The yet-to-be discovered mechanism of anastomotic leakage — Comment to: Lack of evidence for tissue hypoxia as a contributing factor in anastomotic leak following colon anastomosis and segmental devascularization in rats

Dear Editor:
We read the paper from Shakhsheer et al. with great interests, which reported that tissue hypoxia was not a distinctive feature of anastomotic leak.
Our previous study on the same topic have reported similar findings that anastomotic healing was not associated with intraoperative anastomotic perfusion. We believe that these experimental data are of interests and importance not only to the translational research field but also to the clinical surgeons, especially when many intraoperative perfusion measurement devices have been introduced to clinical practice nowadays and colonic cutting-edges are often altered based on the test results. Given the fact that no solid clinical evidence is yet available to demonstrate whether those interventions do prevent colorectal anastomotic leaks or not, these experimental data undoubtedly raise the question of the "yet-to-be discovered mechanism" of how intraoperative tissue hypoxia influence colonic anastomotic healing.
However, we also would like to raise our concerns regarding whether the animal model used in this study is appropriate to demonstrate the author’s original hypothesis. This is because many previous studies have reported that segmental devascularization may not have significant influences that are comparable to clinical outcomes.We therefore chose to ligate the whole ileocolic artery to assure colon hypoxia in our previous study investigating the effectiveness of hyperbaric oxygen therapy in ischemic colonic anastomosis, and significantly higher mortality rate and leak rate were observed in the ischemic group in that study. Those data suggest that such model may be of better representativeness and should be considered as a candidate in the future translational studies focusing on ischemic colorectal anastomosis.
We would like to congratulate the authors for their detailed analysis and investigation of the undiscovered mechanism. Acknowledging that the solid evidence regarding clinical effectiveness of intraoperative perfusion measurement are still awaited, we should be highly aware of the authors’ results. However, one cannot overemphasize the importance of blood supply in colorectal anastomosis. More research is still of request; more patients will benefit from the research in the future.