Vascular anatomy of the splenic flexure, focusing on the accessory middle colic artery and vein

Short- and long-term outcomes after surgical treatment of 5918 patients with splenic flexure colon cancer by extended right colectomy, segmental colectomy and left colectomy: a systematic review and meta-analysis

Background

Colorectal cancer is among the most common cancers in the world, and splenic flexure colon cancer accounts for about 2-5% of them. There is still no consensus on the surgical treatment of splenic flexure colon cancer (SFCC), and the extent of surgical resection and lymph node dissection for SFCC is still controversial.

Aim

To compare the postoperative and long-term oncologic outcomes of extended right colectomy (ERC), segmental colectomy (SC) and left colectomy (LC) for SFCC.

Method

Up to March 2024, retrospective and prospective studies of ERC, SC, and LC for SFCC were searched through databases. Pooled weighted/standardized mean difference (WMD/SMD), odds ratio (OR) and hazard ratio (HR) with 95% confidence interval (CI) were calculated using a fixed effects model or random effects model, and meta-analysis was performed using Stata.

Results

This meta-analysis includes 5,918 patients from 13 studies with more lymph node harvest (OR:6.29; 95%Cl: 3.66-8.91; Z=4.69, P=0), more operation time (WMD: 22.53; 95%Cl: 18.75-26.31; Z=11.68, P=0), more blood loss (WMD:58.44; 95%Cl: 20.20-96.68; Z=2.99, P=0.003), longer hospital stay (WMD:1.74; 95%Cl: 0.20-3.29; Z=2.21, P=0.03), longer time to return to regular diet (WMD:3.17; 95%Cl: 2.05-4.30; Z=5.53, P=0), longer first flatus time (WMD:1.66; 95%Cl: 0.96-2.37; Z=4.61, P=0) in ERC versus SC. More lymph node harvest (WMD: 3.52; 95% Cl: 1.59-5.44; Z=3.58, P=0) in ERC versus LC and LC versus SC (WMD: 1.97; 95% CI: 0.53-3.41; Z=2.68, P=0.007), respectively. There is no significant difference between anastomotic leakage, postoperative ileus, total postoperative complication, severe postoperative complication, wound infection, reoperations, R0 resection, postoperative mortality, 5-year overall survival (OS), 5-year disease-free survival (DFS) in three group of patients. In LC versus SC and ERC versus LC, there is no difference between operation time, blood loss, hospital stay, return to regular diet, and first flatus.

Conclusion

In the included studies, SC and LC may be more advantageous, with fewer postoperative complications and faster recovery. ERC harvests more lymph nodes, but there is no significant difference in long-term OS and DFS between the three surgical approaches. Given that the included studies were retrospective, more randomized controlled trials are needed to validate this conclusion.

Two Types of Variational Arteries' Courses From the Superior Mesenteric Artery to Supply the Splenic Flexure: Gross Anatomical Study

BACKGROUND

Complete mesocolic excision with central vascular ligation is a standard method for managing colon cancer. However, there is no consensus on its procedure, especially for cancer in the splenic flexure of the transverse colon. This is because various types of variational arteries are distributed to the region, and their running course below and near the pancreas leads to difficulty in ligating the artery.

OBJECTIVE

To clarify the arterial distribution to the splenic flexure of the transverse colon using cadavers.

DESIGN

The arteries in the transverse mesocolon distributed to the colon were dissected in cadavers, and their route was quantitatively visualized using drawing software.

SETTINGS

This study was conducted at the Department of Anatomy, Tokyo Medical University.

PATIENTS

Sixty cadavers donated to Tokyo Medical University in 2017-2021 were used.

MAIN OUTCOME MEASURES

The arterial courses to the splenic flexure of the transverse colon in the mesocolon and their patterns were evaluated.

RESULTS

We found 34 variational arteries distributed to the splenic flexure of the transverse colon. Most originated from the superior mesenteric artery and the middle colic artery, with their typical course below the pancreas. We identified another arterial course, crossing the mesocolon away from the pancreas toward the splenic flexure of the transverse colon. Furthermore, the origin of these arteries was not behind the pancreas and can be found in the caudal region of the pancreas.

LIMITATIONS

We cannot discuss how the arteries within the transverse mesocolon are observed by CT examination.

CONCLUSIONS

This study showed 2 types of arterial courses (below the pancreas and within the mesocolon) toward the splenic flexure of the transverse colon for the first time. In the latter case, the complete mesocolic excision with central vascular ligation is likely performed more easily than in the former. See Video Abstract.

DOS TIPOS DE RECORRIDO VARIACIONAL DE LA ARTERIA DESDE LA ARTERIA MESENTRICA SUPERIOR PARA IRRIGAR EL NGULO ESPLNICO ESTUDIO ANATMICO MACROSCPICO

ANTECEDENTES:La escisión mesocólica completa con ligadura vascular central es un método estándar para el cáncer de colon. Sin embargo, no hay consenso sobre su procedimiento, especialmente para el cáncer en el ángulo esplénico del colon transverso. Esto se debe a que varios tipos de arterias variacionales se distribuyen en la región, y su recorrido por debajo y cerca del páncreas dificulta la ligadura de la arteria.OBJETIVO:Este estudio tuvo como objetivo aclarar la distribución arterial al SF del colon transverso utilizando cadáveres.DISEÑO:Las arterias en el mesocolon transverso distribuidas al colon fueron disecadas en cadáveres, y su ruta fue visualizada cuantitativamente utilizando un software de dibujo.AJUSTES:Este estudio se realizó en el Departamento de Anatomía de la Universidad Médica de Tokio.PACIENTES:Se utilizaron sesenta cadáveres donados a la Universidad Médica de Tokio en 2017-2021.PRINCIPALES MEDIDAS DE RESULTADO:Se evaluaron los cursos arteriales al ángulo esplénico del colon transverso en el mesocolon y sus patrones.RESULTADOS:Encontramos 34 arterias variacionales distribuidas al ángulo esplénico del colon transverso. La mayoría se originaron en la arteria mesentérica superior y la arteria cólica media, con su trayecto típico por debajo del páncreas. Identificamos otro curso arterial, cruzando el mesocolon alejándose del páncreas hacia el ángulo esplénico del colon transverso. Además, el origen de estas arterias no estaba detrás del páncreas y se pueden encontrar en la región caudal del páncreas.LIMITACIONES:No podemos discutir cómo se observan las arterias dentro del mesocolon transverso mediante un examen de tomografía computarizada.CONCLUSIONES:Este estudio mostró por primera vez dos tipos de trayectos arteriales (por debajo del páncreas y dentro del mesocolon) hacia el ángulo esplénico del colon transverso. En el último caso, es probable que la escisión mesocólica completa con ligadura vascular central se realice más fácilmente que en el primero. (Traducción-Dr. Aurian Garcia Gonzalez ).

Preoperative Simulation of Ileal Pouch-Anal Anastomosis in Patients With Ulcerative Colitis Using a 3-Dimensional Printed Model

BACKGROUND

During restorative proctocolectomy with ileal pouch-anal anastomosis for ulcerative colitis-associated colorectal cancer or dysplasia, ileal pouch-anal handsewn anastomosis (IAA) is preferred to avoid the risk of cancer development in the remaining rectal mucosa. However, there is a risk of the ileal pouch not reaching the anus with this procedure. Here, we created deformable 3-dimensional (3D) models for simulation.

METHOD

Six patients who underwent IAA without vessel ligation and 5 patients who underwent ileal pouch-anal canal double-stapled anastomosis (IACA) because the ileal pouch did not reach the anus were studied. A 3D printer was used to create deformable 3D models from the data obtained from computed tomography scans. The positional relationship among the mesenteric arteries, pubis, and coccyx were evaluated.

RESULT

The distance between the superior mesenteric artery root and the tip of the ileal artery was longer in the IAA group than that in the IACA group (IAA vs IACA: 26.2 ± 2.1 cm vs 20.9 ± 1.6cm). The distance from the tip of the ileal artery to the coccyx (IAA vs IACA: 6.7 ± 1.7 cm vs 12.1 ± 2.1 cm) and the distance from the tip of the ileal artery to the lower edge of the pubis (IAA vs IACA; 8.1 ± 1.3 cm vs 12.7 ± 2.4 cm) were longer in the IACA group than those in the IAA group.

CONCLUSIONS

We established a method for creating 3D deformable models of patients with ileal pouch-anal anastomosis. These 3D models may be useful for preoperative simulation.

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.

Revisited Surgical Anatomy of the Left Colonic Angle for Tailored Carcinologic Colectomy: A Review

PURPOSE

Although several types of surgical procedure have been advocated to date, the optimal resection of the left colonic angle in cancer treatment remains controversial. Located at the border of the transverse and descending colons, the anatomy of the left colonic angle is complex and characterized by numerous anatomic variations. Recent advances in preoperative (three-dimensional CT angiography with colonography) and/or intraoperative (indocyanine green staining) imaging have allowed for a better identification of these variations.

METHODS

We performed a methodological review of studies assessing the anatomical variations of the left colic artery.

RESULTS

While the left colonic angle is classically vascularized by branches of the superior and inferior mesenteric arteries, an accessory middle colonic artery has been identified from 6 % to 36% of cases, respectively, leading to their classification of five types. In the absence of a left colic artery, this artery becomes predominant. In parallel to the variations in the venous drainage of the left colonic angle, which has been classified into four types, new lymphatic drainage routes have also been identified via this accessory artery and the inferior mesenteric vein.

CONCLUSIONS

Collectively, these newly obtained findings plead for preoperative identification in cases of cancer of the left colonic angle and a surgical strategy adapted to these anatomical variations.

Cadaveric and CT angiography study of vessels around the transverse colon mesentery

BACKGROUND

Laparoscopic and robotic surgery for transverse colon cancer are difficult due to complex fusion of the foregut and midgut and variation of the vessels of the transverse colon. Although the vessels of the right colon have been investigated, middle colic artery (MCA) variation and the relationship with vessels around the transvers colon are unknown. We investigated variation of the MCA using computed tomography angiography (CTA) and cadaver specimen and the relationship between the superior mesenteric vein (SMV) and MCA using CTA. The classification of vessels around the transverse colon may lead to safer and reliable surgery.

METHODS

This study included 505 consecutive patients who underwent CTA in our institution from 2014 to 2020 and 44 cadaver specimens. Vascular anatomical classifications and relationships were analyzed using CT images.

RESULTS

The MCA was defined as the arteries arising from the superior mesenteric artery (SMA) that flowed into the transverse colon at the distal ends. The classifications were as follows: type I, branching right and left from common trunk; type II, the right and left branches bifurcated separately from the SMA; and type III, the MCA branched from a vessel other than the SMA. Type II was subclassified into two subtypes, type IIa with one left branch and type IIb with two or more left branches from SMA. In the CTA and cadaver studies, respectively, the classifications were as follows: type I, n = 290 and n = 31; type IIa, n = 211 and n = 13; type IIb, n = 3 and n = 0; and type III, n = 1 and n = 0. We classified the relationship between the MCA and left side of the SMV into three types: type A, a common trunk runs along the left edge of the SMV (n = 173; 59.7%); type B, a right branch of the MCA runs along the left edge of the SMV (n = 116; 40.0%); and type C, the MCA runs dorsal of the SMV (n = 1; 0.3%).

CONCLUSIONS

This study revealed that The MCA branching classifications and relationship between the SMV and MCA. Preoperative CT angiography may be able to reliably identify vessel variation, which may be useful in clinical practice.

Anatomy of Subpancreatic Transverse Colon Vessel and Its Clinical Significance: An Observational Study

Purpose

To observe and count the probability of presence and the anatomy of the vessel arising via the inferior margin of the pancreas and traveling within the transverse mesocolon, and analyze its clinical significance.

Methods

Patients who underwent radical operation for transverse colon cancer or descending colon cancer from January 2020 to November 2021 and a nonspecific cadaver were included in this study. We observed and recorded intraoperatively for the probability of presence and the anatomy of the vessel arising via the inferior margin of the pancreas and traveling within the transverse mesocolon. And its property was determined by tissue slice.

Results

A total of 84 patients were included, of which, the vessel was observed in 72 (85.7%) patients, and its property was confirmed by tissue slice of one patient after surgery. The vessel was also observed in a nonspecific cadaver. Originating from transverse pancreatic artery, often one, occasionally two, rarely three vessels arose via the inferior margin of pancreas and supplied the left transverse colon. Artery and vein parallel ran, and it was difficult to separate them due to their small diameter, but the vessels may thicken under certain conditions for increasing blood supply.

Conclusion

The vessel, which is not yet reported and named in the literature, can be called the subpancreatic transverse colon vessel, which has a high probability of presence in humans and may be of great significance to human physiological anatomy, surgery, and oncology, and deserves recognition and attention from surgeons.

Anatomical variations of the branches from left colic artery and middle colic artery at splenic flexure

BACKGROUND

Variations of the vasculature at splenic flexure by left colic artery (LCA) and middle colic artery (MCA) remain ambiguous.

OBJECTIVES

This study aim to investigate the anatomical variations of the branches from LCA and MCA at splenic flexure area.

METHODS

Using ultra-thin CT images (0.5-mm thickness), we traced LCA and MCA till their merging site with paracolic marginal arteries through maximum intensity projection (MIP) reconstruction and computed tomography angiography (3D-CTA).

RESULTS

A total of 229 cases were retrospectively enrolled. LCA ascending branch approached upwards till the distal third of the transverse colon in 37.6%, reached the splenic flexure in 37.6%, and reached the lower descending colon in 23.1%, and absent in 1.7% of the cases. Areas supplied by MCA left branch and aMCA were 33.2%, 44.5% and 22.3% in the proximal, middle and distal third of transverse colon of the cases, respectively. The accessory MCA separately originated from the superior mesenteric artery was found in 17.9% of the cases. Mutual correlation was found that, when the LCA ascending branch supplied the distal transverse colon, MCA left branch tended to feed the proximal transverse colon; when the LCA ascending branch supplied the lower part of descending colon, MCA left branch was more likely to feed the distal third of transverse colon.

CONCLUSIONS

Vasculature at splenic flexure by LCA and MCA varied at specific pattern. This study could add more anatomical details for vessel management in surgeries for left-sided colon cancer.

Lymph Node Mapping in Transverse Colon Cancer Treated Using Laparoscopic Colectomy With D3 Lymph Node Dissection

BACKGROUND

Laparoscopic surgery for transverse colon cancer has been excluded from 7 randomized trials for various reasons. The optimal procedure for transverse colon cancer remains controversial.

OBJECTIVE

This study aimed to analyze the patterns of lymph node metastasis in transverse colon cancer and to report short- and long-term outcomes of the treatment procedures.

DESIGN

This was a single-center retrospective study.

SETTINGS

This study was conducted at Cancer Institute Hospital, Tokyo, Japan.

PATIENTS

We enrolled 252 patients who underwent laparoscopic surgery for transverse colon cancer.

INTERVENTIONS

The transverse colon was divided into 3 segments, and the procedures for transverse colon cancer were based on these segments, as follows: right hemicolectomy, transverse colectomy, and left hemicolectomy.

MAIN OUTCOME MEASURES

Postoperatively, the surgeons identified and mapped the lymph nodes from specimens and performed formalin fixation separately to compare the results of the pathological findings.

RESULTS

For right-sided, middle-segment, and left-sided transverse colon cancers, the frequency of lymph node metastases was 28.2%, 19.2%, and 19.2%. Skipped lymph node metastasis occurred in right-sided and left-sided transverse colon cancers but not in middle-segment transverse colon cancers. The pathological vascular invasion rate was significantly higher in right and left hemicolectomy than in transverse colectomy. For right hemicolectomy, transverse colectomy, and left hemicolectomy, 5-year overall survival rates were 96.3%, 92.7%, and 93.7%, and relapse-free survival rates were 92.4%, 88.3%, and 95.5%. In multivariate analysis, the independent risk factor for relapse-free survival was lymph node metastasis.

LIMITATIONS

Selection bias and different backgrounds may have influenced surgical and long-term outcomes.

CONCLUSION

Laparoscopic surgery for transverse colon cancer may be a feasible technique. Harvested lymph node mapping after laparoscopic resection based on D3 lymphadenectomy may help guide the field of dissection when managing patients who have transverse colon cancer. The only independent prognostic factor for relapse-free survival was node-positive cancer. See Video Abstract at http://links.lww.com/DCR/B706.MAPEO DE GANGLIOS LINFÁTICOS EN CÁNCER DE COLON TRANSVERSO TRATADO MEDIANTE COLECTOMÍA LAPAROSCÓPICA CON LINFADENECTOMÍA D3ANTECEDENTES:La cirugía laparoscópica en casos de cáncer de colon transverso fué excluida de siete estudios randomizados mayores por diversas razones. El procedimiento más idóneo en casos de cáncer de colon transverso, sigue siendo controvertido.OBJETIVO:Analizar los patrones de las metástasis en los ganglios linfáticos en casos de cáncer de colon transverso y reportar los resultados a corto y largo plazo de los diferentes procedimientos para su tratamiento.DISEÑO:Estudio retrospectivo en un solo centro de referencia.AJUSTE:Estudio llevado a cabo en el Hospital del Instituto del Cancer, Tokio, Japón.PACIENTES:Fueron incluidos 252 pacientes, sometidos a cirugía laparoscópica por cáncer de colon transverso.INTERVENCIONES:El colon transverso fué dividido en tres segmentos y los procedimientos en casos de cáncer se basaron sobre estos segmentos del tranverso, de la siguiente manera: hemicolectomía derecha, colectomía transversa y hemicolectomía izquierda.PRINCIPALES MEDIDAS DE RESULTADO:En el postoperatorio, los cirujanos identificaron y mapearon los ganglios linfáticos de las piezas quirúrgicas y las fijaron con formaldehido por separado para así poder comparar los resultados con los hallazgos histopatológicos.RESULTADOS:En los cánceres de colon transverso del segmento derecho, del segmento medio y del segmento izquierdo, la frecuencia de metástasis en los ganglios linfáticos fue del 28,2%, 19,2% y 19,2%, respectivamente. Las metástasis en los ganglios linfáticos omitidos se produjo en los cánceres de colon transverso del lado derecho y del lado izquierdo, pero no en los cánceres de colon transverso del segmento medio. La tasa de invasión vascular patológica fue significativamente mayor en la hemicolectomía derecha e izquierda que en la colectomía transversa. Para la hemicolectomía derecha, colectomía transversa y hemicolectomía izquierda, las tasas de supervivencia general a cinco años fueron del 96,3%, 92,7% y 93,7%, y las tasas de supervivencia sin recaída fueron del 92,4%, 88,3% y 95,5%, respectivamente. En el análisis multivariado, el factor de riesgo independiente para la sobrevida sin recidiva fue la metástasis en los ganglios linfáticos.LIMITACIONES:El sesgo de selección y los diferentes antecedentes pueden haber influido en los resultados quirúrgicos a largo plazo.CONCLUSIONES:La cirugía laparoscópica en casos de cáncer de colon transverso puede ser una técnica factible. El mapeo de los ganglios linfáticos recolectados después de la resección laparoscópica basada en la linfadenectomía D3 puede ayudar a guiar el campo de la disección en el manejo de pacientes con cáncer de colon transverso. El único factor pronóstico independiente para el SLR fue el cáncer con ganglios positivos. Consulte Video Resumen en http://links.lww.com/DCR/B706. (Traducción-Dr. Xavier Delgadillo).

Vascular anatomy of the splenic flexure: a review of the literature

Surgical treatment of the transverse colon is difficult because of the many variations of blood vessels. We reviewed the patterns of vascular anatomy and the definition of the vessels around the splenic flexure. We searched the PubMed database for studies on the vascular anatomy of the splenic flexure that were published from January 1990 to October 2020. After screening of full texts, 33 studies were selected. The middle colic arteries were reported to arise independently without forming a common trunk in 8.9-33.3% of cases. The left colic artery was absent in 0-7.5% of cases. The accessory middle colic artery was present in 6.7-48.9% of cases and was present in > 80% of cases without a left colic artery. The reported frequency of Riolan's arch was 7.5-27.8%. The frequency was found to vary widely across studies, partially due to the ambiguous definition of Riolan's arch. A comprehensive preoperative knowledge of the branching patterns of the middle colic artery and left colic artery and the presence of collateral arteries would be helpful in surgery for colon cancer in the splenic flexure.

Surgical anatomy of the accessory middle colic artery: a meta-analysis with implications for splenic flexure cancer surgery

AIM

Surgical resection of splenic flexure cancers (SFCs) is technically demanding due to the complex regional anatomy, characterized by the presence of embryological adhesions, close proximity to the pancreas and spleen, and a highly heterogeneous arterial supply and lymphatic drainage. The accessory middle colic artery (AMCA) is increasingly being recognized as an important source of blood supply to the splenic flexure. The aim of this study is to determine the prevalence and anatomical features of the AMCA.

METHOD

A systematic search of the scientific literature was conducted on PubMed and Embase from inception to November 2020 to identify potentially eligible studies. Data were extracted and prevalence was pooled into a meta-analysis using MetaXL and Meta-Analyst software.

RESULTS

A total of 16 studies (n = 2203 patients) were included. The pooled prevalence (PP) of the AMCA was 25.4% (95% CI 18.1-33.4). Its prevalence was higher in patients without a left colic artery (LCA) (PP = 83.2%; 95% CI 70.4-93.1). The commonest origin for the AMCA was the superior mesenteric artery (PP = 87.9%; 95% CI 86.4-90.7). The AMCA shared a common trunk/gave rise to pancreatic branches in 23.1% of cases (95% CI 15.3-31.9).

CONCLUSION

The AMCA contributes to the vascularization of the splenic flexure in approximately 25% of individuals, and may be an important feeder artery to SFCs, especially in the absence of a LCA. Preoperative identification of this artery is important to ensure optimal surgery for SFC and minimize complications.

Redefining the collateral system between the superior mesenteric artery and inferior mesenteric artery: a novel classification

AIM

The aim of this study was to evaluate the arterial collateral vasculature between the superior mesenteric artery and the inferior mesenteric artery (IMA) from a surgical perspective.

METHOD

A total of 107 fresh adult cadavers (94 male) were studied with emphasis on the vascular anatomy of the left colon. Dissections were carried out mimicking the anterior resection technique. The vasculature of the left mesocolon and the collaterals between the superior mesenteric artery and the IMA with respect to their relationship to the inferior mesenteric vein (IMV) were assessed and classified. Collaterals were classified into three different groups: marginal anastomoses (via the marginal = pericolic artery), intermediate mesocolic anastomoses (parallel to the marginal artery but neither adjacent to the IMV nor close to the duodenum) and central mesocolic anastomoses (next to the IMV at the level of the duodenojejunal junction and the lower border of the pancreas).

RESULTS

All patients had a marginal anastomosis. However, the marginal anastomosis, as the only anastomosis between the superior and inferior mesenteric arteries at the splenic flexure, was observed in 41 cases (38%). In addition to the marginal artery, intermediate mesocolic anastomoses were found in 49 (46%) and a central mesocolic anastomosis was observed in 17 (16%) of the 107 cases in the splenic flexure mesocolon. It is in this latter variant that collateral vessels can be compromised during ligation/transection of the IMV.

CONCLUSION

This new classification can contribute to a precise mesocolic dissection technique and splenic flexure mobilization and help prevent ischaemic damage to the descending colon.

Evaluation of vascular anatomy for colon cancer located in the splenic flexure using the preoperative three-dimensional computed tomography angiography with colonography

PURPOSE

The aim of this study is to reveal the vascular branching variation in SFC (splenic flexure cancer) patients using the preoperative three-dimensional computed tomography angiography with colonography (3D-CTAC).

METHODS

We retrospectively analyzed patients with SFC who underwent preoperative 3D-CTAC between January 2014 and December 2019.

RESULTS

Among 1256 colorectal cancer (CRC) patients, 96 (7.6%) manifested SFC. The arterial branching from the superior mesenteric artery (SMA) was classified into five patterns, as follows: (type 1A) the left branch of middle colic artery (LMCA) diverged from middle colic artery (MCA) (N = 47, 49.0%); (2A) the LMCA diverged from the MCA and the accessory middle colic artery (AMCA) (N = 26, 27.1%); (3A) the LMCA independently diverged from the SMA (N = 16, 16.7%); (4A) the LMCA independently diverged from the SMA and AMCA (N = 3, 3.1%); (5A) only the AMCA and the LMCA was absent (N = 4, 4.1%). Venous drainage was classified into four patterns, as follows: (type 1V) the SFV flows into the inferior mesenteric vein (IMV) then back to the splenic vein (N = 50, 52.1%); (2V) the SFV flows into the IMV then back to the superior mesenteric vein (SMV) (N = 19, 19.8%); (type 3V) the SFV independently flows into the splenic vein (N = 3, 3.1%); (type 4V) the SFV is absent (N = 24, 25.0%).

CONCLUSION

3D-CTAC could reveal accurate preoperative tumor localization and vascular branching. These classifications should be helpful in performing accurate complete mesocolic excision and central vessel ligation for SFC.

Re-interpreting mesenteric vascular anatomy on 3D virtual and/or physical models: positioning the middle colic artery bifurcation and its relevance to surgeons operating colon cancer

Background

The impact of the position of the middle colic artery (MCA) bifurcation and the trajectory of the accessory MCA (aMCA) on adequate lymphadenectomy when operating colon cancer have as of yet not been described and/or analysed in the literature. The aim of this study was to determine the MCA bifurcation position to anatomical landmarks and to assess the trajectory of aMCA.

Methods

The colonic vascular anatomy was manually reconstructed in 3D from high-resolution CT datasets using Osirix MD and 3-matic Medical and analysed. CT datasets were exported as STL files and supplemented with 3D printed models when required.

Results

Thirty-two datasets were analysed. The MCA bifurcation was left to the superior mesenteric vein (SMV) in 4 (12.1%), in front of SMV in 17 (53.1%) and right to SMV in 11 (34.4%) models. Median distances from the MCA origin to bifurcation were 3.21 (1.18–15.60) cm. A longer MCA bifurcated over or right to SMV, while a shorter bifurcated left to SMV (r = 0.457, p = 0.009). The main MCA direction was towards right in 19 (59.4%) models. When initial directions included left, the bifurcation occurred left to or anterior to SMV in all models. When the initial directions included right, the bifurcation occurred anterior or right to SMV in all models. The aMCA was found in 10 (31.3%) models, following the inferior mesenteric vein (IMV) in 5 near the lower pancreatic border. The IMV confluence was into SMV in 18 (56.3%), splenic vein in 11 (34.4%) and jejunal vein in 3 (9.4%) models.

Conclusion

Awareness of the wide range of MCA bifurcation positions reported is crucial for the quality of lymphadenectomy performed. The aMCA occurs in 31.3% models and its trajectory is in proximity to the lower pancreatic border in one half of models, indicating that it needs to be considered when operating splenic flexure cancer.

Supplementary information

The online version of this article (10.1007/s00464-020-08242-8) contains supplementary material, which is available to authorized users.