Spinal Access and Neural Localization

• US 20060258951A1
• Filed: 07/13/2006
• Published: 11/16/2006
• Est. Priority Date: 05/16/2005
• Status: Active Grant

• Current Assignee: Spinal Elements, Inc.
• Original Assignee: Baxano, Inc. (Baxano Surgical, Inc.)
• Inventors: Bleich, Jeffrey L., Bleam, Jefferey, Leguidleguid, Ron
• Granted Patent: US 7,578,819 B2
• Time in Patent Office: Days
• US Class Current: 600/546
• CPC Class Codes: A61B 17/1626 Control means; Display units
• CPC Class Codes: A61B 17/1671 for the spine
• CPC Class Codes: A61B 17/1757 for the spine
• CPC Class Codes: A61B 17/8861 Apparatus for manipulating flexible wires or straps devices for inserting Kirschner wires A61B17/1697
• CPC Class Codes: A61B 17/8897 Guide wires or guide pins

Abstract

A method for locating neural tissue in a patient body may involve: advancing a probe along a natural tissue interface between the neural tissue and another tissue in the body, the probe having a first surface oriented toward the neural tissue and a second surface oriented away from the neural tissue; delivering a first electrical current to a first electrode along the first surface of the probe; delivering a second electrical current to a second electrode along the second surface of the probe; and verifying that the first surface of the advanced probe remains oriented toward the neural tissue and the second surface remains oriented away from the neural tissue by monitoring neural response to the first and second electrical currents.

Claims

1. A method for locating neural tissue in a patient body, the method comprising:

advancing a probe along a natural tissue interface between the neural tissue and another tissue in the body, the probe having a first surface oriented toward the neural tissue and a second surface oriented away from the neural tissue;

delivering a first electrical current to a first electrode along the first surface of the probe;

delivering a second electrical current to a second electrode along the second surface of the probe;

verifying that the first surface of the advanced probe remains oriented toward the neural tissue and the second surface remains oriented away from the neural tissue by monitoring neural response to the first and second electrical currents.

2. A method as in claim 1, wherein the probe comprises an elongate flattened body having an axis and a distal end, the first and second surfaces comprising opposed major surfaces of the elongate body, the electrodes extending along an electrode length proximally of the distal end sufficiently to verify that injury to the neural tissue will be inhibited when treatment of the other tissue is directed along the electrode length from a path of the probe.

3. A method as in claim 2, wherein the tissue interface comprises two adjacent tissue planes, wherein advancing the probe causes the distal end of the probe to dissect the neural tissue from the other tissue along the tissue interface, the other tissue comprising an impinging tissue and being harder than the neural tissue, and further comprising treating the other tissue by directing treatment from the probe path along the electrode length in the verified orientation of the second electrode so as to reduce impingement of the neural tissue.

4. A method as in claim 1, wherein advancing the probe comprises advancing a distal portion of the probe along an interface between a bone or ligament surface and a soft tissue surface so that at least a part of the distal portion of the advanced probe extends into an intervertebral foramen of a spine.

5. A method as in claim 1, further comprising advancing a curved, shape-memory guide member having at least one lumen out of a distal opening on the probe device.

6. A method as in claim 1, further comprising:

determining a first threshold amount of electrical current required to stimulate measurable action potentials in the neural tissue via the first electrode;

determining a second threshold amount of electrical current required to stimulate measurable action potentials in the neural tissue via the second electrode; and

comparing the first and second threshold amounts of current, to determine which of the first and second surfaces is closest to the neural tissue.

7. A method as in claim 6, wherein the threshold amount of current applied to the electrode closest to the neural tissue is less than about 1 milliamp, and wherein the amount of threshold current applied to the electrode farthest from the neural tissue is greater than about 2 milliamps.

8. A method as in claim 6, wherein comparing the first and second threshold amounts of current comprises calculating a ratio of the threshold amount of current applied to the electrode farthest from the neural tissue compared to the threshold amount of current applied to the electrode closest to the neural tissue, and wherein the ratio is greater than or equal to 10.

9. A method as in claim 1, wherein monitoring the neural response to the first and second currents comprises monitoring at least one of somatosensory evoked potentials (SSEP), motor evoked potentials (MEP), electromyography (EMG), visible muscle twitch and tactile muscle twitch.

10. A method for positioning a guidewire between neural tissue and adjacent tissue in a patient body, the method comprising:

positioning a distal portion of a probe device between neural tissue and tissue adjacent the neural tissue in the body;

delivering electrical current to a first electrode coupled with a first surface of the distal portion of the probe;

determining a first threshold amount of electrical current required to provoke a response in the neural tissue via the first electrode;

determining a location of the neural tissue relative to the first surface of the distal portion, based on the first threshold amount of current; and

advancing a guidewire through an opening in the distal portion of the probe.

11. A method as in claim 10, further comprising, before advancing the guidewire through the opening:

delivering electrical current to a second electrode coupled with a second surface of the distal portion;

determining a second threshold amount of electrical current required to provoke a response in the neural tissue via the second electrode; and

comparing the first and second threshold amounts of current, to determine which of the first and second surfaces is closest to the neural tissue.

12. A method as in claim 10, wherein positioning the distal portion comprises positioning at least part of the distal portion in an intervertebral foramen of a spine.

13. A method as in claim 10, wherein positioning the distal portion comprises advancing a curved, shape-memory guide member having at least one lumen out of a distal opening on the probe device.

14. A method as in claim 13, wherein advancing the guide member comprises pushing a slide member coupled with the guide member and disposed on a shaft of the probe.

15. A method as in claim 13, wherein advancing the guidewire comprises advancing through the lumen of the guide member.

16. A method as in claim 10, wherein positioning the distal portion comprises articulating at least part of the distal portion.

17. A method as in claim 10, wherein determining the first and second threshold amounts of current comprises monitoring at least one of somatosensory evoked potentials (SSEP), motor evoked potentials (MEP), electromyography (EMG), visible muscle twitch and tactile muscle twitch.

18. A method as in claim 10, wherein advancing the guidewire comprises advancing a sharp-tipped guidewire through the distal opening and then through tissue in the body.

19. A method as in claim 10, further comprising removing the probe device from the body while leaving the guidewire in place between the neural tissue and adjacent tissue.

20. A method as in claim 19, further comprising:

advancing at least one tissue modification device over the guidewire to position a portion of the device between the neural tissue and adjacent tissue; and

performing a tissue modifying procedure with the tissue modification device.

21. A method as in claim 19, further comprising:

coupling a distal portion of a tissue modification device at or near one end of the guidewire;

pulling the guidewire to pull a portion of the tissue modification device to a desired position between the neural tissue and adjacent tissue; and

performing a tissue modifying procedure with the tissue modification device.

22. A method as in claim 20 or 21, further comprising delivering electrical current to at least one electrode coupled with the tissue modification device to confirm a location of the neural tissue relative to the device.

23. A device for advancing a guidewire in a human body, the device comprising:

an elongate probe having a proximal portion, a distal portion and at least one lumen having a proximal opening and a distal opening;

a curved guide member slidably disposed within the lumen of the probe, wherein at least a portion of the guide member is configured to be advanced out of the distal opening of the lumen to assume a curved shape, and wherein the guide member includes at least one guidewire lumen; and

a slide member coupled with the probe and the guide member to advance the guide member out of the distal opening of the probe.

24. A device as in claim 23, further comprising at least one signal transmitter coupled with at least one of the probe and the guide member and connectible with at least one energy source.

25. A device as in claim 24, wherein the at least one signal transmitter comprises:

a first electrode coupled with a first surface of the probe at or near the distal portion and connectible with the at least one energy source; and

at least a second electrode coupled with a second surface of the probe at or near the distal portion and connectible with the energy source.

26. A device as in claim 23, wherein the elongate probe includes a curve or bend at or near the distal portion.

27. A device as in claim 26, wherein the curve or bend and the distal portion are configured to facilitate passage of at least part of the distal portion into an intervertebral foramen of a spine, and wherein the probe further includes a toe or lip at an extreme distal end of the distal portion.

28. A device as in claim 23, wherein the probe is predominantly rigid.

29. A device as in claim 23, wherein at least part of the probe is flexible.

30. A device as in claim 23, wherein at least part of the distal portion of the probe may be articulated to form more than one curved shape.

31. A device as in claim 30, further comprising at least one wire coupled with the distal portion for pushing or pulling to articulate the distal portion.

32. A device as in claim 23, wherein the probe comprises at least two lumens, wherein one lumen is configured to accept the guide member and the other lumen(s) comprise at least one of a visualization lumen, a suction lumen and a fluid introduction lumen.

33. A device as in claim 32, further comprising a visualization device disposed in the visualization lumen, the visualization device selected from the group consisting of endoscopes, fiber optics, charge-coupled devices (CCD) and complementary metal-oxide semiconductor (CMOS) devices.

34. A device as in claim 23, wherein the proximal opening of the probe lumen is sized to allow passage of a guidewire, so that the guidewire may be passed into the proximal opening, into the guidewire lumen of guide member, and out a distal opening of the guide member.

35. A device as in claim 23, wherein the guide member has a cross-sectional shape selected from the group consisting of round, oval, rectangular, triangular, elliptical and figure-8.

36. A system for localizing neural tissue in a patient body, the neural tissue being separated from an impinging tissue by a natural tissue interface, the system comprising:

a probe having a proximal end and a distal end with an axis therebetween, the distal end suitable for advancing distally along the natural tissue interface, the probe having first and second laterally oriented surfaces;

a first signal transmitter disposed along the first surface of the probe;

a second signal transmitter disposed along the second surface of the probe, the first and second signal transmitters defining an axial verification length; and

a signal source for generating a neural localization signal, the source selectively coupleable with the first and second signal transmitters of the probe such that, by monitoring a response to the neural localization signal when the probe has been advanced along the natural interface with the first surface oriented toward the neural tissue and the second surface oriented away from the neural tissue, orientation of the neural tissue relative to the probe axis throughout the axial verification length can be safely verified.

37. A system as in claim 36, wherein the first and second signal transmitters comprise first and second electrodes, the signal source comprising an electrical source for generating electrical neural stimulation signals.

38. A system as in claim 37, further comprising:

a neural response sensor; and

a processor coupled to the electrical source and the sensor, the processor configured to verify, in response to the neural response to the stimulation applied by the first electrode and the second electrode, that the first surface is oriented toward the neural tissue and the second electrode is oriented away from the neural tissue.

39. A system as in claim 36, wherein the distal portion of the shaft is configured to facilitate its passage into an intervertebral foramen of a spine.

40. A system as in claim 36, wherein the probe further comprises at least one lumen disposed longitudinally through at least a portion of its length, the system further comprising a curved, hollow guide member slidably disposed within, and configured to be advanced out of a distal opening of, the probe lumen, wherein the guide member comprises at least one guidewire lumen.

41. A system as in claim 40, further comprising a slide member coupled with the probe and the guide member to advance the guide member out the distal opening of the probe.

42. A system as in claim 40, further comprising:

a guidewire; and

at least one tissue removal device for advancing along or being pulled into position by the guidewire to remove tissue from the body.

43. A system as in claim 36, further comprising at least one sizing probe configured to perform at least one of the functions of assessing an amount of space between tissues before advancing the probe, increasing the amount of space between tissue before advancing the probe, and assessing the amount of space between tissues after performing a tissue modification procedure.