Neurophysiological apparatus and procedures

• US 20040225228A1
• Filed: 05/10/2004
• Published: 11/11/2004
• Est. Priority Date: 05/08/2003
• Status: Abandoned Application

• Current Assignee: Nuvasive Incorporated
• Original Assignee: Nuvasive Incorporated
• Inventors: Ferree, Bret A.
• Application Number:
  US10/842,192
• Publication Number:
  US 20040225228A1
• Time in Patent Office: Days
• US Class Current: 600/554
• CPC Class Codes: A61B 17/1626 Control means; Display units
• CPC Class Codes: A61B 17/1671 for the spine
• CPC Class Codes: A61B 17/7092 for checking pedicle hole has correct depth or has an intact wall pedicle drill depth limiters A61B17/1626
• CPC Class Codes: A61B 2017/00039 Electric or electromagnetic phenomena other than conductivity, e.g. capacity, inductivity, Hall effect
• CPC Class Codes: A61B 5/388 Nerve conduction study, e.g. detecting action potential of peripheral nerves
• CPC Class Codes: A61B 5/395 Details of stimulation, e.g. nerve stimulation to elicit EMG response
• CPC Class Codes: A61B 5/4566 Evaluating the spine A61B5/4561 takes precedence
• CPC Class Codes: A61B 5/4893 Nerves

Abstract

Neurophysiological instruments and techniques are improved through various enhancements. Stimulation of an instrument is possible while it is advancing into the spine or elsewhere, alerting the surgeon to the first sign the instrument or device (screw) may be too near a nerve. A directional probe helps surgeons determine the location of the hole in the pedicle. Electrically insulating sleeves prevent shunting into the soft tissues. According to a different improvement, the same probe to be used to stimulate different devices, such as screws and wires. Electrical impulses may be recorded from non-muscle regions of the body, including the spine and other portions of the central nervous system as opposed to just the extremities.

Claims

1. Neurophysiological apparatus, comprising:

a system including an electrical stimulator and an electrical sensor that allows real-time or continuous monitoring as to the placement of a device relative to a nerve during a surgical procedure.

2. The apparatus of claim 1, wherein the device is a probe, tap, wire, screw, or pin.

3. The apparatus of claim 1, further including a component that allows the device to rotate during placement without interfering with the monitoring.

4. The apparatus of claim 3, wherein the component is a clip or sleeve that fits around the shaft of a rotating instrument.

5. The apparatus of claim 1, wherein the sensor is a spinal sensor.

6. The apparatus of claim 1, wherein the sensor is adapted for placement around at least a portion of a pedicle.

7. The apparatus of claim 1, including a direction sensor including a tip that is with a partially circumferentially insulated.

8. The apparatus of claim 1, wherein the system further includes an alert if a stimulus was generated but not sensed.

9. The apparatus of claim 1, wherein the system further includes an alert if the device is or is being improperly placed.

10. The apparatus of claim 1, wherein the system further includes an alert if the device should be placed within a pedicle.

11. The apparatus of claim 1, including multiple stimulators or sensors associated with multiple vertebrae.

12. A neurophysiological method, comprising the steps of:

placing a device in a vertebral body;

electrically stimulating one or more nerves; and

sensing at least one electrical impulse at the device to determine how close the device is to a nerve.

13. The neurophysiological method of claim 12, including the step of stimulating one or more spinal nerves.

14. The neurophysiological method of claim 12, including the step of stimulating one or more peripheral nerves.

15. The neurophysiological method of claim 12, including the step of stimulating a spinal cord.

16. The neurophysiological method of claim 12, including the step of stimulating a portion of a brain.

17. The neurophysiological method of claim 12, including the step of sensing an impulse at multiple devices based upon a single stimulus.

18. The neurophysiological method of claim 12, including the step of sensing one or more electrical impulses at an extremity to determine the effectiveness of the stimulus.

19. The neurophysiological method of claim 12, wherein the device is an instrument.

20. The neurophysiological method of claim 12, wherein the device is a pedicle screw.

21. The neurophysiological method of claim 12, wherein the muscle is a paraspinal muscle.

22. The neurophysiological method of claim 12, further including the step of alerting a user if a stimulus was not sensed.

23. The neurophysiological method of claim 12, further including the step of alerting a user if the device is improperly placed.

24. The neurophysiological method of claim 12, wherein the step of sensing at least one electrical impulse includes sensing the amplitude of the stimulus.

25. The neurophysiological method of claim 12, wherein the step of sensing at least one electrical impulse includes sensing the time between the application of the stimulus and the time of sensing the stimulus.

26. The neurophysiological method of claim 12, wherein the step of sensing at least one electrical impulse includes sensing the velocity of the stimulus.

27. The neurophysiological method of claim 12, wherein the step of comparing the amplitude, velocity, or time interval between stimulation and sensing to values derived previously during the surgical procedure.

28. The neurophysiological method of claim 12, wherein the step of comparing the amplitude, velocity, or time interval between stimulation and sensing to one or more predefined reference values.

29. The neurophysiological method of claim 12, wherein the device forms part of a retractor or other surgical instrument.

30. The neurophysiological method of claim 12, wherein the sensor forms part of a retractor or other surgical instrument.

31. A neurophysiological method, comprising the steps of:

electrically stimulating a device associated with a surgical procedure;

placing a sensor in a non-muscle region of a patent undergoing the procedure; and

detecting impulses from the device at the sensor to determine whether the device has been, or is being, properly placed.

32. The method of claim 31, including the step of placing the sensor in a spine or other region of a central nervous system.

33. The method of claim 31, including the step of placing the sensor in a vertebral body.