Electromyography system

• US 20080065178A1
• Filed: 10/31/2007
• Published: 03/13/2008
• Est. Priority Date: 11/24/1999
• Status: Abandoned Application

• Current Assignee: Nuvasive Incorporated
• Original Assignee: Nuvasive Incorporated
• Inventors: Kelleher, Brian, Stone, Corbett, Marino, James, Owens, Jeffrey, Vaughn, Robin
• Application Number:
  US11/981,891
• Publication Number:
  US 20080065178A1
• Time in Patent Office: Days
• US Class Current: 607/99
• 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

A method of determining relative neuro-muscular response onset value thresholds for a plurality of spinal nerves, comprising: depolarizing a portion of the patient'"'"'s cauda equina; and measuring the current intensity level at which a neuro-muscular response to the depolarization of the cauda equina is detected in each of the plurality of spinal nerves. A method for detecting the presence of a nerve adjacent the distal end of at least one probe, comprising: determining relative neuro-muscular response onset values for a plurality of spinal nerves; emitting a stimulus pulse from a probe or surgical tool; detecting neuro-muscular responses to the stimulus pulse in each of the plurality of spinal nerves; and concluding that the electrode disposed on the distal end of the at least one probe is positioned adjacent to a first spinal nerve when the neuro-muscular response detected in the first spinal nerve is detected as a current intensity level less than or equal to a corresponding neuro-muscular response onset value of the first spinal nerve.

Claims

1. A system for determining the proximity of a nerve during surgical access to a spinal target site, comprising:

an instrument configured for advancement through the body tissue of a patient and equipped with an electrode situated near a distal end of said instrument for emitting a stimulation signal of know intensity through while advancing said instrument to said target site;

a stimulator for delivering said stimulation signal to said electrode;

an adjuster for varying the intensity of the stimulation signal generated by said stimulator for delivering to said body tissue through said electrode;

at least one sensor positioned at least one of within and near a myotome for detecting a neuro-muscular response evoked by said stimulation signal;

a signal processor in communication with said sensor for processing said neuro-muscular response and communicating said processed signal to a controller;

a controller in communication with said stimulator and said signal processor, said controller configured to compare the stimulation intensity level at which a neuro-muscular response was detected to a predetermined stimulation intensity level to indicate the relative proximity of said spinal nerve to said distal end of said instrument; and

a communicator for communicating the relative proximity determined by the controller to a user.

2. The system of claim 1, wherein said instrument is a surgical probe.

3. The system of claim 1, wherein said instrument is a surgical access instrument.

5. The system of claim 1, wherein said stimulator may vary at least one of the pulse frequency and pulse duration of the stimulation signal.

6. The system one of claim 1, wherein the adjuster is configured to adjust the intensity level of the stimulation signal until said neuro-muscular response is detected.

7. The system of claim 6, wherein the adjuster is configured to allow incremental adjustments of the stimulation signal.

8. The system of claim 1, wherein said communicator is configured to at least one of visually and audibly indicating to said user the relative proximity of a nerve to said distal end of said instrument.

9. The system of claim 8, wherein said communicator includes at least one LED.

10. The system of claim 8, wherein said communicator includes an LCD screen.

11. The system of claim 1, wherein said communicator is implemented individually.

12. The system of claim 8, wherein said communicator sounds an alarm to indicate the relative proximity determined.

13. The system of claim 12, wherein the volume of the alarm is varied depending on the relative proximity determined.

14. The system of claim 12, wherein the frequency of the alarm is varied depending on the relative proximity determined.

15. The system of claim 8, wherein the communicator displays a color to indicate the relative proximity determined.

16. The system of claim 15, wherein the color is varied depending on the relative proximity of the nerve detected.

4. The system of claim 4, wherein said instrument is a cannula.