Self-sealing cannula

1. A cannula assembly for performing a surgical procedure within an insufflated abdominal cavity, which comprises:

a cannula including a cannula housing and a cannula member extending from the cannula housing, the cannula member defining a longitudinal axis and proximal and distal ends, the cannula having a longitudinal passageway extending therethrough;

an expandable elongated object seal membrane disposed within the longitudinal passageway and at least partially within the cannula member, the elongated seal membrane adapted for expansion from an initial condition to an expanded condition upon introduction of fluids within the elongated seal membrane to establish a sealing relation about an object inserted through the elongated seal membrane, the elongated seal membrane being symmetrically arranged about the longitudinal axis in the initial condition and mounted within the longitudinal passageway to provide a predefined substantially annular space at least between an intermediate portion of the elongated seal membrane and the cannula member when in the initial condition, the annular space adapted to receive fluids to expand the second elongated seal membrane to achieve the expanded condition to establish the sealing relation about the object;

a fluid passage in fluid communication with the annular space for introducing insufflation fluid into the annular space to expand the annular space to thereby cause the elongated seal membrane to achieve the expanded condition to establish the sealing relation about the object, the fluid passage being a throughhole adjacent the distal end of the cannula and in communication with the annular space whereby, when the cannula is positioned within an insufflated body cavity, insufflation gases pass through the throughhole to expand the annular space to thereby cause the second elongated seal membrane to establish the sealing relation about the object; and

a closure seal within the cannula housing and proximal of the elongated seal membrane, the closure being adapted to seal the longitudinal passageway in the absence of the object to substantially prevent release of insufflation gases.

2. The cannula assembly according to claim 1 wherein the fluid passage is in fluid communication with an external source of insufflation fluid and in fluid communication with the annular space for introducing insufflation fluid into the annular space to expand the annular space to assist in establishing the sealing relation about the object.

3. The cannula assembly according to claim 1 wherein the elongated seal membrane is further adapted to substantially close the longitudinal passageway in response to introduction of fluids within the annular space and in the absence of an object inserted therethrough.

4. The cannula assembly according to 1 wherein the elongated membrane includes at least one ridge on an inner surface portion thereof.

5. The cannula assembly according to claim 4 wherein the at least one ridge is arranged on the elongated membrane so as to occupy a void between the inner surface portion of the elongated membrane and the object to facilitate sealing relation with the object.

6. The cannula assembly according to claim 5 wherein the elongated membrane comprises a plurality of ridges radially spaced about the inner surface portion of the elongated membrane.