SYSTEMS AND METHODS FOR PREVENTING CONTAMINATION OF RECORDED BIOLOGICAL SIGNALS DURING SURGERY

• US 20160228018A1
• Filed: 09/30/2014
• Published: 08/11/2016
• Est. Priority Date: 09/30/2013
• Status: Active Grant

• Current Assignee: SafeOp Surgical, Inc. (Alphatec Holdings Incorporated)
• Original Assignee: Safeop Surgical Incorporated
• Inventors: Mahon, Cameron, Labelle, Curt
• Granted Patent: US 10,376,167 B2
• Time in Patent Office: Days
• US Class Current: 1/1
• CPC Class Codes: A61B 2017/00026 Conductivity or impedance, e.g. of tissue
• CPC Class Codes: A61B 5/24 Detecting, measuring or recording bioelectric or biomagnetic signals of the body or parts thereof
• CPC Class Codes: A61B 5/311 for nerve conduction study [NCS]
• CPC Class Codes: A61B 5/377 using evoked responses
• CPC Class Codes: A61B 5/388 Nerve conduction study, e.g. detecting action potential of peripheral nerves
• CPC Class Codes: A61B 5/4041 Evaluating nerves condition
• CPC Class Codes: A61B 5/7217 of noise originating from a therapeutic or surgical apparatus, e.g. from a pacemaker
• CPC Class Codes: A61B 5/725 using specific filters therefor, e.g. Kalman or adaptive filters A61B5/316 take precedence
• CPC Class Codes: A61N 1/0456 Specially adapted for transcutaneous electrical nerve stimulation [TENS]
• CPC Class Codes: A61N 1/20 continuous direct currents

Abstract

A system for recording, processing, and monitoring biosignals is provided, the system being configured to suspend data acquisition whenever an electric surgical tool or other generator of high frequency interference is in use. Such a system may protect the hardware of the system and reduce or eliminate the acquisition of distorted signals. The system of some embodiments includes an amplifier system configured to detect the presence of high frequency interference. Related methods are also disclosed.

Claims

1. An amplifier system, comprising:

a first signal pathway and a second signal pathway, each signal pathway having an input for a detected signal, wherein the detected signal comprises a target signal and high frequency interference,

wherein the first signal pathway is configured to amplify the target signal and comprises, in order;

a low pass filter, an amplifier, an analog to digital converter, and a microprocessor;

wherein the second signal pathway is configured to detect the high frequency interference and comprises;

a band pass filter or high pass filter electrically coupled to a radiofrequency detector, a comparator, a digital to analog converter, and the microprocessor of the first signal pathway;

wherein the comparator is configured to compare signal sizes of a first signal entering from a first leg and a second signal entering from a second leg, the first leg of the comparator being electrically coupled to an output from the radiofrequency detector, and the second leg being electrically coupled via the digital to analog converter to an output from the microprocessor; and

wherein the microprocessor is electrically coupled to an output from the comparator and is configured to detect the presence of high frequency interference within the detected signal when the first signal is greater than the second signal.

2. The amplifier system of claim 1, wherein the second signal is a threshold signal set by a user interacting with the microprocessor via a user interface.

3. The amplifier system of claim 1, wherein the system is configured to temporarily suspend signal amplification upon detection of high frequency interference.

4. The amplifier system of claim 1, wherein the system is configured to temporarily suspend data acquisition upon detection of high frequency interference.

5. The amplifier system of claim 1, further comprising a control line electrically connecting the microprocessor to the amplifier, wherein the control line is configured to deliver an interrupt signal to the amplifier upon detection of high frequency interference.

6. The amplifier system of claim 1, further comprising one or more low pass filters positioned between the comparator and the microprocessor.

7. The amplifier system of claim 1, wherein the band pass filter of the second signal pathway comprises one or more inductors, capacitors, or a combination thereof, configured to pass a frequency band of interest while eliminating signals outside the frequency band of interest.

8. The amplifier system of claim 7, wherein the frequency band of interest is 200 kHz to 6 MHz.

9. The amplifier system of claim 1, wherein the radiofrequency detector comprises an ultrafast diode, a capacitor connected to ground, and a parallel shunt resistor connected to ground.

10. The amplifier system of claim 1, wherein the target signal is a biological signal.

11. The amplifier system of claim 10, wherein the biological signal is an evoked potential.

12. A system for recording a non-distorted evoked potential, comprising:

a signal output operable to couple directly or indirectly to a stimulating electrode to deliver an electrical stimulus to a body;

a signal input operable to couple directly or indirectly to a recording electrode to receive a detected signal, wherein the detected signal comprises high frequency interference and an evoked potential generated by the body'"'"'s nervous system in response to the electrical stimulus; and

a processing circuit coupled to the signal input, wherein the processing circuit comprises;

a microprocessor configured to process and analyze a recorded signal, and an amplifier system,

wherein the amplifier system comprises;

a first signal path configured to amplify the evoked potential, and a second signal path configured to detect the high frequency interference,

wherein the first signal path and the second signal path are connected to the microprocessor, and

wherein the microprocessor is further configured to suspend data acquisition from the first signal path and suspend amplification within the amplifier of the first signal path upon detection of high frequency interference within the detected signal.

13. The system of claim 12, wherein the first signal path comprises a low pass filter, an amplifier, an analog to digital converter, and the microprocessor.

14. The system of claim 12, wherein the second signal path comprises a band pass filter, a radiofrequency detector, a comparator, one or more low pass filters, a digital to analog converter, and the microprocessor.

15. A method performed by an amplifier system within a biosignal monitoring device, the method comprising:

receiving a threshold level input from a user via a user interface;

receiving a first detected signal along a first signal line, wherein the first detected signal comprises a target biosignal and high frequency noise;

filtering the first detected signal to reduce the high frequency noise in the first detected signal;

amplifying the first detected signal to increase a magnitude of the biosignal;

converting the first detected signal from analog to digital for data acquisition by a microprocessor;

receiving a second detected signal along a second signal line, wherein the second detected signal comprises the target biosignal and the high frequency noise;

comparing the second detected signal to the threshold level to determine whether the second detected signal or the threshold level is greater; and

upon detecting that the second detected signal is greater than the threshold level, performing one or more steps to suspend acquisition of the first detected signal.

16. The method of claim 15, wherein the one or more steps performed to suspend acquisition of distorted signals comprises:

suspending acquisition and storage of digital data by a microprocessor, wherein the digital data is received from an analog to digital converter of the first signal line, and wherein the digital data is a digitized first detected signal.

17. The method of claim 15, wherein the one or more steps performed to suspend acquisition of distorted signals comprises:

transmitting an interrupt signal along a control line to an amplifier within the first signal line, wherein the interrupt signal causes the amplifier to temporarily suspend operation.

18. The method of claim 17, wherein the amplifier suspends operation for approximately 5 to approximately 60 seconds.

19. The method of claim 17, wherein the amplifier suspends operations until the second detected signal is no longer detected to be greater than the threshold level, or until a defined time thereafter.

20. The method of claim 17, wherein the amplifier suspends operation until transmission of the interrupt signal ceases.

21. A method for detecting changes in nerve functioning within a subject, comprising:

receiving a biosignal from a patient, as an input at a biosignal detection device;

producing a processed signal having minimal electronic interference or background noise contaminating the processed signal, wherein such a processed signal is produced by reducing, blocking, ignoring, or disregarding detected signals received when high frequency electronic interference or background noise is present;

comparing at least two processed signals received at different time periods; and

identifying a change in the biosignal based upon the comparison of the at least two processed signals.

22. The method of claim 21, wherein the biosignal is an evoked potential.

23. The method of claim 21, further comprising detecting a nerve injury during a medical procedure based on changes observed between the at least two processed signals.