Electromyography system

• US 7,991,463 B2
• Filed: 10/31/2007
• Issued: 08/02/2011
• Est. Priority Date: 11/24/1999
• Status: Expired due to Fees

• Current Assignee: Nuvasive Incorporated
• Original Assignee: Nuvasive Incorporated
• Inventors: Marino, James F., Stone, Corbett W., Kelleher, Brian S., Owens, Jeffrey H., Vaughn, Robin H.
• Primary Examiner(s): Hindenburg; Max
• Assistant Examiner(s): Szmal; Brian
• Application Number:
  US11/982,238
• Publication Number:
  US 20080064977A1
• Time in Patent Office: 1,371 Days
• Field of Search: 600/546, 600/554, 600/545, 600/587, 606/79, 340/930, 607/143, 128/901, 128/902, 128/908
• US Class Current: 600/547
• CPC Class Codes: A61B 17/00234 for minimally invasive surgery A61B17/0218, A61B17/0469, A61B17/12013, A61B17/1285, A61B17/29, A61B17/320016 take precedence
• CPC Class Codes: A61B 2017/00022 Sensing or detecting at the treatment site
• CPC Class Codes: A61B 2017/00039 Electric or electromagnetic phenomena other than conductivity, e.g. capacity, inductivity, Hall effect
• CPC Class Codes: A61B 5/24 Detecting, measuring or recording bioelectric or biomagnetic signals of the body or parts thereof
• CPC Class Codes: A61B 5/296 for electromyography [EMG]
• CPC Class Codes: A61B 5/389 Electromyography [EMG]
• CPC Class Codes: A61B 5/4893 Nerves

Abstract

Systems for determining structural integrity of a bone within the spine of a patient, the bone having a first aspect and a second aspect, wherein the second aspect separated from the first aspect by a width and located adjacent to a spinal nerve. A stimulator is configured to generate an electrical stimulus to be applied to the first aspect of the bone. A monitor is configured to electrically monitor a muscle myotome associated with the spinal nerve to detect if an onset neuro-muscular response occurs in response to the application of the electrical stimulus to the first aspect of the bone. An adjuster is configured to automatically increase the magnitude of the electrical stimulus to until the onset neuro-muscular response is detected. Lastly, a communicator is configured to communicate to a user via at least one of visual and audible means information representing the magnitude of the electrical stimulus which caused the onset neuro-muscular response.

Claims

1. A system for determining structural integrity of a bone within the spine of a patient, the bone having a first aspect and a second aspect, said second aspect separated from said first aspect by a width and located adjacent to a spinal nerve, said system comprising:

a stimulator configured to generate an electrical stimulus to be applied to said first aspect of said bone;

a monitor configured to electrically monitor a muscle myotome associated with said spinal nerve to detect if a neuro-muscular response greater than a predetermined minimum amplitude occurs in response to the application of said electrical stimulus to said first aspect of said bone;

a processor controlled adjuster configured to automatically increase the magnitude of the electrical stimulus generated by said stimulator in a step-by-step staircase fashion until said neuro-muscular response of greater than a predetermined minimum amplitude is detected; and

a communicator configured to display, in response to said monitor detecting said neuro-mucular response, the magnitude of the electrical stimulus which caused said neuro-muscular response of greater than a predetermined minimum amplitude.

2. The system of claim 1, wherein said stimulator is configured to apply said electrical stimulus from an electrode disposed on the distal end of at least one of a probe and surgical tool.

3. The system of claim 1, wherein said stimulator is configured to apply said electrical stimulus as a plurality of electrical stimulus pulses.

4. The system of claim 1, wherein the electrical stimulus is increased within a range from 0.5 to 32.0 milliamps.

5. The system of claim 1, wherein said bone is disposed within one of the cervical, thoracic, and lumbar region of the patient'"'"'s spine.

6. The system of claim 1, wherein said neuro-muscular response of greater than a predetermined amplitude is an electromyography response from a muscle coupled to said spinal nerve.

7. The system of claim 1, wherein said monitor is configured to electrically monitor said muscle myotome through the use of an electrode electrically coupled to said muscle myotome.

8. The system of claim 1, wherein said predetermined minimum amplitude is selected from a range of about 60 mV to about 80 mV.

9. The system of claim 1, wherein said communicator is configured to display the magnitude of the electrical stimulus which caused said neuro-muscular response via at least one of illuminating lights and illuminating lights of various colors which correspond to predetermined warnings.

10. The system of claim 1 and further, wherein said communicator is configured to audibly indicate to an operator the magnitude of the electrical stimulus which caused said neuro-muscular response via at least one of sounding an alarm if said onset neuro-muscular response is detected at said predetermined intensity level and varying at least one of the volume and frequency of said alarm according to said intensity level needed to evoke said onset neuro-muscular response.

11. The system of claim 1, wherein said stimulator is configured to apply said electrical stimulus to a proximal end of a bone screw inserted into said first aspect of said bone.

12. The system of claim 1, wherein said predetermined minimum amplitude of said neuro-muscular response comprises a peak-to-peak amplitude greater than the predetermined minimum value.

13. A system for detecting a defect in a pedicle wall within the spine of a patient, said patient having a spinal nerve lying adjacent to said pedicle, said system comprising:

a stimulator configured to generate an electrical stimulus to be transmitted to said pedicle;

a monitor configured to electrically monitor a plurality of leg muscle myotome locations via a plurality of electromyographic (EMG) sensor electrodes coupled to the leg muscle myotomes locations, at least one of the leg muscle myotome locations being associated with said spinal nerve to detect if a neuro-muscular response greater than a predetermined minimum amplitude occurs in response to the transmission of said electrical stimulus to said pedicle;

a processor controlled adjuster configured to automatically adjust by constant increments the magnitude of the electrical stimulus generated by said stimulator until said neuro-muscular response of a predetermined minimum amplitude is detected; and

a communicator configured to display, in response to said monitor detecting said neuro-mucular response, the magnitude of the electrical stimulus which caused said neuro-muscular response of greater than a predetermined minimum amplitude.

14. The system of claim 13, wherein said stimulator is configured to apply said electrical stimulus from an electrode disposed on the distal end of at least one of a probe and surgical tool.

15. The system of claim 13, wherein adjusting the magnitude of the electrical stimulus by constant increments comprises applying a plurality of electrical stimulus pulses.

16. The system of claim 15, wherein the plurality of electrical stimulus pulses are increased in a step-by-step staircase fashion over time.

17. The system of claim 13, wherein the electrical stimulus is increased within a range from 0.5 to 32.0 milliamps.

18. The system of claim 13, wherein said pedicle is disposed within one of the cervical, thoracic, and lumbar region of the patient'"'"'s spine.

19. The system of claim 13, wherein said predetermined minimum amplitude is selected from a range of about 60 mV to about 80 mV.

20. The system of claim 13, wherein said communicator is configured to display the magnitude of the electrical stimulus which caused said neuro-muscular response via illuminating lights.

21. The system of claim 20, wherein said communicator is configured to display the magnitude of the electrical stimulus which caused said neuro-muscular response via illuminating lights of various colors which correspond to predetermined warnings.

22. The system of claim 13, and further, wherein said communicator is configured to audibly indicate to an operator the magnitude of the electrical stimulus which caused said neuro-muscular response by sounding an alarm corresponding to the determined magnitude.

23. The system of claim 22, and further, wherein said communicator is configured to audibly indicate to an operator the magnitude of the electrical stimulus which caused said neuro-muscular response by varying at least one of the volume and frequency of said alarm according to said magnitude needed to evoke said neuro-muscular response.

24. The system of claim 13, wherein said stimulator is configured to apply said electrical stimulus to a proximal end of a bone screw inserted into said pedicle.

25. The system of claim 13, wherein said predetermined minimum amplitude of said neuro-muscular response comprises a peak-to-peak amplitude greater than the predetermined minimum value.