Minimally invasive complete mesocolic excision for right colon cancer

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.

Prevention of ureteral injury during laparoscopic colorectal cancer surgery with horseshoe kidney using fluorescent ureteral catheters: a case report

BACKGROUND

Horseshoe kidney is one of the most common congenital renal fusion anomalies and is characterized by abnormalities in the position, rotation, vascular supply, and ureteral anatomy of the kidney. When performing surgery for colorectal cancer in patients with horseshoe kidneys, anatomical identification is important to avoid organ injuries. Several reports on surgery for colorectal cancer with horseshoe kidneys have described the usefulness of three-dimensional (3D) computed tomography (CT) angiography for detecting abnormalities in vascular supply. However, few reports have focused on the prevention of ureteral injury in surgery for colorectal cancer with horseshoe kidney, despite abnormalities in the ureteral anatomy. Here, we report a case in which laparoscopic sigmoid colon resection for sigmoid colon cancer with a horseshoe kidney was safely performed using fluorescent ureteral catheters.

CASE PRESENTATION

A 60-year-old Japanese man presented to our hospital testing positive for fecal occult blood. Colonoscopy revealed sigmoid colon cancer, and CT confirmed a horseshoe kidney. The 3D-CT angiography showed aberrant renal arteries from the aorta and right common iliac artery, and the left ureter passed across the front of the renal isthmus. A fluorescent ureteral catheter was placed in the left ureter before the surgery to prevent ureteral injury. Laparoscopic sigmoid colon resection with D3 lymph node dissection was performed. The fluorescent ureteral catheter enabled the identification of the left ureter that passed across the front of the renal isthmus and the safe mobilization of the descending and sigmoid colon from the retroperitoneum. The operative time was 214 min, with intraoperative bleeding of 25 mL. The patient's postoperative course was good: no complications arose and she was discharged on the seventh postoperative day.

CONCLUSION

In patients with horseshoe kidney, the use of fluorescent ureteral catheters and 3D-CT angiography enables safer laparoscopic surgery for colorectal cancer. We recommend the placement of fluorescent ureteral catheters in such surgeries to prevent ureteral injury.

Operative and Pathological Factors in Right-Sided Colon Cancers: How Can We Improve the Outcomes?

INTRODUCTION

Though the tumour-node-metastasis staging classification is the standard approach to risk stratification in patients with colorectal cancer, several other important variables including the presence of extramural venous invasion (EMVI), the tumour mismatch repair status, as well as surgical technique and its influence on lymph node yield all have an impact on long-term survival. This study aims to review both the impact of the type of operation on lymph node yield: complete mesocolic excision (CME) versus right hemicolectomy, and the impact of EMVI and microsatellite instability in predicting overall survival in patients undergoing a right hemicolectomy for colon cancer.

METHODS

Data of all patients who underwent an elective or emergency right hemicolectomy with curative intent for colon cancer between January 2013 and June 2022 (inclusive) was collected for this single-centre retrospective study. Kaplan-Meier survival curves were calculated using the Statistical Package for the Social Sciences (SPSS version 28, IBM Corp., Armonk, NY) software, and the log-rank (Mantel-Cox) test was used to compare survival distribution between different groups.

RESULTS

A total of 421 patients underwent a right hemicolectomy for colon cancer with curative intent during the study period. EMVI was present in 173 (41%) tumours. Survival analysis showed significantly reduced cancer-related survival in patients with EMVI-positive tumours (p < 0.001), with five-year survival rates of 70% in EMVI-positive groups versus 96% in EMVI-negative groups. Subgroup analysis showed a significant difference in survival between node-positive and node-negative tumours in cancers found to have EMVI (p < 0.001). Mean lymph node yield was significantly higher in the CME group versus the standard right hemicolectomy group (p < 0.001). We found no significant difference in survival between patients with microsatellite instability-high (MSI-H) tumours and microsatellite stable (MSS) tumours (p = 0.432).

CONCLUSION

Consideration of tumour biology and adopting the optimum surgical technique are factors that may influence long-term survival in patients with colorectal cancer. Extramural venous invasion is an important prognostic indicator of adverse outcomes in patients with right-sided colon cancer. Our study demonstrates a reduction in survival in patients with EMVI-positive tumours when undertaking subgroup analysis by the presence or absence of nodal disease. Further research needs to be undertaken to compare the relative efficacy of neoadjuvant versus adjuvant chemotherapy in right-sided cancers known to be EMVI-positive as some patients will fail to have adjuvant chemotherapy due to postoperative complications, thereby delaying recovery and missing the optimum window for treatment.