Other

The Cleveland Clinic Foundation

Medtronic Xomed, Inc.

Xomed-treace Inc.

Richard L Prass

David C Hacker

George C Robertson

Joseph A Bova

Several configurations for single and multi-needle electromyographic (EMG) recording electrodes for intraoperative nerve integrity monitoring are disclosed, one of which may concern a multi-needle electrode including one or more cables that are connected directly or indirectly to a nerve integrity monitor, a single hub connected to the one or more cables, and at least two needle electrodes connected to the single hub each having first and second bends along the line of insertion into a patient, wherein the first bend occurs at the hub connection in a downward direction and the second bend occurs in an upward direction from the first bend creating a proximal needle segment from the hub to the second bend and a terminal needle segment from the second bend to the end of each needle.

Single and multi-needle electromyographic (EMG) recording electrode configurations for intraoperative nerve integrity monitoring

An intraoperative neurophysiological monitoring system includes an adaptive threshold detection circuit adapted for use in monitoring with a plurality of electrodes placed in muscles which are enervated by a selected nerve and muscles not enervated by the nerve. Nerve monitoring controller algorithms permit the rapid and reliable discrimination between non-repetitive electromyographic (EMG) events and repetitive EMG events, thus allowing the surgeon to evaluate whether nerve fatigue is rendering the monitoring results less reliable and whether anesthesia is wearing off. An artifact detection electrode provides a reliably detectable impedance imbalance between the electrode leads and antenna-like qualities for enhanced detection of current and electromagnetic artifacts.

Artifact detection electrode

An intraoperative neurophysiological monitoring system includes an adaptive threshold detection circuit adapted for use in monitoring with a plurality of electrodes placed in muscles which are enervated by a selected nerve and muscles not enervated by the nerve. Nerve monitoring controller algorithms permit the rapid and reliable discrimination between non-repetitive electromyographic (EMG) events repetitive EMG events, thus allowing the surgeon to evaluate whether nerve fatigue is rendering the monitoring results less reliable and whether anesthesia is wearing off. The intraoperative monitoring system is designed as a 'surgeon's monitor,' and does not require a neurophysiologist or technician to be in attendance during surgery. The advanced features of the intraoperative monitoring system will greatly assist neurophysiological research toward the general advancement of the field intraoperative EMG monitoring through post-surgical analysis. The intraoperative monitoring system is preferably modular, in order to allow for differential system pricing and upgrading as well as to allow for advances in computer technology; modularity can also aid in execution of the design.

Intraoperative neurophysiological monitoring system

The invention provides a method and apparatus for connecting multiple electrodes into the receiving or head box portion of the nerve integrity monitor. The invention may provide patient connection electrodes, their transmission lines and a manner by which these components may communicate to the main monitoring unit to actuate automatic setup functions and instructions. The &ldquo;off-line&rdquo; setup and diagnostic instructions may be automatically initiated and annunciated to the main portion of the intraoperative nerve integrity monitor. The setup and diagnostic instructions may then automatically executed. The invention also may provide patient connection electrodes with improved resistance to the deleterious effects of spurious electromagnetic artifacts. The invention may also include the incorporation of both stimulation and recording electrodes with a single cable, but with the head boxes for recording and stimulation arranged in a staggered fashion along that cable. The recording electrode portion may appear at the terminal end of the cable and can be placed at the site of recording electrode placement. This arrangement allows use of shorter length electrodes, which may be cheaper to construct and less susceptible to electromagnetic and mechanical (drape movement) artifacts. The stimulus portion may be positioned more proximate to the main unit by several feet. After the recording portion is properly positioned, the stimulus connection box may be approximately at its optimal positioning for access after surgical draping. The all-in-one construction would obviate the need to separately place a stimulus head box apparatus, as for devices that include separate recording and stimulation head boxes and associated cabling. The invention may be particularly applicable for use in monitoring facial electromyograhic (EMG) activity during surgeries in which a facial motor nerve is at risk due to unintentional manipulation, as well as for other neural monitoring procedures.

Method and apparatus for connection of stimulus and recording electrodes of a multi-channel nerve integrity monitoring system

An intraoperative neurophysiological monitoring system includes an adaptive threshold detection circuit adapted for use in monitoring with a plurality of electrodes placed in muscles which are innervated by a selected nerve and muscles not innervated by the nerve. Nerve monitoring controller algorithms permit the rapid and reliable discrimination between non-repetitive electromyographic (EMG) events repetitive EMG events, thus allowing the surgeon to evaluate whether nerve fatigue is rendering the monitoring results less reliable and whether anesthesia is wearing off. The intraoperative monitoring system is designed as a &ldquo;surgeon's monitor,&rdquo; and does not require a neurophysiologist or technician to be in attendance during surgery. The advanced features of the intraoperative monitoring system will greatly assist neurophysiological research toward the general advancement of the field intraoperative EMG monitoring through post-surgical analysis. The intraoperative monitoring system is preferably modular, in order to allow for differential system pricing and upgrading as well as to allow for advances in computer technology; modularity can also aid in execution of the design.

A hand-held bipolar electrical stimulus probe includes first and second insulated conductors having unequal diameters and a stable side-by-side orientation. The conductors are provided with visually perceptible indicia such as color coding for identification. The conductors are carried within a flexible jacket and the terminal portions thereof are deformable. The conductors are each insulated substantially up to their tips to prevent current shunting. The probe may include a momentary contact switch permitting selective monopolar or bipolar operation.

Bipolar electrical stimulus probe with planar electrodes

The invention provides a method and apparatus for connecting multiple electrodes into the receiving or head box portion of the nerve integrity monitor. The invention provides patient connection electrodes, their transmission lines and a manner by which these components may communicate to the main monitoring unit to actuate automatic setup functions and instructions. The &ldquo;off-line&rdquo; setup and diagnostic instructions are automatically initiated and annunciated to the main portion of the intraoperative nerve integrity monitor. The setup and diagnostic instructions are then automatically executed. The invention also provides patient connection electrodes with improved resistance to the deleterious effects of spurious electromagnetic artifacts. The invention is particularly applicable for use in monitoring facial electromyograhic (EMG) activity during surgeries in which a facial motor nerve is at risk due to unintentional manipulation, although it will be appreciated that the invention has broader applications and can be used in other neural monitoring procedures.

Method and apparatus for an automatic setup of a multi-channel nerve integrity monitoring system

The break-apart needle electrode system includes a pair of needle electrodes housed together in a fixed spaced-apart relationship. The needle electrodes are joined to electrical conductive wire for detachable connection to an electrical source. The needle electrodes are used in intraoperative facial nerve monitoring by facial electromyographic recording. Since the needle electrodes are furnished as a bipolar pair with twisted leads in a single break-away housing, they provide standardization, ease of placement and close bipolar recording. In instances where separate placement of needle electrodes is desired, the housing can be broken apart at a break-away joint. The needle electrodes are easily manipulated at the housing section as a tandem unit or as separate entities after the housing is broken apart.

Break-apart needle electrode system for monitoring facial EMG

The add-on circuit arrangement permits selective muting of noise signals which are caused by electrosurgery and by a stimulus source during neurophysiological monitoring of a surgical patient. Switches (39, 7 and 24) are provided to select: electrosurgery noise muting; stimulus artifact muting; and to select fixed or variable recorder recovery time. An inductive pickup (12) is coupled to a conductor (11) which carries radiofrequency signals during active periods of electrosurgery. The pickup (12) and associated circuitry (14-17) generate output signals (ES detect signals) which correspond in time to the active periods of electrosurgery. An active output signal of the '1' output of the flip-flop (38) operates the disable switches 44 which are interposed between the monitoring electrodes (41) and the recorder (46). The flip-flop is set by the ES detect signal and reset by selected recovery time signals. Stimulus artifacts are selectively muted by the stimulus disable switch (7), the pulse generator (4) which responds to synchronizing signals from the stimulus source (1) and the AND gate (9).

Intraoperative neuroelectrophysiological monitoring system

A hand-held instrument for electrically stimulating tissue of a living body in the presence of body fluid comprising an elongated, relatively fine, electrically conductive wire having a planar conductive surface generally transverse to the axis thereof at one end. Insulation carried flush to the tip of the wire is provided along the peripheral surface of the wire to prevent shunting of electrical stimulus by the body fluid through such surface. A tube encases the insulated wire in a manner such that a portion of the wire is external to the tube and is adjustable relative thereto.

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Virginia Beach, VA, United States of America

Richard L Prass