reviewed retrospectively. The primary endpoints were re-intervention rate due to type II endoleaks and the late IMA embolisation rate. Secondary endpoints included EVAR related re-intervention, sac enlargement, aneurysm rupture, and open conversion rates. RESULTS: Strategy A was used to treat 395 patients. The IMA was patent in 268 (67.8%) patients, and embolisation was performed in 164 (41.5%). The corresponding figures for strategy B were 337 patients with 279 (82.8%) patent IMAs, two (0.6%) of which were embolised. The mean duration of follow up was 70 months for strategy A and 68.2 months for strategy B. The re-intervention rates due to a type II endoleak were 12.9% and 10.4%, respectively (p = .29), with no significant difference in the rate of re-interventions to occlude a patent IMA (2.0% and 4.7%, respectively; p = .039). The EVAR related re-intervention rate was similar, regardless of strategy (24.1% and 24.6%, respectively; p = .93). Significant sac enlargement was seen in 20.3% of cases treated with strategy A and in 19.6% treated with strategy B (p = .82). The rupture and conversion rates were 2.5% and 2.1% (p = .69) and 1.0% and 1.5% (p = .40), respectively. CONCLUSION: The strategy of routinely embolising the IMA does not seem to yield any significant clinical benefit and should therefore be abandoned.

Delayed bowel necrosis due to inferior mesenteric artery occlusion in Stanford type A acute aortic dissection.

Although inferior mesenteric artery occlusion due to acute aortic dissection sometimes occurs, it is usually not considered an important finding. Herein, we present an extremely rare case of delayed bowel ischaemia due to inferior mesenteric artery occlusion in Stanford type A acute aortic dissection that highlights the need for cardiac surgeons to be mindful of inferior mesenteric artery occlusion in patients with superior mesenteric artery dissection or vascular anomalies in the mesenteric arteries.

[Surgeon's role in CT-based preoperative determination of inferior mesenteric artery anatomy in colorectal cancer treatment]. / Rol' khirurga v opredelenii anatomii nizhnei bryzheechnoi arterii po dannym komp'yuternoi tomografii pri lechenii kolorektal'nogo raka.

BACKGROUND: The inferior mesenteric artery (IMA) is a blood vessel of great importance in left colon and rectal cancer surgery. We aimed to determine the role of surgeons in computed tomography (CT) based vascular anatomy interpretation. METHOD: Patients with left colon and rectal cancer treated surgically with D3 lymph node dissection and selective vascular ligation were included in this study. All patients (n=250) underwent preoperative CT with intravenous contrast. The IMA anatomy was schematically depicted by surgeon based on CT interpretation. Intraoperatively anatomy was defined by skeletonisation of the IMA. All patients had segmental resection with selective vascular ligation. The concurrence of prospectively obtained results were evaluated by intraclass correlation and Kendall's tau-b test. Misinterpretation of IMA anatomy was analysed by CT-specialist. RESULTS: The preoperative and intraoperative IMA anatomy features were correctly interpreted in 237 cases (in 94.8%) within skeletonisation extent, which is supported by high level of agreement and concordance of preoperative data regards to intraoperative findings (K=0.926; p<0.001; CC=0.912; p<0.001). As a result of the CT-based evaluation of the IMA, E, K, and H types of branching patterns were proposed. IMV position was mistakenly identified in 2.6% of cases. CONCLUSION: Surgeons are able to evaluate the IMA anatomy accurately with CT and use it in routine preoperative planning. The E, K, and H branching types may be used when defining approach to skeletonisation and level of vascular ligation.

Angiographic characteristics of the intermesenteric artery.

PURPOSE: The literature reports the presence of the intermesenteric artery (IA), an anastomosis connecting the superior mesenteric artery (SMA) to the inferior mesenteric artery (IMA) in 9-18% of human cadaver dissections. This is the first study describing the morphological and demographic characteristics of the IA based on in vivo imaging. METHODS: A total of 150 consecutive abdominal computed tomography (CT) angiographies of adult patients identified by sex and age were analyzed. The IA was assessed for its presence, point of origin, pathway, point of insertion, and diameter at its origin. The diameters of the SMA, IMA, and other arteries from which the IA originated and into which it inserted were measured by CT angiography using Radiant™ and Osirix MD™ software. RESULTS: The IA was found in 17 (51.5%) of the females and 60 (51.3%) of the males. The diameters of the SMA and IMA were larger in the males than in the females, but there was no sex difference in the diameter of the IA. The diameter of the SMA was larger than that of the IMA, and the diameter of the IA was smaller than that of the other arteries evaluated. An IA connecting the SMA and IMA trunks was found in 25.9% of the cases, while other connections between the branches of those trunks through an IA occurred less frequently. CONCLUSIONS: The intermesenteric artery is more frequently found than the literature refers and in most of cases directly connects the upper and lower arterial mesenteric circulations.

Usefulness of Computed Tomography Angiography in the Preoperative Workup of Patients With Colorectal Cancer.

OBJECTIVES: The objective of this study is to analyze the main patterns of branching of the inferior mesenteric artery (IMA) and to determine if your knowledge changes the surgical strategy in the colorectal cancer. METHODS: This retrospective study included 63 patients with cancer of the sigmoid or rectum. We assessed the patterns of IMA in 3 subtypes: type A (independent left colic artery [LCA]), type B (LCA and sigmoid artery arising in a common trunk) and type C (LCA, sigmoid artery, and superior rectal artery with a common origin). Colorectal surgeons evaluated how the vascular map changed the type of IMA ligation. RESULTS: Inferior mesenteric artery branching was classified as type A in 55.6% patients, type B in 23.8%, and type C in 20.6%. Knowledge of the vascular map changed the type of ligation from high to low in 20 of the 50 patients who were candidates for surgery. The change was possible in tumors located in the sigmoid colon and the rectosigmoid junction with the type A or B branching. CONCLUSIONS: Preoperative Multidetector Computed Tomography angiography can define the pattern of IMA branching. Based on this information, a low ligation can be performed in tumors located in sigmoid colon and rectosigmoid junction with IMA branching types A and B.

Inferior mesenteric artery diameter and number of patent lumbar arteries as factors associated with significant type 2 endoleak after infrarenal endovascular aneurysm repair.

OBJECTIVES: Our goal was to identify the inferior mesenteric artery diameter and number of patent lumbar arteries causing a significant type 2 endoleak to develop after infrarenal endovascular aneurysm repair. MATERIAL AND METHODS: Included were patients who underwent infrarenal endovascular aneurysm repair between April 2002 and January 2017. Patients with an aneurysm involving the iliac arteries were excluded. Significant type 2 endoleak was defined as a type 2 endoleak observed after infrarenal endovascular aneurysm repair and accompanied by abdominal aneurysm growth of at least 5 mm during that time. RESULTS: A total of 277 patients were included. Mean follow-up was 38.9 (standard deviation 121.6) months. Immediately after infrarenal endovascular aneurysm repair, type 2 endoleaks occurred in 55 patients (20%), resolving spontaneously in 2 patients 6 months after infrarenal endovascular aneurysm repair. Thirty (10.8%) patients revealed a significant type 2 endoleak with aneurysm sack enlargement > 5 mm during follow-up, for which inferior mesenteric artery or lumbar artery coiling was performed. Mean time for coiling after primary infrarenal endovascular aneurysm repair was 25.4 (standard deviation 19.10) months. Twenty-three patients (8.3%) showed a non-significant type 2 endoleak during follow-up (no aneurysm sack enlargement). We found that the inferior mesenteric artery diameter and number of patent lumbar arteries were factors associated with a significant type 2 endoleak (odds ratio 1.755, P = 0.001; odds ratio 1.717, P < 0.001, respectively). Prior to endovascular aneurysm repair, the inferior mesenteric artery was patent in 212 (76.5%) patients; its median diameter measured 3 (0.5-3.8) mm. The median number of patent lumbar arteries was 3 (2-4). According to our receiver operating characteristic curve analysis, an inferior mesenteric artery diameter ≥3 mm (sensitivity 93.3%, specificity 65%) and ≥3 patent lumbar arteries (sensitivity 87.5%, specificity 43.6%) proved to be optimal cut-off values related to developing a significant type 2 endoleak. We therefore propose a composite score for the development of a significant type 2 endoleak [(inferior mesenteric artery diameter + patent lumbar arteries)/2]. CONCLUSIONS: Patients in whom the diameter of the inferior mesenteric artery is ≥ 3 mm and with ≥ 3 patent lumbar arteries carry a higher risk of developing significant type 2 endoleak after infrarenal endovascular aneurysm repair.

Anatomical features of inferior mesenteric and left colic arteries and surgery in colorectal cancer patients with persistent descending mesocolon.

BACKGROUND: Persistent descending mesocolon (PDM) is a fetal abnormality in which the left-sided colon is not fused to the retroperitoneum, and it is often accompanied by the adhesion between the mesocolon and small bowel mesentery. Due to its rarity, whether PDM exhibits anatomical characteristics of the inferior mesenteric artery (IMA) and left colic artery (LCA), and how the anomaly affects laparoscopic surgery are largely unknown. We investigated the branches of these arteries and outcomes of patients who underwent laparoscopic surgery. METHODS: Based on computed tomography (CT) and three-dimensional CT angiography, branching patterns of the IMA, LCA and branches originating from the LCA were analysed in 954 patients with left-sided colon or rectal cancer. PDM was diagnosed by preoperative CT colonography, and confirmed at time of surgery. The anatomical features of the vessels and short-term outcomes of laparoscopic surgery were compared between patient groups stratified by PDM. RESULTS: Twelve patients (1.3%) were diagnosed with PDM. No branching pattern of the IMA specific to PDM was noted. On the other hand, patients with PDM had fewer branches (mean: 1.0) from the LCA than those without PDM (mean: 1.8, p = 0.009). In patients undergoing laparoscopic surgery, outcomes such as operative time, intraoperative blood loss, and number of harvested nodes were comparable between the two patient groups. CONCLUSION: Few branches of the LCA characterize PDM. PDM does not complicate laparoscopic surgery of the left-sided colon and rectum. However, the above anatomical feature increases the risk of poor colonic perfusion when dividing the LCA.