Hundreds of thousands of colorectal surgeries are performed every year to resect a diseased portion of the bowel or intestines. Such resection may necessitate an anastomotic connection between the remaining portions of the bowel and/or intestine. Surgical success may depend on several factors, including tissue viability around the anastomotic connection.
Bowel tissue may be highly sensitive to ischemia. Sufficient blood supply is highly important for successful healing of the anastomosis and avoidance of intestinal ischemia and necrosis. Insufficient microcirculation of the anastomotic region may lead to anastomotic leakage. Such anastomotic leakage may result in an increased length of hospital stay, significant postoperative morbidity and mortality, and tumor recurrence after resections for malignant tumors. The reported incidence of anastomotic leakage may be as high as 20%. According to some statistics, up to 50% of patients with an anastomotic leak die from this postoperative complication. Therefore, it may be appreciated that an intraoperative assessment of tissue viability and microcirculation may be highly useful to reduce the incidence of anastomotic leakage and its comorbidities.
Frequently, intestinal microcirculation and tissue viability are assessed visually—from the color of the serosal surface, presence of bowel peristalsis, pulsation, and bleeding from the marginal arteries. While there may be high confidence that visual assessment alone may properly categorize tissue perfusion as being normal or obviously impaired, some tissues may be difficult to visually categorize. A visual approach can be highly subjective and dependent on the experience level of the surgeon. It may also be deceptive. Tissues having a dark hue may have transient venous insufficiency, while the bowel may in fact be viable. Conversely, an arterial occlusion may appear normal in its early stages. In some clinical studies, visual assessment of bowel viability was only 60% accurate.
Given the uncertainty of accurate visual determination of tissue viability, a surgeon may remove a greater amount of intestine than required for tumor resection to assure healthy tissue at the anastomosis. This approach may lead to excessive intestinal resection that may result in intestinal failure. Even an inch of preserved intestinal tissue can determine a difference between a patient being able to absorb adequate oral diet or rely on permanent parenteral nutrition, a costly consequence of colorectal surgery. Therefore, a more objective, accurate, and easy-to-perform intraoperative technique to assess tissue viability may be needed.