Transdiaphragmatic Approach to Attenuate Porto-Azygos Shunts Inserting in the Thorax

To describe the surgical technique and document the application of a transdiaphragmatic approach to attenuate porto-azygos shunts inserting in the thoracic section of the azygos vein.

Cadaveric study and prospective case series.

Canine cadavers (n=6) and client-owned dogs with porto-azygos shunts inserting in the thoracic section of the azygos vein (n=9).

In the cadavers, the azygos vein was filled with aqueous latex. Landmarks were established for creating a safe transdiaphragmatic approach to the caudal intrathoracic portion of the azygos vein. In the clinical cases, porto-azygos communication was diagnosed by trans-splenic portal scintigraphy. All shunts were attenuated close to their insertion site via ventral midline celiotomy and a transdiaphragmatic approach to the shunt. Perioperative complications were recorded.

A 3-5 cm incision, 0.5-1 cm ventral and lateral to the level of the aortic hiatus, was made in the pars lumbalis part of the diaphragm. Stay sutures at both sides of the diaphragmatic incision were placed to open up the incision and a retractor was used to push the esophagus away from the aorta. Intrathoracic insertion of the shunt was confirmed intraoperative. Exposure of the shunt insertion site at the azygos vein was excellent in all clinical cases. No intraoperative or postoperative complications were encountered.

If thoracic attenuation of a porto-azygos shunt is considered, a transdiaphragmatic approach exposes the insertion site for shunt attenuation. This approach is straightforward, without unnecessary abdominal organ manipulation, and since attenuates at the insertion, avoids missing additional contributing branches.