Efficacy of en bloc ligation of the thoracic duct: descriptive study in 14 dogs.

Abstract

OBJECTIVE: To assess whether en bloc ligation of all caudal mediastinal tissue between the aorta and thoracic vertebrae will occlude all branches of the thoracic duct. STUDY DESIGN: Descriptive study. ANIMALS: Canine cadavers (n=15). METHODS: The cisterna chyli was approached through a right paralumbar abdominal incision and cannulated. A right 10th intercostal thoracotomy was performed and the tissue of the caudal mediastinum dorsal to the aorta and ventral to the thoracic vertebrae was ligated. Radio-opaque contrast material was injected into the cisterna chyli during fluoroscopic imaging of the thorax and cranial abdomen. Still images were obtained before and after contrast injection and a subtraction image produced. Gray values were measured from these images, cranial and caudal to the ligature site. RESULTS: Cannulation of the cisterna chyli in 1 cadaver was impossible and it was, therefore, excluded. In 13 (93%) cadavers contrast material did not pass cranial to the ligature site. In 1 cadaver, an intact thoracic duct was identified on lymphangiography outside the en bloc ligation. CONCLUSION: En bloc ligation of the caudal mediastinal tissue dorsal to the aorta was successful in preventing opacification with contrast material of all branches of the thoracic duct in 93% of cadavers. CLINICAL RELEVANCE: En bloc ligation is successful in 93% of cadavers and reduces the operative time compared with techniques requiring some type of mesenteric lymphangiography to aid identification of the thoracic duct.