SYSTEM AND METHODS FOR DETERMINING NERVE PROXIMITY, DIRECTION, AND PATHOLOGY DURING SURGERY

• US 20100152604A1
• Filed: 02/24/2010
• Published: 06/17/2010
• Est. Priority Date: 07/11/2001
• Status: Active Grant

• Current Assignee: Nuvasive Incorporated
• Original Assignee: Nuvasive Incorporated
• Inventors: Kaula, Norbert F., Gharib, James, Blewett, Jeffrey J., Farquhar, Allen, Medeiros, Goretti
• Granted Patent: US 7,920,922 B2
• Time in Patent Office: Days
• US Class Current: 600/546
• CPC Class Codes: A61B 17/00 Surgical instruments, devices or methods, e.g. tourniquets A61B18/00 takes precedence; contraceptive devices, pessaries, or applicators therefor A61F6/00; eye surgery A61F9/007; ear surgery A61F11/00
• CPC Class Codes: A61B 17/02 for holding wounds open; Tractors specula A61B1/32 ; drainage appliances for wounds A61M27/00
• CPC Class Codes: A61B 18/00 Surgical instruments, devices or methods for transferring non-mechanical forms of energy to or from the body eye surgery A61F9/007; ear surgery A61F11/00
• CPC Class Codes: A61B 2017/00039 Electric or electromagnetic phenomena other than conductivity, e.g. capacity, inductivity, Hall effect
• CPC Class Codes: A61B 5/1106 to assess neuromuscular blockade, e.g. to estimate depth of anaesthesia
• CPC Class Codes: A61B 5/24 Detecting, measuring or recording bioelectric or biomagnetic signals of the body or parts thereof
• CPC Class Codes: A61B 5/389 Electromyography [EMG]
• CPC Class Codes: A61B 5/4893 Nerves
• CPC Class Codes: A61B 5/7217 of noise originating from a therapeutic or surgical apparatus, e.g. from a pacemaker
• CPC Class Codes: A61B 5/743 Displaying an image simultaneously with additional graphical information, e.g. symbols, charts, function plots
• CPC Class Codes: A61N 1/08 Arrangements or circuits for monitoring, protecting, controlling or indicating for external stimulators A61N1/3603; for implantable neurostimulators A61N1/36128; for heart stimulators A61N1/37; for defibrillators A61N1/3925
• CPC Class Codes: A61N 1/36 for stimulation
• CPC Class Codes: A61N 1/36017 with leads or electrodes penetrating the skin

Abstract

The present invention involves systems and methods for determining nerve proximity, nerve direction, and pathology relative to a surgical instrument based on an identified relationship between neuromuscular responses and the stimulation signal that caused the neuromuscular responses.

Claims

1. A method of establishing an operative corridor for spinal surgery, comprising:

mounting a plurality of EMG electrodes proximate to selected leg muscles;

activating a nerve monitoring system that outputs a stimulation current signal to one or more surgical access instruments and that, in response to signals from the EMG electrodes, displays a stimulation current threshold which is indicative of nerve proximity and further displays EMG waveforms;

advancing an initial dilating assembly through bodily tissue having neural structures in a selected path toward a targeted intervertebral disc of a spine, the initial dilating assembly comprising an initial dilator cannula and a removable inner element having at least one stimulation electrode that delivers the stimulation signal to the bodily tissue prior to accessing the spine;

during advancement of the initial dilating assembly through the bodily tissue and prior to accessing the spine, viewing the stimulation current threshold on a display device of the nerve monitoring system when the stimulation signal is delivered to the bodily tissue prior to accessing the spine;

inserting a guide wire through a lumen of the initial dilator cannula after the initial dilator cannula is advanced through the bodily tissue so that the guide wire penetrates an annulus of the targeted intervertebral disc of the spine;

advancing a plurality of sequential dilator cannulas along the selected path toward the targeted intervertebral disc of the spine after the guide wire engages the annulus of the disc;

advancing a working corridor instrument over an outermost dilator cannula of the plurality of sequential dilator cannulas toward the targeted intervertebral disc of the spine after; and

establishing an operative corridor to the targeted intervertebral disc of the spine using the working corridor instrument.

2. The method of claim 1, wherein the removable inner element of the initial dilating assembly comprises an obturator arranged inside the initial dilator cannula and the at least one stimulation electrode.

3. The method of claim 1, further comprising removing the removable inner element from the initial dilator cannula prior to inserting the guide wire through the initial dilator cannula.

4. The method of claim 3, further comprising operating one or buttons of a stimulator driver coupled to the removable inner element of the initial dilating assembly to selectively deliver the stimulation signal.

5. The method of claim 1, further comprising inputting a setting for the stimulation signal using a graphical user interface of the nerve monitoring system.

6. The method of claim 5, wherein the EMG waveforms displayed by the nerve monitoring system comprises the voltage waveforms for eight EMG response channels.

7. The method of claim 1, further comprising removing the initial dilator cannula and the plurality of sequential dilator cannulas from the working corridor instrument prior to establishing the operative corridor to the targeted intervertebral disc of the spine.

8. The method of claim 1, wherein the working corridor instrument comprises a cannula that defines an inner lumen.

9. The method of claim 1, wherein the nerve monitoring system contemporaneously displays the stimulation current threshold which is indicative of nerve proximity and a spine image indicative of electrode placement.

10. A method of establishing an operative corridor for spinal surgery, comprising:

mounting a plurality of EMG electrodes proximate to selected leg muscles;

activating a nerve monitoring system that outputs a stimulation current signal to one or more surgical access instruments and that, in response to signals from the EMG electrodes, displays a stimulation current threshold which is indicative of nerve proximity and further displays EMG waveforms;

advancing a plurality of sequential dilator cannulas through bodily tissue having neural structures in a selected path toward a targeted intervertebral disc of a spine, each of the sequential dilator cannulas having at least one stimulation electrode that delivers the stimulation signal to the bodily tissue before reaching the spine;

during advancement of each respective sequential dilator cannula through the bodily tissue, viewing the stimulation current threshold on a display device of the nerve monitoring system for an indication of nerve proximity when the stimulation signal is delivered to the bodily tissue from the respective sequential dilator cannula;

advancing a working corridor instrument over an outermost dilator cannula of the plurality of sequential dilator cannulas toward the targeted intervertebral disc of the spine; and

establishing an operative corridor to the targeted intervertebral disc of the spine using the working corridor instrument.

11. The method of claim 10, further comprising the step of advancing an initial dilating assembly through the bodily tissue along the selected path toward the targeted intervertebral before advancing the plurality of sequential dilator cannulas, the initial dilating assembly comprising an initial dilator cannula and a removable inner element having a stimulation electrode that delivers the stimulation signal to the bodily tissue prior to accessing the spine.

12. The method of claim 11, further comprising viewing the stimulation current threshold on the display device of the nerve monitoring system during advancement of the initial dilating assembly through the bodily tissue and prior to accessing the spine.

13. The method of claim 12, further comprising inserting a guide wire through a lumen of the initial dilator cannula after the initial dilator cannula is advanced through the bodily tissue so that the guide wire penetrates an annulus of the targeted intervertebral disc of the spine.

14. The method of claim 13, wherein the removable inner element of the initial dilating assembly comprises an obturator arranged inside the initial dilator cannula and the at least one stimulation electrode.

15. The method of claim 13, further comprising removing the removable inner element from the initial dilator cannula prior to inserting the guide wire through the initial dilator cannula.

16. The method of claim 10, wherein the EMG waveforms displayed by the nerve monitoring system comprises the voltage waveforms for eight EMG response channels.

17. The method of claim 10, further comprising removing the plurality of sequential dilator cannulas from the working corridor instrument prior to establishing the operative corridor to the targeted intervertebral disc of the spine.

18. The method of claim 10, wherein the working corridor instrument comprises a cannula that defines an inner lumen.

19. The method of claim 10, wherein the nerve monitoring system contemporaneously displays the stimulation current threshold which is indicative of nerve proximity and a spine image indicative of electrode placement.

20. A method of establishing an operative corridor for spinal surgery, comprising:

mounting a plurality of EMG electrodes proximate to selected leg muscles;

activating a nerve monitoring system that outputs a stimulation current signal to one or more surgical access instruments and that displays neuromuscular response information in response to signals from the EMG electrodes;

advancing an initial dilating assembly through bodily tissue having neural structures in a selected path toward a targeted intervertebral disc of a spine, the initial dilating assembly comprising an initial dilator cannula and a removable inner element having at least one stimulation electrode that delivers the stimulation signal to the bodily tissue prior to accessing the spine;

during advancement of the initial dilating assembly through the bodily tissue and prior to accessing the spine, monitoring the neuromuscular response information displayed by the nerve monitoring system when the stimulation signal is delivered to the bodily tissue prior to accessing the spine;

inserting a guide wire through a lumen of the initial dilator cannula after the initial dilator cannula is advanced through the bodily tissue so that the guide wire penetrates an annulus of the targeted intervertebral disc of the spine;

advancing a plurality of sequential dilator cannulas along the selected path toward the targeted intervertebral disc of the spine after the guide wire engages the annulus of the disc;

advancing a working corridor instrument over an outermost dilator cannula of the plurality of sequential dilator cannulas toward the targeted intervertebral disc of the spine; and

establishing an operative corridor to the targeted intervertebral disc of the spine using the working corridor instrument.

21. The method of claim 20, wherein the neuromuscular response information displayed by the nerve monitoring system comprises a stimulation current threshold which is indicative of nerve proximity.

22. The method of claim 21, wherein the nerve monitoring system contemporaneously displays the stimulation current threshold which is indicative of nerve proximity and a spine image indicative of electrode placement.

23. The method of claim 20, wherein the neuromuscular response information displayed by the nerve monitoring system comprises EMG voltage waveforms.

24. The method of claim 20, further comprising removing the removable inner element from the initial dilator cannula prior to inserting the guide wire through the initial dilator cannula.

25. The method of claim 20, wherein the working corridor instrument comprises a cannula that defines an inner lumen.