Retractor cannula system for accessing and visualizing spine and related methods
Retractor cannula systems may be used for accessing and visualizing the spine and related methods of treatment, including a forward-looking retractor cannula system for creating a working space and the retractor cannula system having atraumatic dissection capability to allow visualization in spine. The devices and methods described may be used, for example, to perform annulus repair, herniated disc excision, and denervation of neurological tissue; to dispense pharmacological agents and/or cell or tissue therapy agents; to diagnose disc degeneration and bony degeneration, spinal stenosis, and nucleus decompression, and to perform disc augmentation.
1. A retractor cannula device comprising:
a tubular assembly comprising at least one lumen configured to hold an endoscopic system; and
a retractor assembly having a longitudinal midline and located at the distal end of the tubular assembly, the retractor assembly including:
a first element with a distal tip having a distal-most portion, a convex outer surface and a concave inner surface; and
a second element with a convex outer surface and a concave inner surface, the first and second elements comprising an optically transparent material,
wherein the retractor assembly further includes an open configuration and a closed configuration, and the first element is pivotable with respect to the tubular assembly such that, as the retractor assembly transitions from the open configuration to the closed configuration, the distal-most portion of the distal tip extends across a line that is parallel to and passes through the longitudinal midline of the retractor assembly and extends through the convex outer surface of the first element.
2. The device of claim 1 , wherein the first and second elements are each pivotably attached to the tubular assembly at first and second side regions and at a central region.
3. The device of claim 2 , wherein the tubular assembly comprises an inner shaft slidably retained within the at least one lumen, and one or more pins pivotably attaching the first and second side regions of the first and second elements to the inner shaft.
4. The device of claim 3 , wherein in the closed configuration, the inner shaft is in a first longitudinal location and in the open configuration, the inner shaft is in a second longitudinal location distal to the first location.
5. The device of claim 2 , wherein the central regions of the first and second elements are attached using flexible hinge structures.
6. The device of claim 2 , wherein the first and second elements have the same longitudinal length.
7. The device of claim 2 , wherein in the closed configuration an inner edge of the first element and an inner edge of the second element form a first angle, and wherein in the open configuration the inner edge of the first element and the inner edge of the second element form a second angle that is greater than the first angle.
8. The device of claim 2 , wherein in the closed configuration, an inner edge of the first element contacts an inner edge of the second element, and in the open configuration, the inner edge of the first element does not contact the inner edge of the second element.
9. The device of claim 8 , wherein the distal tip of the first element is a first distal tip, the second element including a second distal tip, the distal tips of the first and second elements having a semi-elliptical profile.
10. The device of claim 9 , wherein a surface of the first and second elements is curved.
11. The device of claim 10 , wherein the curved surface of the first and second elements is tapered from a proximal portion to a distal portion of the first and second elements.
12. The device of claim 11 , wherein the proximal portion of the first and second elements has a first taper angle and the distal portion has a second taper angle.
13. The device of claim 12 , wherein the first taper angle is different from the second taper angle.
14. The device of claim 13 , wherein the first taper angle is less than the second taper angle.
15. The device of claim 12 , wherein the first taper angle is the same as the second taper angle.
16. The device of claim 1 , wherein the first element is pivotably attached to the tubular assembly by one or more pins on either side of the first element and a flexible hinge connecting a top side of the first element to the tubular assembly, and wherein the second element is fixed with respect to the tubular assembly.
17. The device of claim 16 , wherein the longitudinal length of the second element is longer than the longitudinal length of the first element.
18. The device of claim 1 , further comprising an endoscopic system.
19. The device of claim 1 , wherein the second element is fixed with respect to the tubular assembly.