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

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.