Intrahepatic Shunts: Maximally Invasive Surgery

Introduction:
Animals with congenital portosystemic shunts have a hypoplastic liver and effective hepatic insufficiency due to significantly reduced intrahepatic portal blood flow. A variety of treatments have been used for the management of intrahepatic congenital portosystemic shunts (CPSS) in dogs and cats. Surgical attenuation of the CPSS is recommended for the majority of animals. By reducing blood flow through the CPSS, portal flow is restored or improved and clinical signs resolve.

Surgical attenuation of intrahepatic CPSS (maximally invasive surgery):
Surgical techniques for IHCPSS include suture ligation, ameroid constrictors, cellophane banding and hydraulic occulders. It is recognised that intrahepatic CPSS are more challenging to treat surgically than extrahepatic CPSS due to the location of the abnormal vessel within the liver parenchyma. Intrahepatic CPSS can be divided into three morphological categories based on their location: left divisional, central divisional and right divisional. However, this may be an over simplification with different morphologies seen within each group. Different strategies have been used in order to access the CPSS surgically to allow attenuation and the method employed is dependent on the morphology of the CPSS. Extravascular surgery involves dissection of the CPSS itself, the draining hepatic vein or the portal vein branch supplying it. Depending on the morphology of the CPSS it may be relatively easy to access the vessel e.g. left divisional CPSS. However, some require more extensive liver dissection. Intravascular techniques with hepatic inflow occlusion have also been used to allow attenuation of some IHCPSS, which is technically demanding.  [...]