US Patent 7226451 Minimally invasive access device and method

A device that provides access to a surgical location within a patient has an elongate body that has a proximal end, a distal end, and an inner surface. The inner surface defines a passage that extends through the elongate body. The elongate body is capable of having a configuration when inserted within the patient wherein the cross-sectional area of the passage at a first location is greater than the cross-sectional area of said passage at a second location. The first location is distal to the second location. The passage is capable of having a generally oval shaped cross section between the second location and the proximal end.