The word "fallostomy" is a combination of two words, "fallo" and "stomy". The pronunciation of "fallo" is /ˈfæloʊ/, while the pronunciation of "stomy" is /stɒmi/. "Fallo" is not a common prefix in English, but it could be derived from Latin "fallere", meaning "deceive" or "fail". "Stomy" is derived from Greek "stoma", meaning "mouth". Therefore, "fallostomy" might be a medical term referring to a procedure that involves the creation of an artificial opening in the body for the passage of waste or fluid.
Salpingostomy.
A practical medical dictionary. By Stedman, Thomas Lathrop. Published 1920.