The operative approach to cancers of the non-caecal proximal colon is generally recommended to include high ligation of the middle colic artery[3]. This can bring uncertainty about the point of anastomosis as the distal colonic component then generally receives its blood supply via the inferior mesenteric distribution. However, assessment of this [12] on an individual basis can be difficult laparoscopically especially if the mesocolon is to be respected meaning that a splenic flexure mobilization to enable a ileo-descending colon is often then performed. In this prospective clinical series, 3DVMs were used to provide a personalized map of each patient’s vasculature to make an anatomic decision regarding the fundamental vascular and the adequacy of this perfusion map was then confirmed physiologically using both marginal artery assessment and NIR-ICG. This spared added dissection of the distal transverse colon in many cases and could help moves towards intracorporeal anastomosis which can be otherwise undermined if there is uncertainty regarding adequate perfusion. While NIR-ICG is of course commonly used intraoperatively to determine perfusion sufficiency, its use for the specific purpose of indicating distal transverse colon perfusion sufficiency for anastomosis has not previously been documented to our knowledge. By this means, a generally accurate principled patient-centre plan was made regarding gastrointestinal preservation and restoration in advance of the operation. The use of 3DVMs could be applied to robotic colon surgery in which intra-corporeal anastomosis (IA) is used in ascending and transverse colon surgery [20–21]. Indeed, robotic IA has been found to be superior to extracorporeal approaches though at the expense of operative times [22]. An anatomical road map of a patient’s vasculature may ameliorate this.
3DVM have been introduced and promoted in other surgical specialties mostly for the primary purpose of tumor localization and organ sparing techniques[12–15]. In colonic cancer surgery, the predominant determinant of colonic length excision is not marginal clearance but vascular sufficiency following appropriate lymphadenectomy and the associated major vascular excision. Indeed the current trend is towards increasing this by inclusion of CME with CVL for best oncological outcomes without much consideration of functional preservation[20–23]. Personalised operative extents have previously focused on attempting to preserve the mesocolon in its entirety either by endoscopic address of the primary or sentinel node type resectional strategies[24]. The functional impacts of colonic excision are often overlooked or assumed consequent (or at least secondary) to the “necessary” oncological resection. When specifically looked for, the impact is of course significant especially early in the postoperative phase but may extend in some patients for years[25]. Minimising the length of colonic resection could offset such misery whether in the early phases of recovery or when the patient has resumed other activities of daily life including occupationally.
The concept of CME and CVL has proved practically challenging too for many with concerns regarding vascular injury greater then with standard limited mesocolic plane surgery [3, 4, 7]. 3DVM may potentially offset such concerns bringing some predictability into root mesocolic dissection especially during learning curve experiences. While not perfect, the findings of 3DVM were highly concordant with anatomical findings. Furthermore, studies regarding CME CVL could benefit from 3DVM as such methodology could bring some standardization to the operative groups rather than depending on surgeon reported findings which can be difficult especially in obese and re-operative cases.. However, it is not yet known whether such prediction could enable further limited mesocolic resection based on personalized lymphatic mappings (e.g., whether the presence of an independent right colic artery can enable a limited right meoscolic excision alone without needing middle mesocolic excision and ligation of the MCA). Such a study could be planned now that 3DVM methodology is becoming increasingly available.
This study is limited by the relatively small number of patients included in it but it does serve to communicate the base hypothesis. Especially as right side colon cancer is less common than left sided and rectal cancer, further prospective study will likely need a multicentre design which can now be planned on the basis of this initial experience. A single supplier of 3DVM was used although one that is CE marked and now widely available - other suppliers are expected to be similarly accurate but could be similarly tested (including potentially on the existing dataset) before broader clinical introduction. The additional mesenteric angiographic phase to the CT does add additional radiation dosing to the patient but this can now be viewed in context of the likely gain from such additional investigation. Similar too, the cost of outsourced 3DCT (approximately 700 euros per patient) for this study needs to be considered in the context of the overall cost per cost and the time of an operating theatre list (1000 euros per day). It is difficult to prove cost benefit from individual perioperative practice changes when it is just one element introduced to a complex system of care [26]. However, the cost of the 3DVM could be equated to two units of red blood cells at 800 euros [27], which could be requested in the event of a major vascular injury, along with other potential savings related to patient safety.