Systems and methods for traversing a site of obstruction

1. A system for providing access across a site of obstruction comprising:

a cannula having a proximal end, a distal end, and a lumen extending therebetween;

an everting member being situated within the lumen, having a first end coupled to the distal end of the cannula and a second end, and being inflatable within the cannula;

a push assembly, positioned within the lumen, having a pathway along its entire length, the push assembly being slidably disposed across the proximal end of the cannula into the lumen of the cannula and being connected at its distal end to the second end of the everting member, such that advancement of the push assembly along the lumen of the cannula moves the everting member from an inverted position within the lumen of the cannula to an everted position outside the cannula;

an anchoring member circumferentially placed about an outer surface of the cannula and in the fluid communication with the lumen; and

a tube having a passageway and being coaxially disposed within the pathway of the push assembly, the tube being slidably movable across a proximal end of the push assembly,

wherein the lumen provides a path along which pressurizing fluid can be introduced and evacuated from the cannula, such that in the presence of pressurizing fluid, the anchoring member inflates while the everting member inflates, and in the absence of pressurizing fluid, the anchoring member deflates while the everting member deflates.

2. The system of claim 1 , further comprising a bushing disposed at the distal end of the cannula to couple the first end of the everting member to the distal end of the cannula.

3. The system of claim 1 , wherein the anchoring member being in the fluid communication with the lumen of the cannula and being expandable from a deflated position to an inflated position anchors the cannula near a site of obstruction when the lumen is pressurized to an anchoring pressure sufficient to anchor the cannula in proximity to the site of obstruction.

4. The system of claim 1 , further comprising a sealing member disposed between walls of the lumen and the push assembly to seal the lumen.

5. The system of claim 1 , further comprising a sealing member disposed between walls of the pathway and the tube to seal the pathway.

6. The system of claim 1 , wherein the passageway is configured to receive a guidewire therethrough.

7. A method for traversing a site of obstruction comprising:

advancing a guidewire through a tube and an everting member inverted into a lumen of a cannula;

pressurizing the everting member to grip the guidewire;

everting the everting member from the cannula to distally advance the guidewire gripped by the everting member;

depressurizing the everting member to release the guidewire;

advancing the tube to a distal end of the guidewire;

pressurizing the everting member to grip the tube;

inverting the everting member into the lumen;

depressurizing the everting member to release the tube; and

advancing the cannula to a distal end of the guidewire.

8. The method of claim 7 , wherein, in the advancing step, the cannula further comprises an anchoring member coupled to the cannula, the anchoring member being in fluid communication with the lumen and being expandable from a depressurized position to a pressurized position to anchor the cannula near the site of obstruction when the everting member is pressurized.

9. The method of claim 7 , further comprising:

re-pressurizing the everting member to grip the guidewire;

re-everting the everting member from the cannula to further distally advance the guidewire gripped by the everting member.

10. The method of claim 9 , wherein the step of everting the everting member further comprises advancing a push assembly connected to a proximal end of the everting member to move the everting member from an inverted position inside the cannula to an everted position outside the cannula.

11. The method of claim 10 :

the push assembly slidably disposed within the lumen of the cannula; and

the tube slidably disposed within a pathway of the push assembly and extending through a proximal end of the push assembly into the pathway of the push assembly to selectively move from a first position inside the push assembly to a second position outside the push assembly.