Methods and systems for operating an intraoperative neurophysiological monitoring system in conjunction with electrocautery procedures
Inventors
Amaya, Ivan • Batdorf, Michael • Delvin, Ross • McCann, Jason • Cadwell, John A. • Rhodes, Ethan • Villarreal, Richard A.
Assignees
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Publication Number
US-11596337-B2
Publication Date
2023-03-07
Expiration Date
Abstract
Methods and systems for conditioning a signal indicative of electrosurgical unit activity are described. A hardware circuit acquires AC current from an electrosurgical unit on patient isolated circuitry and conditions the signal in either of two alternate processing methods. The processed signal is routed as input to an analog to digital converter circuit. A method for determining saturation on referential inputs and recovering inputs to an unsaturated state is also described.
Core Innovation
The invention relates to an intraoperative neurophysiological monitoring (IONM) system configured to detect noise causing interference with signals being monitored in electrical communication with a patient, where the noise is characterized by frequencies greater than 100 kHz. It addresses interference originating from an electrosurgical unit (electrosurgical unit (ESU)/electrocautery) via a hardware detector arrangement that forms a capacitance between an isolated ground plane circuit and a second circuit positioned over the first circuit during operation.
A first circuit comprises an isolated ground plane electrically coupled, through the patient, to an electrosurgical unit in electrical communication with the patient, and a second circuit comprises a microcontroller and first and second signal processing paths. During operation, capacitance is formed between the first circuit and the second circuit, and the second signal processing path samples signals transmitted by the first circuit and directs the sample signals through an exponentially weighted variance function.
The system is configured to use at least one of the first signal processing path or the second signal processing path to detect the noise characterized by frequencies greater than 100 kHz. The signal processing includes conditioning to derive decision variables from the detected coupled signals, including use of filtering and, in at least one path, rectification and a DC voltage threshold, and a detection decision is based on processed signals including an exponentially weighted variance function.
Claims Coverage
The independent claim defines an IONM detection system for noise characterized by frequencies greater than 100 kHz, using first and second circuit paths where a detection decision is made using at least one of a first signal processing path or a second signal processing path. The claim expressly requires capacitive coupling between an isolated ground plane circuit and a second circuit portion, and detection using an exponentially weighted variance function in the second signal processing path.
Isolated ground plane capacitively coupled to a second circuit for ESU noise detection
A first circuit comprising an isolated ground plane electrically coupled, through the patient, to an electrosurgical unit in electrical communication with the patient, and a second circuit positioned over the first circuit such that, during operation, a capacitance is formed between the first circuit and the second circuit.
Dual signal processing paths with exponentially weighted variance detection
A second circuit comprising a microcontroller, a first signal processing path and a second signal processing path, wherein the second signal processing path samples signals transmitted by the first circuit and directs the sample signals through an exponentially weighted variance function.
Use of first or second processing path to detect high-frequency noise
Use at least one of the first signal processing path or the second signal processing path to detect said noise characterized by frequencies greater than 100 kHz.
Across the independent claim structure, detection of electrosurgical noise characterized by frequencies greater than 100 kHz is achieved by capacitive coupling between an isolated ground plane circuit and an overlying second circuit, with a microcontroller implementing dual signal processing paths, including a second path that uses an exponentially weighted variance function, and selecting at least one path for noise detection.
Stated Advantages
Not explicitly described in patent.
Documented Applications
Not explicitly described in patent.
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