Intraoperative visualization of morphological patterns of the thoracic duct by subcutaneous inguinal injection of indocyanine green in esophagectomy for esophageal cancer.

To prevent chylothorax after esophageal cancer surgery, it is important to recognize morphological patterns of the thoracic duct intraoperatively. The present study aimed to evaluate the safety and usefulness of near-infrared (NIR) fluorescence imaging with subcutaneous inguinal injection of indocyanine green (SII-ICG) to detect the thoracic duct during thoracoscopic esophagectomy for esophageal cancer. Patients (n = 16) who underwent thoracoscopic esophagectomy in the prone position with SII-ICG at Shinshu University Hospital between June 2020 and January 2022 were enrolled in the present study and retrospectively reviewed. Immediately prior to thoracoscopic esophagectomy, we injected 0.2-0.5 mg/kg ICG into the subcutaneous tissue in the bilateral inguinal region. The identification rate of the thoracic duct was 93.8% (n = 15), and the success rate of fluorescence using SII-ICG was 87.5% (n = 14). The visible thoracic ducts had four patterns: a typical pattern in 50% (n = 8), duplication pattern in 18.8% (n = 3), branching pattern in 12.5% (n = 2), and plexiform pattern in 12.5% (n = 2). In all cases, ICG fluorescence did not disappear and was visible during the thoracic surgery. No SII-ICG-related complications were observed. Intraoperative NIR fluorescence imaging of the thoracic duct using SII-ICG is a simple and safe method with very high detection sensitivity. This method can be a powerful tool for avoiding thoracic duct injuries during esophageal cancer surgery.