System and methods for performing dynamic pedicle integrity assessments

• US 8,255,044 B2
• Filed: 02/02/2010
• Issued: 08/28/2012
• Est. Priority Date: 08/05/2003
• Status: Active Grant

• Current Assignee: Nuvasive Incorporated
• Original Assignee: Nuvasive Incorporated
• Inventors: Miles, Patrick, Martinelli, Scot, Arambula, Jared, Gharib, James, Farquhar, Allen, Flanagan, Patrick
• Primary Examiner(s): Hindenburg, Max
• Assistant Examiner(s): Foreman, Jonathan M
• Application Number:
  US12/699,017
• Publication Number:
  US 20100249644A1
• Time in Patent Office: 938 Days
• Field of Search: 600/300, 600/546, 600/554, 600/595
• 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 17/3472 for bones, e.g. intraosseus injections
• CPC Class Codes: A61B 17/848 Kirschner wires, i.e. thin, long nails
• CPC Class Codes: A61B 5/24 Detecting, measuring or recording bioelectric or biomagnetic signals of the body or parts thereof
• CPC Class Codes: A61B 5/4041 Evaluating nerves condition
• CPC Class Codes: A61N 1/36003 of motor muscles, e.g. for walking assistance

Abstract

The present invention involves systems and related methods for performing dynamic pedicle integrity assessments involving the use of neurophysiology.

Claims

1. A method of delivering stimulation signals to patient tissue during surgery for monitoring neuromuscular evoked potentials, comprising the steps of:

(a) attaching an electrical coupling mechanism having a plunger with an electrical contact surface electrically coupled to a stimulation source to a surgical instrument, (b) advancing the surgical instrument into the patient tissue;

(b) applying a stimulation signal through the electrical coupling mechanism to the surgical instrument; and

(c) monitoring to assess whether nerves are innervating as a result of the step of applying said stimulation signal.

2. The method of claim 1, wherein the plunger is enclosed within a housing.

3. The method of claim 2, wherein the plunger is generally cylindrical in shape.

4. The method of claim 2, wherein the plunger is spring-loaded relative to the housing.

5. The method of claim 4, wherein the plunger is biased in a closed position.

6. The method of claim 5, wherein the housing includes a distal arm situated opposite the electrical contact surface.

7. The method of claim 4, wherein the electrical contact surface is generally arcuate.

8. The method of claim 5, wherein the electrical coupling surface is coupled to an electrical cable that is coupled to the stimulation source.

9. The method of claim 8, wherein pulling on the cable moves the plunger to an open position.

10. The method of claim 1, wherein monitoring to assess whether nerves are innervating as a result of the step of applying the stimulation signal includes detecting voltage responses of a predetermined magnitude with sensors positioned on or within muscles associated with said nerves.

11. The method of claim 10, wherein the stimulation source and the sensors are communicatively linked to a control unit.

12. The method of claim 11, wherein the control unit identifies a relationship between the stimulation signal applied and the voltage response of predetermined magnitude.

13. The method of claim 12, wherein the relationship is the lowest stimulation amplitude required to evoke the voltage response of predetermined magnitude.

14. The method of claim 13, wherein said relationship provides an indication of pedicle integrity.

15. The method of claim 1, wherein said surgical instrument is configured for at least one of pedicle hole formation, pedicle hole preparation, and pedicle screw insertion.

16. A system for monitoring electromyographic (EMG) evoked potentials during surgery, comprising:

a plurality of sensors that detect EMG responses from muscles associated with nerves located proximate to a surgical target site;

an electrical coupling mechanism having a plunger with an electrical contact surface electrically coupled to a stimulation source and coupleable to a surgical instrument to deliver stimulation signals from the stimulation source to the surgical instrument; and

a control unit in communication with the plurality of sensors and the stimulation source, the control unit being operable to (a) direct transmission of the stimulation signals;

(b) receive voltage responses from the plurality of sensors, and (c) determine whether any of the nerves are innervating as a result of the step of applying the stimulation signals to the surgical instrument.

17. The system of claim 16, wherein the surgical instrument is configured for at least one of pedicle hole formation, pedicle hole preparation, and pedicle screw insertion.

18. The system of claim 16, wherein the plunger is enclosed within a housing and spring-loaded relative to the housing.

19. The system of claim 16, wherein the electrical contact surface is generally arcuate.

20. A system for performing pedicle integrity assessments, comprising:

a surgical instrument for use in at least one of pedicle hole formation, hole preparation, and pedicle screw insertion at a pedicle target site, said pedicle target site in the general location of neural structures;

an insulation member through which said surgical instrument is passed comprising a flexible hollow elongated sheath having a proximal end, a distal end, an interior lumen, and a substantially enclosed seal tip attached to said distal end of said hollow elongated member, wherein said seal tip includes an expandable aperture for receiving said surgical instrument;

a sensor configured to detect a voltage response from muscles associated with said neural structures; and

a control unit coupled to said medical instrument and the sensor, the control unit being configured to (a) transmit a stimulation signal to said surgical instrument, (b) receive a voltage response from the sensor, and (c) determine whether said neural structures are innervating as a result of the step of applying said application of stimulation signal to said surgical instrument.