Navigating the mesentery: a comparative pre- and per-operative visualization of the vascular anatomy

Jejunal Lymphatic and Vascular Anatomy Defines Surgical Principles for Treatment of Jejunal Tumors

BACKGROUND

The jejunum has a wide lymphatic drainage field, making radical surgery difficult.

OBJECTIVE

Extrapolate results from 2 methodologies to define jejunal artery lymphatic clearances and lymphovascular bundle shapes for radical bowel-sparing surgery.

DESIGN

Two cohort studies.

SETTINGS

The first data set comprised dissections of cadavers at the University of Geneva. The second data set incorporated preoperative 3-dimensional CT vascular reconstructions of patients included in the "Surgery with Extended (D3) Mesenterectomy for Small Bowel Tumors" clinical trial.

PATIENTS

Eight cadavers were dissected. The 3-dimensional CT data set included 101 patients.

MAIN OUTCOME MEASURES

Lymph vessels ran parallel and interlaced with jejunal arteries. Lymphatic clearance was minimal at the jejunal artery's origin, radially spreading thereafter. Jejunal arteries were categorized into 3 groups based on position to the middle colic artery origin on 3-dimensional CT: group A: jejunal artery origins lie cranially and caudally to the middle colic artery; group B: jejunal artery origins lie caudal to the middle colic artery; and group C: jejunal artery origins lie cranial to the middle colic artery. Jejunal veins were classified into 3 groups based on their trajectories to the superior mesenteric artery (dorsally/ventrally/combined).

RESULTS

Lymph vessel clearances were 1.5 ± 1.0 mm at jejunal artery origins. Group A was present in 81 cases (80.2%), group B in 13 cases (12.9%), and group C in 7 cases (6.9%). Jejunal artery median was 4. Fifty-seven jejunal veins (56.4%) ran dorsally to the superior mesenteric artery, 16 (15.8%) ran ventrally, and 28 (27.8%) had a combined course.

LIMITATIONS

Lymph nodes were not counted during dissection because the main observation was the position of lymph vessels.

CONCLUSIONS

Minimal jejunal artery lymphatic clearance implies ligating tumor-feeding vessels at the origin. The intermingled jejunal artery lymphatics imply lymph node dissection along the proximal and distal vessels to the level of the first arcade. Classifying jejunal arteries and veins could simplify the anatomy for surgeons. See Video Abstract.

CLINICAL TRIAL REGISTRATION NUMBER

NCT05670574.

LA ANATOMA LINFTICA Y VASCULAR DEL YEYUNO DEFINE LOS PRINCIPIOS QUIRRGICOS PARA EL TRATAMIENTO DE LOS TUMORES DEL YEYUNO

ANTECEDENTES:El yeyuno tiene un amplio campo de drenaje linfático, lo que dificulta la cirugía radical.OBJETIVO:Extrapolar los resultados de dos metodologías para definir los aclaramientos linfáticos de la arteria yeyunal y las formas de los haces linfovasculares para la cirugía radical de conservación intestinal.DISEÑO:Dos estudios de cohorte.ESCENARIO:El primer conjunto de datos comprendía disecciones de cadáveres en la Universidad de Ginebra. El segundo conjunto de datos incorporaba reconstrucciones vasculares preoperatorias por TC 3D de pacientes incluidos en el ensayo clínico "Cirugía con mesenterectomía extendida (D3) para tumores del intestino delgado".PACIENTES:Se disecaron ocho cadáveres. El conjunto de datos de TC 3D incluía 101 pacientes.PRINCIPALES MEDIDAS DE VALORACIÓN:Los vasos linfáticos discurrían paralelos y se entrelazaban con las arterias yeyunales. El aclaramiento linfático era mínimo en el origen de la arteria yeyunal, extendiéndose radialmente a partir de allí. Las arterias yeyunales se clasificaron en tres grupos según su posición respecto del origen de la arteria cólica media en la TC tridimensional. Grupo A: los orígenes de la arteria yeyunal se encuentran craneal y caudalmente respecto de la arteria cólica media; Grupo B: los orígenes de la arteria yeyunal se encuentran caudalmente respecto de la arteria cólica media; Grupo C: los orígenes de la arteria yeyunal se encuentran cranealmente respecto de la arteria cólica media. Las venas yeyunales se clasificaron en tres grupos según sus trayectorias hacia la arteria mesentérica superior (dorsal/ventral/combinada).RESULTADOS:Los espacios libres de los vasos linfáticos fueron de 1,5+1,0 mm en los orígenes de la arteria yeyunal. El grupo A estuvo presente en 81 (80,2 %), el grupo B en 13 (12,9 %), el grupo C en 7 (6,9 %) casos. La arteria yeyunal tenía una mediana de 4. Un 57 (56,4 %) de las venas yeyunales discurrían dorsalmente a la arteria mesentérica superior, 16 (15,8 %) discurrían ventralmente y 28 (27,8 %) tenían un trayecto combinado.LIMITACIONES:No se contaron los ganglios linfáticos durante la disección porque la observación principal era la posición de los vasos linfáticos.CONCLUSIÓN:La mínima limpieza linfática de la arteria yeyunal implica la ligadura de los vasos que alimentan el tumor en el origen. Los vasos linfáticos de la arteria yeyunal entremezclados implican la disección de los ganglios linfáticos a lo largo de los vasos proximales y distales hasta el nivel de la primera arcada. La clasificación de las arterias y venas yeyunales podría simplificar la anatomía para los cirujanos. (Traducción-Ingrid Melo )NÚMERO DE ENSAYO CLÍNICO:NCT05670574.

Lymphatic and vascular anatomy define surgical principles for bowel-sparing radical treatment of ileal tumors

BACKGROUND

There is no consensus on the level of vascular ligation and the extent of lymphadenectomy in the treatment of ileal tumors. This study aims to define lymphovascular bundles of the terminal ileal artery (TIA) and subsequent ileal arteries. It also aims to extrapolate results from two distinct methodologies to define the level of arterial ligation and the dissection area for radical and bowel-sparing surgery.

METHODS

Analysis of 3D-CT mesenteric vascular reconstructions of 104 operated patients. The second dataset consisted of 5 human cadavers for anatomical dissection. In one case, harvested viscera underwent the superior mesenteric artery (SMA) perfusion after ligation of the TIA.

RESULTS

The calibers of the first three ileal arteries were: 2.67 ± 0.98 mm, 2.22 ± 0.78 mm, 2.31 ± 1.24 mm. The distances from the first three ileal arteries to the ileocolic artery (ICA) origin were: 12.45 ± 8.79 mm, 27.45 ± 13.47 mm, and 43.04 ± 16.94 mm. The SMA trifurcated in 61 (59%) of cases and bifurcated in 43 (41%). In 89 cases, the combined ICA + first jejunal artery caliber (6.7 ± 1.6 mm) was greater than the TIA caliber (4.84 ± 1.42 mm). The ileal artery lymphatic clearances were 0.85 mm to the preceding vessel. In the D3 volume at the ICA origin, 3-8 lymph nodes were observed. Internal calibers of the small bowel marginal artery, after selective TIA ligation and the SMA perfusion, were: proximal jejunal part 0.417 mm and distal ileal part 0.291 mm.

CONCLUSIONS

Ileal tumors are irrigated through the TIA, which can be ligated without consequences. Lymphadenectomy should encompass the adjacent vessels (1st jejunal artery, ICA) and can include the central nodes (D3 volume) at the surgeon's preference. Preserving the adjacent vessels and the marginal artery is paramount for bowel-sparing surgery.

Inter-rater and intra-rater reliability of multi-slice CT and three-dimensional reconstructed imaging analysis of mesenteric vascular anatomy for planning and performing complete mesocolic excision

AIM

Complete mesocolic excision (CME) for colon cancer has been associated with improved oncological outcomes but requires a detailed understanding of complex mesenteric vasculature. Three-dimensional (3D) reconstructed models derived from patient imaging could enhance preoperative anatomical comprehension, enabling safer, precision CME.

METHODS

In this two-phase, blinded, crossover study, four expert CME surgeons evaluated mesenteric vascular anatomy on CT scans and 3D models. In phase 1, surgeons assessed 66 cases, while 20 were re-evaluated in phase 2. The primary outcome measure was inter-rater reliability by Fleiss's kappa. Secondary outcomes were intra-rater reliability by Cohen's kappa and anatomical accuracy rates measured as a percentage of correct responses on a standardised questionnaire.

RESULTS

In phase 1, inter-rater agreement was higher for 3D models (average kappa 0.6, moderate agreement) than for CT scans (average kappa 0.1, poor agreement). Ileocolic vein drainage and ileocolic artery trajectory showed the highest kappa values with 3D imaging (0.85 and 0.93, respectively). Accuracy was also superior with 3D across all surgeons (mean 89.7% correct) versus CT (mean 79.1% correct, P < 0.001). In phase 2, intra-rater reliability remained higher for 3D (average Cohen's kappa 0.61) than CT scans (Cohen's kappa 0.27).

CONCLUSION

3D mesenteric models significantly improve inter- and intra-rater reliability among CME experts over traditional CT scans while markedly enhancing anatomical comprehension accuracy about critical right-sided colonic vasculature. 3D planning could facilitate CME by enabling superior preoperative visualisation of these vessels.

Partial intestinal obstruction caused by duodenal obstruction by the superior mesenteric artery and abdominal aorta in a middle-aged woman: A case report

A 55-year-old woman with non-small cell lung carcinoma complained of epigastric pain, bloating, anorexia and postprandial nausea and vomiting over a five-year period. An upper gastrointestinal pan-glucosamine contrast examination revealed a distinctive large, hook-shaped, ptotic gastric lumen with normal motility. The contrast agent demonstrated an abnormal round-trip flow anterior to the spine at the duodenal level, with pooling and gradual passage through this region in strands after prolonged retention. Contrast-enhanced computed tomography of the abdomen revealed an abnormal proximity between the superior mesenteric vein (SMV) and the abdominal aorta (AA). The images clearly showed external compression of the third part of the duodenum as it traversed between the SMV and AA, where the distance between the SMV and AA measured 4.7 mm. It was considered that the compression of the duodenum between the SMV and AA in the patient resulted in intermittent duodenal obstruction.

Preoperative CT-Scan Angiography Reconstruction Before Right Colectomy with Complete Mesocolon Excision: A Systematic Review and Meta-analysis

BACKGROUND

Complete mesocolon excision (CME) and central vascular ligation for right colonic cancers have been developed to improve oncological outcomes. However, it has been linked with a higher risk of morbidity and technical difficulties in operating near major vessels. This study investigated the impact of preoperative surgical planning utilizing CT reconstruction on surgical outcomes in right colectomy with CME.

METHODS

This systematic review and meta-analysis followed PRISMA and AMSTAR 2 guidelines. The analysis included clinical trials and observational studies comparing outcomes after preoperative CT scan reconstruction (navigation group) vs. no preoperative CT reconstruction (control group).

RESULTS

Four eligible studies (published between 2013 and 2023) were included, comprising 420 patients (203 in the navigation group and 217 in the control group). Preoperative navigation was associated with significantly lower blood loss (SMD = - 77.50; 95% CI [- 126.77, - 28.22], p = 0.002), shorter operative time (SMD = - 24.44; 95% CI [- 33.33, - 15.55], p < 0.00001), and a higher number of harvested lymph nodes (SMD = 1.39; 95% CI [0.58, 2.20], p = 0.0007). There was no statistically significant difference between the two groups in terms of overall morbidity (OR = 0.82; 95% CI [0.28, 2.40], p = 0.71), intraoperative complications (OR = 1.39; 95% CI [0.37, 5.26], p = 0.63), anastomotic leak (OR = 1.10; 95% CI [0.16, 7.63], p = 0.92), or hospital stay (SMD = - 0.06; 95% CI [- 0.48, 0.37], p = 0.80).

CONCLUSION

Preoperative navigation using CT reconstruction could help better delineate the complex vascular anatomy of the right colon. It may reduce operative time and increase the yield of harvested lymph nodes.

Assessing anatomical variations of the superior mesenteric artery via three-dimensional CT angiography and laparoscopic right hemicolectomy: a retrospective observational study

OBJECTIVE

This study aimed to analyse the anatomical relationships and differences between the superior mesenteric vessels and their branches by reviewing a laparoscopic right hemicolectomy surgery video and comparing it with preoperative three-dimensional computed tomography (3D-CT) angiography and to verify the accuracy of 3D-CT vascular reconstruction techniques.

METHODS

Surgical videos and preoperative imaging data of 52 patients undergoing laparoscopic right hemicolectomy were analysed to observe and summarize the probability of occurrence and adjacency of superior mesenteric vascular branches, and the lengths of specific sites of their branches were measured using the above two methods.

RESULTS

Preoperative CT images and surgical video showed that the ileocolic artery (ICA) was present in 98.1% (51/52) and the ileocolic vein (ICV) was present in 100% (52/52), and ICA was present in 13.7% (7/51) of the ICV directly anteriorly, 13.7% (7/51) anteriorly superiorly, 3.9% (2/51) anteriorly inferiorly, 11.8% (6/51) directly posteriorly, 37.2% (19/51) post superiorly, and 19.7% (10/51) posteriorly inferiorly. In the surgical video, the probability of presence of the right colic artery (RCA) was 21.2% (11/52). On CT images, the RCA was present in 10 patients. The length of the origin of the middle colic artery (MCA) from its bifurcations was 2.33 ± 0.87 cm measured intraoperatively using a sterile isometric filament, and the length measured using 3D-CT vascular reconstruction was 2.36 ± 0.91 cm; the difference was not statistically significant (P = 0.348). The length of the MCA and ICA initiation points was 3.22 ± 0.75 cm measured intraoperatively using sterile isometric filaments and 3.36 ± 0.72 cm measured using 3D-CT vascular reconstruction, which was a statistically significant difference (P < 0.001).

CONCLUSIONS

3D-CT vascular reconstruction can accurately predict the vessels related to right hemicolectomy in most cases. It is an important method for preoperative prediction of superior mesenteric vessels, which can guide surgeons in the intraoperative vessel identification.

Laparoscopic segmental colectomy with extensive D3 lymph node dissection for right transverse colon cancer

OBJECTIVE

We herein propose a novel approach, laparoscopic segmental colectomy with extensive D3 lymph node dissection (ED3LND), for right-sided transverse colon cancer (TCC).

METHODS

Forty-two patients with right-sided TCC were randomly assigned to two groups: Group 1 (segmental colectomy with D3LND) and Group 2 (segmental colectomy with ED3LND). Clinical characteristics, surgical and pathological outcomes, and oncological outcomes were retrospectively compared between the two groups.

RESULTS

The number of lymph nodes retrieved, apical lymph nodes retrieved, and apical lymph node metastases were significantly lower in Group 1 than in Group 2. No significant differences were observed in the operation time, length of hospital stay, estimated blood loss, lymph node metastases, postoperative lymphoceles, or other Clavien-Dindo grade ≥III postoperative complications between the two groups. The 3-year disease-free survival rate was 82.6% in Group 1 and 84.2% in Group 2, with no significant difference.

CONCLUSIONS

Laparoscopic segmental colectomy with ED3LND for right-sided TCC may offer better oncological outcomes than D3LND. A large-scale prospective randomized controlled study is needed to further validate the oncological benefits of this novel procedure.

A hemodynamic study of the relationship between the left and right liver volumes and the blood flow distribution in portal vein branches

BACKGROUND

Cirrhosis patients often exhibit clinical symptoms such as right liver atrophy, portal hypertension, spleen enlargement and increased blood supply, which exhibit considerable variation between the left and right liver sections. These differences are hypothesized to stem from disparities in blood flow within the left and right portal vein (PV) branches. However, rigorous quantitative evidence remains scarce.

PURPOSE

We mainly aim at quantitatively revealing the relationship between the blood flow rates of two PV branches and liver volumes, and providing quantitative evidence and theoretical support for the diagnosis and treatment of cirrhosis from the perspective of hemodynamics.

METHODS

Five cirrhotic patients and two healthy volunteers from Beijing Friendship Hospital are investigated. Their PV blood flow models are established based on computed tomography (CT) images and finite volume simulations. The volume of the left and right liver lobes are measured in 3-matic. The distributions of blood source in the PV branches are tracked by streamline analysis. The blood flow rates are quantitatively counted by integrating the blood source velocities. Linear analysis is performed to build the relationship between liver volumes and PV blood flow distributions.

RESULTS

Streamline analysis reveals significant differences in blood distribution between the left and right PV branches. The majority of blood from the superior mesenteric vein (SMV) flowed into the right portal vein (RPV), while most blood from the splenic vein (SV) entered the left portal vein (LPV). The main PV pressure drop linearly increases with the SV blood velocity for all PV structures of patients and healthy volunteers. The flow rate ratio QRPV/QLPV demonstrates an increase in tandem with the volume ratio VR/VL, exhibiting a linear correlation with the Pearson correlation coefficient being 0.93.

CONCLUSION

The differences in the blood distributions are consistent with the clinicians' knowledge and validate our simulations. We demonstrated a linear increase in PV pressure with elevated SV blood velocity. Additionally, the volumes of the left and right hepatic lobes exhibited a positive correlation with blood flow rates in the corresponding PV branches.

Endovascular Stenting for Idiopathic Stenosis of the Superior Mesenteric Vein: A Case Report

Idiopathic superior mesenteric vein (SMV) stenosis, where no clear causative factor is identifiable, remains a clinical rarity. We present a detailed case report of a patient with idiopathic stenosis of the SMV who underwent successful endovascular stenting. This report outlines the patient's clinical presentation, diagnostic imaging findings, procedural approach by the interventional radiology team, and subsequent management. Endovascular stenting is a viable therapeutic option for patients with idiopathic SMV stenosis. This case demonstrates that with appropriate interventional and post-procedural management, long-term stent patency and thrombosis prevention can be achieved. The success of this case encourages further investigation into endovascular treatments for venous stenoses.

A SICE (Società Italiana di Chirurgia Endoscopica e Nuove Tecnologie) observational prospective multicenter study on anatomical variants of the superior mesenteric artery: intraoperative analysis during laparoscopic right hemicolectomy-CoDIG 2 database (ColonDx Italian Group)

Colorectal cancer, the third most common cancer worldwide, affects 40-45% of patients on the right side. Surgery, especially minimally invasive methods such as laparoscopic and robotic procedures, is the preferred treatment. However, these techniques present technical complications. The anatomical complexity and variations in vessel branching patterns pose challenges, particularly for less experienced surgeons. The CoDIG 2 is a nationwide observational study involving 76 specialized Italian general surgery departments focused on colorectal surgery. The centres were directed to maintain their standard surgical and clinical practices. The aim of this study was to analyse the intraoperative vascular anatomy of Italian patients who underwent laparoscopic right colectomy and explore the ligature techniques used by Italian surgeons. Surgeons reported information about vascularization of the right colon for 616 patients and about surgical anatomy of RCA for 368 patients. Fifty-three patients (10.8%) showed no RCA intraoperatively. The right colic artery (RCA) was categorized according to the Yada classification (types 1-4) during evaluation, and intraoperative assessments revealed that Yada type 1 was the most common type (55.2%), while radiologic evaluations revealed a higher prevalence of type 2. Furthermore, compared with the superior mesenteric vein (SMV), the RCA is more often located anteriorly according to intraoperative and contrast-enhanced CT examination; 59.9% were found in the anterior position during intraoperative examination, while 40.1% were found in the same position on preoperative contrast-enhanced CT. Vascularization of the right colon, including missing branches, additional branches, shared trunks, and retro-superior courses of the mesenteric vein, exhibited notable variations. To understand vascular variations, a preoperative radiological study is necessary; although there was no concordance between the intraoperative and radiological evaluations, this is a limitation of preinterventional radiological evaluation (PII) because it is always needed for oncological staging. This approach is especially critical for inexperienced surgeons to avoid potential complications, such as problematic bleeding.

Mesenteric sparing approach for advanced nodal extent in small intestinal neuroendocrine tumors. Is there a limit to the vascular resection in order to avoid creating a short small bowel syndrome? An anatomic research study

PURPOSE

By selectively perfusing the first three jejunal arteries (JA), we aim to assess the individual perfusion length of small bowel (SB) and its impact on nodal resection in stage III-up small-intestinal neuroendocrine tumors (SI-NET).

METHODS

Our anatomical research protocol implies a midline laparotomy and three measures of the SB length. We then perform a classical anterior approach of the superior mesenteric vessels. We carry on with the complete dissection and checking of the superior mesenteric artery (SMA) in order to identify the first three JA. Then we selectively perfuse each artery with colored latex solutions and measure the length of small bowel perfused respectively.

RESULTS

We conducted our protocol on six cadaveric subjects. Mean(SD) SB length was 413(5.7), 535(13.2), 485(15), 353(25.1), 730(17.3) and 525(16° cm respectively from subject one to six. Most JA originated from the left side of the SMA. The first JA originated from its posterior wall in two subjects. Mean(SD) distance of origin of the first three JA was 4.6(1.3)cm, 6(1.1)cm and 7.1(0.9)cm respectively. Mean(SD) diameter of SMA was 10.8(3.3)mm. Mean diameter of the three first JA was 4(1.4)mm, 4(1.5)mm and 5(1.2)mm respectively. Mean(SD) SB length perfused by first and second JA was 224(14.9)cm, 175(8.6)cm, 238.3(7.6)cm, 84.3(5.1)cm, 233.3(5.8)cm and 218.3(10.4)cm respectively from subject one to six.

CONCLUSION

We observed a trend suggesting that the first and second JA may sustain a SB length beyond the viable 1.5 m limit, implying the feasibility of stage III-up SI-NET resection with just two JA.

A case of MCA arising from ICA: a case report

BACKGROUND

Complete mesocolic excision (CME) and central vascular detachment are very important procedures in surgery for colorectal cancer. Preoperative and intraoperative assessments of the anatomy of major colorectal vessels are necessary to avoid massive bleeding, especially in endoscopic surgery. A case with a rare anomaly in which the middle colic artery (MCA) and ileocolic artery (ICA) had a common trunk is reported.

CASE PRESENTATION

The patient was a 73-year-old woman diagnosed with ascending colon cancer on colonoscopy. Preoperative abdominal contrast-enhanced computed tomography confirmed that the MCA and ICA had a common trunk. She underwent laparoscopic ileocecal resection for the ascending colon cancer with D3 lymph node dissection. Intraoperative indocyanine green fluorescence imaging was conducted. After confirming vessel bifurcation, the ICA was dissected at the distal end of the MCA bifurcation. The patient has been followed as an outpatient, with no signs of recurrence as of 2 years postoperatively.

CONCLUSION

A case of an ascending colon cancer with a unique vascular bifurcation pattern was presented. Preoperative and intraoperative evaluations of the major colorectal vessels are very important for preventing perioperative and postoperative complications.

Are Metastatic Central Lymph Nodes (D3 volume) in right-sided Colon Cancer a Sign of Systemic Disease? A sub-group Analysis of an Ongoing Multicenter Trial

OBJECTIVE

Assess outcomes of patients with right-sided colon cancer with metastases in the D3 volume after personalized surgery.

BACKGROUND

Patients with central lymph node metastasis (D3-PNG) are considered to have a systemic disease with a poor prognosis. A 3-dimensional definition of the dissection volume allows the removal of all central nodes.

MATERIALS AND METHODS

D3-PNG includes consecutive patients from an ongoing clinical trial. Patients were stratified into residual disease negative (D3-RDN) and residual disease positive (D3-RDP) groups. D3-RDN was further stratified into 4 periods to identify a learning curve. A personalized D3 volume (defined through arterial origins and venous confluences) was removed " en bloc" through medial-to-lateral dissection, and the D3 volume of the specimen was analyzed separately.

RESULTS

D3-PNG contained 42 (26 females, 63.1 SD 9.9 y) patients, D3-RDN:29 (17 females, 63.4 SD 10.1 y), and D3-RDP:13 (9 females, 62.2 SD 9.7 y). The mean overall survival (OS) days were D3-PNG:1230, D3-RDN:1610, and D3-RDP:460. The mean disease-free survival (DFS) was D3-PNG:1023, D3-RDN:1461, and D3-RDP:74 days. The probability of OS/DFS were D3-PNG:52.1%/50.2%, D3-RDN:72.9%/73.1%, D3-RDP: 7.7%/0%. There is a significant change in OS/DFS in the D3-RDN from 2011-2013 to 2020-2022 (both P =0.046) and from 2014-2016 to 2020-2022 ( P =0.028 and P =0.005, respectively).

CONCLUSION

Our results indicate that surgery can achieve survival in most patients with central lymph node metastases by removing a personalized and anatomically defined D3 volume. The extent of mesenterectomy and the quality of surgery are paramount since a learning curve has demonstrated significantly improved survival over time despite the low number of patients. These results imply a place for the centralization of this patient group where feasible.

[Personalized evaluation of D3-lymph node dissection complexity for right colorectal cancer considering anatomy of superior mesenteric vessels]

OBJECTIVE

To provide a personalized approach to D3 lymph node dissection (LND) in right colon cancer using a proper analysis and interpretation of CT angiography of superior mesenteric vessels.

MATERIAL AND METHODS

An observational cross-sectional study included 34 patients who underwent surgery for right colon cancer with D3 LND along superior mesenteric artery (SMA) and vein (SMV). Characteristics of surgically relevant vascular anatomy were evaluated as 0 or 1 depending on complexity of anatomical characteristic. Patients were classified into groups of standard (0 points) and complex (1-3 points) LND according to complexity of vascular anatomy.

RESULTS

SMA and SMV crossed each other at the level of ileocolic artery (ICA) orifice or above in 23.5% of cases (n=8). In 76.5% of cases, they passed parallel to each other (n=25). Ileocolic artery passed posteriorly to SMV in 47.1% (n=16) of cases. A closed type of SMA with a restricted access to D3 area was observed in 41.2% of cases (n=14). Duration of LND significantly differed (43.6±17.8 min in standard cases and 61.9±18.6 min in complex ones, p=0.006).

CONCLUSION. V

Ascular anatomy can predict complexity of D3 LND in right colon cancer surgery. The complexity scale is an important tool for preoperative planning of D3 LND and identifying technical difficulties associated with vascular anatomy.

Evaluation of the mesenteric arterial vasculature by computed tomography angiography and its implications for colorectal cancer surgery

Objective

To determine the branching patterns of the inferior mesenteric artery (IMA) and to describe the clinical applicability of computed tomography (CT) angiography in the evaluation of these vessels to facilitate the planning of colorectal cancer surgery.

Materials and Methods

We included 100 patients who underwent CT angiography of the abdomen and pelvis. The branching patterns of the IMA were examined and classified as type 1 (bifurcated), including 1A (sigmoid and left colic arteries arising from a common trunk), 1B (sigmoid and superior rectal arteries arising from a common trunk) and 1C (sigmoid arteries arising from both trunks); type 2 (trifurcated); and type 3 (no left colic branch).

Results

Among the 100 patients evaluated, we found the variant to be type 1A in 9%, type 1B in 47%, type 1C in 24%, type 2 in 16%, and type 3 in 4%.

Conclusion

Preoperative CT angiography for evaluating the IMA branching pattern could inform decisions regarding the surgical approach to colorectal cancer.

Exceptional vascular variants during oncological right colectomy: Case reports

INTRODUCTION

Carcinological right colectomy with complete D3 mesocolon excision has to be guided by vascular variants in order to avoid complications especially in exceptional cases as illustrated by our two cases.

CASE PRESENTATIONS

Two women had right colectomies with compete D3 mesocolon excision via laparotomy for right colon tumors with a non-modal anatomy: an X-shaped relationship between the superior mesenteric artery and the superior mesenteric vein and a Y-shaped superior mesenteric vein, an ileocolic artery behind the two trunks, a right colic artery behind the left trunk, and the middle colic artery anterior to the main trunk of the superior mesenteric vein respectively.

DISCUSSION

Our cases illustrated extremely rare vascular variants during right colectomy with complete mesocolic excision. These variants should be identified based on the computed tomography with coronal reconstructions allowing to guide surgical procedure before the operating room in order to anticipate per-operative difficulties and reduce morbidity.

CONCLUSIONS

Vascular anatomical study based on computed tomography with coronal reconstructions was mandatory before right colectomy with complete mesocolic excision and D3 lymphadenectomy.

Complications after open and laparoscopic right-sided colectomy with central lymphadenectomy for colon cancer: randomized controlled trial

BACKGROUND

A central lymphadenectomy in right-sided colon cancer involves dissection along the superior mesenteric axis, but the extent is debated due to a lack of consensus and the fear of major complications. This randomized controlled trial compared the rate of postoperative morbidity in patients undergoing laparoscopic versus open right-sided colectomy with central lymphadenectomy.

METHODS

This open, prospective, randomized controlled trial compared patients operated on with open and laparoscopic right-sided colectomy (cStages I-III) with a central lymphadenectomy at two Norwegian institutions between October 2016 and December 2021. Dissections were conducted along the superior mesenteric vein in the laparoscopic group, and along the left anterior border of the superior mesenteric artery in the open group, both according to complete mesocolic excision principles. Surgery was standardized and performed by three experienced surgeons for each study group. The primary outcome of interest was to measure postoperative 30-day complications (Clavien-Dindo ≥ grade II).

RESULTS

Of 273 eligible patients, 135 were randomized and 128 analysed (63 operated on with open and 65 using laparoscopic procedures). Postoperative complications occurred in 42.8 per cent of the patients treated with open and 38.4 per cent of the patients treated using laparoscopic surgery, P = 0.372. The incidence of Clavien-Dindo grade IIIb complications was 7.9 per cent in the open versus 4.6 per cent in the laparoscopic group, P = 0.341. There were no grade IV or V complications, and no re-operations due to anastomotic leakages. There was no significant difference in the mean(s.e.m.) number of removed lymph nodes (open versus laparoscopic respectively: 31.9(1.8) versus 29.3(1.3); P = 0.235).

CONCLUSION

There was no significant difference in complications between the two groups. Standardized oncologic right-sided colectomy with central lymphadenectomy along the mesenterial root was performed safely, both open and laparoscopic, with incidence of major complications ranging between 4.6 and 7.9 per cent and no re-operations for anastomotic leakage. Radicality in terms of lymphadenectomy was comparable between the two groups.Registration number: NCT03776591 (http://www.clinicaltrials.gov).

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.

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.

Comparing 5-Year Survival Rates Before and After Re-stratification of Stage I-III Right-Sided Colon Cancer Patients by Establishing the Presence/Absence of Occult Tumor Cells and Lymph Node Metastases in the Different Levels of Surgical Dissection

BACKGROUND

To establish the impact of re-stratification on the outcomes of patients (stage I-III right-sided colon cancer) based on the presence/absence of occult tumor cells (OTC) and/or metastatic lymph nodes in the different levels of surgical dissection.

METHODS

Consecutive patients were drawn from a multicenter prospective trial. After surgery, the surgical specimen was divided into the D1/D2 and D3 volumes before being further analyzed separately. All lymph nodes were examined with cytokeratin CAM 5.2 immunohistochemically. Lymph nodes containing metastases and OTC (micrometastases; isolated tumor cells) were identified. Re-stratification was as follows: RS1, stages I/II, no OTC in D1/D2 and D3 volumes; RS2, stages I/II, OTC in D1/D2 and/or D3; RS3, stage III, lymph node metastases in D1/D2, with/without OTC in D3; RS4, stage III, lymph node metastases in D3, with/without OTC in D3.

RESULTS

Eighty-seven patients (39 men, 68.4 + 9.9 years) were included. The standard stratified (SS) group contained the following: stages I/II (SS1) 57 patients; stage III (SS2) 30 patients. Re-stratified (RS) contained RS1 (38), RS2 (19), RS3 (24), and RS4 (6) patients. Lymph node ratio (OTC) RS2: 0.157 D1/D2; 0.035 D3 and 0.092 complete specimens. Lymph node ratio RS3: 0.113 D1/D2; complete specimen 0.056. Overall survival and disease-free survival were p = 0.875 and p = 0.049 for SS and p = 0.144 and p = 0.001 for RS groups, respectively.

CONCLUSION

This re-stratification identifies a patient group with poor prognosis (RS4). Removing this group from SS2 eliminates all the differences in survival between RS2 and RS3 groups. The level of dissection of the affected nodes may have an impact on survival.

CLINICAL TRIAL

"Safe Radical D3 Right Hemicolectomy for Cancer through Preoperative Biphasic Multi-Detector Computed Tomography (MDCT) Angiography" registered at http://clinicaltrials.gov/ct2/show/NCT01351714.

Variation of the ileocolic artery and superior mesenteric artery in a patient with right-sided colon cancer with Lynch syndrome: a case report

Background

Complete mesangectomy and central vascular detachment are the core elements of laparoscopic right hemicolectomy. Failure to identify vascular variations in patients undergoing laparoscopic right hemicolectomy can result in unwanted bleeding, a prolonged surgical time, transfer to open surgery, and an elevated risk of postoperative complications. In this case report, we describe a new vascular variation that has not yet been reported in the literature. Parallelly vascular variation and the management of vessels in key areas are essential for successful surgery.

Case Description

The patient was a 32-year-old female who was referred to the department of gastrointestinal surgery of our hospital due to intermittent abdominal pain accompanied by changes in stool habits for 3 months. She had not experienced other symptoms. Physical examination revealed mild tenderness in the right lower abdomen. Subsequently, she underwent laparoscopic radical right hemicolectomy for ascending colon cancer under general anesthesia in our hospital. Preoperative abdominal contrast-enhanced computed tomography (CT) and intraoperative photos confirmed that there were two ileocolic arteries derived from the superior mesenteric artery (SMA). On the other side, the SMA and superior mesenteric vein (SMV) were found to be accompanied like "X"-shaped variant. The final surgical pathological diagnosis was pT3N1aM0 adenocarcinoma of the ascending colon. Given the patient's family history of colon and uterine cancer combined with the results of immunohistochemical staining and next-generation sequencing, we concluded that she had Lynch syndrome (LS).

Conclusions

This report describes the first case of simultaneous variation of the ileocolic artery (ICA) and SMA in a female patient with colon cancer. This type of vascular variation should be fully recognized by surgeons in order to avoid unnecessary intraoperative bleeding.

Laparoscopic Complete Mesocolic Excision with Central Vascular Ligation (CME + CVL) for Right-Sided Colon Cancer: A New "Superior Mesenteric Artery First" Approach

PURPOSE

It remains a technical challenge to perform "superior mesenteric artery (SMA) first" approach for laparoscopic right hemicolectomy with complete mesocolon excision (CME) as the vascular anatomy of the right colon varies a lot, which may cause difficulty in early location of SMA and the risk of vascular damage during central vascular ligation (CVL). The purpose of this study was to describe a new "SMA first" approach for laparoscopic CME with CVL in right hemicolectomy with Treitz's ligament and ileocolic vascular pedicle as the anatomical landmarks for early identification of and exposure of SMA.

METHODS

This procedure was performed on 21 patients with right colon cancer between March 2020 and August 2021. To start, the transverse mesocolon was retracted to expose the ligament of Treitz, and the pedicle of ileocolic vessels was anteriorly grasped. Next, the peritoneum near the right border of the ligament of Treitz was divided along the left side of SMA until the peritoneum below the ileocolic vessels. Next, the mesenteric lymphatic adipose tissue outside of the sheath of SMA was dissected from medial to lateral. Then, laparoscopic right hemicolectomy with complete mesocolic excision (CME) was performed. Patients' preoperative baseline characteristics and intraoperative and postoperative complications were examined.

RESULTS

The median operative time was 180 min, and the median intraoperative blood loss was 50 ml (interquartile range 40-90). Chylous leakage occurred in four patients, and all the patients resolved with percutaneous drainage. The total harvested lymph nodes was 21.0 (range 16-27). The median times to first flatus and liquid diet intake were both 3.0 days. The median number of postoperative hospital days was 10.0 days. No severe postoperative complications, such as abdominal infection, anastomotic leakage, or bleeding, were observed.

CONCLUSIONS

This new "SMA first" approach is safe and technically feasible for laparoscopic CME with CVL in right hemicolectomy.

Anatomic patterns and clinical significance of gastrocolic trunk of Henlé in laparoscopic right colectomy for colon cancer: Results of the HeLaRC trial

BACKGROUND

Recent interest in laparoscopic right colectomy with D3 lymphadenectomy for right colon cancer, has raised renewed attention to the anatomic variations of the gastrocolic trunk of Henlé (GTH). Understanding the vascular structure of the GTH region for individual patients should improve surgical outcomes. The goal of this nationwide multicenter study (Anatomical Classification of Henlé's Trunk in Laparoscopic Right Hemi-colectomy (HeLaRC) trial) was to study the anatomic patterns of the GTH region, to clarify the implications of GTH in laparoscopic right colectomy with D3 lymphadenectomy (D3-RC) and analyze their clinical significance.

METHODS

We enrolled 583 patients from 26 centers across China who underwent D3-RC. The number of tributaries, length and types of GTH constitutions and their influence on intra-operative data were investigated. A nomogram score (based on the length of GTH, body mass index (BMI), tumor location, T stage and type of GTH (type I vs. non-type I) was established to assess the potential hazard of bleeding.

RESULTS

The GTH was found in 567 patients (97.3%). The distribution of GTH types was 0 (14.1%, n = 80), I (53.3%, n = 302), II (27.0%, n = 153), III (5.6%, n = 32). Of note, the type I GTH, T1 stage and tumor location at ileocecal or ascending colon were correlated with shorter exposure time of the GTH region (P < 0.0001). Short length of GTH (P = 0.002) and tumor location (transverse colon vs. non transverse colon) (P = 0.003) were correlated with the amount of GTH bleeding during the surgery. Nomogram discrimination was good (C-index: 0.72 (95% CI: 0.64, 0.80)). The dissection plane was better in patients with type I GTH than with other types (P = 0.023).

CONCLUSION

GTH pattern variations may affect surgical outcomes in patients undergoing D3-RC. Better recognition of GTH anatomy might lead to a safer operation with better oncologic quality.

Vascular Anatomy and Variants: Knowledge during Laparoscopic Right Colectomy

From the review of the literature and clinical data, it is clear that the anatomy of the vessels of the right colon is remarkably variable, especially those of Henle branch. This justifies why the laparoscopic colectomy (LRC) plus complete mesocolon excision (CME) is often difficult to perform with the conversion rate due to the lesion of the vessels. The objective of this study was to retrospectively review the videos and literature of the right laparoscopic colectomy plus CME to highlight the greatest number of vascular variations of the right colon, to record them, and to highlight the methods by which cope with these variations during surgery.

Risk factors of chylous ascites and its relationship with long-term prognosis in laparoscopic D3 lymphadenectomy for right colon cancer

BACKGROUND

Chylous ascites (CA) after laparoscopic D3 lymphadenectomy for right colon cancer is not rare. However, the risk factors for CA have not been fully explored. Few studies have investigated the effect of CA on long-term prognosis.

METHODS

The clinical data of patients with right colon cancer who underwent laparoscopic D3 lymphadenectomy in five centers from January 2013 to December 2018 were retrospectively collected. Univariate and multivariate analyses were performed to determine the clinicopathological factors associated with CA. Then, the long-term prognosis of patients with and without CA was compared by propensity score matching and Kaplan-Meier survival analysis.

RESULTS

The incidence of CA was 4.4% (48/1090). Pathological T stage (p = 0.025), dissection along the left side of the superior mesenteric artery (p < 0.001) and the number of retrieved lymph nodes (p < 0.001) were independent risk factors for CA. After propensity score matching, 48 patients in the CA group and 353 patients in the non-CA group were enrolled. Kaplan-Meier survival analysis indicated that CA was not associated with overall survival (p = 0.454) and disease-free survival (p = 0.163). In patients with stage III right colon cancer, there were no significant differences in overall survival (p = 0.501) and disease-free survival (p = 0.254).

CONCLUSIONS

Pathological T stage, number of retrieved lymph nodes, and left side dissection along the superior mesenteric artery were independent risk factors for CA after laparoscopic D3 lymphadenectomy. CA does not impair the oncological outcomes of patients.

Vascular variants in laparoscopic extended right hemicolectomy with central vascular ligation for right colon cancer

PURPOSE

To evaluate the right colic vascularity, focusing on the confluences of veins.

METHODS

The subjects of this retrospective study were 100 patients who underwent laparoscopic extended right hemicolectomy (Lap-ERHC) between April 2015 and September 2020, at our hospitals. Veins draining into the superior mesenteric vein (SMV) included the ileocecal vein (ICV), the right colic vein (RCV), the middle colic vein (MCV), and the gastrocolic trunk of Henle (GCT). Veins draining into vessels other than the SMV were defined as accessory colic veins (aICV, aRCV or aMCV).

RESULTS

The GCT, aRCV, and aMCV were found in 86, 89, and 15 patients, respectively. In 66 patients with one aRCV, drainage was split as the anterior superior pancreaticoduodenal vein (ASPDV) in 12, the right gastroepiploic vein (RGEV) in 7, and the GCT in 47. In 23 patients with two aRCVs, drainage was split as the ASPDV in 4, the RGEV in 1, the GCT in 11, and the ASPDV and GCT in 7. In 14 patients with one aMCV, drainage was split as the GCT in 8, the splenic vein in 5, and the first jejunal vein (FJV) in 1. One patient had two aMCVs, draining into the GCT and the FJV.

CONCLUSIONS

The findings of our evaluation of vascular anatomy, focusing on confluences of the colic veins, provides useful information for colorectal surgeons.

Reconstructing topography and extent of injury to the superior mesenteric artery plexus in right colectomy with extended D3 mesenterectomy: a composite multimodal 3-dimensional analysis

Background

Superior mesenteric artery plexus (SMAP) injury is reported to cause postoperative intractable diarrhea after pancreatic/colonic surgery with extended lymphadenectomy. This study aims to describe the SMAP microanatomy and extent of injury after right colectomy with extended D3 mesenterectomy for cancer.

Methods

Three groups (I) anatomical dissection, (II) postmortem histology, and (III) surgical specimen histology were included. Nerve count and area were compared between groups II and III and paravascular sheath thickness between groups I and II. 3D models were generated through 3D histology, nanoCT scanning, and finally through 3D printing.

Results

A total of 21 specimens were included as follows: Group (I): 5 (3 females, 80–93 years), the SMAP is a complex mesh surrounding the superior mesenteric artery (SMA), branching out, following peripheral arteries and intertwining between them, (II): 7 (5 females, 71–86 years), nerve count: 53 ± 12.42 (38–68), and area: 1.84 ± 0.50 mm2 (1.16–2.29), and (III): 9 (5 females, 55–69 years), nerve count: 31.6 ± 6.74 (range 23–43), and area: 0.889 ± 0.45 mm2 (range 0.479–1.668). SMAP transection injury is 59% of nerve count and 48% of nerve area at middle colic artery origin level. The median values of paravascular sheath thickness decreased caudally from 2.05 to 1.04 mm (anatomical dissection) and from 2.65 to 1.17 mm (postmortem histology). 3D histology models present nerve fibers exclusively within the paravascular sheath, and lymph nodes were observed only outside. NanoCT-derived models reveal oblique nerve fiber trajectories with inclinations between 35° and 55°. Two 3D-printed models of the SMAP were also achieved in a 1:2 scale.

Conclusion

SMAP surrounds the SMA and branches within the paravascular sheath, while bowel lymph nodes and vessels lie outside. Extent of SMAP injury on histological slides (transection only) was 48% nerve area and 59% nerve count. The 35°–55° inclination range of SMAP nerves possibly imply an even larger injury when plexus excision is performed (lymphadenectomy). Reasons for later improvement of bowel function in these patients can lie in the interarterial nerve fibers between SMA branches.

The impact of three-dimensional reconstruction and standardised CT interpretation (AMIGO) on the anatomical understanding of mesenteric vascular anatomy for planning complete mesocolic excision surgery: A randomised crossover study

BACKGROUND

Preoperative planning is a crucial aspect of safe complete mesocolic excision (CME) surgery. 3D models derived from imaging may help improve anatomical understanding of the complex vascular anatomy. Here, we assessed the effect of 3D models on surgeons' anatomical understanding in comparison to a systematic approach for CT scan interpretation (AMIGO).

METHOD

Fifteen cases were included in the study. Two GI radiology consultants reviewed each scan to ascertain the vascular anatomy. Virtual 3D models were produced and displayed on a web-based platform (https://skfb.ly/6OZUZ). A total of 13 surgical trainees were recruited. Candidates were assessed after baseline anatomical training and subsequently using the AMIGO method and 3D models. Five cases were randomly allocated in each round of testing for each participant. The primary outcome measure was an objective vascular anatomy knowledge score. The secondary outcome measure was subjective feedback from participants.

RESULTS

Both 3D and AMIGO significantly improved anatomical understanding in comparison to baseline testing. However, 3D was superior to AMIGO (3D [n = 65; median score 8/14] vs. AMIGO [n = 65; median score 6/14; p < 0.0001]. For 13/15 patient cases examined, 3D was superior to the AMIGO method. Eleven participants demonstrated better anatomical understanding using 3D models versus AMIGO. Ten participants preferred 3D models in comparison to standard CT imaging.

CONCLUSIONS

3D models improve anatomical understanding of mesenteric vascular anatomy in a group of colorectal surgical trainees in comparison to a formal CT interpretation method. 3D models may be a useful planning adjunct to 2D imaging for CME surgery.

Laparoscopic segmental colectomy with extensive D3 lymph node dissection: a good choice for right transverse colon cancer

Background

Previous research was yet to establish a definite operation for transverse colon cancer (TCC); surgical procedure was often dictated by the surgeon’s preference in clinical practice. The main surgical methods could be summarized in two main points: segmental colectomy (transverse colectomy) and right hemicolectomy.

Method

The first patient was a 78-year-old woman, who was diagnosed with right TCC. Computed tomography revealed a right TCC and a very long transverse colon; laparoscopic exploration revealed an enlarged apical lymph node surrounding the ileocolic vessels. We performed a segmental colectomy with extensive apical lymph node dissection along the superior mesenteric vessels and its main branches for her. To distinguish it from the previous radical operations for TCC, we called this operation a segmental colectomy with extensive D3 lymph node dissection. Then, this surgical intervention was performed on 8 other TCC patients.

Results

The total operating time was 158 min. Pathological examination confirmed 2 apical lymph node metastases; among them, one apical lymph node metastasis was in group No.203. For all 9 patients, the median operative time was 160 min (range, 140–185 min), the average number of lymph node retrieval was 30 (range, 25–39), and the average number of apical lymph node (No.203, No.213, and No.223) retrieval was 5.9 (range, 0–11). Because of the preservation of the ileocecal junction and part of the ascending colon, all patients recovered uneventfully after surgery, and long-term diarrhea, water-electrolyte imbalance, and other Clavien–Dindo grade III or greater postoperative complications did not occur.

Conclusions

Our procedure combined the advantages of segmental colectomy and right hemicolectomy and gave consideration to oncological and functional outcomes. It may be an optimal choice for TCC patients with a very long transverse colon and preoperative diagnosis of lymph node metastasis.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12957-022-02530-4.

ICG-Guided Lymphadenectomy during Surgery for Colon and Rectal Cancer-Interim Analysis of the GREENLIGHT Trial

Lymphadenectomy is crucial for an optimal oncologic resection of colon and rectal cancers. However, without a direct visualization, an aberrant route of lymph node (LN) diffusion might remain unresected. Indocyanine-green (ICG) lymphatic mapping permits a real-time LNs visualization. We designed the GREENLIGHT trial to explore in 100 patients undergoing robotic colorectal resection the clinical significance of a D3 ICG-guided lymphadenectomy. The primary endpoint was the number of patients in whom ICG changed the extent of lymphadenectomy. We report herein the interim analysis on the first 70 patients. After endoscopic ICG injection 24 h (n = 49) or 72 h (n = 21) ahead, 19, 20, and 31 patients underwent right colectomy, left colectomy, and anterior rectal resection. The extent of lymphadenectomy changed in 35 (50%) patients, mostly (29 (41.4%)) for the identification of LNs (median two) outside the standard draining basin. Identification of such LNs was less frequent in rectal tumors that had undergone chemoradiotherapy (26.3%) (p > 0.05). A non-significant correlation between time-to-ICG injection and identification of aberrant LNs was observed (48.9% at 24 h vs. 23.8% at 72 h). The presence of LN metastases did not affect a proper fluorescent mapping. These data indicate that ICG lymphatic mapping provides relevant information in 50% of patients, thus increasing the accuracy of potentially curative resections.

Precision anatomy for safe approach to pancreatoduodenectomy for both open and minimally invasive procedure: A systematic review

BACKGROUND

Minimally invasive pancreatoduodenectomy (MIPD) has recently gained popularity. Several international meetings focusing on the existing literature on MIPD were held; however, the precise surgical anatomy of the pancreas for the safe use of MIPD has not yet been fully discussed. The aim of this study was to carry out a systematic review of available articles and to show the importance of identifying the anatomical variation in pancreatoduodenectomy.

METHODS

In this review, we described variations in surgical anatomy related to MIPD. A systematic search of PubMed (MEDLINE) was conducted, and the references were identified manually.

RESULTS

The search strategy yielded 272 articles, with 77 retained for analysis. The important anatomy to be considered during MIPD includes the aberrant right hepatic artery, first jejunal vein, first jejunal artery, and dorsal pancreatic artery. Celiac artery stenosis and a circumportal pancreas are also important to recognize.

CONCLUSIONS

We conclude that only certain anatomical variations are associated directly with perioperative outcomes and that identification of these particular variations is important for safe performance of MIPD.

Surgeon's role in CT-based preoperative determination of inferior mesenteric artery anatomy in colorectal cancer treatment

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.

Current and future role of three-dimensional modelling technology in rectal cancer surgery: A systematic review

BACKGROUND

Three-dimensional (3D) modelling technology translates the patient-specific anatomical information derived from two-dimensional radiological images into virtual or physical 3D models, which more closely resemble the complex environment encountered during surgery. It has been successfully applied to surgical planning and navigation, as well as surgical training and patient education in several surgical specialties, but its uptake lags behind in colorectal surgery. Rectal cancer surgery poses specific challenges due to the complex anatomy of the pelvis, which is difficult to comprehend and visualise.

AIM

To review the current and emerging applications of the 3D models, both virtual and physical, in rectal cancer surgery.

METHODS

Medline/PubMed, Embase and Scopus databases were searched using the keywords "rectal surgery", "colorectal surgery", "three-dimensional", "3D", "modelling", "3D printing", "surgical planning", "surgical navigation", "surgical education", "patient education" to identify the eligible full-text studies published in English between 2001 and 2020. Reference list from each article was manually reviewed to identify additional relevant papers. The conference abstracts, animal and cadaveric studies and studies describing 3D pelvimetry or radiotherapy planning were excluded. Data were extracted from the retrieved manuscripts and summarised in a descriptive way. The manuscript was prepared and revised in accordance with PRISMA 2009 checklist.

RESULTS

Sixteen studies, including 9 feasibility studies, were included in the systematic review. The studies were classified into four categories: feasibility of the use of 3D modelling technology in rectal cancer surgery, preoperative planning and intraoperative navigation, surgical education and surgical device design. Thirteen studies used virtual models, one 3D printed model and 2 both types of models. The construction of virtual and physical models depicting the normal pelvic anatomy and rectal cancer, was shown to be feasible. Within the clinical context, 3D models were used to identify vascular anomalies, for surgical planning and navigation in lateral pelvic wall lymph node dissection and in management of recurrent rectal cancer. Both physical and virtual 3D models were found to be valuable in surgical education, with a preference for 3D printed models. The main limitations of the current technology identified in the studies were related to the restrictions of the segmentation process and the lack of 3D printing materials that could mimic the soft and deformable tissues.

CONCLUSION

3D modelling technology has potential to be utilised in multiple aspects of rectal cancer surgery, however, it is still at the experimental stage of application in this setting.

Interactions of occult tumor spread and surgical technique on overall and disease-free survival in patients operated for stage I and II right-sided colon cancer

PURPOSE

To determine if "medial to lateral" (ML) dissection with devascularization first is superior to "lateral to medial" (LM) dissection regarding numbers of lymph node micro metastases (MM) and isolated tumor cells (ITC) as well as 5-year disease-free (5YDFS) and 5-year overall survival (5YOS) in stage I/II right-sided colon cancer.

METHODS

Two datasets are used. ML group consists of consecutive stage I/II patients from a prospective trial. LM group is the original dataset from a previous publication. All harvested lymph nodes are examined with monoclonal antibody CAM 5.2 (immunohistochemically). Lymph node harvest and 5YOS/5YDFS were compared between ML/LM groups, stage I/II tumors and MM/ITC presence/absence.

RESULTS

117 patients included ML:51, LM:66. MM/ITC positive in ML 37.3% (19/51), LM 31.8% (21/66) p = 0.54. The 5YDFS for patients in ML 70.6% and LM 69.7%, p = 0.99, 5YOS: 74.5% ML and 71.2% LM (p = 0.73). No difference in 5YDFS/5YOS between groups for Stage I/II tumors; however, LM group had an excess of early tumors (16) when compared to ML group, while lymph node harvest was significantly higher in ML group (p < 0.01) 15.1 vs 26.7. 5YDFS and 5YOS stratified by MM/ITC presence/absence was 67.5%/71.4%, p = 0.63, and 75.0%/71.4%, p = 0.72, respectively. Death due to recurrence in MM/ITC positive was significantly higher than MM/ITC negative (p = 0.012).

CONCLUSION

Surgical technique does not influence numbers of MM/ITC or 5YDFS/5YOS. Presence of MM/ITC does not affect 5YOS/5YDFS but can be a potential prognostic factor for death due to recurrence.

CLINICAL TRIAL

Safe Radical D3 Right Hemicolectomy for Cancer through Preoperative Biphasic Multi-Detector Computed Tomography (MDCT) Angiography" registered at http://clinicaltrials.gov/ct2/show/NCT01351714 .

A systematic review and meta-analysis of variants of the branches of the superior mesenteric artery: the Achilles heel of right hemicolectomy with complete mesocolic excision?

AIM

Dissection with subsequent ligation and resection of arteries at their origin (central vascular ligation) is essential for adequate oncological resection during right hemicolectomy with complete mesocolic excision. This technique is technically demanding due to the highly variable arterial pattern of the right colon. Therefore, this study aims to provide a comprehensive evidence-based assessment of the arterial vascular anatomy of the right colon.

METHODS

A thorough systematic literature search through September 2020 was conducted on the electronic databases PubMed, Scopus and Web of Science to identify studies eligible for inclusion. Data were extracted and pooled into a meta-analysis using MetaXl software.

RESULTS

A total of 41 studies (n = 4691 patients) were included. The ileocolic artery (ICA), right colic artery (RCA) and middle colic artery (MCA) were present in 99.7% (95% CI 99.4%-99.8%), 72.6% (95% CI 61.3%-82.5%) and 96.9% (95% CI 94.2%-98.8%) respectively of patients. Supernumerary RCA and MCA were observed in 3.2% and 11.4% respectively of all cases. The RCA shared a common trunk with the ICA and MCA in 13.2% and 17.7% respectively of patients. A retro-superior mesenteric vein course of the ICA and RCA was observed in 55.1% and 11.4% respectively of all cases.

CONCLUSION

The vascular anatomy of the right colon displays several notable variations, namely the absence of some branches (RCA absent in 27.4% of cases), supernumerary branches, common trunks, and retro-superior mesenteric vein courses. These variations should be taken into consideration during right hemicolectomy with complete mesocolic excision to ensure adequate oncological resection while minimizing intra-operative complications.

A stepwise approach to laparoscopic right hemicolectomy with D2 excision. An illustrated video guide for training colorectal surgeons - a video vignette

We present a stepwise approach to performing a laparoscopic right hemicolectomy along with D2 excision. The video illustrates a modular approach for set up and resection, performed on a 60-year-old male patient, with a cancer in the ascending colon. The procedure is divided into its key steps, which include patient position, port placement and anatomical exposure, medial to lateral dissection with vessel control, sub-ileal dissection, lateral mobilization, hepatic flexure mobilization and extraction with extracorporeal anastomosis. The key regional anatomy is highlighted alongside diagrams illustrating standard anatomy and common anatomical variants. We believe this video provides a valuable resource for trainee surgeons to expand their understanding regarding steps of the procedure and associated anatomy.

Stool dynamics after extrinsic nerve injury during right colectomy with extended D3-mesenterectomy

INTRODUCTION

To improve oncological outcome in right colon cancer surgery, an extended mesenterectomy (D3) is under evaluation. In this procedure, all tissue anterior and posterior to the superior mesenteric vessels from the middle colic to ileocolic artery origin is removed, causing injury to the superior mesenteric nerve plexus. The aim was to study the effects of this injury on bowel dynamics and quality of life (QoL).

METHODS

Patients undergoing right colectomy with conventional D2- and extended D3-mesenterectomy were asked to record stool number and consistency for 60 d after surgery and complete questionnaires regarding QoL and bowel function (BF) before and after recovery from surgery. We compared early postoperative stool dynamics and long-term QoL in the groups and presented graphs depicting the temporal profile of stool numbers and consistency.

RESULTS

Thirty-three patients operated with a D3-resection and 12 patients with a D2-resection participated. The results revealed significantly higher stool numbers in the D3-group until day 26, with significantly more loose-watery stools until day 40. The most pronounced difference was found on day 9 (Mean difference in the total number of stools: 2.25 stools/day, p=.004. Mean difference in loose-watery stools/day: 2.81 p<.001). About 25% in the D2- and 69.7% in the D3-group reported having more than three stools/day in the early postoperative phase. There were no differences in long-term QoL and BF between the groups except in stool consistency (p=.039).

DISCUSSION/CONCLUSIONS

Denervation following extended D3-mesenterectomy leads to transitory reduced consistency and increased frequency. It does not affect long-term QoL or BF.

Predictive value of computed tomography with coronal reconstruction in right hemicolectomy with complete mesocolic excision for right colon cancers: a retrospective study

Background

Understanding the vascular anatomy is critical for performing central vascular ligation (CVL) in right hemicolectomy with complete mesocolic excision (CME). This study aimed to investigate the predictive value of multi-slice spiral computed tomography (MSCT) with coronal reconstruction in right hemicolectomy with CME.

Methods

This is a retrospective descriptive study. Eighty patients with right colon cancer who underwent right hemicolectomy from December 2015 to January 2020 were included. The intraoperative reports (including imaging data) and MSCT images with coronal reconstruction were analysed and compared. The detection rates of the ileocolic vein (ICV) and ileocolic artery (ICA) roots and the accuracy in predicting their anatomical relationship were analysed. The detection rate and accuracy in predicting the location of the gastrocolic trunk of Henle (GTH), middle colic artery (MCA) and middle colic vein (MCV) were analysed. The distance from the ICV root to the GTH root (ICV-GTH distance) was measured and analysed. The maximum distance from the left side of the superior mesenteric artery (SMA) to the right side of the superior mesenteric vein (SMV), named the ‘lsSMA-rsSMV distance’, was also measured and analysed.

Results

In seventy-four (92.5%) patients, both the ICV and ICA roots were located; their anatomical relationship was determined by MSCT, and the accuracy of the prediction was 97.2% (72/74). The GTH was located by MSCT in 75 (93.7%) patients, and the accuracy of the prediction was 97.33% (73/75). The MCA was located by MSCT in 47 (58.75%) patients, and the accuracy was 78.72% (37/47). The MCV was located by MSCT in 51 (63.75%) patients, and the accuracy of the prediction was 84.31% (43/51). The ICV-GTH distance was measured in 73 (91.2%) patients, and the mean distance was 4.28 ± 2.5 cm. The lsSMA-rsSMV distance was measured in 76 (95%) patients, and the mean distance was 2.21 ± 0.6 cm.

Conclusions

With its satisfactory accuracy in predicting and visualising the information of key anatomical sites, MSCT with coronary reconstruction has some predictive value in CME with CVL in right hemicolectomy.

Management of intraoperative complications during laparoscopic right colectomy

BACKGROUND

Minimally invasive right colectomy is increasingly performed as standard treatment for diseases of right colon. Complete mesocolic excision has been introduced for cancer treatment to improve oncological results. Both standard and complete mesocolic excision techniques are associated with intraoperative complications. The purpose of this study was to analyse incidence and management of intraoperative complications in patients who underwent laparoscopic right colectomy with complete mesocolic excision in a single institution.

METHODS

This is a retrospective study conducted in a single Italian centre from April 2017 to October 2020. Data of non-metastatic cancer patients who underwent laparoscopic right colectomy were collected to analyse onset of intraoperative complications, their management and rate of conversion to open surgery.

RESULTS

A total of 92 patients were included in this study. The 1.09% of patients were converted to open surgery due to adhesions and bowel occlusion. The 5.43% of patients had intraoperative complications: bleeding from Henle's trunk, pre-pancreatic plane and ileocolic artery stump account for 3.26%, gonadal vessel injury for 1.09% and bowel lesion for 1.09%.

CONCLUSIONS

Despite the limits of this study, it shows that bleeding is one of the most frequent complications in laparoscopic right colectomy. Bleeding, occlusion and adhesions are most common reasons for conversion to open surgery.

Discrepancy between surgeon and radiological assessment of ligation level of the inferior mesenteric artery in patients operated for rectal cancer-impacting registry-based research and surgical practice

Background

The reliability of the registered ligation level of the inferior mesenteric artery (IMA) in the Swedish Colorectal Cancer Registry has been questioned. The primary aim of this study was to evaluate this parameter in the registry by comparing the registered ligation levels with a postoperative computed tomography angiography (CT-angiography) in patients operated for rectal cancer.

Methods

Patients operated for rectal cancer at two Swedish university hospitals were prospectively included between December 2016 and December 2019. At the 1-year postoperative follow-up, an additional CT-angiography was performed and independently examined by two radiologists. The radiological assessment of the ligation level was compared to registry data, using different measures of agreement.

Results

A total of 94 patients were included, 55 (59%) were men and 39 (41%) women. All patients underwent abdominal resection: conventional or robot-assisted laparoscopic surgery, n=56 (60%), or open resection, n=38 (40%). The ligation level as assessed on CT-angiography was high in 29 (31%) patients and low in 65 (69%). The registered level of ligation of the IMA and the radiological assessment of the CT-angiographies were consistent in 77/94 cases, demonstrating an 82% agreement and a sensitivity and specificity of 86% and 72%, respectively. The estimated Kappa value was 0.58, reaching 0.64 after prevalence bias adjustment.

Conclusion

This study showed that CT-angiography can be used to evaluate the reliability of the registered ligation level in the Swedish Colorectal Cancer Registry. The demonstrated agreement between the registry and postoperative CT-angiography was moderate to good. This discrepancy impacts registry-based research using IMA ligation data and may ultimately influence surgical practice.

Trial registration

Clinical Trials identifier NCT03875612

Supplementary Information

The online version contains supplementary material available at 10.1186/s12957-021-02222-5.

Segmental versus extended colectomy for tumours of the transverse colon: a systematic review and meta-analysis

AIM

There is no consensus on the appropriate extent of oncological resection for tumours of the transverse colon. Concerns regarding tumour factors such as pattern of lymph node spread and technical factors such as anastomotic perfusion lead to a variety of procedures being performed.

METHODS

A comprehensive search for published studies examining outcomes following segmental versus extended colectomy for transverse colon tumours was performed adhering to PRISMA (Preferred Reporting Items in Systematic Reviews and Meta-analyses) guidelines. Random effects methods were used to combine data.

RESULTS

Seven comparative series examining outcomes in 3395 patients were identified. Segmental colectomy results in shorter operating times (mean difference 15.80 min, 95% CI -20.98 to -10.62, P < 0.001) and less ileus (OR 0.52, 95% CI 0.33-0.81, P = 0.004). There was no difference in length of hospital stay (mean difference 1.53 days, 95% CI -3.79 to 0.73, P = 0.18). Extended colectomy results in a lower rate of anastomotic leak (OR 0.62, 95% CI 0.40-0.97, P = 0.04). There are fewer nodes retrieved in segmental colectomy (mean difference 7.60 nodes, 95% CI -9.60 to -5.61, P < 0.001) but no difference in disease recurrence (OR 0.88, 95% CI 0.59-1.34, P = 0.56) or overall survival (OR 0.98, 95% CI 0.68-1.4, P = 0.9).

CONCLUSIONS

Available data are limited due to a lack of randomized controlled trials. However, based on current evidence, segmental resection for transverse colon tumours is associated with less ileus but lower lymph node yields and higher anastomotic leak rates. Length of stay is similar. Oncological outcomes are equivalent.

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.

Precision image-guided colonic surgery: proof of concept for enhanced preoperative and intraoperative vascular imaging

BACKGROUND

Colorectal surgery has benefited from advances in precision medicine such as total mesorectal resection, and recently, mesocolon resection, fluorescent perfusion imaging, and fluorescent node mapping. However, these advances fail to address the variable quality of mesocolon dissection and the directed extent of vascular dissection (including high ligation) or pre-resection anastomotic perfusion mapping, thereby impacting anastomotic leaks. We propose a new paradigm of precision image-directed colorectal surgery involving 3D preoperative resection modeling and intraoperative fluoroscopic and fluorescence vascular imaging which better defines optimal dissection planes and vascular vs. anatomy-based resection lines according to our hypothesis.

METHODS

Six pigs had preoperative CT with vascular 3D reconstruction allowing for the preoperative planning of vascular-based dissection. Laparoscopic surgery was performed in a hybrid operating room (OR). Superselective arterial catheterization was performed in branches of the superior mesenteric artery (SMA) or the inferior mesenteric artery (IMA). Intraoperative boluses of 0.1 mg/kg or a continuous infusion of indocyanine green (ICG) (0.01 mg/mL) were administered to guide fluorescent-based sigmoid and ileocecal resections. Fluorescence was assessed using proprietary software at several regions of interest (ROI) in the right and left colon.

RESULTS

The approach was feasible and safe. Selective catheterization took an average of 43 min. Both bolus and continuous perfusion clearly marked pre-identified vessels (arteries/veins) and the target colon segment, facilitating precise resections based on the visible vascular anatomy. Quantitative software analysis indicated the optimal resection margin for each ROI.

CONCLUSION

Intra-arterial fluorescent mapping allows visualization of major vascular structures and segmental colonic perfusion. This may help to prevent any inadvertent injury to major vascular structures and to precisely determine perfusion-based resection planes and margins. This could enable tailoring of the amount of colon resected, ensure good anastomotic perfusion, and improve oncological outcomes.

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.