Computed tomography in suspected anastomotic leakage after colorectal surgery: evaluating mortality rates after false-negative imaging

Purposes: We sought to investigate the accuracy of abdominal CT scanning for anastomotic leakage and the effect of false-negative scans on the delay in therapeutic intervention and clinical outcome. Method: Data from a prospectively bi-institutionally maintained database of all patients who underwent elective colorectal surgery with primary anastomosis for malignant or benign disease between 2010 and 2017 were reviewed. Patients with confirmed anastomotic dehiscence at reintervention who underwent a postoperative CT scan for suspected leakage were identified and radiological reports were retrieved. Results: Seventy-six patients with anastomotic dehiscence were included in the study. American Society of Anesthesiologists score, sex, type of surgical procedure, malignancy, and type of anastomosis do not correlate with postoperative false-negative CT imaging. Postoperative false-negative CT scan, however, led to delayed reintervention (3 vs. 6 h, p = 0.023) and increased mortality (five deaths vs. no deaths, p = 0.043). Free abdominal air (p = 0.001) and extraluminal contrast extravasation (p = 0.001) were found to be predictive of accuracy in anastomotic leakage diagnosis. Conclusion: The suboptimal specificity of a postoperative CT scan in suspected anastomotic leakage after colorectal surgery can delay reintervention and increase mortality.