Systems and methods for performing neurophysiologic monitoring during spine surgery

• US 9,066,701 B1
• Filed: 02/06/2013
• Issued: 06/30/2015
• Est. Priority Date: 02/06/2012
• Status: Active Grant

• Current Assignee: Nuvasive Incorporated
• Original Assignee: Nuvasive Incorporated
• Inventors: Finley, Eric, Gharib, James, O'Brien, Richard A., Snow, Robert
• Primary Examiner(s): Yang, Andrew
• Assistant Examiner(s): Chang, Olivia C
• Application Number:
  US13/761,098
• Time in Patent Office: 874 Days
• Field of Search: 600201-246, 606/90, 606/99, 606/129
• US Class Current: 1/1
• CPC Class Codes: A61B 17/0206 with antagonistic arms as supports for retractor elements
• 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 2017/00115 with audible or visual output with imaging means A61B90/37, A61B34/20
• CPC Class Codes: A61B 2017/00199 with a console, e.g. a control panel with a display
• CPC Class Codes: A61B 2017/00225 Systems for controlling multiple different instruments, e.g. microsurgical systems
• CPC Class Codes: A61B 34/25 User interfaces for surgical systems
• CPC Class Codes: A61B 90/30 Devices for illuminating a surgical field, the devices having an interrelation with other surgical devices or with a surgical procedure

Abstract

A surgical access system comprising a tissue retraction assembly equipped with two or more electrodes for use in monitoring the status of nearby neural structures, including the localized depth of neural structures relative to one or more components of the tissue retraction assembly. Additional neurological testing may be performed to monitor the health and status of the neural structures during the portions of the surgical procedure in which the tissue retraction assembly is used to maintain the operative corridor.

Claims

1. A method for determining at least one of the depth, proximity, health, and status of the femoral nerve during lateral lumbar spine surgery, comprising:

establishing a lateral, trans-psoas operative corridor to a surgical target site in the lumbar spine using a retractor assembly including a retractor body and a plurality of retractor blades extending generally perpendicularly to the retractor body, the retractor body being operable to separate the plurality of retractor blades relative to each to retract tissue away from the interior of the retractor blades when the tissue retractor is advanced to the surgical target site and the retractor blades are separated to thereby form an operative corridor to the surgical target site, wherein at least one of the plurality of retractor blades includes at least two electrode members associated with the at least one retractor blade, the at least two electrode contacts configured to at least one of transmit an electrical stimulation signal to tissue adjacent the distal portion of the at least one retractor blade and record an evoked neurophysiologic response received by the at least one retractor blade;

placing at least one stimulation electrode in position to stimulate the inguinal ligament ipsilateral to the operative corridor;

providing a stimulation current to the stimulation electrode;

calculating a first I_Thresh value at a first recording electrode positioned within the operative corridor adjacent to an inferior aspect of the at least one retractor blade;

calculating a second I_Thresh value at a second recording electrode positioned within the operative corridor adjacent to a superior aspect of the at least one retractor blade; and

comparing the first and second I_Thresh values to determine at least one of the depth, proximity, health, and status of the femoral nerve.

2. The method of claim 1, wherein, one of the at least one retractor blade is the posterior retractor blade.

3. The method of claim 2, wherein the at least two electrode contacts are integrally formed with the retractor blade.

4. The method of claim 3, wherein the at least two electrode contacts are integrally formed on opposite side surfaces of the retractor blade.

5. The method of claim 2, wherein the at least two electrode contacts are provide on a shim member removably attached to the retractor blade.

6. The method of claim 1, wherein the step of calculating a first I_Thresh value comprises increasing the stimulation current at the stimulation electrode until a significant neuromuscular response is elicited at the first recording electrode.

7. The method of claim 1, wherein the step of calculating a second I_Thresh value comprises increasing the stimulation current at the stimulation electrode until a significant neuromuscular response is elicited at the second recording electrode.

8. The method of claim 1, wherein the first and second I_Thresh values are determined using one of a linear and a non-linear hunting algorithm.

9. The method of claim 1, wherein the steps of calculating the first I_Thresh value, calculating the second I_Thresh value, and comparing the first and second I_Thresh values are performed more than once during the portions of the surgical procedure in which the tissue retractor assembly is maintaining the operative corridor.