Techniques for Diagnosing Anastomotic Leaks Intraoperatively in Colorectal Surgeries: A Review

Colorectal cancer is one of the most common surgically curable malignancies worldwide, having a good prognosis even with liver metastasis. This improved patient outcome is marred by anastomotic leaks (AL) in operated patients of colorectal cancer despite a microscopically margin-negative resection (R0). Various risk factors have been attributed to causing this. Preoperative non-modifiable factors are age, male sex, cancer cachexia, and neoadjuvant chemo-radiotherapy, and modifiable factors are comorbidities, peripheral vascular disease, anemia, and malnutrition. Intraoperative risk factors include intraoperative surgical duration, blood loss and transfusions, fluid management, oxygen saturation, surgical technique (stapled, handsewn, or compression devices), and approach (open, laparoscopic, or robotic). Postoperative factors like anemia, infection, fluid management, and blood transfusions also have an effect. With the advent of enhanced recovery after surgery (ERAS) protocols, many modifiable factors can be optimized to reduce the risk. Prevention is better than cure as the morbidity and mortality of AL are very high. There is still a need for an intraoperative technique to detect the viability of anastomotic ends to predict and prevent AL. Prompt diagnosis of an AL is the key. Many surgeons have proposed using methods like air leak tests, intraoperative endoscopy, Doppler ultrasound, and near-infrared fluorescence imaging to decrease the incidence of AL. All these methods can minimize AL, resulting in significant intraoperative alterations to surgical tactics. This narrative review covers the methods of assessing of integrity of anastomosis during the surgery, which can help prevent anastomotic leakage.