Abstract: The invention provides, in one embodiment, a multifunctional, multi-piece medical device and related method for providing access to an internal body cavity, such as for use with a vacuum lift shell. The device can include a cannula and a cannula extension. The device provides a conduit between the external environment and operative field inside the patient's body during medical procedures, including diagnostic, therapeutic and surgical procedures. The invention allows entry and exit of air or gas to help create and maintain the operative field. The invention can be used to provide an open and unobstructed working path, and allows the operative space to be maintained at ambient conditions of pressure and temperature.