A laparotomy is a surgical procedure involving an incision through the abdominal wall to gain access into the abdominal cavity. It is also known as coeliotomy.

In diagnostic laparotomy (most often referred to as an exploratory laparotomy and abbreviated Ex-Lap), the nature of the disease is unknown, and laparotomy is deemed the best way to identify the cause.

In therapeutic laparotomy, a cause has been identified (e.g. peptic ulcer, colon cancer) and laparotomy is required for its therapy.

Usually, only exploratory laparotomy is referred to as a surgical operation by itself; and when a specific operation is already planned, laparotomy is considered merely the first step of the procedure.

From http://en.wikipedia.org/wiki/Laparotomy