Navigating the mesentery: part II. Vascular abnormalities and a review of the literature

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.

[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.

Impact of imaging magnification on colorectal surgery: a matched analysis of a single tertiary center

BACKGROUND

Laparoscopy has been increasingly applied in colorectal surgery, and imaging systems have been improving concurrently. The present study aims to compare outcomes following colorectal surgery with the 4K and traditional high-definition (HD) video systems.

METHODS

All consecutive patients undergoing laparoscopic colorectal surgery between April 2016 and June 2020 were retrospectively retrieved from a prospective institutional database. The study population was matched according to the imaging system (4K versus HD groups) through a propensity score matching (PSM) based on perioperative characteristics of 15 patients. A stratified analysis according to surgical procedures (right, left colectomy, and low anterior resection) was also performed. Primary endpoints were intraoperative blood loss and perioperative transfusions. Also, intra- and postoperative morbidity, operative time, lymph node harvest, and length of hospital stay (LOS) were investigated as secondary outcomes.

RESULTS

After PSM, 225 patients were included in both 4K and HD groups. The intraoperative blood loss was significantly lower in the 4K group (p = 0.008), although no different volumes of blood transfusion were required. Postoperative complications presented in similar proportions, while significantly higher rates of abdominal collection (p = 0.045), reoperation (p = 0.005), and postoperative urinary disorders occurred in the HD group. After stratification, the right colectomy subgroup shared similar associations with the study population. LOS did not change between groups, although readmissions were significantly lower in the 4K group (p < 0.001).

CONCLUSIONS

The 4K imaging system represents a technological advance providing better surgical outcomes, such as the minimization of intraoperative blood loss and postoperative morbidity.

Variations of the double superior mesenteric vein are not rare: An observational study using computed tomography, three-dimensional image reconstruction, and surgery

INTRODUCTION

Few studies have evaluated variations of the main trunk of the superior mesenteric vessels. Particularly, the double superior mesenteric vein (DSMV) has not been described in detail. This study aimed to establish the definition, anatomical characteristics, and underlying clinical significance of the DSMV.

MATERIALS AND METHODS

A total of 115 patients with colorectal cancer were included in this retrospective study between March 2020 and March 2022. The anatomical characteristics were analyzed using computed tomography, three-dimensional image reconstructions, and surgical videos.

RESULTS

Among the patients enrolled, 22 (19.1%) had DSMVs. The median diameters of the right and left superior mesenteric veins were similar. The superior mesenteric artery was sandwiched between the right and the left superior mesenteric veins. The left superior mesenteric vein mainly crossed the ventral side of the superior mesenteric artery (63.6%). In 1 case, the right superior mesenteric vein was mistakenly resected intraoperatively. The DSMV was classified into types I and II based on whether the right and left trunks formed a common trunk; it was further classified into subtypes a and b based on the colonic vein confluence. The proportions of type I-a, I-b, II-a, and II-b were 4.5%, 27.3%, 9.1%, and 59.1%, respectively. The middle colic veins drained into the left superior mesenteric vein in 19 cases (86.4%).

CONCLUSIONS

The DSMV is more common than previously thought. For the first time, the definition and four types of the DSMV were proposed. The presence of a DSMV should be considered during right hemicolectomies.

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.

A significant vascular variant in oncologic pancreaticoduodenectomy: the arc of Buhler

Background

The arc of Buhler (AOB), a rare anastomosis connecting the superior mesenteric artery (SMA) to the celiac trunk (CA), was found in a patient suffering from an adenocarcinoma of the pancreatic head.

Case presentation

Oncologic pancreaticoduodenectomy required resection of the AOB to achieve complete tumor removal. After an uneventful clinical course in the first days, the patient suffered a severe complication. Due to ischemia of the stomach and spleen, complete resection of the stomach, spleen, and remaining pancreas had to be performed.

Conclusions

The hemodynamic impact of this arterial variant has been discussed mainly for liver perfusion, which remained intact at all times in our case. Because of the serious obstacles mentioned above, we strongly recommend that the presence of AOB be considered in preoperative diagnosis and preservation when possible. If the AOB is likely to be ligated, stenosis of the SMA or CA should be excluded and resolved before surgery.

Right Colectomy with Extended D3 Mesenterectomy: Anterior and Posterior to the Mesenteric Vessels

BACKGROUND

In right colectomy for cancer, complete mesocolic excision and D3 lymphadenectomy each leave behind lymphatic tissue anterior and posterior to the superior mesenteric vein (SMV) and artery (SMA). In this article, we present D3 extended mesenterectomy: a surgical technique that excises the lymphatic tissue en bloc with the right colectomy specimen.

MATERIAL AND METHODS

A 3D map of the mesentery of the right colon was reconstructed from staging CT-angiogram scans. The surgical technique of right colectomy with D3 extended mesenterectomy consisted of eight steps: 1) reveal the SMV and SMA; 2) isolate the ileocolic artery; 3) isolate the middle colic artery; 4) resolve the anterior mesenteric flap; 5) specimen de-vascularization; 6) colectomy; 7) resolve the posterior mesenteric flap; and 8) anastomosis.

RESULTS

One-hundred-seventy-six patients (77 men) 66 years of age were operated upon from February 2011 to January 2017. There were 169 adenocarcinomas: 16.0% Stage I, 49.1% Stage II, 33.7% Stage III, 1.2% Stage IV. Tumor locations were 50.6% cecum, 41.5% ascending colon, 4.5% hepatic flexure, and 2.3% transverse colon. Mean operating time was 200 minutes, blood loss 273 ml, and length of stay 7.9 days. There were 9 anastomotic leakages and 15 reoperations. One patient underwent small bowel resection due to SMA tear. There was no postoperative mortality. The mean number of lymph nodes per specimen (40.9) was comprised of 27.1 in the D2 volume and 13.8 in the D3 volume. The mean number of metastatic lymph nodes was 1.2 in the D2 volume and 0.13 in D3. There were 7 patients with lymph node metastasis in D3, 2 of whom had node metastasis solely within D3.

CONCLUSION

This study shows that 1.2% of patients would have been incorrectly diagnosed as Stage II if extended D3 mesenterectomy had not been performed. Similarly, lymph node metastases would have been left behind in 4.1% of patients if extended D3 mesenterectomy had not been performed.

Preoperative anatomical road mapping reduces variability of operating time, estimated blood loss, and lymph node yield in right colectomy with extended D3 mesenterectomy for cancer

OBJECTIVE

To assess the impact of individual patient anatomy on operating time, estimated blood loss (EBL), and lymph node yield in right colectomy with extended D3 mesenterectomy, where surgeons have access to a preoperative 3-D reconstruction of the vascular anatomy of patients before surgery. Data on the impact of individual patient vascular anatomy when surgeons have an anatomical road map as a guide at surgery is still missing in the literature.

METHOD

Consecutive patients enrolled in an ongoing trial were classified into 4 groups and 2 subgroups using a 3-D vascular anatomy reconstruction derived from the staging CT. Outcome measures are operating time, EBL, vascular events, and D3 volume lymph node yield. SPSS was used for statistical analysis.

RESULTS

One hundred seventy-six (77 men) patients included. Mean operating time was 200 ± 50 min. Type 4b required significantly longer operating time (mean, 219 ± 59) compared to type 3 (mean, 188 ± 43) (p = 0.004). Vascular events occurred most often in anatomy type 4b (20.0%) and 3 (19.2%). No difference in EBL and lymph node yield was found (p = 0.102 and p = 0.803, respectively).

CONCLUSION

The use of a roadmap at surgery seems to even differences in operating time, EBL, and lymph node yield, independent of the complexity of the individual patient's central mesenteric vascular anatomy. The incidents of vascular events requiring hemostasis do not cause differences in EBL between the anatomy groups, suggesting that preoperative awareness of the anatomy is beneficial at surgery.

PHARYNGO-ILEO-COLO-ANASTOMOSIS WITH MICRO-VASCULAR BLOOD SUPPLY AUGMENTATION FOR ESOPHAGO-GASTRIC REPLACEMENT DUE TO ESOPHAGO-GASTRIC NECROSIS AFTER CAUSTIC INGESTION

BACKGROUND

Complete esophago-gastric necrosis after caustic ingestion is a challenging surgical scenario for reconstruction of the upper digestive transit.

AIM

To present a surgical technique for reconstruction of the upper digestive tract after total esophagectomy and gastrectomy due to esophageal and gastric necrosis.

METHOD

The transit was re-established by means of a pharyngo-ileo-colic interposition with microsurgical arterial and venous anastomosis for augmentation of blood supply. Colo-duodeno-anastomosis and ileo-transverse colic anastomosis were performed for complete digestive transit reconstruction.

RESULT

This procedure was applied in a case of 41 years male attempted suicide by ingesting alkali caustic liquid (concentrated sodium hydroxide). Total necrosis of the esophagus and stomach occurred, which required initially total esophago-gastrectomy, closure at the level of the crico-pharyngeal sphincter and jejunostomy for enteral feeding with a highly deteriorated quality of life . The procedure was performed later and there were no major early and late postoperative complications and normal nutritional conditions were re-stablished.

CONCLUSION

The procedure is feasible and must be managed by multidisciplinary team in order to re-establish a normal quality of life.

Retromesenteric course of the middle colic artery-challenges and pitfalls in D3 right colectomy for cancer

BACKGROUND

The middle colic artery (MCA) is of crucial importance in abdominal surgery, for laparoscopic or open right and transverse colectomies. Against this background, a high number of reports concerning anatomical variations of the MCA have been published intended to contribute to the improvement of operative techniques for the treatment of colon cancer. Despite this extensive literature, briefly reviewed in the present paper, a course of the MCA posterior to the superior mesenteric vein, called a retromesenteric trajectory, has been related to only once, to the best of our knowledge.

METHODS

A total series of 507 patients included in two prospective trials concerning laparoscopic or open right colectomy for cancer between 2011 and 2017 are reported. The investigation included preoperative or postoperative multidetector-computed tomography angiography.

RESULTS

We found four (0.79%) cases of retromesenteric MCA. They all underwent meticulous image analysis with mesenteric vessels' road mapping, detailed morphometry, and surgical validation which revealed that, apart from their course, those cases did not differ significantly from the rest of the series.

CONCLUSION

This paper therefore documents the worth-knowing behavior causing considerable confusion for the operating surgeon unaware of the abnormality and shows its concrete impact on patient-tailored surgical practice, in particular for laparoscopic D3 colectomy (including the "uncinated process first" approach).