FLEXIBLE CANNULA DEVICES AND METHODS
Various devices and methods are provided for dilating tissue. In one embodiment, a trocar cannula is provided and includes an elongate tubular member defining an inner lumen extending therethrough and configured to receive a surgical instrument therethrough. The tubular member is configured to radially expand to increase an inner diameter of the inner lumen and thereby dilate tissue. In one embodiment, the tubular member has an expansion element incorporated therein and the expansion element is configured to maintain the tubular member in a radially expanded position when no instrument is disposed within the inner lumen.
1 . A trocar cannula, comprising:
an elongate tubular member defining an inner lumen extending therethrough and configured to receive a surgical instrument therethrough, the tubular member being configured to radially expand to increase an inner diameter of the inner lumen when an instrument is disposed within the inner lumen, and the tubular member having an expansion element incorporated therein and configured to maintain the tubular member in a radially expanded position when no instrument is disposed within the inner lumen.
2 . The trocar cannula of claim 1 , wherein the expansion element is biased to an expanded position.
3 . The trocar cannula of claim 2 , wherein the tubular member includes a sheath disposed therearound and configured to retain the expansion element in an unexpanded configuration such that removal of the sheath allows the expansion element to radially expand.
4 . The trocar cannula of claim 3 , wherein the sheath includes a closed distal end to provide a seal for the tubular member as the tubular member is inserted through tissue.
5 . The trocar cannula of claim 1 , wherein the tubular member is formed from a mesh material.
6 . The trocar cannula of claim 5 , wherein the expansion element comprises at least one radially expandable ring disposed within a wall of the mesh material.
7 . The trocar cannula of claim 6 , wherein the at least one radially expandable ring comprises a coiled wire.
8 . The trocar cannula of claim 6 , wherein the at least one radially expandable ring is configured to expand from a first diameter to a second diameter that is four times greater than the first diameter.
9 . The trocar cannula of claim 1 , wherein the tubular member includes an internal sheath disposed therein and configured to provide resiliency to a distal end of the tubular member to prevent inversion of the distal end of the tubular member when the tubular member is in the radially expanded position.
10 . The trocar cannula of claim 9 , wherein the internal sheath extends from inside the tubular member and around the distal end of the tubular member.
11 . The trocar cannula of claim 1 , wherein the expansion element comprises a plurality of pleats formed in the tubular member and extending longitudinally along the tubular member.
12 . The trocar cannula of claim 11 , wherein each pleat includes a peak having a rib formed thereon and extending longitudinally along the tubular member, the ribs being configured to provide longitudinal stiffness to the tubular member.
13 . The trocar cannula of claim 11 , wherein the pleats are configured to interlock with one another to maintain the tubular member in an unexpanded position, and wherein insertion of an instrument through the inner lumen of the tubular member is configured to cause the pleats to unlock to allow radial expansion of the tubular member.
14 . The trocar cannula of claim 1 , wherein a proximal end of the tubular member is mated to a housing having an inner lumen extending therethrough and aligned with the inner lumen of the tubular member, and at least one seal disposed therein and configured to form a seal around an instrument inserted therethrough.
15 . A method of dilating tissue, comprising:
inserting a radially expandable cannula into tissue such that an inner lumen of the cannula defines an opening extending through the tissue and into a body cavity;
inserting an instrument through the inner lumen of the cannula, the instrument causing the radially expandable cannula to expand into an expanded configuration wherein a diameter of the inner lumen is increased; and
removing the instrument from the inner lumen of the cannula, wherein an expansion element integrally formed with the radially expandable cannula maintains the cannula in the radially expanded configuration.
16 . The method of claim 15 , wherein the expansion member is a radially expandable ring disposed within a wall of the cannula, the ring being biased to the expanded configuration, and wherein the radially expandable ring expands from a first diameter to a second greater diameter upon insertion of the instrument through the inner lumen of the cannula.
17 . The method of claim 15 , wherein the expansion member is a plurality of pleats formed in the cannula that extend longitudinally along the cannula, and wherein each pleat includes a peak having a rib formed thereon that provides longitudinal stiffness to the tubular member upon insertion of the instrument through the inner lumen of the cannula.
18 . A method of dilating tissue, comprising:
inserting a radially expandable cannula into tissue such that an inner lumen of the cannula defines an opening extending through the tissue and into a body cavity, the cannula including at least one expansion element biased to an expanded position; and
removing a sheath disposed around an outer surface of the cannula such that the expansion element expands to cause the radially expandable cannula to expand into an expanded configuration wherein a diameter of the inner lumen is increased.