A control circuit is provided for use with a surgical tool, illustratively a vacuum-assisted surgical tool. The vacuum-assisted surgical tool has an outer cannula for insertion into a body to a point adjacent to a mass to be examined, and a cutter device may be housed within the outer cannula. In one embodiment, various other surgical devices may be housed within a multi-purpose outer cannula.A rinse or other liquid can be provided for assisting in the removal of the mass to be examined. Other desirable fluids and materials may also be provided and placed in communication with the surgical tool. A vacuum source may also be provided for assisting in the removal of the mass to be examined. A cabinet may house portions of the pneumatic circuit and control circuit.