This prospective study aimed to evaluate the different levels of inferior mesenteric artery ligation (high-low) and its impact on leakage and LNs retrieval. Anastomotic leakage is one of the short-term complications of high ligation, which is debated most dominantly for a long. Despite the benefits of high ligation and IMA root LNs resection which has distinct long-term oncological survival importance.
In our prospective study among 369 cases, 239 went under high ligation and 130 in the low ligation group. The presence of lymph nodes at IMA root was seen in 349(94.6%) cases where at LCA root was only in 12(20.6%) cases. The IMA cancer positive lymph nodes were in 12(3.25%) cases where LCA cancer positive LNs was just one (0.27%) case among all harvest lymph nodes. IMA root has shown a greater number of harvested lymph nodes and positive malignant lodging than the LCA deposits. Interestingly IMA root positive LNs do not have necessarily LCA root positive lymph nodes, despite all these cases were staged as T3 or greater. Additionally, the LCA, lymphatic station comes first then IMA along the path from cancer origin and metastasis. This phenomenon may indicate somehow skipping sentinel LNs in the case of colorectal surgery. In another sense, it may display a comparative picture of potent Sentinel Lymph nodes station at IMA, irrespective of the location of cancer origin colorectal surgery. Possibly it may have a direct relationship with prognosis. Besides these results of IMA and LCA, there is some other malignant para mesenteric deposition of LNs which has shown a maximum number of malignant LNs deposition among all harvested LNS. This may support the concept of possible total mesocolon-resection or TME.
Further Analysis of the relation of leakage between Hight and low ligation hasn’t shown any significant difference in our prospective study. In total 239(64.8%) cases of high ligations,18(7.5%) cases were seen with complications where just 2(0.83%) with leakage. On the other hand, 130(35.3%) cases of low ligation had 14(10.7%) cases of complication and 2(1.5%) cases of leakage which is statically higher than high ligation. This analysis demonstrates the controversial relation of leakage with high ligation and contrary to the condemned opinion of high ligation just because of leakage. However, it’s hard to conclude in this small number of cases. Thus, in our short-term prospective research, the analysis attempted to rethink our procedure from a different future approach rather than making a current judgmental decision.
In our previous meta-analysis, we found high ligation and IMA root LNs clearance carries a beneficial oncological outcome whenever it has lymphatic metastasis.[6] Collectively, these outcomes support high ligation with IMA LNs resection and should be preferably suitable for the prognostic dilemma of the oncological patient instead of low ligation concerning anastomotic leakage.
Currently, In the early stage of cancer with low risk of IMA positive or in the advanced stage with a high risk of IMA lymphatic metastasis, and application of high or low ligation solely depends upon the practitioner. In both cases, the surgeon’s opinion varies. The controversy over the choice of high or low ligation of IMA has focused on the anastomotic leakage and oncological outcomes, these two have their own aspects.[7] High ligation ensures the IMA lymphatic clearance even though debated for increasing the risk of anastomotic leakage as it jeopardized the blood supply of LCA.[8, 9] Low ligation preserves the LCA and ensured blood supply of the marginal artery while leading to incomplete lymphatic resection of IMA.[10] As far concerning anastomosis leakage, A basic study recommends sigmoid colon is only not suitable for anastomosis due to its natural course of insufficient vascular supply but the marginal artery delivers sufficient vascular supply to the transverse and descending colon. Thus, the sigmoid colon is sacrificed and there should be no uncertainty in performing a high ligation.[2]Therefore, the prognostic significance of IMA lymphatic clearance dominates the choice of surgeons over the risk of anastomotic leakage which is a short-term outcome.
The origin of IMA is the third station of lymphatic drainage from the sigmoid and rectum. The incidence of IMA lymph node metastasis has been reported in fewer studies. It is associated predominantly with histopathological tumor staging along the course of IMA. Chen et al[11] reported, the IMA lymph node metastases were 0% (pT1 ), 1.0 %(pT2), 2.6% (pT3) and 4.3% (pT4) by of TNM staging. Korematsu et al [12]study showed the 8·3 percent (99 of 1188) incidence of metastasis to the origin of LCA. Nodal metastasis occurred more commonly in patients with pT3 and pT4 lower rectal cancer. The incidences of metastasis are at the root of IMA about 1·7 percent (20 of 1188). This represented how residual metastatic nodes could usually have been forgotten in low ligation if the IMA root not been cleared. Some surgeons still claim no evidence that high ligation may increase the prognosis and prefer to apply low ligation even in advanced cancer cases. However, our findings do not support low ligation without clearing IMA root LNs in advanced or suspicious cases metastasis cases.
Reviewing articles on anastomosis leakage, Some studies have concluded, high ligation has no indisputable proof of increased survival, Although the usage of IMA high ligation plays an important role in the improvement of lymph node retrieval, the precision of tumor staging, and to avoid tension in low pelvic anastomoses.[2, 7, 10] Dworkin et al [13]reported the high ligation results 41%-86% decrease in sigmoid blood supply around Five days. The sacrifice of LCA leads to Poor blood supply and it is one of the most important risk factors for anastomotic leakage. However, an RCT has shown the level of IMA ligation in patients with rectal cancer didn't show any difference in anastomotic leakage.[14] In an addition, The local recurrence of cancer, hand-sewn versus stapled anastomoses, age, Intraoperative blood pressure, nutritional status of the patient including other factors subsequently leads to anastomotic leakage and can reduce survival[15–17]. Therefore, the accessible studies on the anatomical concern of leakage are controversial and somehow favor the high ligation from the oncological perspective. In fact, the supply of blood could be satisfied once if the colonic marginal arch was well maintained. Furthermore, a meta-analysis showed high ligation reduced 13% of 5-year OS compared to low ligation.[11]
Regardless of the above major related issues, available research for the anatomical consideration preferred the high ligation. A significant benefit of the high ligation is definitely by the resection of the IMA at its origin, which allows it to gain extra length and facilitate tension-free anastomosis.[18] Ghavami et al [19] reported, the precise mobilization of the splenic flexure significantly reduces, the anastomotic tension and in most cases allows the preservation of LCA. However, practically it's very difficult to achieve the additional length in low Colo-anal anastomosis or even in colonic J-pouch surgery unless high ligation of IMA. LCA is comparatively shorter and less feasible to the low Colo-anal anastomosis. The advantages of additional length usually support anastomosis using the descending colon rather than the sigmoid when performing an anastomosis. Not just the sigmoid colon generates fairly high pressure but additionally because it could consequently lead to relatively poor function and more importantly, the marginal artery may be minimal or absent in the sigmoid which is prone to ischemia if used for anastomosis. Hence in colonic implant anastomosis will almost always need a high ligation. However, this is for technical rather than cancer-specific reasons which also does support high ligation. [20]
The modern aspect of surgical evolution to visualize real-time lymphatic channels and vasculatures plays a great role in the prevention of anastomotic leakage as well as a high volume of LNs retrieval. The technology as the ICG Imaging System provides a real-time intraoperative evaluation of vascular perfusion. It's the best tool for Intraoperative evaluation of bowel anastomosis perfusion. Hypoperfusion can be well-recognized which is the main reason behind anastomotic leakage. It is normally subjectively approximated throughout the surgery by the surgeon based on the color or pulsation of the bowel in addition to a visible assessment of pulsatile bleeding from the edge of the bowel for use for anastomosis.[21–23] In another hand, ICG can also ensure an imaging approach for the discovery of tiny LNS, its channels, precise hepatic Mets, and peritoneal metastatic deposits.it may enable much better staging plus more comprehensive surgical resection of lymph nodes across the major artery and division of vessels which may potentially help to prevent compromise blood vessels and consequently ischemia. This is having a potential prognostic benefit for patients.[24–26] This technique may help even for clearing IMA root without compromising the left colic artery with complete mesocolon resection.