Intraoperative neural monitoring method with statistical confidence determination
Inventors
Wybo, Christopher • Nay, David S. • Scarfe, Darren P. • Scarfe, Lukas T. • O'Neil, Samantha J.
Assignees
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Publication Number
US-11850040-B1
Publication Date
2023-12-26
Expiration Date
Abstract
A method of alerting a user to the existence of an artificially induced neuromuscular response in a subject includes: generating a series of electrical stimuli at a predetermined period with an electrode disposed at a distal end portion of an elongate medical device; detecting a series of mechanomyographic (MMG) responses of the subject using a mechanical sensor, each MMG response indicative of a contraction of a muscle of the subject; determining a degree of statistical confidence that the detected series of MMG responses was artificially induced by the series of electrical stimuli; and outputting, to the user, both an alert that a series of MMG responses has been detected, and the determined degree of statistical confidence that the detected series of MMG responses was artificially induced by the series of electrical stimuli.
Core Innovation
The invention provides intraoperative neural monitoring and user alerting of an artificially induced neuromuscular response in a subject. A processor generates a series of electrical stimuli at a predetermined period and transmits the series to an electrode disposed at a distal end portion of an elongate medical device. A mechanical sensor in mechanical communication with a muscle receives physical movement and provides an indication from which the processor detects mechanomyographic (MMG) responses indicative of muscle contraction.
The processor determines a degree of statistical confidence that the detected series of MMG responses was artificially induced by the series of electrical stimuli. The degree of statistical confidence is a function of a periodicity of the series of MMG responses and the predetermined period of the electrical stimuli, and in related formulations is further based on a quantity of sequential identified MMG events and an algorithm used to identify the one or more MMG events. The method outputs to the user both an alert that a series of MMG responses has been detected and an indication of the determined degree of statistical confidence.
The MMG analysis can identify MMG events using wavelet-transform processing that produces convolution coefficients for daughter wavelets derived from a common mother wavelet. The processor sums convolution coefficients across the plurality of daughter wavelets to generate a net-convolution coefficient (NCC) that varies across timesteps, and identifies one or more peaks in the NCC via a peak finding algorithm, where each NCC peak is an MMG response or an MMG event indicative of an artificially induced neuromuscular response caused by electrical stimuli.
Claims Coverage
The partial content identifies five independent claims (clm-00001, clm-00005, clm-00008, clm-00010, clm-00016) covering user alerting and statistical-confidence determination of artificially induced neuromuscular responses. Across these independent claims, the inventive features comprise stimulating via a distal electrode, mechanically sensing and detecting MMG responses/events, determining statistical confidence as a function of periodicity and/or event quantity and algorithm, and outputting an alert with a confidence indication, with additional confidence-lock, threshold-current, and robotic integration features appearing in dependent portions.
Distal electrical stimulation at a predetermined period
Generating, via a processor, a series of electrical stimuli at a predetermined period and transmitting the series of electrical stimuli to an electrode disposed at a distal end portion of an elongate medical device.
Mechanically sensed muscle motion and MMG response detection
Receiving an indication of a physical movement of the muscle from a mechanical sensor in mechanical communication with a muscle of the subject, and detecting a series of mechanomyographic (MMG) responses of the muscle from the received indication.
Statistical confidence as a function of MMG periodicity vs stimulus period
Determining, via the processor in communication with both the electrode and the mechanical sensor, a degree of statistical confidence that the detected series of MMG responses was artificially induced by the series of electrical stimuli, wherein the degree of statistical confidence is a function of a periodicity of the series of MMG responses and the predetermined period of the electrical stimuli.
Dual output of MMG-detection alert and confidence indication
Outputting, to the user, via a display in communication with the processor, both an alert that a series of MMG responses has been detected and an indication of the determined degree of statistical confidence.
Wavelet-transform-based NCC peak detection for MMG event identification
Applying a wavelet transform to the MMG output signal to determine a convolution coefficient for each of a plurality of daughter wavelets derived as time-scaled variants of a common mother wavelet, summing the convolution coefficients to generate a net-convolution coefficient (NCC) that varies across a plurality of timesteps, and identifying one or more peaks in the NCC via a peak finding algorithm, wherein each peak in the NCC is an MMG response of the series.
Confidence determined from sequential event quantity and event-identification algorithm
Determining a level of statistical confidence that the identified one or more MMG events were caused by the electrical stimuli, wherein the level of statistical confidence is a function of a quantity of sequential identified MMG events, an algorithm used to identify the one or more MMG events, and a function of a comparison of a periodicity of the detected MMG events and the predetermined period of the electrical stimuli.
Wavelet-transform-based NCC peak finding as part of event analysis
Analyzing the MMG output signal to identify one or more MMG events by applying a wavelet transform to determine convolution coefficients for daughter wavelets from a common mother wavelet, generating an NCC by summing across the plurality of daughter wavelets over timesteps, and identifying one or more peaks in the NCC via a peak finding algorithm where each NCC peak is an MMG event.
Alert including confidence level and indication of detected MMG events
Providing an alert to a user via a display in communication with the processor, wherein the alert includes the level of statistical confidence and an indication of detected MMG events.
Confidence-lock during algorithmic targeting when confidence exceeds a threshold
Establishing a confidence lock during the algorithmic targeting technique when the determined degree of statistical confidence exceeds a threshold, and displaying an indication of the confidence lock via the display.
Across the identified independent claims, the core coverage centers on stimulating via a distal electrode with a predetermined period, detecting mechanically derived MMG responses, and computing a statistical confidence that responses/events are artificially induced using periodicity relative to the stimulus period and, in other formulations, sequential event quantity and an algorithm used for event identification. The claim coverage further includes wavelet-based generation of convolution coefficients and NCC peak finding to identify MMG responses/events, and presenting user alerts that include both detection and the confidence level.
Stated Advantages
Outputs an alert to the user that a series of MMG responses has been detected.
Outputs an indication of a determined degree of statistical confidence that detected MMG responses were artificially induced by the series of electrical stimuli.
Identifies MMG responses or MMG events by applying wavelet transform processing to generate an NCC and performing peak finding on the NCC.
Provides a level of statistical confidence that accounts for periodicity and, in related formulations, quantity of sequential events and an event-identification algorithm.
Provides a confidence lock based on the determined confidence exceeding a threshold.
Documented Applications
Intraoperative neural monitoring in a surgical procedure, including providing an alert with confidence and detected MMG events to a user via a display.
Alerting a user to the existence of an artificially induced neuromuscular response in a subject using electrical stimuli delivered to a distal electrode and mechanomyography-based detection.
Intraoperative neural monitoring in a surgical procedure in which an alert can be provided to a robotic surgical system such that preventive measures are implemented when the alert meets a threshold statistical confidence level.
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