It is a surgical process that removes your spleen; an organ under the ribcage on the upper left side of your abdomen. this helps fight infection and filters unneeded material such as old or damaged blood cells. the most common reason to get an splenectomy is to treat a ruptured spleen, often caused by abdominal injury. also used for other conditions, like a enlarged spleen, some blood disorders, certain cancers, infection, and noncancerous cysts of tumors.