DEVICES AND METHODS FOR ACCESSING THE EPIDURAL SPACE

• US 20080132926A1
• Filed: 11/30/2007
• Published: 06/05/2008
• Est. Priority Date: 12/01/2006
• Status: Active Grant

• Current Assignee: Board of Trustees of the Leland Stanford Junior University (Stanford University)
• Original Assignee: Board of Trustees of the Leland Stanford Junior University (Stanford University)
• Inventors: EICHMANN, Stephen E., Malchano, Zachary J., Wu, Kenneth S., Wall, James K.
• Granted Patent: US 7,922,738 B2
• Time in Patent Office: Days
• US Class Current: 606/167
• CPC Class Codes: A61B 17/22032 having inflatable gripping elements balloon catheters A61M25/10
• CPC Class Codes: A61B 17/3401 Puncturing needles for the peridural or subarachnoid space or the plexus, e.g. for anaesthesia local anaesthesia A61M19/00
• CPC Class Codes: A61B 17/3415 for introducing tubes or catheters, e.g. gastrostomy tubes, drain catheters A61B17/3417 takes precedence; body piercing catheter guide needles A61M25/06
• CPC Class Codes: A61B 17/3439 with means for changing the inner diameter of the cannula, e.g. expandable A61B17/3423, A61B17/3431 take precedence; catheters A61M25/0662
• CPC Class Codes: A61B 2017/22034 for gripping the obstruction or the tissue part from inside
• CPC Class Codes: A61B 2017/320048 Balloon dissectors
• CPC Class Codes: A61B 2017/3488 Fixation to inner organ or inner body tissue
• CPC Class Codes: A61B 2017/349 Trocar with thread on outside

Abstract

An apparatus for accessing the epidural space in a mammal has a cutting sheath with a distal end adapted to transition from a closed cutting configuration to an open configuration. A tissue engagement device is in a hollow portion of the sheath. The tissue engagement device has a blunt distal end and an engagement feature. A method of accessing an epidural space includes the step of forming an opening to a position at or near the ligamentum flavum using the cutting sheath. Another step of the method is positioning a tissue engagement device within the hollow portion of the cutting sheath. Another step of the method is transitioning the cutting sheath from the closed cutting configuration to the open configuration. Another step of the method is manipulating the tissue engagement device to controllably advance the tissue engagement device at least partially through the ligamentum flavum.

Claims

1. An apparatus for accessing the epidural space in a mammal, comprising:

a cutting sheath having an open proximal end and a distal end adapted to transition from a closed cutting configuration to an open configuration;

a hollow portion within the sheath extending from the open proximal end along the longitudinal axis of the sheath;

a tissue engagement device disposed within the hollow portion of the cutting sheath, the tissue engagement device having an elongate body with a proximal end and a blunt distal end;

an engagement feature on the surface of the elongate body;

an aperture formed in the distal end of the elongate body; and

a conduit within the elongate body in communication with the aperture and the elongate body proximal end.

2. The apparatus of claim 1 wherein the engagement feature on the surface of the elongate body is a screw thread.

3. The apparatus of claim 2 wherein the screw thread comprises an asymmetric thread form.

4. The apparatus of claim 2 wherein the screw thread comprises a reverse buttress thread form.

5. The apparatus of claim 1 wherein the engagement feature on the surface of the elongate body comprises a plurality of ridges.

6. The apparatus of claim 5 further comprising:

a balloon positioned within the distal end of the tissue engagement device.

7. The apparatus according to claim 1 wherein the cutting sheath distal end transitions from

a closed cutting configuration to an open configuration by moving the elongate body within the hollow portion of the cutting sheath.

8. The apparatus according to claim 7 wherein moving the elongate body within the hollow portion of the cutting sheath comprises sliding the elongate body within the hollow portion of the cutting sheath.

9. The apparatus according to claim 7 wherein moving the elongate body within the hollow portion of the cutting sheath comprises rotating the elongate body within the hollow portion of the cutting sheath.

10. The apparatus according to claim 1, the cutting sheath further comprising:

at least one predefined movable section.

11. The apparatus according to claim 10, the cutting sheath further comprising:

a hinge that joins the at least one predefined movable section to the distal end of the cutting sheath.

12. The apparatus according to claim 10 wherein the at least one predefined movable section is defined by a scoring pattern in a sidewall of the cutting sheath.

13. The apparatus according to claim 10 wherein the at least one predefined movable section is cut into the distal end of the sheath.

14. The apparatus according to claim 1 wherein the aperture is formed in the sidewall of the elongate body proximal to the blunt distal end.

15. The apparatus according to claim 1 wherein the aperture is formed in the blunt distal end.

16. A method of accessing an epidural space in a mammal, comprising:

forming an opening in the mammal to a position at or near the ligamentum flavum using a cutting sheath having an open proximal end and a distal end adapted to transition from a closed cutting configuration to an open configuration and a hollow portion within the sheath extending from the open proximal end;

positioning within the hollow portion of the cutting sheath a tissue engagement device having an elongate body with a proximal end, a blunt distal end and an engagement feature on the exterior surface of the elongate body;

transitioning the distal end of the cutting sheath from the closed cutting configuration to the open configuration; and

manipulating the engagement feature on the exterior surface of the elongate body to controllably advance the blunt distal end of the elongate body at least partially through the ligamentum flavum.

17. The method according to claim 16, the transitioning step further comprising:

moving the tissue engagement device relative to the cutting sheath.

18. The method according to claim 17, wherein moving the tissue engagement device relative to the cutting sheath comprises pulling the cutting sheath proximally relative to the tissue engagement device.

19. The method according to claim 17, wherein moving the tissue engagement device relative to the cutting sheath comprises rotating the tissue engagement device within the hollow central portion of the cutting sheath.

20. The method according to claim 16, the transitioning step further comprising:

moving a portion of the distal end of the cutting sheath about a hinge.

21. The method according to claim 16 wherein at least one of the transitioning step or the manipulating step are performed by rotating the tissue engagement device.

22. The method according to claim 16 wherein at least one of the transitioning step or the manipulating step are performed by longitudinal movement between the tissue engagement device and the cutting sheath.

23. The method according to claim 16 further comprising:

ceasing the manipulating step when a pressure drop within the tissue engagement device is detected.

24. The method according to claim 16 wherein at least one section on the distal end of the cutting sheath moves in a predetermined manner during the opening step.

25. The method according to claim 16 further comprising:

advancing a substance, therapeutic instrument or diagnostic instrument completely through a conduit within the tissue engagement device.

26. The method according to claim 16 the manipulating step further comprising:

inflating a balloon within the distal end of the elongate body to at least partially dissect the ligamentum flavum.

27. The method according to claim 16 wherein the transitioning step exposes the blunt distal end of the tissue engagement device to the ligamentum flavum.

28. The method according to claim 16 the transitioning step comprising:

removing a stylet from within the hollow portion prior to the positioning step.

29. An apparatus for accessing the epidural space in a mammal, comprising:

a cutting sheath having an open proximal end and a distal end adapted to transition from a closed cutting configuration to an open configuration;

a hollow portion within the sheath extending from the open proximal end to the distal end;

a stylet placed within the hollow portion when the cutting sheath is in the closed cutting configuration;

a tissue engagement device disposed within the hollow portion when the cutting sheath is in the open configuration, the tissue engagement device having an elongate body with a proximal end and a blunt distal end;

an engagement feature on the surface of the elongate body;

an aperture formed in the distal end of the elongate body; and

a conduit within the elongate body in communication with the aperture and the elongate body proximal end.