Cannula and methods of use

1. A surgical instrument, comprising:

an expandable cannula including a first end, an opposite second end, and at least a first wall member and a second wall member extending between the first end and the second end, the first wall member and the second wall member being moveable between an unexpanded configuration and an expanded configuration;

a collar coupled to the expandable cannula adjacent the first end thereof, the collar comprising an extension portion and a first locking element provided on the extension portion; and

a patient attachable ring comprising a first passageway and a second locking element, the first passageway having a central axis and being configured to receive portions of the expandable cannula therethrough, and the first locking element being configured to engage the second locking element to control the movement of the cannula within the patient attachable ring, the second locking element including a radial groove extending in a radial direction with respect to the central axis, and a first circumferential groove extending in a circumferential direction with respect to the central axis, the radial groove and the first circumferential groove communicating with one another, and a portion of the first locking element being moveable within the radial groove and the first circumferential groove to facilitate corresponding radial and circumferential movement of the first locking element relative to the central axis, the expandable cannula being selectively positionable from at least a first cannula position to a second cannula position via corresponding movement of the first locking element from a first position within the second locking element to a second position within the second locking element;

wherein the first wall member includes a first longitudinal axis, and the first longitudinal axis is moveable with respect to the central axis of the first passageway via movement of the expandable cannula between the unexpanded configuration and the expanded configuration, and via movement of the expandable cannula due to selective positioning of the first locking element within the second locking element.

2. The surgical instrument as recited in claim 1 , wherein the first and second locking elements are detachable from one another.

3. The surgical instrument as recited in claim 1 , wherein the second locking element includes a second circumferential groove extending in a circumferential direction with respect to the central axis, the radial groove, the first circumferential groove, and the second circumferential groove communicating with one another, the first locking element being moveable within the radial groove, the first circumferential groove, and the second circumferential groove.

4. The surgical instrument as recited in claim 3 , wherein the first and second locking elements define a sliding dovetail joint.

5. The surgical instrument as recited in claim 3 , wherein the first locking element is a tapered tenon and the second locking element is a mortise that slidingly engages the tenon such that the tenon and the mortise define a sliding dovetail joint.

6. The surgical instrument as recited in claim 3 , wherein the first locking element is a tapered tenon and the radial groove, the first circumferential groove, and the second circumferential groove of the second locking element each comprise a mortise that are in communication with one another, the tenon slidingly engaging one of the mortises to define a sliding dovetail joint.

7. The surgical instrument as recited in claim 3 , further comprising a plurality of second locking elements positioned around the patient attachable ring.

8. The surgical instrument as recited in claim 1 , wherein the collar engages the expandable cannula to prevent axial translation of the collar relative the expandable cannula along the central axis.

9. The surgical instrument of claim 1 , wherein the cannula comprises a light source.

10. A method of using a cannula positioning system, the method comprising:

providing a system including:

an expandable cannula including a first end, an opposite second end, and at least a first wall member and a second wall member extending between the first end and the second end, the first wall member and the second wall member being moveable between an unexpanded configuration and an expanded configuration;

a collar coupled to the expandable cannula adjacent the first end thereof, the collar comprising an extension portion and a first locking element provided on the extension portion; and

a patient attachable ring comprising a first passageway and a second locking element, the first passageway having a central axis and being configured to receive portions of the expandable cannula therethrough, and the first locking element being configured to engage the second locking element to control the movement of the expandable cannula within the patient attachable ring, the second locking element including a radial groove extending a radial direction with respect to the central axis, and a first circumferential groove extending in a circumferential direction with respect to the central axis, the radial groove and the first circumferential groove communicating with one another, and a portion of the first locking element being moveable within the radial groove and the first circumferential groove to facilitate corresponding radial and circumferential movement of the first locking element relative to the central axis;

engaging the first and second locking elements together to secure the position of the expandable cannula within the patient attachable ring;

moving the expandable cannula between the unexpanded configuration and the expanded configuration; and

selectively positioning the first locking element from a first position within the second locking element to a second position within the second locking element to correspondingly move the expandable cannula from a first cannula position to a second cannula position;

wherein the first wall member includes a first longitudinal axis, and the first longitudinal axis is moveable with respect to the central axis of the first passageway via the movement of the expandable cannula between the unexpanded configuration and the expanded configuration, and via movement of expandable cannula due to the selective positioning of the first locking element within the second locking element.

11. The method of claim 10 , wherein the first and second locking elements define a sliding dovetail joint.

12. The method of claim 10 , wherein the first and second locking elements are detachable from one another.

13. The method of claim 10 , wherein the second locking element includes a second circumferential groove extending in a circumferential direction with respect to the central axis, the radial groove, the first circumferential groove, and the second circumferential groove communicating with one another, the first locking element being moveable within the radial groove, the first circumferential groove, and the second circumferential groove.

14. The method of claim 13 , wherein the first and second locking elements define a sliding dovetail joint.

15. The method of claim 13 , wherein the first locking element is a tapered tenon and the second locking element is a mortise that slidingly engages the tenon such that the tenon and the mortise define a sliding dovetail joint.

16. The method of claim 13 , wherein the first locking element is a tapered tenon and the radial groove, the first circumferential groove, and the second circumferential groove of the second locking element each comprise a mortise that are in communication with one another, the tenon slidingly engaging one of the mortises to define a sliding dovetail joint.

17. The method of claim 13 , further comprising a plurality of second locking elements positioned around the patient attachable ring.