Both suffixes indicate the surgical removal of something, but they differ in their specific applications:
* -otomy refers to the cutting into or making an incision into something, often for the purpose of examining or accessing something inside. Examples: tracheotomy (cutting into the trachea), laparotomy (cutting into the abdomen).
* -ectomy refers to the surgical removal of something, usually a whole organ or part. Examples: appendectomy (removal of the appendix), hysterectomy (removal of the uterus).
While both suffixes indicate a surgical procedure, -ectomy usually implies a more complete removal, whereas -otomy suggests a more exploratory incision.