Developing a phantom for simulating robotic-assisted complete mesocolic excision using 3D printing and medical imaging.

BACKGROUND: Robotic-assisted complete mesocolic excision is an advanced procedure mainly because of the great variability in anatomy. Phantoms can be used for simulation-based training and assessment of competency when learning new surgical procedures. However, no phantoms for robotic complete mesocolic excision have previously been described. This study aimed to develop an anatomically true-to-life phantom, which can be used for training with a robotic system situated in the clinical setting and can be used for the assessment of surgical competency. METHODS: Established pathology and surgical assessment tools for complete mesocolic excision and specimens were used for the phantom development. Each assessment item was translated into an engineering development task and evaluated for relevance. Anatomical realism was obtained by extracting relevant organs from preoperative patient scans and 3D printing casting moulds for each organ. Each element of the phantom was evaluated by two experienced complete mesocolic excision surgeons without influencing each other's answers and their feedback was used in an iterative process of prototype development and testing. RESULTS: It was possible to integrate 35 out of 48 procedure-specific items from the surgical assessment tool and all elements from the pathological evaluation tool. By adding fluorophores to the mesocolic tissue, we developed an easy way to assess the integrity of the mesocolon using ultraviolet light. The phantom was built using silicone, is easy to store, and can be used in robotic systems designated for patient procedures as it does not contain animal-derived parts. CONCLUSIONS: The newly developed phantom could be used for training and competency assessment for robotic-assisted complete mesocolic excision surgery in a simulated setting.

Radiological characteristics and diagnostic clues for persistent descending mesocolon in patients with rectal cancer.

PURPOSE: Persistent descending mesocolon (PDM) increases the difficulty and colonic ischemia in the surgery of colorectal cancer, but the preoperative diagnostic criteria have not yet been clearly demonstrated. This study explored the MR imaging features and diagnostic criteria of PDM to improve the preoperative diagnostic rate. METHODS: The clinical data of 54 patients with PDM and 270 patients without PDM who underwent rectal surgery at the Department of Colorectal Surgery, Fujian Medical University Union Hospital, from March 2018 to December 2022 were analyzed, retrospectively. The radiological parameters of PDM from MRI were analyzed. RESULTS: On MRI T2WI axial image, the left edge of the abdominal aorta was defined as the reference line. The shortest vertical distance between the right edge of the descending colon and this line (dN) and the maximum transverse diameter of the peritoneal cavity (dA) at the same level and the maximum vertical distance between the right edge of the descending colon and this line (dW) were measured. There were significant statistical differences in dN, dW, dN/dW, and dN/dA between the PDM group and the non-PDM group. dN, dN/dW, and dN/dA have high diagnostic performance for the PDM. dN < 4.16 cm, dN/dW < 0.52, and dN/dA < 0.15 can all be used as clues to diagnose PDM. CONCLUSIONS: We propose a feasible set of diagnostic criteria for PDM based on abdominal MRI, which can quickly and accurately diagnose PDM, and provide some reference for preoperative planning and surgical decision-making.

Role of preoperative CT angiography with multimodality imaging reconstruction to perform laparoscopic Complete Mesocolic Excision (CME) and Central Vascular Ligation (CVL) in right-sided colon cancer: Is it really useful? A prospective clinical study.

BACKGROUND: The concept of complete mesocolic excision (CME) and central vascular ligation (CVL) in right colonic resections appears to improve the oncological outcomes. The highest rate of complications reported in the literature in patients undergoing CME is related to difficult surgical manuevers and intraoperative bleeding due to the central vascular dissection. METHODS: We used preoperative findings obtained with the CT angiography, multiplanar reformation (MPR), maximum intesity projection (MIP) and 3D volume rendering (VR) technique to verify if this preoperative radiological assessment had significant benefits regarding the difficulty of dissection of the embryological planes, the identification of vascular structures and central lymph nodes with reduction in mean operative time, intraoperative complications and better short-term outcomes versus standard contrast enhanced CT scan. We also have administered a questionnaire to investigate the subjective responses on the degree of difficulty of the surgical procedure both by the surgical team expert in CME and by a group of young surgeons. RESULTS: Statistical analysis showed that overall operative time was significant shorter in patients underwent to radiological assessment (224,5 min; range 160-300 versus 252,6 min; range 200-340; p-value 0.023) with a significant lower rate of intraoperative complication (2.7% versus 4.2%; p-value 0.043). No differences were reported with respect to blood loss, conversion rate, anastomotic leakage or other surgical results. Analysis of the questionnaire underlined a progressive awareness of the correspondence between the radiological imaging and the surgical field. CONCLUSION: The possibility of identifying the characteristics and course of the vascular structures along the axis of the superior mesenteric vessels certainly increases the surgeon's knowledge of the operating field, making him more confident with surgical maneuvers and significantly reducing the duration of the operating time and intraoperative complications.

Acute abdominal pain due to sigmoid volvulus with persistent descending mesocolon: a case report.

BACKGROUND: Persistent descending mesocolon, an anomaly of fixation of the mesentery of the descending colon, can sometimes cause complications such as intestinal obstruction and intussusception. We present the first reported case of sigmoid volvulus with persistent descending mesocolon. CASE PRESENTATION: An 82-year-old Japanese man had intermittent lower abdominal pain. Abdominal computed tomography showed dilation and a shift to the right side of the sigmoid colon, but no findings of volvulus. The next day, he presented continuous lower abdominal pain with bloody stool. A second abdominal computed tomography showed strangulation and dilation of the sigmoid colon, with shift from the right side of the abdominal cavity to the pelvic space. This suggested the descending colon was running to the medial side with sigmoid volvulus. Emergency surgery was performed for volvulus with persistent descending mesocolon. Operative findings revealed dilation of the sigmoid colon with a partial poorly colored region and strangulation that caused volvulus. After releasing the strangulation of the sigmoid colon, the descending colon was revealed to be running more to the medial side, with adherence to small intestinal mesentery. There was no Toldt's fusion fascia at the descending colon. Persistent descending mesocolon was therefore diagnosed due to abnormality of fixation of the descending colon. The sigmoid colon, including the poorly colored region, was resected and reconstructed, while the inferior mesenteric and left colonic arteries were preserved because of the complexity of the vascular system running around the descending and sigmoid colon due to the shortened mesentery. These findings were pathologically compatible with circulatory compromise and intestinal degeneration due to sigmoid volvulus. The patient had no complications after discharge, including in relation to defecation. CONCLUSION: Persistent descending mesocolon can occasionally cause acute abdominal symptoms requiring immediate treatment. A computed tomography finding of the descending colon running more to the medial side than ordinary cases can aid diagnosis of persistent descending mesocolon.

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.

Radiological features and clinical implications of persistent congenital mesocolon: Pictorial essay.

In human foetus, the mesenteries that carry vascular and neural supply to the alimentary tube play an important role in its development and anatomical location within the abdominal cavity. The mesenteric attachments of the small bowel, transverse colon and sigmoid allow them to be intraperitoneally mobile structures. In contrast, the ascending and descending colon lose their mesenteries by fusion with the parietal peritoneum and become fixed in retroperitoneal position along the posterolateral walls of the abdomen. In about 2%-4% of individuals, this process is disrupted, causing a complete or partial retention of their congenital mesocolon. The ascending or descending colon will then remain intraperitoneally mobile, affecting the normal visceral anatomy and causing potential complications. This article reviews the spectrum of radiological manifestations and clinical consequences of these anomalies.

Primary extraskeletal osteosarcoma of sigmoid mesocolon: a case report and a review of the literature.

BACKGROUND: Extraskeletal osteosarcoma (ESOS) is a rare mesenchymal malignancy, which produces osteoid, bone, or chondroid material and is located in the soft tissue without attachment to skeletal bones and periosteum. One of the things that ESOS originated from mesentery is much rarer. CASE PRESENTATION: A 75-year female had a history of pain in the left lower abdomen for more than 4 months. Abdominal computerized tomography (CT) and magnetic resonance imaging revealed a large, irregular, and solid-cystic mass (largest diameter was 11.5 cm). The tumor was radically removed during an open operation. It was composed of abundant osteoid and polyhedral-shaped tumor cells with high atypia and high mitotic activity microscopically. The final pathological diagnosis was osteoblastic osteosarcoma, arising from the sigmoid mesocolon with negative margins. A 9-month follow-up by CT exhibited signs of peritoneal metastasis. CONCLUSIONS: Given the rarity of cases of mesenteric ESOS, diagnosis mainly depended on pathology findings or should be taken into consideration when the mesenteric mass was found. Its most effective treatment had not been determined, with surgical excision being generally accepted. Ensuring negative surgical margins may be an important factor affecting prognosis.

The use of ultrasound in central vascular ligation during laparoscopic right-sided colon cancer surgery: technical notes.

BACKGROUND: Complete mesocolic excision (CME) with central vascular ligation (CVL) requires the surgeon to sharply dissect the mesocolon and approach the superior mesenteric artery (SMA) and superior mesenteric vein (SMV) for ligation of the supplying vessels relating to right-sided colon cancer at their origin. Even with preoperative images, it can still be challenging to identify these structures during laparoscopic surgery because of various intraoperative conditions. The aim of this study was to assess the efficacy of intraoperative ultrasound (IOUS) for identification of blood vessels during right-sided colon cancer surgery. METHODS: We performed IOUS on 19 patients diagnosed with right-sided colon cancer at our institution, in January-October 2020. Preoperatively, a three-dimensional computed tomography (3D-CT) angiogram was obtained for the majority of patients to visualize the SMA, SMV, and their respective branches. The running position of the ileocolic artery (ICA) and right colic artery (RCA) related to the SMV and the presence of the middle colic artery were identified and compared using preoperative 3D-CT, IOUS, and intraoperative findings. RESULTS: Nineteen patients [seven men and 12 women with a mean age of 73.9 ± 8.4 years (range 58-82 years)] were studied, including some with a body mass index of > 30 kg/m2, locally advanced cancer, and severe adhesion. There were IOUSs that detected the SMA, SMV, and their tributaries in all patients. The positional relationships between the SMV and the ICA and RCA revealed by IOUS were consistent with the preoperative and intraoperative findings. CONCLUSION: IOUS is a safe, feasible, and reproducible technique that can assist in detecting the branching of the SMA and SMV during CME with CVL in laparoscopic right-sided colon cancer surgery, regardless of individual conditions.

Routine CT evaluation of central vascular ligation in patients undergoing complete mesocolic excision for sigmoid colon cancer.

AIM: Objective and reproducible quality measures of complete mesocolic excision (CME) for colon cancer are not currently available. This study aimed to measure the inferior mesenteric stump length following CME for sigmoid colon cancer and explore surgical, pathological and oncological outcomes in patients with a stump length of <10 mm vs. ≥10 mm. METHOD: This was a single-centre, retrospective cohort study including patients undergoing minimally invasive surgery for sigmoid colon cancer between May 2013 and May 2015. Follow-up CT scans were reviewed, and a vascular stump cut-off of <10 mm for adequate central ligation of the inferior mesenteric artery was applied. Differences in perioperative, histopathological and oncological outcome parameters (overall, disease-free and recurrence-free survival) were explored between <10 mm vs. ≥10 mm groups. RESULTS: A total of 127 patients (43% female) with a median age of 68 years were included. The median follow-up time was 68 months. CT measurements showed good interrater agreement (90% absolute agreement) and reliability among raters (kappa = 0.77, 95% CI 0.53-1.00, p < 0.001). A stump length ≥10 mm was associated with longer operating time (150 vs. 180 min, p = 0.021), intramesocolic resection (p = 0.008), and a shorter distance from the bowel wall to vascular tie (120 vs. 102 mm, p = 0.005). CONCLUSION: An arterial stump length ≥10 mm in sigmoid resection for colon cancer was associated with key clinical quality measures. Measurement of arterial stump length using routine follow-up CT may serve as a quality indicator of vascular ligation in CME surgery.

Minimally invasive surgery for colorectal cancer with persistent descending mesocolon: radiological findings and short-term outcomes.

BACKGROUND: Persistent descending mesocolon (PDM) is typically asymptomatic. However, features such as adhesion and variations in vessel anatomy could affect the surgical techniques for colorectal cancer (CRC). This study aimed to investigate the frequency and radiological features of PDM. Short-term outcomes after conventional laparoscopic surgery (CLS) for CRC with PDM were also investigated to assess the feasibility of CLS and identify strategies for minimally invasive surgery (MIS) in CRC with PDM. METHODS: Patients who underwent MIS, including CLS and robot-assisted laparoscopic surgery (RALS), for left-sided CRC between April 2016 and June 2019, were investigated. PDM was defined as the existence of the right border of the descending colon inside the right border of the left kidney based on preoperative computed tomography findings. RESULTS: Radiological findings of 837 patients were examined, and PDM was found in 19 (2.3%) patients. Radiality of the inferior mesenteric artery (IMA) was found in 5 of 19 (26.3%) PDM cases, which was significantly higher than that in non-PDM cases. The median lengths between the IMA and inferior mesenteric vein (IMV) and between the IMV and descending colon in PDM cases were 14.8 mm and 17.2 mm, respectively, which were significantly shorter than those in non-PDM cases. Short-term outcomes were evaluated only in CLS cases since the rate of hybrid surgery among RALS cases differed between non-PDM and PDM cases (0% vs. 44.4%), which would affect the surgical outcomes. The short-term outcomes in 447 CLS cases were similar between PDM and non-PDM cases. The frequency of extracorporeal division of the left colic artery (LCA) and IMV was significantly higher in PDM than in non-PDM cases (70.0% vs. 5.7%). CONCLUSIONS: This radiological definition of PDM was feasible. CLS for left-sided CRC with PDM was feasible, and dividing the LCA and IMV extracorporeally would be vital for safe surgery.

Navigating the mesentery: Part III. Unusual anatomy of ileocolic vessels.

AIM: The ileocolic vessels are important landmarks in advanced surgery of the midgut. The aim of the present study is to present variations of ileocolic vessels relevant to complete mesocolic excision with D3 lymphadenectomy of the right colon, within their detailed and precise morphometric framework and deriving from a large and consistent series of operated patients. METHODS: An ongoing prospective trial 'Safe Radical D3 Right Hemicolectomy for Cancer through Preoperative Biphasic Multidetector Computed Tomography Angiography' was reviewed. The imaging datasets underwent manual segmentation and 3D reconstruction, and the results were validated at surgery. A total of 356 patients were included in the study. RESULTS: A cross-section of the series revealed five cases (1.4%) with variation of ileocolic vessels relevant to complete mesocolic excision or D3 extended mesenterectomy. There were two cases with absence of a true classical ileocolic artery, two cases with absence of a true classical ileocolic vein, and one case of precocious bifurcation of the ileocolic artery, left to the superior mesenteric vein. The entire D3 area in all the cases was thoroughly documented and analysed from the morphometric point of view (calibres, lengths of vessels, crossing patterns). CONCLUSION: The preoperative visualization of a patient's individual 3D anatomy is a powerful tool in identifying the variations whose negligence could have dire consequences in complete mesocolic excision of the right colon.

Superior Mesenteric Vein-First Approach for Robotic Salvage Surgery with Indocyanine Green Fluorescence Angiography.

INTRODUCTION: Inadequate lymphadenectomy is still a major concern in colon cancer surgery. The superior mesenteric vein (SMV)-first approach is a novel, standardized, reproducible method for robotic complete mesocolic excision surgery. OBJECTIVE: Our aim was to present the application of the SMV-first approach principles to facilitate robotic salvage surgery for recurrent disease within the mesocolon. METHODS: A 78-year-old female presented with a malignant lymph node deposit within residual right mesocolonic tissue, approximately 3 months following a laparoscopic right hemicolectomy for colon cancer. Dissection was initiated with a transverse curvilinear incision along the inferior aspect of the remaining ileocolic pedicle to identify the SMV. Dissection continued along the ventral aspect of the SMV in a cephalad direction to identify and expose the middle colic vessels at their origin. The use of idocyanine green (ICG) confirmed the vascular anatomy, demonstrating the right branch of the middle colic artery traversing the malignant deposit in the residual mesocolon. Following ligation at the origin of the right branch of the middle colic and ileocolic vessels, the retro-mesocolic plane dissection was completed to excise the malignant deposit and the residual mesocolon. RESULTS: The patient was discharged home the following day. The pathological specimen confirmed metastatic poorly differentiated adenocarcinoma in one of nine lymph nodes, and the vascular pedicle resection margin was negative for tumor. CONCLUSION: Following the SMV-first approach principles provides a safe plane for dissection, and, in conjunction with ICG, facilitates the delineation of the vascular anatomy, to enable robotic salvage surgery to be performed.1-3.

The sigmoid take-off: An anatomical imaging definition of the rectum validated on specimen analysis.

BACKGROUND: A pre-operative imaging landmark to define the rectum would optimise clinical care of rectal cancer patients and research efforts to improve outcomes. The sigmoid take-off has been suggested as an imaging landmark for the rectosigmoid junction (RSJ). This study aimed to investigate whether this imaging definition of the rectum was validated by surgical specimen analysis. METHODS: This prospective study recruited 20 patients undergoing surgery and undertook radiological and pathological analysis of their rectal specimens. The radiological landmark of the sigmoid take-off was identified on pre-operative magnetic resonance imaging (MRI), and the distance to the anterior peritoneal reflection was measured by two readers. After surgery, the distance from the beginning of the sigmoid mesocolon to the anterior peritoneal reflection to the beginning of the sigmoid mesocolon on the specimen was measured, and compared to the distance on MRI using Pearson's Correlation Coefficient and Bland-Altman plots. RESULTS: In 17 patients, the mean distance from the anterior peritoneal reflection to the RSJ on MRI was 20.3 mm and 23.1 mm for two readers, and on pathology was 20.6 mm. The mean differences between MRI and specimen measurements were -0.31 mm (-2.83 to 2.20 mm), and 2.51 mm (95% confidence interval -0.31 to 5.33 mm) for each reader, with correlation coefficients of 0.77 and 0.81. CONCLUSION: The sigmoid take-off has been validated on specimen analysis to be an imaging landmark that defines the termination of the rectum. This anatomical landmark can be used to classify tumours and guide treatment and research of sigmoid colon and rectal cancer.

Ex vivo specimen MRI and pathology confirm a rectosigmoid mesenteric waist at the junction of the mesorectum and mesocolon.

AIM: Continuity of the mesentery has recently been established and may provide an anatomical basis for optimal colorectal resectional surgery. Preliminary data from operative specimen measurements suggest there is a tapering in the mesentery of the distal sigmoid. A mesenteric waist in this area may be a risk factor for local recurrence of colorectal cancer. This study aimed to investigate the anatomical characteristics of the mesentery at the colorectal junction. METHOD: In this cross-sectional study, 20 patients were recruited. After planned colorectal resection, the surgical specimens were scanned in a MRI system and subsequently dissected and photographed as per national pathology guidelines. Mesenteric surface area and linear measurements were compared between MRI and pathology to establish the presence and location of a mesenteric waist. RESULTS: Specimen analysis confirmed that a narrowing in the mesenteric surface area was consistently apparent at the rectosigmoid junction. Above the anterior peritoneal reflection, the surface area and posterior distance of the mesentery of the upper rectum initially decreased before increasing as the mesentery of the sigmoid colon. These anatomical properties created the appearance of a mesenteric 'waist' at the rectosigmoid junction. Using the anterior reflection as a reference landmark, the rectosigmoid waist occurred at a mean height of 23.6 and 21.7 mm on MRI and pathology, respectively. CONCLUSION: A rectosigmoid waist occurs at the junction of the mesorectum and mesocolon, and is a mesenteric landmark for the rectum that is present on both radiology and pathology.

Clinical Value of Multi-Slice Spiral CT Angiography, Colon Imaging, and Image Fusion in the Preoperative Evaluation of Laparoscopic Complete Mesocolic Excision for Right Colon Cancer: a Prospective Randomized Trial.

PURPOSE: To evaluate the clinical value of CT angiography (CTA), CT colonography (CTC), and image fusion in the preoperative evaluation of laparoscopic complete mesocolic excision (CME) for right colon cancer. METHODS: In this randomized prospective study, 80 patients undergoing laparoscopic CME for right colon cancer were randomly divided into two groups: image fusion [the original images were reconstructed using CTA and CTC, then fused into three-dimensional images of the blood vessels and intestines (n = 40)] and control (without CTA and CTC reconstruction before surgery). All patients underwent plain and enhanced abdominal CT before surgery. RESULTS: In the image fusion group, the gastrocolic trunk of Henle was present in 33 cases, and its branches originated from the colon vein, right gastroepiploic vein, and superior anterior pancreaticoduodenal vein. Among these patients, 5 exhibited the right gastroepiploic vein and superior anterior pancreaticoduodenal vein; 21 exhibited a gastrointestinal trunk consisting of 2 or 3 branches of the right gastroepiploic vein, right colon vein, and middle colon vein; and 7 exhibited 3 or 4 gastro-pancreatic and colon trunks consisting of the right colon vein, middle colon vein, right gastroepiploic vein, and superior anterior pancreaticoduodenal vein. The correspondence with the anatomy actually observed during surgery was 100%. Compared with the conventional CT group, the duration of the operation in the image fusion group was shorter, with reduced intraoperative bleeding, and more lymph node dissection. There were no significant differences in the incidence of complications and length of hospital stay between the two groups (p > 0.05). CONCLUSIONS: For laparoscopic CME for right colon cancer, CTA, CTC, and image fusion were effective preoperative evaluation methods, which avoided some unseen dangers in the operation process and led to better therapeutic outcomes.

Complete mesocolic excision and central vascular ligation for right colon cancer: an introduction for abdominal radiologists.

OBJECTIVE: To provide an overview of complete mesocolic excision, along with a review of the relevant vascular anatomy and locoregional staging concepts, for abdominal radiologists. RESULTS: Complete mesocolic excision (CME) with central vascular ligation (CVL) for colon cancer has emerged as a technique that has growing interest in surgical oncology. Specific anatomic considerations and patterns of nodal spread have thus gained clinical significance, and should be familiar to abdominal radiologists. This review article provides an overview of CME with CVL, and discusses some of the important anatomic considerations in patients with colon cancer that are relevant to radiologists. CONCLUSION: Knowledge of CME with CVL and the relevant anatomic and staging considerations is important for abdominal radiologists, as this surgical technique becomes increasingly utilized.

A rare solitary fibrous tumour of the ascending mesocolon: a case report.

Solitary fibrous tumours are rare mesenchymal tumours which mostly arise from pleura. Such tumours occurring in the mesocolon are exceptionally rare. A 35-year-old man was referred to the general surgery department with a painless and nonpalpable mass in the right quadrant of the abdomen, which was detected incidentally on magnetic resonance imaging. The patient had no symptoms and the physical examination revealed no findings. The patient underwent surgical resection and excisional biopsy results revealed an intra-abdominal solitary fibrous tumour originating from the ascending mesocolon. He was discharged two days after surgery and remained disease-free at the end of the two-month follow-up period.