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

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 ).

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.

Analysis of surgical outcomes of laparoscopic versus open surgery for locally advanced mid-transverse colon cancer

PURPOSE

This study compared the surgical outcomes between laparoscopic colectomy (LC) and open colectomy (OC) for mid-transverse colon cancer (MTC).

METHODS

This multicenter retrospective study compared the short- and long-term surgical outcomes for patients with advanced MTC (T3 and T4 with or without nodal involvement) who underwent LC or OC between January 2008 and December 2019 using a propensity score-matched analysis.

RESULTS

A total of 177 patients with advanced MTC were enrolled. After matching, 58 cases for the OC and LC groups were selected. No significant differences in age, sex, tumor progression, or procedure type (extended resection or segmental resection) existed between groups. The LC group had significantly less blood loss (20 mL vs. 50 mL, p=0.048) and a shorter postoperative hospital stay (8 days vs. 12 days, p<0.001) than the OC group. Postoperative complications (Clavien-Dindo grade ≥ 2) occurred in 27.6% and 25.9% of the OC and LC groups respectively (p=1). Three patients (5.2%) and one patient (1.7%) of the OC and LC groups respectively developed anastomotic leakage (p=0.62). Re-operation was required in five patients (8.6%) in the OC group and one patient (1.7%) in the LC group (p=0.21). No surgery-related deaths occurred in either group. The 3-year overall survival rates (stage II: LC 100% vs. OC 92.8%, p=0.15; stage III: 88.9% vs. 84.3%, p=0.88, respectively) were similar between the two groups.

CONCLUSION

LC is a minimally invasive technique with lesser blood loss, shorter postoperative hospital stays, and oncologic equivalence to OC. Hence, LC is useful for MTC treatment.

TRIAL REGISTRATION

UMIN000042676.

Laparoscopic extended right hemicolectomy versus laparoscopic transverse colectomy for mid-transverse colon cancer: a multicenter retrospective study from Kanagawa Yokohama Colorectal Cancer (KYCC) study group

PURPOSE

The laparoscopic surgery approach for mid-transverse colon cancer (MTC) varies depending on tumor characteristics and the guidelines implemented by each surgeon; the optimal surgical procedure for MTC has not been established. This study aimed to compare the surgical outcomes of laparoscopic extended right hemicolectomy (Lap-ERHC) and laparoscopic transverse colectomy (Lap-TC) for MTC.

METHODS

This was a multicenter, retrospective study. We surveyed eight hospitals, by questionnaire, on MTC surgery policies and retrospectively compared the short- and long-term surgical outcomes for patients with MTC who underwent Lap-ERHC or Lap-TC between January 2008 and December 2019.

RESULTS

A total of 129 patients were enrolled, of whom 35 underwent Lap-ERHC and 94 underwent Lap-TC. There were no significant differences in tumor progression between the two groups. Operation time was significantly longer (202 min vs. 185 min, p = 0.026). We observed a higher complication rate (≥ grade 3) in the Lap-ERHC group than in the Lap-TC group (11.4% vs. 3.2%, p = 0.086). Three patients (8.6%) who underwent Lap-ERHC developed anastomotic leakage; none of the patients who underwent Lap-TC had this complication (p = 0.018). The 3-year overall survival rates (stage I: 100% vs. 91.9%, p = 0.64; stage II: 100% vs. 95.5%, p = 0.46; stage III: 100% vs. 88.2%, p = 0.91, respectively) were similar between the two groups.

CONCLUSION

Lap-ERHC for MTC has the same long-term outcomes as Lap-TC. However, Lap-ERHC for MTC has a higher complication rate. Therefore, Lap-TC may be recommended for patients with MTC.

TRIAL REGISTRATION

UMIN000042674.

Comparison of laparoscopic and open colectomy for splenic flexure colon cancer: a systematic review and meta-analysis

PURPOSE

This study examined the short- and long-term outcomes of laparoscopic and open splenic flexure colon cancer (SFCC) surgery.

METHOD

Systematic literature searches were performed in PubMed and Ovid to compare laparoscopic and open colectomy for SFCC. The last search was conducted on November 7, 2021. Surgical and survival outcomes were collected and analyzed. This meta-analysis was performed using Review Manager Software (v 5.3).

RESULTS

This study included seven publications with 2397 patients published between 2011 and 2021. A significant difference in operative time was seen in the laparoscopic group (P = 0.01, WMD = 50.13, 95%CI [10.32, 89.94], I² = 97%); loss of blood estimated (P < 0.001, WMD =  -101.88, 95%CI [-161.65, -42.11], I² = 82%) and the incidence of overall complications (P < 0.001, OR = 0.53, 95%CI [0.38, 0.75], I² = 0%) of laparoscopic procedure were greatly decreased. There were similar results as compared in the two groups in terms of lymph node harvesting (P = 0.71, WMD = 0.49, 95%CI [-2.13, 3.12], I² = 93%) and the distance of proximal (P = 0.50, WMD =  -1.09, 95%CI [-4.26, 2.08], I² = 96%) or distal (P = 0.18, WMD = 2.44, 95%CI [-1.13, 6.01], I² = 97%) resection margin. In addition, no significant differences were observed on overall/disease-free survival over 3/5 years between the two procedures. An analysis of subgroups that used propensity matching scores produced similar results.

CONCLUSION

The laparoscopic procedure is clinically safe and feasible for SFCC. It shows the advantages in decreasing intraoperative blood loss and overall complications, and the long-term survival outcomes would not be affected. Randomized clinical trials with a larger sample size are warranted in the future for further investigation.

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.