US20220331591A1

US20220331591A1 - Spinal cord stimulator electrode positioning system

Info

Publication number: US20220331591A1
Application number: US17/723,197
Authority: US
Inventors: Karthik Seshan; Craig Crookston; Rahul Gole; Jeremy Bamford; Chris Martin
Original assignee: Spinestim Nm LLC
Current assignee: Spinestim Nm LLC
Priority date: 2021-04-16
Filing date: 2022-04-18
Publication date: 2022-10-20
Also published as: US20220331593A1; US20220330878A1

Abstract

A Spinal Cord Stimulator (SCS) electrode placement system that includes a stimulator, at least one amplifier, a processing unit, the processing unit programmable with software. The automated system aids surgeons in placing SCS electrodes by determining neurophysiologic position. It does this by adjusting parameters and stimulating the muscles of a patient from the SCS electrode to capturing electrophysiologic signal such as Electromyography (EMG) data from different muscles. This data is then collected at various positions on the SCS electrode and then aggregated to display the location of the SCS electrode. The data is then visually outputted to the surgeon to help make a lateralization decision. All aspects of the system can be manually adjusted by the surgeon.

Description

CROSS REFERENCE TO RELATED APPLICATIONS

The present application claims the benefit of U. S. Provisional Patent Application No. 63/175,944 filed Apr. 16, 2021, entitled “Spinal Cord Stimulator Electrode Positioning System (“SCS-EPS”),” the entire disclosure of which is hereby incorporated herein by reference.

FIELD OF THE DISCLOSURE

Exemplary embodiments of the subject disclosure generally relate to a medical device in the field of neuromodulation for assisting in the placement of spinal cord stimulation electrodes, and more particularly related, to the placement of spinal cord electrodes for use in spinal cord stimulation therapy.

BACKGROUND

The subject matter discussed in the background section should not be assumed to be prior art merely as a result of its mention in the background section. Similarly, a problem mentioned in the background section or associated with the subject matter of the background section should not be assumed to have been previously recognized in the prior art. The subject matter in the background section merely represents different approaches, which in and of themselves may also correspond to implementations of the claimed technology.
Spinal cord stimulation (SCS) therapy is often used to deliver electrical stimulation to activate areas of a spinal cord to treat or manage chronic pain for a patient suffering from failed back surgery syndrome (FBSS) and chronic pain. Typically, SCS therapy makes use of spinal cord stimulators. The spinal cord stimulators are surgical implants used to treat FBSS and chronic pain by stimulating areas of the spinal cord containing the sensory and other specific tracts, thereby minimizing or masking pain signals from reaching the patient's brain. Further, SCS therapy allows a surgeon or a doctor to tailor treatment based on the patient's individual needs.
Further, SCS therapy includes two phases, the first phase is a trial phase, and the second phase is a permanent lead placement phase. It can be noted that temporary trials are placed in-office setting using lead electrodes, and the lead electrodes are placed using a small needle. The lead electrodes are further attached to an external battery. After a successful trial, SCS electrodes are placed intraoperatively by performing a small laminectomy to make space to insert and place the electrodes under fluoroscopy inside the patient's body (near the patient's spinal cord). Thus, such accurate placement of the SCS electrode impacts spinal cord stimulation treatment efficacy, and error in that can lead to a failure.
Currently, due to various complexities involved and lack of precision, the SCS electrode placement is less efficient. The SCS electrode placement has a 29% failure rate, and 34% of failures are due to inadequate pain relief. Suboptimal intraoperative electrode placement is a leading factor. The use of fluoroscopy, anatomical landmarks for the SCS electrode placement, and assuming that spinal column anatomy reflects the anatomical positioning of the spinal cord. However, the center of the spinal cord may be more than 2 mm from the canal center in 40% of patients, and imaging of the actual spinal cord intraoperatively is expensive and time-consuming due to the use of techniques like O-arm and I-Magnetic resonance imaging (MRI). Further, functional mapping is performed manually, using specialized equipment run by a neurophysiologist with oversight, thus adding to the overall expenditure, labor, and time of the SCS therapy.
Numerous prior arts exist that disclose monitoring the muscle movement, electrodes, and control unit to send the pulses out to the spinal cord. However, there is a need to enhance surgeons' efficiency and safety using pre-clinical and real-time data. Further, there is a need for an automated way to assess the electrodes' functional placement and modify the stimulation and recording parameters. Further, there is a need to allow the surgeon or doctor to view and modify the stimulation parameters. Therefore, there is a need for an improved system to facilitate accurate and efficient placement of spinal cord electrodes for use in spinal cord stimulation therapy.

SUMMARY

Various embodiments of the disclosure provide an electrode positioning system that provide for visualization of a Spinal Cord Stimulator (SCS) electrode, spinal cord location, detection, and validation of the placement of the SCS electrode relative to the spinal cord. In accordance with an exemplary embodiment of the subject disclosure, an electrode positioning system is provided. The electrode positioning system includes a pulse generator, the pulse generator configured to generate electrical pulse currents based on a parameter; a Spinal Cord Stimulator (SCS) electrode, the SCS electrode configured to apply the generated electrical pulse currents at a contact point from a plurality of contact points; a recording electrode configured to measure electrophysiologic signals triggered by application of the generated electrical pulse currents; an output device configured to indicate the contact point of the SCS electrode; and a base unit, the base unit having a processor configured to: analyze measured electrophysiologic signals, by: performing an electrical stimulation cycle methodology, performing a lateralization based on the electrical stimulation cycle methodology, determining a mid-contact point of the SCS electrode based on the electrical stimulation cycle methodology and the lateralization, identifying a location of a length of the spinal cord based on the determined mid-contact point, and identifying a location of the SCS electrode relative to the location of the length of the spinal cord based on an aggregation of the measured electrophysiologic signal, and outputting the location of the length of the spinal cord and the location of the SCS electrode to the output device.
In accordance with an aspect of the subject disclosure, the output device includes a display, and wherein the processor is further configured to output the location of the length of the spinal cord on the display.
In accordance with another aspect of the subject disclosure, the processor is further configured to display the location of the SCS electrode relative to the location of the length of the spinal cord based on the measured electrophysiologic signal.
In accordance with still another aspect of the subject disclosure, the processor is further configured to display an overlay of the location of the SCS electrode and the location of the spinal over an image captured by another modality of an area surrounding the SCS electrode.
In accordance with yet another aspect of the subject disclosure, the measured electrophysiologic signal is an electromyography (EMG) signal or a Compound Muscle Action Potential (CMAP).
In accordance with still another aspect of the subject disclosure, the measured electrophysiologic signal indicates a level of myotomal activation.
In accordance with yet another aspect of the subject disclosure, the base unit further includes an amplifier configured to amplify the measured electrophysiologic signal.
In accordance with still another aspect of the subject disclosure, the electrical stimulation cycle methodology includes: generating electrical pulse currents based on the parameter; applying the generated electrical pulse currents at the contact point; measuring electrophysiologic signals triggered by the application of the generated electrical pulse currents; comparing the measured electrophysiologic signals to a reference electrophysiologic signal; determining a deviation based on the comparison; adjusting the parameter based on the deviation; repeating the generation of the electrical pulse currents, the application of the generated electrical pulse currents, the measurement of the electrophysiologic signals, the comparison of the measured electrophysiologic signals, the determination of the deviation, and the adjusting of the parameter until the deviation is minimized; storing the contact point of the SCS electrode in which the deviation is minimized in a memory as stored data; and moving the SCS electrode to another contact point of the plurality of contact points and repeating the generation of the electrical pulse currents, the application of the generated electrical pulse currents, the measurement of the electrophysiologic signals, the comparison of the measured electrophysiologic signals, and the determination of the deviation until the plurality of contact points has been exhausted.
In accordance with yet another aspect of the subject disclosure, the adjusting the parameter includes incrementally increasing an intensity of the generated electrical pulse currents, changing a pulse width of the generated electrical pulse currents, or changing a pattern of the generated electrical pulse currents.
In accordance with still another aspect of the subject disclosure, the moving of the SCS electrode contact point includes a rostral-to-caudal or a left-to-right directional movement.
In accordance with yet another aspect of the subject disclosure, the electrical stimulation cycle methodology further includes determining whether the parameter is within a predetermined threshold after being adjusted.
In accordance with still another aspect of the subject disclosure, performing the lateralization includes: determining a Root Mean Square (RMS) value of the stored data; comparing the RMS value of the stored data corresponding to one of the plurality of contact points to the RMS value of the stored data corresponding to another one of the plurality of contact points; calculating a ratio between the RMS value of the stored data corresponding to the one of the plurality of contact points and the RMS value of the stored data corresponding to another one of the plurality of contact points; designating the one of the plurality of contact points as a left contact point, upon the ratio being less than 1; designating the one of the plurality of contact points as a right contact point, upon the ratio being more than 1; designating the one of the plurality of contact points as the mid-contact point, upon the ratio being 1, and storing the designated mid-contact point; repeating the determining, the comparing, the calculating, and the designating for each data of the plurality of contact points; and collating the plurality of contacting points that are designated as the mid-contact point to form a midline, wherein the midline corresponds to a length of a spinal cord.
In accordance with another exemplary embodiment of the subject disclosure, an electrode positioning method is provided. The electrode positioning method includes attaching a recording electrode on a patient; using the recording electrode, receiving an electrophysiologic signal from muscles of the patient that is triggered by electrical pulse currents applied by a Spinal Cord Stimulator (SCS) electrode of the electrode positioning system of claim 1, wherein electrode positioning system is configured to: perform an electrical stimulation cycle methodology, perform a lateralization based on the electrical stimulation cycle methodology, determine a mid-contact point of the SCS electrode based on the electrical stimulation cycle methodology and the lateralization, identify a location of a length of the spinal cord based on the determined mid-contact point, and identify a location of the SCS electrode relative to the location of the length of the spinal cord, based on an aggregation of the received electrophysiologic signal; output the location of the length of the spinal cord and the location of the SCS electrode to the output device; and repositioning the SCS electrode based on the outputted location of the length of the spinal cord and the location of the SCS electrode.
In accordance with another exemplary embodiment of the subject disclosure, an electrode positioning system is provided. The electrode positioning system has a non-transitory computer readable medium having stored thereon instructions for causing a processing circuitry configured to perform the steps of: performing an electrical stimulation cycle methodology; performing a lateralization based on the electrical stimulation cycle methodology; determining a mid-contact point of the SCS electrode based on the electrical stimulation cycle methodology and the lateralization; identifying a location of the spinal cord based on the determined mid-contact point; identifying the location of the SCS electrode the length of the spinal cord and the location of the SCS electrode and the midpoint signal; and outputting the location of the length of the spinal cord and the location of the SCS electrode and the midpoint to an output device.

BRIEF DESCRIPTION OF THE DRAWINGS

The accompanying drawings illustrate various embodiments of systems, methods, and embodiments of various other aspects of the disclosure. Any person with ordinary skills in the art will appreciate that the illustrated element boundaries (e.g., boxes, groups of boxes, or other shapes) in the figures represent one example of the boundaries. In some examples, one element may be designed as multiple elements, or multiple elements may be designed as one. In some examples, an element shown as an internal component of one element may be implemented as an external component in another and vice versa. Furthermore, elements may not be drawn to scale. Non-limiting and non-exhaustive descriptions are described with reference to the following drawings. The components in the figures are not necessarily to scale, emphasis instead being placed upon illustrating principles.

FIG. 1 illustrates a schematic diagram of a medical device system, according to an embodiment.

FIG. 2 illustrates a schematic diagram of a spinal cord stimulator (SCS) system to facilitate the placement of spinal cord electrodes, according to an embodiment.

FIG. 3A illustrates a block diagram showing electrode connections in the SCS system, according to an embodiment.

FIG. 3B illustrates the block diagram showing electrodes connection in the SCS system, using an adaptor, according to another embodiment.

FIG. 4A illustrates a block diagram showing a user interface (UI) for allowing a surgeon to input stimulation parameters in the SCS system, according to an embodiment.

FIG. 4B illustrates a block diagram showing an exemplary UI for allowing the surgeon to select electrode type in the SCS system, according to an embodiment.

FIG. 5 illustrates a block diagram showing an exemplary scenario of the SCS system, according to an embodiment.

FIG. 6 illustrates a block diagram showing the UI which facilitates the surgeon to start lateralization in the SCS system, according to an embodiment.

FIG. 7A illustrates a diagram showing datasheets related to lateralization of the SCS electrode, according to an embodiment.

FIG. 7B illustrates a diagram showing datasheets related to lateralization of the SCS electrode, according to an embodiment.

FIG. 7C illustrates a diagram showing datasheets related to lateralization of the SCS electrode, according to an embodiment.

FIG. 8A illustrates a block diagram showing the UI which facilitates the surgeon to run the neuromodulation method, according to an embodiment.

FIG. 8B illustrates a flow chart showing the method of neuromodulation in the SCS system, according to an embodiment.

FIG. 9A illustrates a block diagram showing the UI which displays the surgeon a failure status corresponding to the neuromodulation method, according to an embodiment.

FIG. 9B illustrates a block diagram showing the UI which displays the surgeon a pass status corresponding to the neuromodulation method, according to an embodiment.

FIG. 10 illustrates a block diagram showing the UI having a heat map, a visual box, a decision box, and one or more input boxes to receive input from the surgeon, according to an embodiment.

FIG. 11A illustrate a flow chart showing a method of operation of the SCS system, according to an embodiment.

FIG. 11B illustrate a flow chart showing a continued method of operation of the SCS system, according to an embodiment.

DETAILED DESCRIPTION

Some embodiments of this disclosure, illustrating all its features, will now be discussed in detail. The words “comprising,” “having,” “containing,” and “including,” and other forms thereof are intended to be equivalent in meaning and be open-ended in that an item or items following any one of these words is not meant to be an exhaustive listing of such item or items, or meant to be limited to only the listed item or items.
It must also be noted that as used herein and in the appended claims, the singular forms “a,” “an,” and “the” include plural references unless the context dictates otherwise. Although any systems and methods similar or equivalent to those described herein can be used to practice or test embodiments of the present disclosure, the preferred systems and methods are now described.
Embodiments of the present disclosure will be described more fully hereinafter with reference to the accompanying drawings in which like numerals represent like elements throughout the several figures and in which example embodiments are shown. However, embodiments of the claims may be embodied in many different forms and should not be construed as limited to the embodiments set forth herein. The examples set forth herein are non-limiting examples and are merely examples among other possible examples.
FIG. 1 illustrates a medical device system 100, according to an embodiment. As currently practiced, the medical device system 100 may include an electrode representative 102, an Intraoperative Neuromonitoring (IONM) clinician 104, and a surgeon 106. It can be noted that all may be communicating with each other to treat a patient 108 by accurately placing a spinal cord stimulator (SCS) electrode 110 in the patient's body.
At first, the electrode representative 102 may control the stimulation of the SCS electrode 110 and contact points of the SCS electrode 110. In one embodiment, the SCS electrode 110 may be placed inside the patient's body, such as, but not limited to, along a dorsal column of the spinal cord of the patient 108. Successively, the stimulation of the SCS electrode 110 may generate signals to mask or mitigate pain signals from reaching the brain of the patient 108, suffering from failed back surgery syndrome (FBSS) and chronic pain, based on one or more stimulation parameters. Examples of the one or more stimulation parameters may include but are not limited to pulse width, stimulation intensity, stimulation pattern repetition rate, and frequency. Successively, the patient's body may respond to the stimulation of the SCS electrode 110. The position of the SCS electrodes 110 may also be a stimulation parameter that can be adjusted. In an exemplary embodiment, the SCS electrode 110 may be manufactured by different manufacturers such as but not limited to Medtronic, Boston Scientific, and Abbott Laboratories.
Further, the SCS electrode 110 may be either paddle electrodes or cylindrical electrodes. In the case of paddle electrodes, a laminectomy may be required to implant the paddle electrodes in the patient's body. Further, in the case of cylindrical electrodes, the patient 108 might be lightly sedated, as the surgeon 106 slides the electrodes along the spinal cord in a procedure requiring minimal surgical manipulation. Further, there are different types of orientation of the SCS electrodes 110. It will be apparent to one skilled in the art that the examples mentioned above of SCS electrode 110 have been provided only for illustration purposes, without departing from the scope of the disclosure.
Further, the recording electrodes 112 placed on the muscles of the patient 108 may measure electromyography (EMG) activity in the patient 108 in the specific area of nerves where the SCS electrode 110 is positioned. In one exemplary embodiment, the recording electrodes 112 may be subdermal. In another exemplary embodiment, sticky pads may be used instead of recording electrodes 112 to measure the EMG activity. EMG data refers to any neurophysiologic data that is output by the patient 108 and measured by the recording electrodes 112, in response to the electric current output by the system 100 and applied by the SCS electrode 110. Successively, EMG signals or compound muscle action potential (CMAP) signals may be sent to the IONM clinician 104. The IONM clinician 104 may assist the surgeon 106 with analysis or lateralization based on the received signals. In one embodiment, interpretation may refer to a deduced meaning of the signals received from the recording electrodes 112. Further, lateralization may refer to adjusting the SCS electrode 110 in the patient's body. After that, the surgeon 106 may take appropriate action based on the analysis of the signals. After the clinician gives feedback on the SCS electrode 110, the surgeon can do the following things: 1—Physically move the SCS electrode 110 across the spinal cord (lateralization) to get better responses. 2—change which contact points on the SCS electrode 110 are being stimulated to see if you can get better responses. 3—ask the rep to change the stimulation parameters to acquire better signal data. In one case, the surgeon 106 may perform manual adjustment, i.e., movement of the SCS electrode 110 from one position to another. In another case, the surgeon 106 may perform lateralization. In another case, the surgeon 106 may send the stimulation parameters or contact points to the electrode representative 102 to adjust the SCS electrode 110 in the patient's body. Stimulation parameters include adjusting the power, intensity, repetition rate of a current pattern, and frequency on the stimulating SCS electrodes 110.
FIG. 2 illustrates a schematic diagram of a spinal cord stimulator (SCS) system 200 to facilitate placement of the SCS electrode 110, according to an embodiment. It should be noted that the SCS system 200 may take input from different SCS electrodes 110. The SCS system 200 may automate functional myotomal mapping of the spinal cord to optimize the placement of the SCS electrode 110. The myotomal mapping may be achieved by an algorithm for lateralization, neuromodulation, and interpretation to optimize placement of the SCS electrode 110, wherein the algorithm for lateralization may be for placement of the SCS electrode 110 at the center of the spinal cord. Further, neuromodulation may be for modulation or adjustment of the stimulation and recording parameters by delivering electrical impulse directly to a target area, and interpretation may be for processing and visualization of placement of the SCS electrode 110. Here, adjustments to recording parameters may include adjustments to gains and filters with respect to the recording electrodes 112.
The SCS system 200 may allow the surgeon 106 to accurately place the SCS electrode 110 inside the patient's body to maximize its effectiveness in mitigating and mediating pain in the patient's spinal cord 108. The SCS system 200 may be a surgeon-controlled standalone unit that guides the surgeon 106 in the placement of the SCS electrode 110 using neurophysiological data to optimize the position of the SCS electrode 110 and stimulation level for the SCS electrode 110, to optimize pain control of the patient 108. Further, the SCS system 200 may allow the surgeon 106 to easily modify and optimize stimulation and position of the SCS electrode 110 in substantially real-time without the need for additional clinical resources that are often costly and time-consuming. Further, the SCS system 200 may reduce risk by allowing the patient 108 to be placed under general anesthesia during the initial placement of the SCS electrodes 110. Such SCS system 200 may limit exposure of a patient's spinal cord during the initial placement of the SCS electrode 110 on the spinal cord.
As shown in FIG. 2, the SCS system 200 may include a stimulator 202 and a base unit 204 (e.g., a device, a receiver, or an amplifier unit including an amplifier). In one embodiment, the stimulator 202 may be configured as a pulse generator. The stimulator 202 may be in communication with the SCS electrode 110. Further, the stimulator 202 may be operable to generate electrical pulses based on a variety of predetermined parameters provided by the surgeon 106 and based on the individual needs of the patient 108. In one embodiment, the predefined parameters may be referred to as stimulation parameters. The stimulation parameters may include but are not limited to pulse width, stimulation intensity, repetition rate, and frequency. For example, pulse widths within the time range outside a physical muscle movement may be eliminated. For a second example, intensity that is below a given predetermined threshold may be considered noise. For a third example, a repetition rate of a signal greater than the time range outside a physical muscle movement may be eliminated and considered noise. The position of the SCS electrodes 110 may also be a stimulation parameter that can be adjusted. It should be noted that the electrical pulses may be used to negate and/or mitigate pain in targeted regions of the patient 108, for example, in the lower back and legs of the patient 108.
Successively, the stimulator 202 may send the electrical pulses to the SCS electrode 110 to help with the myotomal mapping. Further, the recording electrodes 112 attached to the patient 108 may measure EMG data or activity in the patient 108 in the specific area of nerves where the SCS electrode 110 is positioned. Further, the EMG activity may be triggered by nerve activation resulting from electrical pulses sent to the SCS electrode 110. In one exemplary embodiment, the recording electrodes 112 may be subdermal recording electrodes 112. In another exemplary embodiment, sticky pads may be used instead of recording electrodes 112 to measure the EMG activity. Further, the SCS system 200 includes the base unit 204 that amplifies with an amplifier (not shown) and analyzes the EMG data received from the recording electrodes 112. Further, the base unit 204 may detect the type of the SCS electrode 110, based at least on different parameters such as the manufacturing company and pin configuration of the SCS electrode 110.
Further, the base unit 204 may include an algorithm module (I.e., processor programmed with application or software stored in a memory) 206 and a display device 208. In some embodiments, there may not be a separate display device 208, but rather export HDMI video information that can be y-adapted to a fluoroscopy screen such that the animated image of the cord location identified by the algorithm module 206 can be superimposed over the fluoroscopy screen (or a screen showing image captured using another modality) and displayed on the display device 208 in real time. In an embodiment, the superimposed image may also be saved in data storage or memory (not shown). That way, the physician simply has to look at one screen, and on it, they get a view of the bony vertebral column and the cord's location at the same time in the same image. This integration may require a reference point to ensure the two are aligned, but that is doable using a radiopaque marker in the surgical field or the electrode array itself. Waveform images may be ported to an HDMI output to another monitor in the room. If the device remains in the room between procedures, then a dedicated monitor could be set up or included as a video set that the control room manages. Electrophysiology labs, in particular, are very adept at routing tracings in this way, though for a surgical suite, some staff training may be required. The algorithm module 206 may process the EMG data using an algorithm to filter the EMG data. The EMG data is filtered to reduce the impact of artifacts generated by the stimulator 202. EMG data can also be filtered to remove any ambient noise in the room or usually introduced by other noisy equipment like OR lights, OR Bed, bear hugger, etc. It can be noted that the EMG data corresponds to real-time data. In another embodiment, the algorithm module 206 may access pre-clinical data related to the SCS electrode 110 and the recording electrodes 112. Further, the algorithm module 206 may compare the pre-clinical data to the real-time data. Based at least on the comparison of the pre-clinical data to the real-time data, the algorithm module 206 can identify and display whether the real-time position of the SCS electrode 110 is the same as the pre-clinical position, and if the positions are not the same, determine how far the real-time position of the SCS electrode 110 is from the pre-clinical position. In one embodiment, the algorithm module 206 may store the pre-clinical and real-time data in a data storage (e.g., memory) 207.
In another embodiment, the algorithm module 206 may display the compared data on the display device 208 for the surgeon 106. The display device 208 may be configured to display the compared data such as, but not limited to, the EMG activity, position of SCS electrode 110, the stimulation parameters that were used at each contact point for the SCS electrode 110 for the surgeon 106. The display device 208 displays the difference in the real-time data, the pre-clinical data, and the current lateral position of the SCS electrode 110. The stimulation parameters may include but are not limited to pulse width, stimulation intensity, repetition rate, and frequency. The surgeon 106 may view the processed data so that the surgeon 106 can take the appropriate action. The action may be, but not limited to, changing the position of the SCS electrode 110, changing stimulation parameters related to the recording electrodes 112, changing which contact points on the electrode are being stimulated to see if a better response can be generated, and changing electrode type. It can be noted that such use of the algorithm module 206 may optimize the placement of the SCS electrode 110.
In one embodiment, the display device 208 may correspond to output devices including, but not limited to, video displays, graphical displays, speakers, headphones. It can be noted that the function of the display device 208 may indicate to the surgeon 106 related to the EMG data. In another embodiment, the display device 208 may correspond to an input/output device like a touch screen, capable of receiving inputs from the surgeon 106, such as selecting the desired option, at the display device 208. In one embodiment, the SCS electrode 110 may be connected to the base unit 204 via an adapter, as explained in conjunction with FIG. 3A and FIG. 3B.
Further, the display device 208 may be connected to an external screen or monitor to visualize the location of the SCS electrode 110, based on the EMG activity from the algorithm module 206. In one embodiment, the external screen or monitor may display the relative location of SCS electrode 110 on the spinal column based on EMG activity in real-time. The visualization of the SCS electrode 110 may vary based on the vendor and type of stimulator electrodes utilized. Additionally, the external display may provide a visual representation of the dermatomes and/or myotomes, i.e., areas of skin/muscles, that the SCS electrode 110 is activating. It can be noted that the SCS system 200, via the display device 208, may receive feedback for positioning the SCS electrode 110 in real-time.
In another embodiment, the displayed data may be used by the surgeon 106 to adjust parameters related to the SCS electrode 110 and the location of the SCS electrode 110. In yet another embodiment, the parameters related to the recording electrodes 112 may be adjusted based on workflow or experience of the surgeon 106, i.e., doctor (i.e., what the doctor's experience is doing). In one embodiment, the parameters related to the recording electrodes 112 may be adjusted based on neurophysiology (i.e., needles are in the right place, but nerves don't react) or placement of the recording electrodes 112 workflows or experience of the surgeon 106. Further, the parameters related to the recording electrodes 112 may be modified manually by the surgeon 106, based upon muscle responses and data gathered from the recording electrodes 112. In one embodiment, the algorithm module 206 may allow the surgeon 106 to manually modify stimulation parameters and position of the SCS electrode 110, based on the lateral location of the SCS electrode 110 displayed by the display device 208.
There are various scenarios of the algorithm module 206 for adjusting the stimulation parameters applied to the SCS electrode 110. In one exemplary scenario, the algorithm module 206 may be configured to adjust the parameters applied to each SCS electrode 110 based upon what is happening in the workflow of the surgeon 106 or doctor (i.e., what the doctor is doing during a procedure). In a first scenario, the algorithm module 206 may run a gamut of stimulation parameters applied to the SCS electrode and monitor any changes in the EMG response to the SCS electrode 110 stimulation. When no response is monitored in the EMG activity, a “no response” record is recorded in the system 200, the parameter may be adjusted (e.g., current may be increased), and the sequence may run again, to ensure the presence of the EMG response.
In another exemplary scenario, the algorithm module 206 may be configured to perform an impedance check on the SCS electrode 110. This ensures that the SCS electrode 110 is making proper contact with actual tissue. Here, a pulse is applied to the SCS electrode 110, and impedance is recorded by the recording electrode 112. If no impedance is recorded, then it may be gathered that the SCS electrode 110 is not properly contacting the tissue, such as a spinal cord. Alternatively, it may also be the case that the recording electrode 112 is not properly contacting the muscles for recording the impedance.
For example, Alex suffers from back pain around his spinal cord's 7th, 8th, and 9th thoracic levels, and Dr. T. is operating on Alex. The SCS electrode 110 is initially placed near the midline of the spinal cord at the 9^ththoracic level of the spinal cord of Alex. Further, the recording electrodes 112 collect real-time data related to Alex, like EMG activity and lateral location of the SCS electrode 110 at the 9^ththoracic level of the spinal cord of Alex. On the other hand, the algorithm module 206 accesses pre-clinical data indicating that Alex experiences minimum pain when the SCS electrode 110 is positioned at the lateral right of the midline of the spinal cord of Alex. Further, the algorithm module 206 compares the real-time data of SCS electrode 110 at the midline of the spinal cord of Alex to the pre-clinical data of the position of the SCS electrode 110 at the lateral left of the midline of the spinal cord. Based at least on the comparison, the algorithm module 206 may adjust the stimulation parameters, (e.g., the intensity of electric current to be reduced by 0.5 milli-ampere (mA)) and/or the position of the SCS electrode 110, (e.g., changes the position of the SCS electrode 110 to the lateral left of the midline of the spinal cord of Alex) that optimizes therapeutic effect for Alex, in which the pain signals being suffered by Alex may be effectively interrupted by the stimulation from reaching the brain. Here, pain signals may separately be measured by the EMG response of the patient.
In another case, based on the comparison, the algorithm module 206 provides an output signal to the display device 208, indicating a difference in the real-time and pre-clinical data. The display device 208 displays the difference in the real-time data, the pre-clinical data, and the current lateral position of the SCS electrode 110 at the 9^ththoracic level of the spinal cord of Alex. Based on the displayed data, Dr. T. changes the position of the SCS electrode 110 to the lateral left of the midline of the spinal cord of Alex. In another embodiment, Dr. T. changes stimulation parameters like the intensity of electric current to be reduced by 0.5 milli-ampere (mA) and thus reduces the pain experienced by Alex.
In one embodiment, the base unit 204 may include a User Interface (UI) to manually allow the surgeon 106 to enter the stimulation parameters to modify the placement of the SCS electrode 110 based upon muscle responses and data from the subdermal electrode, as explained in conjunction with FIG. 4A and FIG. 4B. In one embodiment, the surgeon 106 may adjust the placement of the SCS electrode 110 and not adjust the stimulation parameters. In another embodiment, the surgeon 106 may adjust the stimulation parameters and not adjust electrode placement without departing from the scope of the disclosure. The user interface may allow the EMG data to be overlayed on top of imaging data of another modality (e.g., fluoroscopy data) to allow the surgeon to see all the data he needs in one place.
FIG. 3A illustrates a block diagram 300 showing electrodes connection in the base unit 204, according to an embodiment. FIG. 3A is explained in conjunction with FIG. 3B, which illustrates the block diagram 300 showing the SCS electrode 110 connected with the base unit 204, according to another embodiment. In one embodiment, when the SCS electrode 110 is directly compatible with the base unit 204, then the SCS electrode 110 is connected directly to the base unit 204 of the SCS system 200, via an input 302 (e.g., a plug), as shown in FIG. 3A. It should be noted that once the SCS electrode 110 is in the base unit 204 of the SCS system 200, it may initialize. In another embodiment, when the SCS electrode 110 is not directly compatible with the base unit 204, then the SCS electrode 110 is connected indirectly to the base unit 204, using an adaptor 304, as shown in FIG. 3B.
As shown in FIG. 4A, the base unit 204 may include a user interface (UI) 402 to manually allow the surgeon 106 to manually enter the stimulation parameters to modify the placement of the SCS electrode 110 based upon muscle responses (e.g., contractions) triggered by SCS electrode 110 stimulation and data from the recording electrodes 112. It can be noted that the recording electrodes 112 may be used to record the EMG data associated with patient 108. The recording electrodes 112 may record the EMG data associated with the patient 108 in a specific target area of the nerves where the SCS electrodes 110 are positioned. In one embodiment, the UI 402 may include a first button 404 for adjusting stimulation parameters for the SCS electrodes 110. In an exemplary scenario, the UI 402 may be used to manually allow stimulation parameters and modifying the recording parameters based on muscle responses and data from a subdermal electrode or impedance. In another embodiment, the UI 402 may include a second button 406 to select a particular electrode type, as shown in FIG. 4B. In another embodiment, the UI 402 may include a third button 408 to view results corresponding to changes in the stimulation parameters, based on the muscle responses and the EMG activity received from the recording electrodes 112.
FIG. 4B illustrates an exemplary user interface (UI) 402 showing an electrode selection page 410 displayed for the surgeon 106. It can be noted that once an electrode is selected (as shown in FIG. 4A), the SCS system 200 initializes a protocol to detect or select an electrode. In one embodiment, the electrode selection page 410 may display a list of currently available electrodes used in the market from various manufacturers. Further, the UI 402 may request the surgeon 106 select an electrode from the list. Further, the electrode selection page 410 may include an auto-detect button 412, facilitating automatic detection of the type of the SCS electrode 110. Based on the selection or detection of the SCS electrode 110, the SCS system 200 may initialize the electrode type. Successively, based on the electrode type, the SCS system 204 may recognize the orientation of contact points 414 of the SCS electrode 110, as shown in FIG. 4B.
FIG. 5 illustrates a block diagram 500 showing an exemplary setup of the SCS system 200, according to an embodiment. The SCS electrode 110 may be connected to the SCS system 200 through the inputs 302 of the base unit 204 (shown as a device in FIG. 5). Further, the recording electrodes 112 may hook up to the patient 108 to the appropriate muscles. Further, the surgeon 106 may prepare and finalize the setup by confirming the connections complete and proper. Successively, the anesthesia may be given to the patient 108, and keep track of the degree of muscle relaxation of the patient 108 by interpreting muscle response during testing of SCS electrode 110 may be made. Further, the SCS system 200 may be using the bi-polar recoding through an eight-channeled machine 504 to collect one or more EMG data. In one exemplary embodiment, the eight-channeled machine 504 may include recording electrodes 112. The SCS system 200 may take in bilateral iliopsoas muscles, quadriceps muscles, tibialis anterior muscles, abductor hallucis muscles EMG signals. Further, the other ends of eight-channeled machine 504 may be connected to muscles of the patient 108. In one embodiment, the eight-channeled machine 504 may be connected to at least the legs and trunk of the patient 108. It can be noted that the surgeon 106 may confirm if all the connections are complete and proper. Successively, display 208 in the base unit 204 may be activated to show the EMG data received from the recording electrodes 112.
It should be noted that the SCS electrode 110 may be hooked in the base unit 204, (i.e., the device 204) and the recording electrodes 112 are hooked into the SCS system 200. After that, surgeon 106 may start lateralizing the SCS electrode 110 to position the SCS electrode 110 in the patient's body. It should be noted that the surgeon 106 may confirm that all inputs and outputs are hooked up. In one embodiment, the surgeon 106 may initiate the lateralization by selecting a start lateralization button 602 in the UI 402 of the SCS system 200, as shown in FIG. 6. Successively, the surgeon 106 may initiate the lateralization after measuring the impedances of the recording electrodes 112. The surgeon 106 may determine the electrode area used to stimulate, such as but not limited to “middle” or “top right” which depends on the type of SCS electrode 110 placed. In an exemplary embodiment, the type of SCS electrode 110 may vary from single column leads to multi-column paddle electrodes. In another exemplary embodiment, the SCS electrode 110 may have multiple leads/electrodes each having a bipolar configuration with a single cathode and anode. Successively, surgeon 106 may adjust the SCS electrode 110 positioning to optimize left/right symmetry and/or cover localized areas of pain in the patient's body. In one embodiment, the surgeon may have preconfigured preferences for how to cycle through the contact points on the SCS electrode 110. For example, a surgeon may prefer the electrodes to be cycled individually, or along the rostral caudal axis, by quadrants, etc. The algorithm may cycle through contact points based on the mode selected by the surgeon. It can be noted that data related to lateralization of the SCS electrode 110 may be represented by FIG. 7A, FIG. 7B, and FIG. 7C.
FIG. 7A, FIG. 7B, and FIG. 7C show datasheets 700, 710, and 720, respectively, related to lateralization of the SCS electrode 110 collected and stored in the SCS system 200. The data may correspond to SCS electrode 110 positioning data. It can be noted that datasheet 700 may represent an example of SCS electrode 110 configuration data. Further, datasheet 710 may represent the EMG data after interpretation. Further, datasheet 720, which is the same as datasheet 710, may additionally include final data with the position of the SCS electrode 110. In an exemplary embodiment, the SCS electrode 110 is determined to be at midline (i.e., mid contact point). That is, towards the bottom right of the datasheet 720, position and lateralization decision at each SCS electrode 110 position is determined based on the above. The total positional data is then interpreted and decided as the midline (e.g., mid contact point of the SCS electrode 110 in relation to a length of the spinal cord).
Further, during pre-clinical trials, the SCS system 200 may facilitate storage and retrieval of stimulation data collected corresponding to the patient's body-specific spinal cord. Such data may include, at least but not limited to, EMG results, SCS electrode 110 positioning data, stimulation parameters, and pain-related data.
The lateralization described above is part of the algorithm performed by the algorithm module that includes the above-described impedance check of the currents applied by the SCS electrode 110, followed by noise and filter check, neuromodulation, storage of data from the neuromodulation for each of the contact point (e.g., six contact points) of the SCS electrode 110, performing of the above-described lateralization, in determining and designating the placement location of the SCS electrode 110 as left, right, or mid-contact/bilateral relative to a spinal cord, and making an aggregate lateralization decision based on the results of the lateralization.
FIGS. 8A and 8B describe the neuromodulation algorithm performed by the SCS system 200. Here, the SCS system 200 may start the algorithm for the neuromodulation at each position (i.e., contact point) of the SCS electrode 110. It can be noted that the neuromodulation algorithm may be used to maximize the EMG activity. In one embodiment, as shown in FIG. 8A, the SCS system 200 may display the position of the SCS electrode 110 along with the status of running neuromodulation. For example, as shown by FIG. 8A, the UI 402 displays “Position 1” as the position of the SCS electrode 110, which may represent the first cycle of SCS electrode 110 configuration (e.g., at a first quadrant on a top left, or at a column 1 to the left of the patient's body). Further, the flowchart 800 of FIG. 8B shows a method of neuromodulation in the SCS system 200, according to an embodiment. It should also be noted that in some alternative implementations, the functions noted in the blocks may occur out of the order noted in the drawings. For example, two blocks are shown in succession in FIG. 8B may be executed substantially concurrently, or the blocks may sometimes be executed in the reverse order, depending upon the functionality involved. In addition, the process descriptions or blocks in flow charts should be understood as representing decisions made by a hardware structure such as a state machine.
The flowchart 900 starts at step 902 and proceeds to step 912. At first, the SCS system 200 may start to follow the cycle methodology neuromodulation protocol. It can be noted that the neuromodulation protocol may be used to maximize EMG activity at each position. The stimulation may start with an initial value of pulse width, current, and position, at step 902. In an exemplary embodiment, the initial value of pulse width is 50 us, the current is 5 ma, and the position is 1. In other embodiments, the pulse width may begin with a fixed value, such as 200-300 us. Successively, a type of activity may be determined at step 904. In one embodiment, the type of activity may correspond to a suboptimal activity like a particular Compound Muscle Action Potential (CMAP). Suboptimal activity may be defined as a deviation from a known desired EMG signal. Suboptimal activity may also be defined based on the most desirable EMG signal received with a number of successive readings with different input parameters. Successively, the value of current may be increased at step 906 for a suboptimal activity. In one exemplary embodiment, the value of current is increased by 0.5 mA. After increasing the current value, the safety of stimulation may be checked to determine whether the stimulation is safe or not, at step 908. In one embodiment the current is increased in 1 mA increments to reduce testing time. The current increase increment may also be higher when the total current is below a threshold and lower above the threshold. For example, it may increase in 1 mA increments until it reaches 10 mA and increase in increments of 0.5 mA above that threshold. In one case, when the stimulation is safe, then the stimulation may be started with the initial value of pulse width, current, and position, at step 902.
In another case, when the stimulation is not safe, the SCS system 200 may check whether all pulse widths have been tried at step 910. In one case, when all pulse widths have been tried, the SCS system 200 may move to the next SCS electrode 110 or indicate replacement of the SCS electrode 110. In another case, when all pulse widths have not been tried, then the value of the pulse width may be changed and resetting the current value to zero, at step 912. After that, the method may follow step 906 again to increase the value of current. It can be noted that steps 908 to 912 may be followed for determining the efficient value of pulse width, current, and position of the SCS electrodes 110. It can be noted that the EMG data may be interpreted to identify the maximum CMAP.
If the neuromodulation mentioned above fails or the SCS system 200 cannot elicit a CMAP, then the SCS system 200 may display a message on UI 402, as shown by 1002 in FIG. 9A. The message shows whether the surgeon 106 would like to proceed or not and whether the surgeon 106 would like to enter Manual Mode. In the Manual mode, the surgeon 106 may modify one or more parameters related to nerves on the contact point. In another case, if the neuromodulation mentioned above method is passed, then the SCS system 200 may pass through all set positions as indicated by the UI 402 as 1004 in FIG. 9B, and store the data measured by the recording electrode 112 in the data storage 207. It can be noted that data may be stored in a 4×2 array.
After successful neuromodulation, the SCS system 200 may perform a process of interpretation including lateralization. The SCS system 200 may take each contact point from the stored data and determine the aggregate lateralization decision, as described with regards to FIGS. 7A-7C above. The lateralization, which is performed at each configured SCS electrode 110 position, may be based on the collection of EMG data recorded by the recording electrode 112. It should be noted that the lateralization may be determined for each contact point used by the eight-channel machine having eight sensors for the EMG data (for a maximum of eight EMG outputs). Based on the received EMG data, the SCS system 200 may determine if the EMG data corresponds with SCS electrode 110 being placed on a left position or a right position, relative to the location of the spinal cord.
After successful interpretation of the lateralization post-neuromodulation, visualization of the interpretation may be displayed on the UI 402, as shown in FIG. 10. FIG. 10 illustrates a block diagram 1100 showing the UI 402 to display a heat map 1106, a visual representation 1102 of the electrode and the spinal cord based on the EMG data, a decision box 1104 showing the quantitative measure of the position of the SCS electrode 110, and how fax it is from the desired location, and one or more input boxes 1108 to receive input from the users, such as to view raw data or to re-run the algorithm. It can be noted that the SCS system 200 may display the location of the SCS electrode 110 in the spinal cord in the visual box 1102, based on the collected data. Further, the SCS system 200 may display a statement regarding the position of the SCS electrode 110 in the decision box 1104 based on the collected data. Further, the SCS system 200 may decide based on the data and output a statement. In an exemplary embodiment, the decision box 1104 may display the SCS electrode 110 is left-biased and positioned at 80% left side. Further, the SCS system 200 may display the heat map 1106 or a visual to show the functional representation of the SCS electrode 110. In one embodiment, the functional representation shows the position of the SCS electrodes 110 on the left side or right side. Further, the UI 402 may display the input boxes 1108 to enable the users to view the raw data related to the positioning of the SCS electrodes 110 or re-run the algorithm to perform the lateralization, neuromodulation, and interpretation. In one exemplary embodiment, if the surgeon 106 is unhappy with the placement of the SCS electrodes 110, then he may change the position of the SCS electrodes 110 towards left or right based on the data and select the re-run option to start the program.
The flowchart 1200 of FIGS. 11A and 11B show a method of operation of the SCS system 200, according to an embodiment. It should also be noted that in some alternative implementations, the functions noted in the blocks may occur out of the order noted in the drawings. For example, two blocks are shown in succession in FIGS. 11A and 11B may be executed substantially concurrently, or the blocks may sometimes be executed in the reverse order, depending upon the functionality involved. In addition, the process descriptions or blocks in flow charts should be understood as representing decisions made by a hardware structure such as a state machine. Flowchart 1200 starts at step 1202 and proceeds to step 1248.
At first, the SCS electrode 110 may be identified at step 1202. In one embodiment, the SCS may identify the SCS electrode 110 based on the configuration of the SCS electrode 110, such as but not limited to 2×6, 1×6, and 1×4. In another embodiment the SCS electrode 110 may be identified by a user. Post identification, the SCS electrode 110 may be placed at the spinal cord of the patient's body at step 1204. The algorithm module 206 may successfully check if the SCS electrode 110 contacts the spinal cord at step 1206. The system may perform an impedance check for EMG muscles. An impedance check for muscles will use a process of dropping a current and measuring that voltage to calculate the impedance measured by the recording electrodes 112. Acceptable values for the algorithm will range between 1 kohm-2 kohms. Impedance Check for SCS electrodes 110. Impedance check for muscles will use a process of dropping a current and measuring that voltage to calculate the impedance measured by the recording electrodes 112. Acceptable values for the algorithm will range between 1 kohm-2 kohms. In one case, based on the checking, if the SCS electrode 110 is not making any contact with the spinal cord, then the algorithm module 206 may execute step 1204 of placing the SCS electrode 110 at the spinal cord of the patient's body. In another case, when the SCS electrode 110 is contacting the spinal cord, the algorithm module 206 may check if the EMG data is noisy at step 1208. The root mean square (RMS) will be calculated across the EMG signals. If the baseline noise is above <15 μVrms, the system will not be able to function properly. New recoding electrodes 112 need to be placed, or the source of noise will have to be detected. When the EMG data is noisy, the algorithm module 206 may apply a noisy filter on the EMG data at step 1210. Successively, the algorithm module 206 may check if the EMG data is clean, i.e., noise-free, at step 1212. In one case, when the EMG data is still not clean based on the checking, then the algorithm module 206 may check if there are any more filters left in the SCS system 200, at step 1214.
Based on the checking, if more filters are left, the algorithm module 206 may follow steps 1208 to 1212. In another case, if there are no filters left, then the algorithm module 206 may go back to step 1204. As discussed above, at step 1208, when the EMG data is not noisy, then the algorithm module 206 may load the SCS electrode configuration, at step 1216. Post loading the SCS electrode configuration, the algorithm module 206 may start the stimulation process at step 1218.
In one embodiment, the SCS electrode 110, which may include pairs of contact electrodes, may be moved to contact multiple selected contact points to apply current and begin stimulation based on the SCS electrode configuration that is loaded at step 1216. That is, the SCS electrode 110 may apply current and begin stimulation at a first contact point, as indicated by the loaded SCS electrode configuration. Next, the SCS electrode 110 may be moved in a rostro caudal (i.e., left to right) direction, and testing of rostro caudal adjacent positive and negative contact pairs placed at the selected contact points may begin. That is, the system 200 will start with the data from the loaded SCS electrode configuration corresponding to the most rostral, left-lateral pair. The system 200 will then move to the data corresponding with the next available pair caudal to the previous pair, until all pairs have been exhausted. Then, the system 200 will move to the next row medial to the first pair and repeat the process until all pairs are tested. (i.e., rostral to caudal/left to right) The system 200 will have the ability to reduce the number of pairs tested by prioritizing pairs that have previously had a high correlation to the desired output (e.g., selecting pairs that obtain values that are above a predetermined threshold, such as selecting pairs that obtain values that are above top 10%, 50%, etc.). In an alternative, a doctor using the system 100 may limit the pairs to be tested. These allow for a shorter analysis time.
In one embodiment, for SCS electrode 110 neuromodulation/EMG optimization, the system 100 will for each contact point start 0.0 ma and ramp up to 7.0 ma in increments of 0.5 ma, measuring the Root Mean Square (RMS) value of the EMG signal at each iteration. The system will compare the RMS of the system to baseline values. If there is no change, the system 100 will move on to the next iteration (i.e., the next SCS electrode 110 contact position). The system 100 will continue to compare the RMS of the system to baseline until there is an increase in the RMS. Once there is an increase, the system will compare that RMS value to the next iteration (i.e., next set of detected EMG values resulting from the another set of stimulation parameters) until no change in the RMS by going to the next set of stimulation parameters or safety threshold has been reached. If the RMS values are still compared to baseline at the end of the safety threshold, the system will filter to the next pulse width (PW) and repeat the process.
In one embodiment, for SCS electrode 110 contact lateralization, the system will calculate the RMS values for each sensed EMG signal and compare them to their bi-lateral counterpart (i.e., positive and negative contacts). The ratio of the L/R RMS values for each sensor will be calculated. If the values are >1, the RMS values will be designated as “L,” indicating that the SCS electrode 110 is placed on to the left of a spinal cord. If they <1, they will be designated as “R,” indicating that the SCS electrode 110 is placed to the left of the spinal cord. The average of the ratios will be calculated, and if they are >1, that contact point will be designated as “left” and if it is <1 it will be designated as “right.”
In one embodiment and referring to FIG. 11 for SCS electrode 110 electrode lateralization, the system 200 will map the L/R/BL (i.e., Left, Right, or Bi-Lateral (mid) contact points for the SCS electrode 110 for the surgeon to see on a display 1110. By drawing a line connecting the B/L contact points (i.e., mid contact points for the SCS electrode 110), one may identify the midline on the display 1100. In an embodiment, the midline may correspond with a length or longitudinal axis of a spinal cord.
Referring back to FIG. 12A, the stimulation may start with an initial value of pulse width, current, and position, at step 1218. In an exemplary embodiment, the initial value of pulse width is 50 μs, the current is 5 ma, and the position is 1. Successively, a type of activity may be determined at step 1220. In one embodiment, the type of activity may correspond to a suboptimal activity identified by detected compound muscle action potential (CMAP) corresponding to unwanted stimulation being sent to a muscle group, which would be determined by a physician, who compare the detected CMAP to a predetermined threshold CMAP reading. Successively, the value of current may be increased at step 1222 for a suboptimal activity. In one exemplary embodiment, the value of current is increased by 0.5 mA. After increasing the current value, the safety of stimulation may be checked to determine whether the stimulation is safe or not, at step 1224. In one case, when the stimulation is safe, then the stimulation may be started with the initial value of pulse width, current, and position, at step 1218. In another case, when the stimulation is not safe, the SCS system 200 may check whether all pulse widths have been tried at step 1226. In one case, when all pulse widths have not been tried, then the value of the pulse width may be changed and resetting the current value to zero, at step 1228. After that, the method may follow step 1222 again to increase the value of current. When all pulse widths have been tried, the SCS system 200 may move to the next SCS electrode 110 or indicate replacement (i.e., change the position) of the SCS electrode 110 at step 1230. In some embodiments only a subset of pulse widths may be tested to reduce testing time. After placing the SCS electrode 110 in the next position, the SCS system 200 may store the position data at step 1232. Further, the SCS system 200 may check again if any more positions are left at step 1234. In one case, when there are more positions left, the SCS system 200 may change the SCS electrode 110 to the next position while keeping the rest of the parameters at an initial value, at step 1236. After that, the SCS system 200 may again start the process of stimulation at step 1218. In another case, when there are no more positions left, the SCS system 200 may retrieve the stored data regarding each position of the SCS electrode 110 at step 1238. Thus, after retrieving the stored data, the algorithm module 206 may perform the lateralization at step 1240. Finally, the SCS system 200 may display the SCS electrode 110 in the UI 402 of the SCS system 200, at step 1242.
In another case, at step 1220, when the activity is determined to be an optimal activity, the SCS system 200 may store data corresponding with the position of the SCS electrode 110, at step 1244. Suboptimal activity may be defined as a deviation from a known desired EMG signal. Suboptimal activity may also be defined based on the most desirable EMG signal received with a number of successive readings with different input parameters. Further, the SCS system 200 may determine if there are any more positions left for the SCS electrode 110 at step 1246. In one case, when there are positions left for the SCS electrode 110, the SCS system 200 may change the position of the SCS electrode 110 to the next position while keeping the rest of the parameters at an initial value, at step 1248. After that, the SCS system 200 may again start the process of stimulation at step 1218. In another case, when there are no more positions left, the SCS system 200 may retrieve the stored data regarding each position of the SCS electrode 110 at step 1238. Thus, after retrieving the stored data, the algorithm module 206 may perform the lateralization at step 1240. Finally, the SCS system 200 may display the SCS electrode 110 in the UI 402 of the SCS system 200, at step 1242.
The subject disclosure describes a method for using a standalone spinal cord SCS electrodes 110 positioning system to visually guide the surgeon 106 in the placement of SCS electrodes 110 in real-time based on a display of the position of SCS electrodes 110 on the spinal column along with corresponding EMG data at said positions.
It will be appreciated by those skilled in the art that changes could be made to the exemplary embodiments described above without departing from the broad inventive concept thereof. Therefore, it is to be understood that this disclosure is not limited to the particular embodiments disclosed, but it is intended to cover modifications within the spirit and scope of the subject disclosure as disclosed above.

Claims

What is claimed is:

1. An electrode positioning system, comprising:

a pulse generator, the pulse generator configured to generate electrical pulse currents based on a parameter;

a Spinal Cord Stimulator (SCS) electrode, the SCS electrode configured to apply the generated electrical pulse currents at a contact point from a plurality of contact points;

a recording electrode configured to measure electrophysiologic signals triggered by application of the generated electrical pulse currents;

an output device configured to indicate the contact point of the SCS electrode; and

a base unit, the base unit having a processor configured to:

analyze measured electrophysiologic signals, by:

performing an electrical stimulation cycle methodology,

performing a lateralization based on the electrical stimulation cycle methodology,

determining a mid-contact point of the SCS electrode based on the electrical stimulation cycle methodology and the lateralization,

identifying a location of a length of the spinal cord based on the determined mid-contact point, and

identifying a location of the SCS electrode relative to the location of the length of the spinal cord based on an aggregation of the measured electrophysiologic signal, and

outputting the location of the length of the spinal cord and the location of the SCS electrode to the output device.

2. The electrode positioning system of claim 1, wherein the output device comprises a display, and wherein the processor is further configured to output the location of the length of the spinal cord on the display.

3. The electrode positioning system of claim 2, wherein the processor is further configured to display the location of the SCS electrode relative to the location of the length of the spinal cord based on the measured electrophysiologic signal.

4. The electrode positioning system of claim 3, wherein the processor is further configured to display an overlay of the location of the SCS electrode and the location of the spinal over an image captured by another modality of an area surrounding the SCS electrode.

5. The electrode positioning system of claim 1, wherein the measured electrophysiologic signal is an electromyography (EMG) signal or a Compound Muscle Action Potential (CMAP).

6. The electrode positioning system of claim 1, wherein the measured electrophysiologic signal indicates a level of myotomal activation.

7. The electrode positioning system of claim 1, wherein the base unit further includes an amplifier configured to amplify the measured electrophysiologic signal.

8. The electrode positioning system of claim 1, wherein the electrical stimulation cycle methodology includes:

generating electrical pulse currents based on the parameter;

applying the generated electrical pulse currents at the contact point;

measuring electrophysiologic signals triggered by the application of the generated electrical pulse currents;

comparing the measured electrophysiologic signals to a reference electrophysiologic signal;

determining a deviation based on the comparison;

adjusting the parameter based on the deviation;

repeating the generation of the electrical pulse currents, the application of the generated electrical pulse currents, the measurement of the electrophysiologic signals, the comparison of the measured electrophysiologic signals, the determination of the deviation, and the adjusting of the parameter until the deviation is minimized;

storing the contact point of the SCS electrode in which the deviation is minimized in a memory as stored data; and

moving the SCS electrode to another contact point of the plurality of contact points and repeating the generation of the electrical pulse currents, the application of the generated electrical pulse currents, the measurement of the electrophysiologic signals, the comparison of the measured electrophysiologic signals, and the determination of the deviation until the plurality of contact points has been exhausted.

9. The electrode positioning system of claim 8, wherein the adjusting the parameter includes incrementally increasing an intensity of the generated electrical pulse currents, changing a pulse width of the generated electrical pulse currents, or changing a pattern of the generated electrical pulse currents.

10. The electrode positioning system of claim 8, wherein the moving of the SCS electrode contact point includes a rostral-to-caudal or a left-to-right directional movement.

11. The electrode positioning system of claim 8, wherein the electrical stimulation cycle methodology further includes determining whether the parameter is within a predetermined threshold after being adjusted.

12. The electrode positioning system of claim 8, wherein performing the lateralization includes:

determining a Root Mean Square (RMS) value of the stored data;

comparing the RMS value of the stored data corresponding to one of the plurality of contact points to the RMS value of the stored data corresponding to another one of the plurality of contact points;

calculating a ratio between the RMS value of the stored data corresponding to the one of the plurality of contact points and the RMS value of the stored data corresponding to another one of the plurality of contact points;

designating the one of the plurality of contact points as a left contact point, upon the ratio being less than 1;

designating the one of the plurality of contact points as a right contact point, upon the ratio being more than 1;

designating the one of the plurality of contact points as the mid-contact point, upon the ratio being 1, and storing the designated mid-contact point;

repeating the determining, the comparing, the calculating, and the designating for each data of the plurality of contact points; and

collating the plurality of contacting points that are designated as the mid-contact point to form a midline, wherein the midline corresponds to a length of a spinal cord.

13. An electrode positioning method, the electrode positioning method comprising:

attaching a recording electrode on a patient;

using the recording electrode, receiving an electrophysiologic signal from muscles of the patient that is triggered by electrical pulse currents applied by a Spinal Cord Stimulator (SCS) electrode of the electrode positioning system of claim 1, wherein electrode positioning system is configured to:

perform an electrical stimulation cycle methodology,

perform a lateralization based on the electrical stimulation cycle methodology,

determine a mid-contact point of the SCS electrode based on the electrical stimulation cycle methodology and the lateralization,

identify a location of a length of the spinal cord based on the determined mid-contact point, and

identify a location of the SCS electrode relative to the location of the length of the spinal cord, based on an aggregation of the received electrophysiologic signal;

output the location of the length of the spinal cord and the location of the SCS electrode to the output device; and

repositioning the SCS electrode based on the outputted location of the length of the spinal cord and the location of the SCS electrode.

14. An electrode positioning system having a non-transitory computer readable medium having stored thereon instructions for causing a processing circuitry configured to perform the steps of:

performing an electrical stimulation cycle methodology;

performing a lateralization based on the electrical stimulation cycle methodology;

determining a mid-contact point of the SCS electrode based on the electrical stimulation cycle methodology and the lateralization;

identifying a location of the spinal cord based on the determined mid-contact point;

identifying the location of the SCS electrode the length of the spinal cord and the location of the SCS electrode and the midpoint signal; and

outputting the location of the length of the spinal cord and the location of the SCS electrode and the midpoint to an output device.