A patient with portosystemic encephalopathy, hyperammonemia, and a spontaneous splenorenal shunt was admitted to the authors' institution after a failed attempt at transvenous retrograde shunt obliteration. As an alternative approach, the authors separated splenic and portal flows by embolizing only the proximal splenic vein while leaving the shunt intact. Thus, the splenic flow could escape into the systemic circulation and an extreme increase in portal pressure was avoided. The procedure could provide rapid decreases in blood ammonia levels and a fast resolution of symptoms, but repeated interventions were required.