Surgical access device, system, and methods of use

1. A method of creating a surgical access passage, comprising:

percutaneously inserting to a surgical site an elongate member comprising a proximal end, a distal end, and a plurality of retractor members each having an inner surface that together define a lumen of the elongate member, the lumen having a first cross-sectional dimension that is substantially constant between the proximal end and the distal end of the elongate member, wherein the inner surfaces of the retractor members are positioned around a stylet in an insertion configuration in which the stylet also includes a proximal portion extending proximally from the proximal end of the elongate member and a distal end extending distally from the distal end of the elongate member, wherein percutaneously inserting the elongate member includes guiding the stylet and elongate member in the insertion configuration to position the distal end of the elongate member at the surgical site so that the lumen of the elongate member provides the surgical access passage to the surgical site when the stylet is removed from the lumen;

removing the stylet from the lumen of the elongate member after percutaneously inserting the elongate member;

inserting an expandable body into the lumen of the elongate member after removing the stylet, wherein the expandable body has a length that is substantially the same as a length of the elongate member from the proximal end to the distal end of the elongate member;

expanding the expandable body along the length of the expandable body to move the plurality of retractor members radially outward to any second cross-sectional dimension on a continuum that is equal to or less than a maximum cross-sectional dimension, wherein the plurality of retractor members move simultaneously away from one another so that the second cross-sectional dimension of the lumen is substantially constant from the proximal end to the distal end of the elongate member and expansion of the expandable body provides gradual tissue dilation along the length of the elongate member as the plurality of retractor members move radially outward; and

contracting the expandable body and removing the expandable body from the surgical access passage.

2. The method of claim 1 , wherein percutaneously inserting the elongate member further comprises:

providing an insertion instrument having a guide wire bore and a guide wire threaded through the guide wire bore;

percutaneously inserting the insertion instrument to provide an insertion passage to the surgical site;

removing the insertion instrument from the insertion passage, while leaving the guide wire in the insertion passage;

the stylet comprising a stylet guide wire bore extending through the stylet; and

threading the stylet guide wire bore over the guide wire to insert the stylet and the elongate member into the insertion passage to the surgical site.

3. The method of claim 1 , further comprising securing the retractor members in a position comprising the first cross-sectional dimension or in a position comprising the second cross-sectional dimension.

4. The method of claim 3 , further comprising a retractor member arm extending outwardly from the proximal end of each retractor member, the method further comprising

placing a retainer ring comprising a plurality of retractor member guide channels at the proximal end of and concentric to the plurality of retractor members, each retractor member arm positioned and slidable within one of the guide channels,

wherein securing the retractor members further comprises securing each of the retractor member arms with a threaded wheel lock adjustably inserted through the retainer ring into each guide channel into securing contact with the retractor member arm positioned therein.

5. The method of claim 1 , further comprising

placing a retainer ring at the proximal end and concentric to the plurality of retractor members after percutaneously inserting the elongate member to the surgical site,

wherein expanding the expandable body further comprises expanding the expandable body to one cross-sectional dimension from a range of cross-sectional dimensions between the first cross-sectional dimension of the lumen and the maximum cross-sectional dimension which is equal to an inside diameter of the retainer ring.

6. The method of claim 1 , wherein the surgical access passage comprises a substantially constant cross-sectional dimension between the proximal end exterior a body and the distal end at the surgical site.

7. The method of claim 1 , wherein the surgical access passage comprises a cross-sectional dimension having a diameter in the range of ¾ inch to 1¼ inch.

8. The method of claim 1 , further comprising moving one of the retractor members radially outward more or less than another one of the retractor members to provide the surgical access passage having a non-circular cross-sectional configuration after moving the plurality of retractor members radially outward to the second cross-sectional dimension.

9. The method of claim 1 , further comprising illuminating the surgical site with a light source positioned at a periphery of the surgical site.

10. The method of claim 1 , further comprising inserting a plurality of surgical instruments into the surgical access passage.

11. The method of claim 1 , further comprising performing a surgical procedure under direct visualization of the surgical site.

12. The method of claim 1 , wherein the surgical site comprises a spine.

13. The method of claim 1 , wherein the surgical site comprises a joint.