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Publication numberUS20040225228 A1
Publication typeApplication
Application numberUS 10/842,192
Publication dateNov 11, 2004
Filing dateMay 10, 2004
Priority dateMay 8, 2003
Also published asUS9131947, US20090138050
Publication number10842192, 842192, US 2004/0225228 A1, US 2004/225228 A1, US 20040225228 A1, US 20040225228A1, US 2004225228 A1, US 2004225228A1, US-A1-20040225228, US-A1-2004225228, US2004/0225228A1, US2004/225228A1, US20040225228 A1, US20040225228A1, US2004225228 A1, US2004225228A1
InventorsBret Ferree
Original AssigneeFerree Bret A.
Export CitationBiBTeX, EndNote, RefMan
External Links: USPTO, USPTO Assignment, Espacenet
Neurophysiological apparatus and procedures
US 20040225228 A1
Abstract
Neurophysiological instruments and techniques are improved through various enhancements. Stimulation of an instrument is possible while it is advancing into the spine or elsewhere, alerting the surgeon to the first sign the instrument or device (screw) may be too near a nerve. A directional probe helps surgeons determine the location of the hole in the pedicle. Electrically insulating sleeves prevent shunting into the soft tissues. According to a different improvement, the same probe to be used to stimulate different devices, such as screws and wires. Electrical impulses may be recorded from non-muscle regions of the body, including the spine and other portions of the central nervous system as opposed to just the extremities.
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Claims(33)
I claim:
1. Neurophysiological apparatus, comprising:
a system including an electrical stimulator and an electrical sensor that allows real-time or continuous monitoring as to the placement of a device relative to a nerve during a surgical procedure.
2. The apparatus of claim 1, wherein the device is a probe, tap, wire, screw, or pin.
3. The apparatus of claim 1, further including a component that allows the device to rotate during placement without interfering with the monitoring.
4. The apparatus of claim 3, wherein the component is a clip or sleeve that fits around the shaft of a rotating instrument.
5. The apparatus of claim 1, wherein the sensor is a spinal sensor.
6. The apparatus of claim 1, wherein the sensor is adapted for placement around at least a portion of a pedicle.
7. The apparatus of claim 1, including a direction sensor including a tip that is with a partially circumferentially insulated.
8. The apparatus of claim 1, wherein the system further includes an alert if a stimulus was generated but not sensed.
9. The apparatus of claim 1, wherein the system further includes an alert if the device is or is being improperly placed.
10. The apparatus of claim 1, wherein the system further includes an alert if the device should be placed within a pedicle.
11. The apparatus of claim 1, including multiple stimulators or sensors associated with multiple vertebrae.
12. A neurophysiological method, comprising the steps of:
placing a device in a vertebral body;
electrically stimulating one or more nerves; and
sensing at least one electrical impulse at the device to determine how close the device is to a nerve.
13. The neurophysiological method of claim 12, including the step of stimulating one or more spinal nerves.
14. The neurophysiological method of claim 12, including the step of stimulating one or more peripheral nerves.
15. The neurophysiological method of claim 12, including the step of stimulating a spinal cord.
16. The neurophysiological method of claim 12, including the step of stimulating a portion of a brain.
17. The neurophysiological method of claim 12, including the step of sensing an impulse at multiple devices based upon a single stimulus.
18. The neurophysiological method of claim 12, including the step of sensing one or more electrical impulses at an extremity to determine the effectiveness of the stimulus.
19. The neurophysiological method of claim 12, wherein the device is an instrument.
20. The neurophysiological method of claim 12, wherein the device is a pedicle screw.
21. The neurophysiological method of claim 12, wherein the muscle is a paraspinal muscle.
22. The neurophysiological method of claim 12, further including the step of alerting a user if a stimulus was not sensed.
23. The neurophysiological method of claim 12, further including the step of alerting a user if the device is improperly placed.
24. The neurophysiological method of claim 12, wherein the step of sensing at least one electrical impulse includes sensing the amplitude of the stimulus.
25. The neurophysiological method of claim 12, wherein the step of sensing at least one electrical impulse includes sensing the time between the application of the stimulus and the time of sensing the stimulus.
26. The neurophysiological method of claim 12, wherein the step of sensing at least one electrical impulse includes sensing the velocity of the stimulus.
27. The neurophysiological method of claim 12, wherein the step of comparing the amplitude, velocity, or time interval between stimulation and sensing to values derived previously during the surgical procedure.
28. The neurophysiological method of claim 12, wherein the step of comparing the amplitude, velocity, or time interval between stimulation and sensing to one or more predefined reference values.
29. The neurophysiological method of claim 12, wherein the device forms part of a retractor or other surgical instrument.
30. The neurophysiological method of claim 12, wherein the sensor forms part of a retractor or other surgical instrument.
31. A neurophysiological method, comprising the steps of:
electrically stimulating a device associated with a surgical procedure;
placing a sensor in a non-muscle region of a patent undergoing the procedure; and
detecting impulses from the device at the sensor to determine whether the device has been, or is being, properly placed.
32. The method of claim 31, including the step of placing the sensor in a spine or other region of a central nervous system.
33. The method of claim 31, including the step of placing the sensor in a vertebral body.
Description
    REFERENCE TO RELATED APPLICATION
  • [0001]
    This application claims priority from U.S. Provisional Patent Application Serial Nos. 60/468,981, filed May 8, 2003, and Ser. No. 60/530,427, filed Dec. 17, 2003, the entire content of both of which are incorporated herein by reference.
  • FIELD OF THE INVENTION
  • [0002]
    This invention relates to neurophysiological techniques and, in particular, to improved instruments and procedures to ensure accurate, real-time, temporary or permanent placement of surgically implanted devices.
  • BACKGROUND OF THE INVENTION
  • [0003]
    Pedicle instrumentation is often used to facilitate spinal fusion. Pedicle screws extend through the pedicles of vertebrae and into the body of the vertebrae. The screws are connected by rods or plates to eliminate motion between the vertebrae that are fused together.
  • [0004]
    Misplaced pedicle screws can injury the nerves and blood vessels that surround the vertebrae. Numerous techniques are used to help surgeons guide screws into the pedicles of the vertebrae. For example, surgeons often use x-rays including fluoroscopy to confirm the position of pedicle screws.
  • [0005]
    Nerve compression by pedicle screws can also be determined through electrical stimulation of the pedicle screws. Prior-art techniques involve recording electrical impulses in the legs or arms after electrical stimulation of the pedicles. High conductivity of the electrical impulses suggests the pedicle screws are too close to spinal nerves. High conductivity is determined by recording electrical impulses in the legs or arms of a patient after applying electrical impulses of relatively low amplitude to the pedicle screws.
  • [0006]
    Prior art “neurophysiology” techniques have several deficiencies. First, existing systems rely on the conductivity through a patient's body from the pedicle screw to electrodes in extremities or electrodes on the skin of the extremities. False negative values, low conductivity, can occur if the nerves or the skin do not conduct electricity well. Damaged nerves can be relatively poor conductors of electricity. Second, electrical impulses of relatively high magnitudes must be used to overcome the resistance of the skin, muscles, and nerves. Stimulation by electrical impulses of large amplitude can damage nerves. Third, the variable resistance of patient's bodies leads to a relatively wide range of “normal” values recorded from the extremities. The wide range of normal values decreases the sensitivity and the specificity of the prior art technologies.
  • [0007]
    NuVasive, Inc. of San Diego, Calif. offers a product that uses “screw test” technology to determine if a screw or similar device is being positioned close to a nerve during a surgical procedure. Surgeons typically use NuVasive's system to stimulate screws, guidewires, and taps placed into the pedicles of vertebrae. Recording surface electrodes are placed over the legs of the patient. Nerves conduct electricity very efficiently, such that electrical stimulation of the metal objects placed into the vertebrae can be recorded in the legs.
  • [0008]
    Using the NuVasive system, an electrical charge is sent through the screw, and a circle lights up on a computer screen giving a simple number to indicate the amount of charge reaching sensors placed on the patient's leg muscles. A high number, such as a 20, suggests the screw is clear of the nerve. A lower reading, like a 3, indicates the nerve is being stimulated and the surgeon needs to consider moving the screw. Thus, the lower the amplitude needed to record activity in the legs, the closer the metal objects are to the spinal nerves.
  • [0009]
    Research has shown that if the surface electrodes record electrical activity with stimulation of less than 8 milliamps, the metal objects are too close to the spinal nerves. The system can also be used in the cervical spine. The surface electrodes are placed on the arms for recording stimulation of devices placed into the cervical spine.
  • [0010]
    The NuVasive system has a several shortcomings. For one, the system does not yield real-time data. Nor does the system allow for efficient, repeated stimulation of instruments that are turned. This is due to the fact that the NuVasive system uses a ball-tipped stimulating probe, and the ball of the probe slips off the circular shaft of the instruments. In addition, while the system helps surgeons identify holes in the pedicle, it does not identify the location of the hole in the pedicle. Also, the instruments and screws that are placed into the spine cannot touch the skin, muscles, and subcutaneous tissues surrounding the spine during electrically stimulation. If the metal instruments touch the surrounding tissues during stimulation, the electricity can be shunted from the vertebrae. Shunting of electricity can lead to false recordings in the legs or arms (during stimulation in the cervical spine). Furthermore, the existing NuVasive system requires two different probes; one to stimulate screws and a second probe to stimulate wires.
  • SUMMARY OF THE INVENTION
  • [0011]
    This invention improves upon neurophysiological techniques through provision of several enhancement features. According to one aspect of this invention, stimulation of an instrument is possible while it is advancing into the spine or elsewhere, alerting the surgeon to the first sign the instrument or device (screw) may be too near a nerve. Early identification of misdirected instruments or screws may thus help prevent nerve damage.
  • [0012]
    A different aspect involves a directional probe that helps surgeons determine the location of the hole in the pedicle. Yet a further aspect provides an insulation sleeves to prevent shunting into the soft tissues. According to a different improvement, the same probe to be used to stimulate different devices, such as screws and wires.
  • [0013]
    One embodiment of the invention involves a clip that allows the use of continuous monitoring during curette, pedicle probe, tap, pedicle screw, and/or lateral mass screw insertion. The clip fits around the cylindrical shafts of these and instruments used to insert devices, including screws. The clip allows the shafts of the instruments to rotate without rotating the probe that sends electrical impulses for the testing. The surgeon may rotate an instrument to insert a tap, for instance, while an assistant repeatedly fires the probe. Thus, the surgeon can detect a breach of the pedicle wall as soon as it occurs rather than after the tap, etc. is fully inserted. Theoretically, early detection of a breach in the pedicle may prevent nerve injury and prevent enlarging a mal-aligned hole.
  • [0014]
    Other apparatus and methods of this invention improve upon existing neurophysiology technology in that electrical impulses are recorded from the spine rather than the extremities. Recording the impulses closer to the stimulated pedicle screws overcomes the deficiencies of prior-art techniques as outlined above.
  • BRIEF DESCRIPTION OF THE DRAWINGS
  • [0015]
    [0015]FIG. 1 is a lateral view of the side of the current probe and a novel clip of the present invention;
  • [0016]
    [0016]FIG. 2 is an exploded view of the invention of FIG. 1;
  • [0017]
    [0017]FIG. 3A is a lateral view of a curette to “sound” the pedicle and the probe with a clip attachment;
  • [0018]
    [0018]FIG. 3B is a lateral view of the probe of FIG. 1 attached to the curette of FIG. 3A;
  • [0019]
    [0019]FIG. 3C is a cross section of the shaft of an instrument surrounded by the novel clip of the present invention;
  • [0020]
    [0020]FIG. 4 is a lateral view of an alternative embodiment instrument shaft;
  • [0021]
    [0021]FIG. 5 is a lateral view of the embodiment of the instrument drawn in FIG. 4;
  • [0022]
    [0022]FIG. 6 is the lateral view of an instrument to retract the soft tissues during pedicle screw or instrument stimulation;
  • [0023]
    [0023]FIG. 7 shows the insulated soft tissue retractor drawn in FIG. 6;
  • [0024]
    [0024]FIG. 8A is a lateral view of the probe and the novel tip;
  • [0025]
    [0025]FIG. 8B is an axial cross section of a vertebra and probes with the novel tips;
  • [0026]
    [0026]FIG. 9A is a lateral view of a screw driver, pedicle screw, and a novel insulating sleeve;
  • [0027]
    [0027]FIG. 9B is a lateral view of apparatus drawn in FIG. 9A;
  • [0028]
    [0028]FIG. 9C is a cross section of the apparatus drawn in FIG. 9B;
  • [0029]
    [0029]FIG. 9D is a lateral view of the apparatus drawn in FIG. 9B;
  • [0030]
    [0030]FIG. 10A is a lateral view of an alternative embodiment of the insulation sleeve, pedicle screw, and sleeve expander;
  • [0031]
    [0031]FIG. 10B is a lateral view of the apparatus drawn in FIG. 10A;
  • [0032]
    [0032]FIG. 10C is an axial cross section of the sleeve, screw, and sleeve expander drawn in FIG. 10A;
  • [0033]
    [0033]FIG. 10D is an axial cross section of an alternative embodiment of the sleeve expander drawn in FIG. 10C;
  • [0034]
    [0034]FIG. 11A is a lateral view of an alternative embodiment of the insulating sleeve;
  • [0035]
    [0035]FIG. 11B is an exploded view of the embodiment of the invention drawn in FIG. 11A;
  • [0036]
    [0036]FIG. 11C is a cross section of the apparatus drawn in FIG. 11A;
  • [0037]
    [0037]FIG. 12A is a lateral view of an alternative embodiment of the novel sleeve, a screw, and a screwdriver;
  • [0038]
    [0038]FIG. 12B is a lateral view of the apparatus drawn in FIG. 12A;
  • [0039]
    [0039]FIG. 13A is a sagittal cross section through an alternative embodiment of that drawn in FIG. 3;
  • [0040]
    [0040]FIG. 13B is a sagittal cross section through an alternative embodiment of that drawn in FIG. 13A;
  • [0041]
    [0041]FIG. 14A is a sagittal cross section of an alternative embodiment of invention drawn in FIG. 13B;
  • [0042]
    [0042]FIG. 14B is an exploded lateral view of the embodiment of the invention drawn in FIG. 14A;
  • [0043]
    [0043]FIG. 14C is a sagittal cross section of an alternative embodiment of the invention drawn in FIG. 14A;
  • [0044]
    [0044]FIG. 14D is an exploded lateral view of the embodiment of the invention drawn in FIG. 14C;
  • [0045]
    [0045]FIG. 15A is a sagittal cross section of an alternative embodiment of the invention drawn in FIG. 14C;
  • [0046]
    [0046]FIG. 15B is an exploded lateral view of the embodiment of the invention drawn in FIG. 15A;
  • [0047]
    [0047]FIG. 16A is a lateral view of an alternative embodiment of the invention drawn in FIG. 14A;
  • [0048]
    [0048]FIG. 16B is an oblique view of an alternative embodiment of the invention drawn in FIG. 16A;
  • [0049]
    [0049]FIG. 17A is a lateral view of an alternative embodiment of the invention drawn in FIG. 14A;
  • [0050]
    [0050]FIG. 17B is an exploded lateral view of the embodiment of the invention drawn in FIG. 17A;
  • [0051]
    [0051]FIG. 18 is an oblique view of a portion of a vertebra and the preferred apparatus;
  • [0052]
    [0052]FIG. 19A is a view of the dorsal aspect of a portion of a vertebra and a recording electrode;
  • [0053]
    [0053]FIG. 19B is a view of the dorsal aspect of a portion of a vertebra and a recording electrode;
  • [0054]
    [0054]FIG. 20A is a view of the dorsal aspect of a portion of a vertebra and a recording electrode on the inferior lateral surface of a pedicle;
  • [0055]
    [0055]FIG. 20B is a view of the dorsal aspect of a portion of a vertebra and a recording electrode;
  • [0056]
    [0056]FIG. 21A is an oblique view of the apparatus drawn in FIG. 18;
  • [0057]
    [0057]FIG. 21B is an exploded view of the apparatus drawn in FIG. 21A;
  • [0058]
    [0058]FIG. 21C is a view of the top of the connecting component, the recording and stimulating electrodes;
  • [0059]
    [0059]FIG. 22 is an oblique view of a portion of a vertebra, a pedicle instrument or screw, and the recording electrode;
  • [0060]
    [0060]FIG. 23 is an oblique view of a portion of a vertebra, a pedicle screw, recording and stimulating electrodes use in an alternative embodiment of the apparatus;
  • [0061]
    [0061]FIG. 24 is a view of apparatus according to the invention including a stimulating probe;
  • [0062]
    [0062]FIG. 25 is a view of the posterior aspect of the spine;
  • [0063]
    [0063]FIG. 26 is the view of the front of an alternative embodiment of the device drawn in FIG. 24;
  • [0064]
    [0064]FIG. 27A is a posterior view of the spine similar to the view described in FIG. 25;
  • [0065]
    [0065]FIG. 27B is a posterior view of the spine as described in FIG. 27A;
  • [0066]
    [0066]FIG. 28 is a posterior view of the spine, similar to the view drawn in FIG. 27B;
  • [0067]
    [0067]FIG. 29 is a posterior view of the spine similar to the view drawn in FIG. 28;
  • [0068]
    [0068]FIG. 30 is a posterior view of the spine, similar to the view drawn in FIG. 29, showing the alternative use of a reference electrode;
  • [0069]
    [0069]FIG. 31 is an axial view of a pedicle;
  • [0070]
    [0070]FIG. 32A is a lateral view of a needle-tipped stimulating or recording electrode;
  • [0071]
    [0071]FIG. 32B is a lateral view of an alternative embodiment of the tip of the electrode drawn in FIG. 32A;
  • [0072]
    [0072]FIG. 32C is a lateral view of an alternative embodiment of the tip of the electrode drawn in FIG. 32A;
  • [0073]
    [0073]FIG. 33 is an oblique view of an alternative embodiment of the invention;
  • [0074]
    [0074]FIG. 34A is a lateral view of another embodiment of the invention drawn in FIG. 33;
  • [0075]
    [0075]FIG. 34B is an anterior view of the embodiment of the device drawn in FIG. 34A;
  • [0076]
    [0076]FIG. 34C is an oblique view of the embodiment of the device drawn in FIG. 34A;
  • [0077]
    [0077]FIG. 35 is an anterior view of another embodiment of the device drawn in FIG. 33;
  • [0078]
    [0078]FIG. 36 is a posterior view of a peripheral nerve and another embodiment of the invention; and
  • [0079]
    [0079]FIG. 37 is a lateral view of a nerve root retractor that stimulates the spinal nerves.
  • DETAILED DESCRIPTION OF THE INVENTION
  • [0080]
    [0080]FIG. 1 is a lateral view of the side of the current probe 102 and a novel clip 104 according to this invention. One end of the clip snaps around instruments. The second end of the clip snaps over the tip of the probe. Alternatively, a second probe tip could be manufactured that incorporates the novel tip end. FIG. 2 is a detached view of the probe and tip of FIG. 1.
  • [0081]
    [0081]FIG. 3A is a lateral view of a curette 302 used to “sound” the pedicle and the probe 102 with a clip attachment 104. The shaft of the instrument 302 may be machined with a groove 310 to cooperate with the clip. FIG. 3B is a lateral view of the probe of FIG. 1 attached to the curette of FIG. 3A. FIG. 3C is a cross section.
  • [0082]
    [0082]FIG. 4 is a lateral view of an alternative embodiment, wherein the shaft of the tap has a raised portion 402 to cooperate with a clip 404. The raised portion 402 avoids the stress riser created by a groove in the shaft. FIG. 5 is a lateral view of the embodiment of the instrument drawn in FIG. 4. The clip of the probe surrounds the shaft of the pedicle screw insertion tool. The clip rides on the enlargement of the shaft.
  • [0083]
    [0083]FIG. 6 is the lateral view of an instrument 602 used to retract the soft tissues during pedicle screw or instrument stimulation. The retraction instrument is made of plastic or other material that does not conduct electricity in the preferred embodiment.
  • [0084]
    As an alternative to the insulated soft tissue retractor of FIG. 6, an insulated sleeve drawn in FIG. 7 may be used. FIG. 7 is an axial cross section through a vertebra and the surrounding muscles, skin, and subcutaneous tissues. A plastic sleeve would be particularly useful when stimulating percutaneous guide pins inserted into the pedicles. The insulating sleeve 706 prevents the transmission of electricity from the guide pin to the muscles or surrounding soft tissue. A similar apparatus could be used for testing modular taps. For example, the handle of a tap could be removed, thus allowing the insulating sheath to be placed over the tap.
  • [0085]
    Although the NuVasive monitoring system helps surgeons identify breaches of the walls of the pedicles, the system does not suggest where the pedicle wall has been breached. According to this invention, however, since the probe tip may be insulated circumferentially around the majority of the tip of the probe, the non-insulated portion of the tip can be rotated within the pedicle to determine the direction that requires the least amount of stimulation to record activity in the lower extremity.
  • [0086]
    [0086]FIG. 8A is a lateral view of the probe and a tip according to the invention. The dark area of the tip conducts electricity. The remainder of the tip 806 is insulated to prevent the conduction of electricity.
  • [0087]
    [0087]FIG. 8B is an axial cross section of a vertebra and probes using these tips. The medial walls of the pedicles have been breached. The probe on the left side of the drawing has the non-insulted portion of the tip directed toward the hole in the pedicle. The probe on the right side of the drawing has the insulated portion of the tip facing the hole in the pedicle. Less current will be required to stimulate the nerves on the left side of the drawing. For example, the surface electrodes could record activity in the lower extremity with stimulation of the probe at 4 milliamps with the exposed (conducting) area of the probe directed toward the medial wall of the pedicle (probe on the left side of the drawing) and the surface electrodes could record electrical activity in the lower extremities with stimulation of the probe at 10 milliamps with the exposed (conducting) area of the probe directed toward the lateral wall of the pedicle (probe on the right side of the drawing). Thus, the surgeon knows the medial wall of the pedicle has been breached. Consequently, the surgeon knows to redirect the pedicle screw more laterally, away from the holes in the pedicle
  • [0088]
    [0088]FIG. 9A is a lateral view of a screwdriver 902, pedicle screw 904, and an insulating sleeve 906. The insulating sleeve is preferably constructed of a flexible material that does not conduct electricity. For example, the sleeve could be made of plastic or natural or synthetic rubber. The sleeve can be seen folded back over itself at 908 just above the pedicle screw.
  • [0089]
    [0089]FIG. 9B is a lateral view of apparatus drawn in FIG. 9A. The insulating sleeve 906 has been unfolded and placed over the head of the pedicle screw. The insulating sleeve prevents the transmission of electricity into the tissues that surround the spine. Electricity from stimulating the shaft of the screwdriver, of the shaft of the screwdriver exits through the threads of the screw. The sleeve enables the screwdriver to lie against the muscles of the spine without stimulating the muscles of the spine.
  • [0090]
    [0090]FIG. 9C is a cross section of the apparatus drawn in FIG. 9B. The flexible insulation sleeve can be stretched to fit tightly against the shaft of the screwdriver and the pedicle screw.
  • [0091]
    [0091]FIG. 9D is a lateral view of the apparatus drawn in FIG. 9B. The insulation sleeve may be removed by pulling on a cord 980 which tears the sleeve. Alternative mechanisms can be used to remove the sleeve from the screw. For example, the sleeve could be pulled from the screw while exerting counter pressure on the screw by the screwdriver. The sleeve could also be folded on itself as the sleeve is removed from the screw.
  • [0092]
    [0092]FIG. 10A is a lateral view of an alternative embodiment of an insulating sleeve 1002, pedicle screw 1004, and screwdriver with a sleeve expander 1006. The sleeve is drawn in its expanded shape. The tip of the sleeve expander fits into the pedicle screw. In the preferred embodiment, the sleeve expander is flush with the top of the pedicle screw. The sleeve in this embodiment of the device is made of material that plastically deforms at its tip. The sleeve does not transmit electricity.
  • [0093]
    [0093]FIG. 10B is a lateral view of the apparatus drawn in FIG. 10A with the sleeve in its contracted shape. The tip of the sleeve contracts to surround the head of the pedicle screw. Ideally the sleeve is more rigid than sleeve drawn in FIG. 9A. The rigidity of the sleeve enables it to be forced over the screw by pushing on the top of the sleeve. This embodiment of the device would be easier to use after the screw has been placed into the spine.
  • [0094]
    [0094]FIG. 10C is an axial cross section of the sleeve 1002, screw 1004, and sleeve expander 1006 in FIG. 10A. The sleeve expander 1006 fits into the opening in the pedicle screw. FIG. 10D is an axial cross section of an alternative embodiment of the sleeve expander 1016, a screw 1014, and the sleeve 1012. The tip of the sleeve expander in this case is round to fit in the circular opening in the pedicle screw.
  • [0095]
    [0095]FIG. 11A is a lateral view of an alternative embodiment of the insulating sleeve. 1108 assembled over a pedicle screw 1110. FIG. 11B is an exploded cross-sectional view of the embodiment of the invention drawn in FIG. 11A. FIG. 11C is a cross section of the apparatus drawn in FIG. 11A. FIG. 12A is a lateral view of an alternative embodiment of the novel sleeve 1202, a screw 1204, and a screwdriver 1206. The insulating sleeve is placed over the pedicle screw and screwdriver prior to insertion of the pedicle screw into the spine.
  • [0096]
    [0096]FIG. 12B is a lateral view of the apparatus drawn in FIG. 12A. The sleeve has been pulled off of the pedicle screw. Longitudinal force on the sleeve may be used to split the sleeve along a pre-stressed area in the sleeve.
  • [0097]
    [0097]FIG. 13A is a sagittal cross section through an alternative embodiment of the invention, wherein a probe 1302 is placed into the center of an instrument 1304. The illustration shows application of the probe to a tap. Placing the instrument onto or into the center of the instrument allows rotation of the instrument during repeated stimulation of the instrument.
  • [0098]
    [0098]FIG. 13B is a sagittal cross section through an alternative embodiment of that drawn in FIG. 13A. The probe connects to an intermediate piece 1330 that connects to the center of the instrument.
  • [0099]
    [0099]FIG. 14A is a sagittal cross section of an alternative embodiment of invention drawn in FIG. 13B. The spherical end of an electrode 1404 is captured in the instrument by a cannulated, threaded cap 1406. The shaft of the instrument 1410 conducts electricity. The joint between the tip of the electrode allows movement between the electrode and the instrument, while maintaining continuous contact between the two components. FIG. 14B is an exploded lateral view of the embodiment of the invention drawn in FIG. 14A.
  • [0100]
    [0100]FIG. 14C is a sagittal cross section of an alternative embodiment of the invention utilizing a flat-tipped electrode 1440 captured by a threaded component 1444. The joint between the electrode and the instrument allows rotation. FIG. 14D is an exploded lateral view of the embodiment of the invention drawn in FIG. 14C. Connections between electrodes of alternative shaped tips and instruments of alternative shapes are contemplated so long as the joints between the components permit rotation and keep the two components in contact.
  • [0101]
    [0101]FIG. 15A is a sagittal cross section of an alternative embodiment of the invention, wherein an electrode 1550 is threaded over the shaft of the instrument 1552. The threaded connection between the electrode and the instrument holds the two components together. Rotation may occur across the flat surfaces of the two components. FIG. 15B is an exploded lateral view of the embodiment of the invention drawn in FIG. 15A.
  • [0102]
    [0102]FIG. 16A is a lateral view of an alternative embodiment of the invention drawn in FIG. 14A. A wire 1660 for the electrode is connected to a ratcheting component 1664 on the shaft of the instrument. The ratcheting component permits advancement of screws and taps with small rotations of the handle of the instrument forward and backward. The electrode does not wrap around the instrument because the handle of the instrument does not require rotation through 360 degrees.
  • [0103]
    [0103]FIG. 16B is an oblique view of an alternative embodiment of the invention drawn in FIG. 16A. The electrode is connected to a conducting component within the handle of the instrument. The conducting component transmits electrical impulses between the electrode and the shaft of the instrument. The ratcheting mechanism prevents wrapping the cord of the electrode around the instrument as the instrument is rotated.
  • [0104]
    [0104]FIG. 17A is a lateral view of an alternative embodiment of the invention including an electrode 1780 connected to a collar that rotates around the shaft of the instrument. The collar is held between projections from the shaft of the instrument. The collar remains in contact with the shaft of the instrument. Rotation between the shaft of the instrument and the collar prevents wrapping the cord of the electrode around the instrument as a screw or tap is advanced. FIG. 17B is an exploded lateral view of the embodiment of the invention drawn in FIG. 17A. The rotating collar is held on the shaft of the instrument by a removable threaded component 1788.
  • [0105]
    [0105]FIG. 18 is an oblique view of a portion of a vertebra and preferred apparatus including a recording electrode 1802 placed around a portion of the pedicle of a vertebra 1800. The recording electrode is connected to a monitor 1804. The area 1806 represents a pedicle probe, tap, screw, or other instrument that will be placed into the pedicle. The pedicle instrument or screw is connected to a stimulating electrode. The recording and stimulating electrodes can be connected by third component 1810. The connecting component is represented by the area of the drawing with diagonal lines. In the preferred embodiment, the connecting component 1810 is radiolucent and made of a material that conducts electricity poorly.
  • [0106]
    [0106]FIG. 19A is a view of the dorsal aspect of a portion of a vertebra and a recording electrode 1802. The lamina of the vertebra has been removed to better illustrate the pedicles of the vertebra. The arms of the recording electrode can be seen surrounding the inferior, medial, and lateral surfaces of the pedicle. The recording electrode was inserted from the inferior and/or lateral side of the vertebra.
  • [0107]
    [0107]FIG. 19B is a view of the dorsal aspect of a portion of a vertebra and a recording electrode 1802. The recording electrode can be seen over the medial, superior, and inferior surfaces of a pedicle. The recording electrode was inserted from the medial side of the pedicle. A laminectomy could be performed to aid placement of the electrode.
  • [0108]
    [0108]FIG. 20A is a view of the dorsal aspect of a portion of a vertebra and a recording electrode 1802 on the inferior lateral surface of a pedicle. FIG. 20B is a view of the dorsal aspect of a portion of a vertebra and a recording electrode. The recording electrode has been advanced over the pedicle. The arms of the recording electrode can be spring loaded to ease insertion of the electrode over the pedicle.
  • [0109]
    [0109]FIG. 21A is an oblique view of the apparatus drawn in FIG. 18. The connector 1810 aligns the instrument or screw to be inserted into the pedicle with the arms of the recording electrode. For example, pedicle screws can be directed into the center of the arms of the recording electrode. Thus, if the arms of the recording electrode surround a portion of the pedicle, the pedicle screw or instrument can be directed into the center of the pedicle.
  • [0110]
    [0110]FIG. 21B is an exploded view of the apparatus drawn in FIG. 21A. A removable handle is also illustrated. The removable handle can be placed over the recording electrode after placement of the connecting component over the recording component.
  • [0111]
    [0111]FIG. 21C is a view of the top of the connecting component, the recording and stimulating electrodes. The radiolucent connecting component allows surgeons to view insertion of the stimulating electrode between the arms of the recording electrodes with fluoroscopy. The arms of the recording electrode surround a portion of the pedicle.
  • [0112]
    [0112]FIG. 22 is an oblique view of a portion of a vertebra, a pedicle instrument or screw, and the recording electrode. The pedicle instrument can be seen penetrating the wall of the pedicle. The recording electrode can be moved up and down or around the pedicle to aid detection of the electrical impulse.
  • [0113]
    [0113]FIG. 23 is an oblique view of a portion of a vertebra, a pedicle screw, recording and stimulating electrodes use in an alternative embodiment of the apparatus. The recording electrode detects impulses in the spinal canal, nerves, muscles, vertebrae, and other spinal tissues or tissues that surround the spine. For example, the recording electrode could be placed on a spinal nerve, or the thecal sac. Penetration of the pedicle screw or instrument would be predicted by recording electrical impulses from the spinal nerve or thecal sac after stimulating the pedicle instrument with electrical impulses with relatively low amplitudes. The recording electrode could also be placed in other spinal tissues such as the paraspinal muscles. Fluid or other material could be placed around the pedicle to aid the conduction of electrical impulses. For example, saline could be placed into the spinal canal during the stimulation and recording of the electrical impulses.
  • [0114]
    The invention also anticipates reversing the stimulating and the recording electrodes. That is, electrical impulses could be recorded from pedicle screws or instruments after stimulating a portion of the spine. For example, the outer wall of the pedicle could be stimulated. Additionally, the sensitivity and specificity of the apparatus, as well as prior art apparatus, could be improved by measuring the time between stimulation and recording the electrical impulses. Relatively high rates of electrical conduction suggest the pedicle screw or instrument lies on or too near a nerve.
  • [0115]
    [0115]FIG. 24 is a view of apparatus according to the invention including a stimulating probe 2406 used to stimulate the spinal nerves (or other nerves). The stimulating probe is inserted into a port on the device marked “Stimulus”. A recording cable 2408 is inserted into a port on the device marked “Instrument”. The recording cable attaches to an instrument placed in the pedicle. For example, the “Instrument” recording cable could be attached to the ratcheting instrument described in FIG. 16A. The ratcheting instrument is used to insert screws or taps into the vertebrae.
  • [0116]
    A second recording cable 2410 is inserted into a port on the device marked “Muscle”. The “Muscle” recording cable may include a bundle of wires. The wires within the “Muscle” recording cable attach to leads placed over muscles. For example, the “muscle” leads could be placed over the myotomes of both lower extremities or both upper extremities. Alternatively, the “Muscle” cable could be attached to leads over the gluteal muscles, the paraspinal muscles, or tissues of the body.
  • [0117]
    A green indicator light indicates safe placement of the pedicle instrument. The green light illuminates if the “Muscle” recording cable sends an electrical impulse into the device after stimulation of a spinal nerve (alternatively other nerves could be stimulated) and the “Instrument” recording cable does not send an electrical impulse into the device after stimulation of the spinal nerve. A 6 ma stimulus could be delivered to the stimulus probe. Alternative stimuli between 0.01 ma to 40 ma could be delivered.
  • [0118]
    A red indicator light indicates a potentially misplaced pedicle instrument. The red light illuminates if the “Instrument” recording cable sends an electrical impulse into the device after stimulation of the spinal nerve or the “Muscle” recording cable fails to send an electrical impulse into the device. Two additional lights are used to determine why the red light illuminated. A “Muscle” light illuminates if the “Muscle” recording cable fails to send an electrical impulse into the device. Failure of the “muscle” recording cable to send an electrical impulse into the device suggests the nerve was not properly stimulated. An “Instrument” light illuminates if the “Instrument” cable sends an electrical impulse into the device. Illumination of the “Instrument” light alerts the surgeon the pedicle instrument has received an electrical impulse. The pedicle instrument receives an electrical impulse, if the instrument has breached the walls of the pedicle and the instrument is lying against the stimulated nerve. The device may also have ports that receive ground and reference electrodes.
  • [0119]
    Existing systems monitor all of the myotomes of both extremities. An electrical stimulus is delivered to the instrument within the pedicle. Detection of the electrical impulse after low levels of stimulation, for example 8 ma, in any myotome is indication of a potentially misplaced pedicle instrument. A preferred embodiment of this invention records from the instrument or screw within the pedicle rather than stimulating the instrument or screw within the pedicle. Recording leads over the muscles are used to confirm an electrical impulse has been applied to a spinal nerve (or other nerve). As such, recording a stimulus from any muscle in the extremities or potentially other muscles such as the gluteal or paraspinal muscles indicates the stimulus has been properly delivered. Recording from fewer, multiply innervated muscles, simplifies the device. Recording from fewer muscles and recording from the gluteal or paraspinal muscles also assists the surgeon. The present invention decreases the amount of time surgeons must spend applying the recording leads over multiple myotomes of both extremities while using prior art systems. The simplicity of the device enables surgeons to test and monitor their patients. The device does not require a highly compensated Neurophysiologist to interpret the data. Other embodiments of the invention eliminate the need to monitor any of the muscles.
  • [0120]
    [0120]FIG. 25 is a view of the posterior aspect of the spine. The lamina have been removed to better illustrate the pedicles 2502 and the nerves 2504. The black circle in the center of one of the white circles indicates the cross section of an instrument within the pedicle (for example) a screw, tap, or curette.
  • [0121]
    In the embodiment of the invention depicted in FIG. 24, an electrical stimulus is delivered to the lower spinal nerve at point S. A recording electrode is attached at R to the instrument within pedicle. One or more additional recording electrodes are placed over muscles. A second stimulus is delivered to the spinal nerve at S′, or, alternatively at S″. If the pedicle instrument breaches the medial wall (spinal canal side) or the inferior wall of the pedicle, and the instrument lies against the spinal nerve, stimulation of the lower spinal nerve will stimulate the instrument in the pedicle. If the pedicle instrument breaches the lateral or superior wall of the pedicle, and the instrument lies against the spinal nerve, stimulation of the upper spinal nerve will stimulate the instrument within the pedicle. Instruments in adjacent pedicles on the same side of the spine may be tested simultaneously by stimulating a single spinal nerve. For example, stimulation of the L4 nerve simultaneously tests the integrity of the medial and inferior walls of the L4 pedicle and the superior and lateral walls of the L5 pedicle. Simultaneous testing of instruments within the pedicles requires a multi-channel device.
  • [0122]
    Prior art systems may detect a hole or a crack in a pedicle, but they do not indicate the location of the crack or hole in the pedicle. If surgeons know the location of the hole in the pedicle, then they can reposition a screw and safely direct the screw away from the hole in the pedicle. This invention helps surgeons determine if the misplaced pedicle instrument was placed through the inferior and/or the medial surface of the pedicle or through the superior and/or lateral wall of the pedicle.
  • [0123]
    [0123]FIG. 26 is the view of the front of an alternative embodiment of the device drawn in FIG. 24. The multi-channel device can be used to simultaneously test instruments in more than one pedicle. The cables extending from ports on right side of the device marked “Instrument 1” and “Instrument 2” can be attached to instruments in different pedicles. The stimulus probe can be used to deliver electrical impulses to a spinal nerve. The cables extending from the ports marked “Muscle 1 & Muscle 2” can be attached to surface electrodes over muscles supplied by the stimulated nerve. A single recording electrode may also be used when testing the instruments in two pedicle screws. For example, the cable attached to “Instrument 1” could be attached to a tap in the left LA pedicle.
  • [0124]
    The cable attached to “Instrument 2” could be attached to a screwdriver attached to a pedicle screw in the left L5 pedicle. The cables extending from the “Muscle 1” and/or “Muscle 2” ports could be attached to needle electrodes placed into the Gluteus Medius and the Gluteus Maximus Muscles of the left buttock. The Gluteus Medius is innervated by the superior gluteal nerve. The superior gluteal nerve arises from the LA, L5, & S1 nerves. The Gluteus Maximus is innervated by the inferior gluteal nerve. The inferior gluteal nerve arises from the L5, S1, and S2 nerves. Surface electrodes could be used rather than needle electrodes. A stimulus could be applied to the left L4 nerve root. The LA nerve root courses along the inferior and medial surfaces of the L4 pedicle, and the superior and lateral portion of the L5 pedicle.
  • [0125]
    The indicator lights are similar to the indicator lights drawn in FIG. 24. If both green lights illuminate, then device did not detect electrical impulses from either instrument in the pedicles, and the device detected an electrical impulse from the recorded muscles. The device may use a reference recording lead to compare to the muscle recording lead. The device may contain a microprocessor. If the muscle recording lead receives a much stronger impulse than the reference electrode receives, then the nerve has likely been stimulated properly. Alternatively, the microprocessor may compare the impulses received by the recording electrodes to reference values. The reference values enable the device to indicate if the nerve has been properly stimulated or the soft tissues around the nerve were mistakenly stimulated. The device may use a ground lead.
  • [0126]
    The red light by the large number one will illuminate if the instrument attached to the cable from the “Instrument 1” port receives an electrical impulse or the device fails to receive an impulse from both or either “Muscle” recording electrodes. Similarly, the red light by the large number two will illuminate if the instrument attached to the cable from the “Instrument 2” port receives an electrical impulse or the device fails to receive an impulse from both or either “Muscle” recording electrodes. The “Instrument 1 & 2” and the “Muscle 1 & 2” lights are used as described in the text of FIG. 24, to indicate if the instruments have been stimulated or the muscles were not stimulated.
  • [0127]
    [0127]FIG. 27A is a posterior view of the spine similar to the view described in FIG. 25. The dark circles represent instruments in the pedicles. R1 and R2 represent recording electrodes that are attached to the instruments in the pedicles. S1, S2, & S3 represent a few of the possible stimulation sites. The figure illustrates a nerve may be stimulated below the pedicle, at the level of the pedicle, or above the pedicle. Stimulation of the nerve below the pedicle relies on transmission of the impulse in a caudal direction to test the superior and lateral aspects of the pedicle below the stimulated nerve and transmission of the impulse in a caudal direction to stimulate the muscle. Stimulation of the nerve below the pedicle relies on transmission of the impulse in a cephalic direction to test the inferior and medial surfaces of the pedicle above the stimulated nerve. Spinal nerves carry electrical impulses in both cephalic and caudal directions. Motor portions of the nerves transmit impulses away from the spinal cord to the muscles (caudal direction). Sensory portions of the nerves transmit impulses from the sensation receptors to the spinal cord (cephalic direction). The device drawn in FIG. 26 could be used to test the instruments in the adjacent pedicles drawn in FIG. 27A. A single stimulus delivered at S3 would test the instruments in both pedicles. Additional stimulus sites could be used to complete the testing. For example, stimulus sites S4 and S2 could be used to complete the testing.
  • [0128]
    [0128]FIG. 27B is a posterior view of the spine as described in FIG. 27A. The cross sections of pedicle instruments are seen in all of the pedicles. The drawing illustrates other embodiments of the invention. The embodiments drawn in FIG. 27B do not require monitoring the muscles in the extremities. In one embodiment of the invention the recording electrodes are placed in or over the nerves. Techniques well know to those specialists who perform EMG testing could be used to locate the nerves. Alternatively, the electrodes could be placed on or in the nerves under direct observation.
  • [0129]
    A stimulus is applied at S1. The recording electrodes are attached to the instrument in the pedicle (R1) and another portion of the stimulated nerve. If the R2 electrode detects the stimulated impulse and the R1 electrode does not detect the impulse, then it is unlikely the pedicle instrument is contacting the stimulated nerve. A multi-channel device could be used to test the instruments in more than one pedicle simultaneously. The R2 electrode could be placed in a spinal nerve or a peripheral nerve that has components that arise from the stimulated nerve. For example, for testing the pedicles in the lumbar spine, the R2 electrode could be placed in the sciatic nerve (L4, L5, S1, S2, & S3) or branches from the sciatic nerve, the femoral nerve (L2, L3, & LA) or branches from the femoral nerve, or other nerves. The spinal nerve components that form the sciatic and femoral nerves are listed in parentheses behind the words sciatic nerve and femoral nerve respectively. Naturally other nerves would be stimulated and recorded when testing instruments in the cervical and thoracic spine.
  • [0130]
    The invention is more sensitive and more accurate than prior-art devices. Prior-art devices may record a false positive if electrical impulses are delivered through a crack in the pedicle, but the instrument is contained within the pedicle. The present invention allows testing with smaller electrical impulses. The smaller impulses are less likely to stimulate a pedicle instrument through cracks in the pedicle. Prior art devices may record a false negative if the recording electrodes over the muscles in the extremities fail to detect an impulse. As noted previously, nerves that conduct impulses poorly, poor conduction through the surface electrodes, etc., may falsely indicate the instrument is safely contained in the pedicle.
  • [0131]
    Prior-art systems generally send multiple stimuli of increasing amplitude into the instrument within the pedicle. Prior art systems attempt to record the amount of stimuli necessary to record the impulse over the lower extremities. Recording an impulse over the lower extremities decreases the probability of a false negative result. Stimulating pedicle instruments with multiple stimuli with increasing amplitude is time consuming and requires sophisticated software. The present invention improves upon prior art devices by generally only requiring the application of a single stimulus per pedicle instrument undergoing testing. Some embodiments of the invention allow testing pedicle instruments in multiple vertebrae with the application of a single stimulus.
  • [0132]
    Note that the invention may also be used to test nerves while retracting nerves or performing other spinal procedures. The distance between S1 and R2 could be predetermined. In fact, S1 and R2 could extend from the same instrument. Electrical impulses could be periodically delivered to the nerve at S1 during surgery. For example, the electrical impulses could be delivered at a frequency of one per minute. The microprocessor within the monitor could signal an alarm, for example, illuminate a light bulb, if the amplitude of the impulse detected at R2 decreased when compared to a reference amplitude obtained by stimulating the nerve before manipulating the nerve during the operation. The microprocessor could also cause an alarm to signal if the time between the stimulus delivered at S1 and recorded at R2 increased when compared to a reference time obtained for the nerve before manipulating the nerve during the operation.
  • [0133]
    Standard reference amplitudes and velocities may also be preprogrammed into the microprocessor. Standard reference velocities require fixed distances between S1 and R2. The S1 impulse could be delivered through a nerve root retractor or a stimulus probe. A stimulus delivering retractor is drawn in FIG. 37. As noted above, R2 may lie anywhere along the course of the spinal nerve, nerves supplied by the spinal nerve, or muscles supplied by the spinal nerve. The device alerts surgeons of potential nerve injury before the nerve injury occurs. For example, excessive retraction of a nerve root may injure the nerve root. The device detects diminished nerve function within seconds or minutes of the excessive retraction. Embodiments of the invention for use with peripheral nerves are described in FIG. 36.
  • [0134]
    In the drawings, R4 represents an alternative recording position. One or more R4 electrodes could be placed over or in muscles of the body including muscles in the extremities, the muscles in the buttock, the muscles about the shoulder, or muscles about the spine. In contrast to prior-art devices, the R4 electrode may be used to confirm the nerve has been properly stimulated. Any muscle innervated by the stimulated muscle may be monitored. A single muscle that is supplied by multiple nerve roots may be monitored while testing instruments in pedicles at different levels of the spine. For example, the gluteus medius muscle could be monitored to confirm the L4, L5, or S1 nerves have been successfully stimulated. The gluteal muscles and the skin over the muscles are easily reached during surgeries on the lumbar spine. Prior-art systems require monitoring of many muscles of the body. Failure to detect stimulation of one of the muscles may lead to a false negative reading. A false negative reading fails to properly detect an instrument, such as a pedicle screw, is compressing or injuring a nerve. Prior-art systems typically require monitoring over four separate locations over each extremity. Preparing the skin over multiple sites and placing the electrodes over multiple sites is time consuming.
  • [0135]
    The present invention alerts surgeons if the R4 electrode is improperly placed or if the R4 electrode/electrodes has/have shifted during the operation. The red light on the device and the muscle light on the device illuminate if the R4 electrode does not record an impulse. The novel invention enables surgeons to monitor the paraspinal muscles. The paraspinal muscles area easily accessible in the surgical field. Prior art devices do not use the paraspinal muscles. Surgical exposure of the spine may injure the paraspinal muscles or the nerves to the muscles. Injury to the nerves to the paraspinal muscles or injury of the paraspinal muscles may cause prior art devices and methods to yield a false negative result, if the devices fail to record an impulse. Failure of prior art methods and devices to detect stimulation of the paraspinal muscles could indicate: (a) that the pedicle instrument is contained within the pedicle, (b) the nerve to the paraspinal muscle is not functioning properly, (c) the paraspinal muscles are not functioning properly or, (d) the stimulated muscle has not been recorded. Explanations (b), (c), and (d) lead to false negative results. Thus, prior-art systems do not monitor the paraspinal muscles. The present invention alerts the surgeon if injury to the nerves to the paraspinal muscles or the paraspinal muscles precludes monitoring the muscles. If the surgeon is unable to detect recordings from the paraspinal muscles after delivering a stimulus to the nerves, then the surgeon is alerted to monitor other muscles, such as the gluteal muscles. The ventrally, segmentally, innervated intertransversalis muscles are monitored in one embodiment of the invention. Other paraspinal muscles may be monitored.
  • [0136]
    [0136]FIG. 28 is a posterior view of the spine, similar to the view drawn in FIG. 27B. An alternative embodiment of the invention is illustrated in the drawing. S1 represents stimulation of a peripheral nerve such as the sciatic nerve, femoral nerve, branches the sciatic nerve, branches of the femoral nerve, or other peripheral nerve. R3 & R4 represent recording sites on or in the spinal nerves. Alternative R3 & R4 sites include nerves within the thecal sac, the spinal cord, or the brain. The R3 & R4 sites are monitored to confirm the nerve has been stimulated correctly. The R1 & R2 are monitored to detect stimulation of the instruments within the pedicles. A single electrical stimulus from S1 could be used to test multiple pedicles simultaneously. Stimulation of the sciatic nerve may allow simultaneous testing of the pedicles near the L4, L5, S1, S2, & S3 nerves. Stimulation of the femoral nerve may allow testing of the pedicles near the L2, L3, and L4 nerves. A multi-channel device allows simultaneous testing of multiple pedicles.
  • [0137]
    [0137]FIG. 29 is a posterior view of the spine similar to the view drawn in FIG. 28. The alternative embodiment of the invention stimulates multiple spinal nerves simultaneously. S1 represents a stimulus delivered over the nerves in the thecal sac, the spinal cord, or the brain. An electrical or magnetic stimulus may be used. R1B, R2B, R3B, & R4B are recording sites to confirm the spinal nerves near the pedicles undergoing testing are properly stimulated. R1A, R2A, R3A, & R4A are recording sites from the instruments that lie within the pedicles. If R1B, R2B, R3B, or R4B fail to detect an impulse, the device will alert the surgeon that the pedicle instruments at the R1A, R2A, R3A, or R4A sites respectively, has not been adequately tested. Failure to detect an impulse at a RnB site signals the stimulus was not applied to the surface of the pedicle by the nerve monitored by the RnB electrode. A S1 needle electrode may be placed through the dura. The S1 site may be cephalad or caudal to the tested pedicles. If all RB sites record impulses and none of the RA sites record impulses, then all of the instruments are likely contained within the pedicles. A multi-channel device, with at least four groups of alarm lights like those illustrated in FIG. 24, could be used in this embodiment of the invention.
  • [0138]
    [0138]FIG. 30 is a posterior view of the spine, similar to the view drawn in FIG. 29, showing the alternative use of a reference electrode. A microprocessor within the device compares the impulse detected by the R2 electrode to the impulse detected by the reference (R3) electrode. The microprocessor triggers an alarm, such as illuminating a light bulb, if the stimulus received by R2 is below a preset value or the stimulus received by R2 is near or below that received by R3. The alarm alerts the surgeon that the electrodes at the R2 or S1 sites are not properly contacting the spinal nerve.
  • [0139]
    [0139]FIG. 31 is an axial view of a pedicle. The drawing illustrates an alternative embodiment of the invention. The black circle represents the cross section of an instrument in the pedicle. S1 represents a stimulation site. R1 represents a recording site on the instrument in the pedicle. R2 represent a recording site on the pedicle. If the R1 electrode detects a smaller signal than the R2 electrode the instrument is likely contained in the pedicle.
  • [0140]
    [0140]FIG. 32A is a lateral view of a needle-tipped stimulating or recording electrode. The area of the drawing with diagonal lines represents insulating material. The needle tipped electrode is generally placed in nerves or muscles. FIG. 32B is a lateral view of an alternative embodiment of the tip of the electrode drawn in FIG. 32A. The balled tipped probe is generally placed on nerves or muscles. FIG. 32C is a lateral view of an alternative embodiment of the tip of the electrode drawn in FIG. 32A. The curved tip is easier to insert through the neuroforamina. The tip may help the surgeon direct the electrode to the S1 position drawn in FIG. 30.
  • [0141]
    [0141]FIG. 33 is an oblique view of an alternative embodiment of the invention. This embodiment of the invention demonstrates the use of stimulating (S1) and recording (R1) electrodes in an instrument. For example the instrument may be a cannula as drawn in FIG. 33. Other than the electrodes, the instrument is made of a non-electrical conducting material in the preferred embodiment of the device. A monitor with microprocessor measures the amplitude and velocity of an impulse delivered from S1 to R1. Rapid transfer of a high amplitude impulse suggests the cannula is against a tissue that readily transfers impulses. Nerves transmit impulses better than muscles transmit impulses. The novel cannula could be used to alert surgeons when the instrument is against a nerve. Surgeons could use the novel cannula to navigate between the nerves in muscles. For example, surgeons could use the device for trans-psoas approaches to the spine.
  • [0142]
    [0142]FIG. 34A is a lateral view of another embodiment of the invention drawn in FIG. 33. Recording and stimulating electrodes are used in the walls of a stylet or a blunt dissector. Other than the electrodes, the stylet or dissector is made of a material that conducts electricity poorly. The stylet can be used within a cannula. The blunt tip helps surgeons separate the fibers of muscles. The electrodes and the monitor alert surgeons when the instrument lies against a nerve. FIG. 34B is an anterior view of the embodiment of the device drawn in FIG. 34A. FIG. 34C is an oblique view of the embodiment of the device drawn in FIG. 34A. FIG. 35 is an anterior view of another embodiment of the device drawn in FIG. 33. The electrodes are incorporated into the ends of a retractor.
  • [0143]
    [0143]FIG. 36 is a posterior view of a peripheral nerve and another embodiment of the invention. This embodiment of the invention may be used to protect peripheral nerves during non-spinal operations. The nerve is stimulated at one location S1. Recording electrodes/electrode are placed in another location along the nerve or a branch of the nerve (R1). Alternatively recording electrodes/electrode may be placed in muscles that are supplied by the stimulated nerve (R2). A device, with a microprocessor, delivers electrical impulses at S1 periodically during the operation. For example, the device may deliver one impulse per minute. The device measures the amplitude of the impulses recorded at R1 and/or R2 and the time between the delivery of the stimulus and recording of the stimulus. The device triggers an alarm, for example illuminates a light bulb, if the amplitude or velocity of the transmitted stimulus deteriorates during the surgical procedure.
  • [0144]
    The microprocessor may also be programmed to compare the recorded values for the stimulus to standard values. The distance between S1 and R1 or R2 could be fixed or measured to enable the microprocessor to calculate velocity figures. For example, this embodiment of the device could be used during hip replacement surgery. A needle electrode (S1) could be placed into the sciatic nerve at the level of the sciatic notch. The S1 electrode could be sutured into place. Alternatively, the mechanisms use to hold pacemaker electrodes in position could be used to hold the S1 electrode in the tissues near the sciatic nerve while the tip of the S1 electrode lies in the nerve. The device would quickly alarm the surgeon if sciatic nerve function deteriorated during surgery. The device would alert the surgeon to diminish traction on the sciatic nerve before the injury became permanent. This embodiment may be used on other peripheral nerves in the body. It may also be used to detect additional causes of nerve injury such as pressure on the nerve or surgical dissection around the nerve.
  • [0145]
    [0145]FIG. 37 is a lateral view of a nerve root retractor that stimulates the spinal nerves. The retractor can be used to deliver the stimulus at the S1 site as described in FIG. 30.
  • [0146]
    According to this invention, electric impulses may be recorded from an instrument placed into and possibly through the pedicle of a vertebra. Peripheral nerves, spinal nerves, the sciatic nerve, the femoral nerve, or a plexus of nerves may be stimulated. Recording electrodes are also placed over spinal nerves. A recording electrode may be placed through the dura. If the recording electrode over, or within, a nerve detects an impulse transmitted through the nerve and the recording electrode on an instrument placed into a pedicle does not detect an impulse, then it is likely the instrument within the pedicle does not breach the walls of the pedicle. Alternatively, the spinal nerves could be stimulated with recording electrodes placed over or in peripheral nerves, the nerves in the thecal sac, and the instrument/instruments in the pedicles.
  • [0147]
    Stimulation and/or recording electrodes can be used over the dura or through the dura cephald and/or caudal to the level the pedicle screw or screws are inserted. Multiple pedicle screws could be tested simultaneously by a single stimulating impulse. For example, a trans-dural stimulating electrode could be placed cephald to the pedicle screws. A second trans-dural recording electrode could be placed caudal to the pedicle screws. Alternatively, multiple recording electrodes could be placed over or in the spinal nerves near the pedicle screws. The recording electrodes listed above could be changed to stimulating electrodes and the stimulating electrodes listed above could be changed to recording electrodes. If recording electrodes placed on instruments within the pedicles do not detect an electrical impulse, but the recording electrodes over or within the nerves detect an impulse, then the screws, curettes, or taps are likely within the pedicles. Testing of the invention will likely determine thresholds (for stimulation and recording) at which penetration of the pedicle wall by an instrument is unlikely. Techniques well known to those who perform EMG testing could be used to help locate spinal and peripheral nerves.
  • [0148]
    An electrode placed over or within a myotome may be used to confirm stimulation of a nerve. For example, if an electrode over the L5 myotome detects a impulse applied to the L5 nerve and a recording electrode from an instrument in a pedicle near the L5 nerve does not record an impulse, it is unlikely the instrument within the pedicle near the L5 nerve penetrates the wall of the pedicle. The invention eliminates the need for repeated stimulation at successively higher impulses as used in prior art systems. Prior art systems use successively higher impulses to record a value in the extremities in an effort to avoid a false negative. Failure to record a stimulus over the myotome in prior art systems may confirm the instrument does not penetrate the walls of the pedicle. Alternatively, failure to record a stimulus over the myotome in prior art systems may indicate a problem with the conductivity of the nerve, the junction between skin and the electrode, or other technical problem. Recording and/or stimulating electrodes can be placed in or over the tissues about the spine including the disc, the gluteal muscles, muscles about the hip or shoulder girdle, or the extremities.
  • [0149]
    Velocity calculations and measurements (of transmittance of the electrical impulse) may also be used. A single monitor or instrument may have recording and stimulating electrodes. A fixed distance between the recording and stimulating electrodes would ease velocity calculations. For example, a non-conducting cannula with one or more stimulating electrodes and one or more recording electrodes may be used in trans-psoas approaches. An impulse that travels with high velocity from the stimulating electrode to the recording electrode suggests the cannula is near or against a nerve. Stimulation may be in the range of 0.01 ma-50 ma.
Patent Citations
Cited PatentFiling datePublication dateApplicantTitle
US208227 *Mar 9, 1878Sep 24, 1878 Improvement in vaginal speculums
US1548184 *Apr 11, 1923Aug 4, 1925Cameron Will JHolder and control for pulp testers
US2704064 *Sep 10, 1952Mar 15, 1955Meditron CompanyNeurosurgical stimulator
US2736002 *Sep 2, 1952Feb 21, 1956 oriel
US3364929 *Dec 21, 1964Jan 23, 1968Burroughs Wellcome CoMethod for administering muscle relaxant drug
US3664329 *Mar 9, 1970May 23, 1972ConceptNerve locator/stimulator
US3682162 *Dec 4, 1969Aug 8, 1972Wellcome FoundCombined electrode and hypodermic syringe needle
US3785368 *Aug 23, 1971Jan 15, 1974Lumb DAbnormal nerve pressure locus detector and method
US3830226 *Jun 15, 1973Aug 20, 1974ConceptVariable output nerve locator
US3957036 *Feb 3, 1975May 18, 1976Baylor College Of MedicineMethod and apparatus for recording activity in intact nerves
US4099519 *Jan 14, 1977Jul 11, 1978Warren Fred EDiagnostic device
US4164214 *Jul 25, 1977Aug 14, 1979The Regents Of The University Of CaliforniaMethod and apparatus for measuring the sensitivity of teeth
US4207897 *Jul 13, 1977Jun 17, 1980Spembly LimitedCryosurgical probe
US4224949 *Nov 17, 1977Sep 30, 1980Cornell Research Foundation, Inc.Method and electrical resistance probe for detection of estrus in bovine
US4285347 *Jul 25, 1979Aug 25, 1981Cordis CorporationStabilized directional neural electrode lead
US4291705 *Sep 10, 1979Sep 29, 1981The Regents Of The University Of CaliforniaNeuromuscular block monitor
US4461300 *Jan 18, 1982Jul 24, 1984Sutter Biomedical, Inc.Bone and tissue healing device including a special electrode assembly and method
US4515168 *Jul 22, 1983May 7, 1985Chester Martin HClamp-on nerve stimulator and locator
US4519403 *Apr 29, 1983May 28, 1985Medtronic, Inc.Balloon lead and inflator
US4562832 *Jan 21, 1984Jan 7, 1986Wilder Joseph RMedical instrument and light pipe illumination assembly
US4573448 *Oct 5, 1983Mar 4, 1986Pilling Co.Method for decompressing herniated intervertebral discs
US4592369 *Jul 8, 1983Jun 3, 1986National Research Development Corp.Method and apparatus for use in temporal analysis of waveforms
US4595018 *Jun 6, 1984Jun 17, 1986Instrumentarium Corp.Method of further developing the measuring of a neuro-muscular junction
US4633889 *Dec 12, 1984Jan 6, 1987Andrew TalallaStimulation of cauda-equina spinal nerves
US4658835 *Jul 25, 1985Apr 21, 1987Cordis CorporationNeural stimulating lead with fixation canopy formation
US4744371 *Apr 27, 1987May 17, 1988Cordis Leads, Inc.Multi-conductor lead assembly for temporary use
US4759377 *Nov 26, 1986Jul 26, 1988Regents Of The University Of MinnesotaApparatus and method for mechanical stimulation of nerves
US4807642 *Aug 18, 1986Feb 28, 1989Brown David AElectromyographic repetitive strain injury monitor
US4892105 *Jan 11, 1988Jan 9, 1990The Cleveland Clinic FoundationElectrical stimulus probe
US4926865 *Jan 17, 1989May 22, 1990Oman Paul SMicrocomputer-based nerve and muscle stimulator
US5007902 *Feb 22, 1989Apr 16, 1991B. Braun Melsungen AgCatheter set for plexus anesthesia
US5081990 *May 11, 1990Jan 21, 1992New York UniversityCatheter for spinal epidural injection of drugs and measurement of evoked potentials
US5092344 *Nov 19, 1990Mar 3, 1992Lee Tzium ShouRemote indicator for stimulator
US5127403 *Aug 21, 1990Jul 7, 1992Cardiac Control Systems, Inc.Pacemaker catheter utilizing bipolar electrodes spaced in accordance to the length of a heart depolarization signal
US5196015 *Apr 30, 1992Mar 23, 1993Neubardt Seth LProcedure for spinal pedicle screw insertion
US5282468 *Jan 8, 1992Feb 1, 1994Medtronic, Inc.Implantable neural electrode
US5284153 *Apr 14, 1992Feb 8, 1994Brigham And Women's HospitalMethod for locating a nerve and for protecting nerves from injury during surgery
US5284154 *Oct 23, 1992Feb 8, 1994Brigham And Women's HospitalApparatus for locating a nerve and for protecting nerves from injury during surgery
US5299563 *Jul 31, 1992Apr 5, 1994Seton Joseph ZMethod of using a surgical retractor
US5312417 *Jul 29, 1992May 17, 1994Wilk Peter JLaparoscopic cannula assembly and associated method
US5313956 *Dec 3, 1991May 24, 1994Dorsograf AbApparatus for measuring the transport time of nerve signals
US5327902 *May 14, 1993Jul 12, 1994Lemmen Roger DApparatus for use in nerve conduction studies
US5333618 *Jun 30, 1993Aug 2, 1994Gregory LekhtmanPortable self-contained instrument for the measurement of nerve resistance of a patient
US5383876 *Mar 22, 1994Jan 24, 1995American Cardiac Ablation Co., Inc.Fluid cooled electrosurgical probe for cutting and cauterizing tissue
US5480440 *Jul 7, 1993Jan 2, 1996Smith & Nephew Richards, Inc.Open surgical technique for vertebral fixation with subcutaneous fixators positioned between the skin and the lumbar fascia of a patient
US5482038 *Jun 28, 1994Jan 9, 1996Cadwell Industries, Inc.Needle electrode assembly
US5484437 *Jun 10, 1993Jan 16, 1996Michelson; Gary K.Apparatus and method of inserting spinal implants
US5540235 *Jun 30, 1994Jul 30, 1996Wilson; John R.Adaptor for neurophysiological monitoring with a personal computer
US5549656 *May 15, 1995Aug 27, 1996Med Serve Group, Inc.Combination neuromuscular stimulator and electromyograph system
US5593429 *Jun 28, 1994Jan 14, 1997Cadwell Industries, Inc.Needle electrode with depth of penetration limiter
US5599279 *Jan 29, 1996Feb 4, 1997Gus J. SlotmanSurgical instruments and method useful for endoscopic spinal procedures
US5630813 *Dec 8, 1994May 20, 1997Kieturakis; Maciej J.Electro-cauterizing dissector and method for facilitating breast implant procedure
US5707359 *Nov 14, 1995Jan 13, 1998Bufalini; BrunoExpanding trocar assembly
US5711307 *Apr 13, 1995Jan 27, 1998Liberty Mutual Insurance CompanyMethod and apparatus for detecting myoelectric activity from the surface of the skin
US5728046 *Mar 18, 1996Mar 17, 1998Aesculap AgSurgical retractor
US5741253 *Oct 29, 1992Apr 21, 1998Michelson; Gary KarlinMethod for inserting spinal implants
US5759159 *Sep 25, 1996Jun 2, 1998Ormco CorporationMethod and apparatus for apical detection with complex impedance measurement
US5772661 *Feb 27, 1995Jun 30, 1998Michelson; Gary KarlinMethods and instrumentation for the surgical correction of human thoracic and lumbar spinal disease from the antero-lateral aspect of the spine
US5775331 *Jun 7, 1995Jul 7, 1998Uromed CorporationApparatus and method for locating a nerve
US5779642 *Feb 18, 1997Jul 14, 1998Nightengale; ChristopherInterrogation device and method
US5785658 *Jun 7, 1995Jul 28, 1998Sexant Medical CorporationIn vivo tissue analysis methods and apparatus
US5797854 *Aug 1, 1995Aug 25, 1998Hedgecock; James L.Method and apparatus for testing and measuring current perception threshold and motor nerve junction performance
US5860973 *Oct 30, 1996Jan 19, 1999Michelson; Gary KarlinTranslateral spinal implant
US5862314 *Nov 1, 1996Jan 19, 1999Micron Electronics, Inc.System and method for remapping defective memory locations
US5872314 *Jul 25, 1997Feb 16, 1999Clinton; Robert P.Method and apparatus for measuring characteristics of meat
US5885219 *Oct 21, 1997Mar 23, 1999Nightengale; ChristopherInterrogation device and method
US5888196 *Jun 5, 1995Mar 30, 1999General Surgical Innovations, Inc.Mechanically expandable arthroscopic retractors
US5902231 *Oct 24, 1996May 11, 1999Sdgi Holdings, Inc.Devices and methods for percutaneous surgery
US5926728 *Apr 8, 1997Jul 20, 1999Taiwan Semiconductor Manufacturing Company, Ltd.Method for fabricating tungsten polycide contacts
US5928139 *Jul 8, 1998Jul 27, 1999Koros; Tibor B.Retractor with adjustable length blades and light pipe guides
US5928158 *Mar 25, 1997Jul 27, 1999Aristides; ArellanoMedical instrument with nerve sensor
US6027456 *Jul 10, 1998Feb 22, 2000Advanced Neuromodulation Systems, Inc.Apparatus and method for positioning spinal cord stimulation leads
US6038477 *Dec 23, 1998Mar 14, 2000Axon Engineering, Inc.Multiple channel nerve stimulator with channel isolation
US6050992 *May 19, 1997Apr 18, 2000Radiotherapeutics CorporationApparatus and method for treating tissue with multiple electrodes
US6074343 *Apr 16, 1999Jun 13, 2000Nathanson; MichaelSurgical tissue retractor
US6104957 *Aug 21, 1998Aug 15, 2000Alo; Kenneth M.Epidural nerve root stimulation with lead placement method
US6104960 *Jul 13, 1998Aug 15, 2000Medtronic, Inc.System and method for providing medical electrical stimulation to a portion of the nervous system
US6206826 *Jun 18, 1999Mar 27, 2001Sdgi Holdings, Inc.Devices and methods for percutaneous surgery
US6224549 *Apr 20, 1999May 1, 2001Nicolet Biomedical, Inc.Medical signal monitoring and display
US6259945 *Apr 30, 1999Jul 10, 2001Uromed CorporationMethod and device for locating a nerve
US6266558 *Dec 1, 1998Jul 24, 2001Neurometrix, Inc.Apparatus and method for nerve conduction measurements with automatic setting of stimulus intensity
US6425859 *Nov 9, 1999Jul 30, 2002Sdgi Holdings, Inc.Cannula and a retractor for percutaneous surgery
US6425901 *Dec 4, 1997Jul 30, 2002Loma Linda University Medical CenterVascular wound closure system
US6564078 *Jun 4, 1999May 13, 2003Nuvasive, Inc.Nerve surveillance cannula systems
US6760616 *May 18, 2001Jul 6, 2004Nu Vasive, Inc.Tissue discrimination and applications in medical procedures
US6902569 *Aug 17, 2001Jun 7, 2005Image-Guided Neurologics, Inc.Trajectory guide with instrument immobilizer
US6929606 *May 13, 2003Aug 16, 2005Depuy Spine, Inc.Retractor and method for spinal pedicle screw placement
US7050848 *Mar 29, 2004May 23, 2006Nuvasive, Inc.Tissue discrimination and applications in medical procedures
US7079883 *May 7, 2003Jul 18, 2006Nuvaslve, Inc.Nerve surveillance cannulae systems
US7177677 *Oct 16, 2002Feb 13, 2007Nuvasive, Inc.Nerve proximity and status detection system and method
US20020007129 *Jun 8, 2001Jan 17, 2002Marino James F.Nerve movement and status detection system and method
US20020072686 *May 18, 2001Jun 13, 2002Nuvasive, Inc.Tissue discrimination and applications in medical procedures
US20030105503 *Dec 31, 2002Jun 5, 2003Nuvasive, Inc.Relative nerve movement and status detection system and method
US20050004593 *Jul 26, 2004Jan 6, 2005Depuy Spine, Inc.Non cannulated dilators
US20050004623 *Apr 30, 2004Jan 6, 2005Patrick MilesSystem and methods for performing percutaneous pedicle integrity assessments
US20050075578 *Mar 25, 2004Apr 7, 2005James GharibSystem and methods for performing surgical procedures and assessments
US20050149035 *Oct 18, 2004Jul 7, 2005Nuvasive, Inc.Surgical access system and related methods
US20050182454 *Jan 9, 2004Aug 18, 2005Nuvasive, Inc.System and methods for determining nerve proximity, direction, and pathology during surgery
US20070016097 *Jul 15, 2005Jan 18, 2007Nuvasive, Inc.System and methods for determining nerve direction to a surgical instrument
Referenced by
Citing PatentFiling datePublication dateApplicantTitle
US7657308Feb 2, 2010Nuvasive, Inc.System and methods for performing dynamic pedicle integrity assessments
US7664544Apr 30, 2004Feb 16, 2010Nuvasive, Inc.System and methods for performing percutaneous pedicle integrity assessments
US7691057Apr 6, 2010Nuvasive, Inc.Surgical access system and related methods
US7811138Mar 2, 2009Oct 12, 2010Pioneer Surgical Technology, Inc.Electrical connector for surgical systems
US7819801Feb 27, 2004Oct 26, 2010Nuvasive, Inc.Surgical access system and related methods
US7892173Dec 7, 2009Feb 22, 2011Nuvasive, Inc.Surgical access system and related methods
US7905840Oct 18, 2004Mar 15, 2011Nuvasive, Inc.Surgical access system and related methods
US7920922Feb 24, 2010Apr 5, 2011Nuvasive, Inc.System and methods for determining nerve proximity, direction, and pathology during surgery
US7935051Apr 22, 2009May 3, 2011Nuvasive, Inc.Surgical access system and related methods
US7942826Jun 6, 2006May 17, 2011Nuvasive, Inc.Insulated pedicle access system and related methods
US7962191Oct 31, 2007Jun 14, 2011Nuvasive, Inc.Nerve surveillance cannulae systems
US7963927Jun 21, 2011Nuvasive, Inc.Electromyography system
US7987001Jan 25, 2007Jul 26, 2011Warsaw Orthopedic, Inc.Surgical navigational and neuromonitoring instrument
US7991463Aug 2, 2011Nuvasive, Inc.Electromyography system
US8000782Aug 16, 2011Nuvasive, Inc.System and methods for performing surgical procedures and assessments
US8005535Aug 23, 2011Nuvasive, Inc.System and methods for performing surgical procedures and assessments
US8016767Apr 23, 2007Sep 13, 2011Nuvasive, Inc.Surgical access system and related methods
US8027716Sep 27, 2011Nuvasive, Inc.System and methods for performing surgical procedures and assessments
US8050769May 1, 2009Nov 1, 2011Nuvasive, Inc.System and methods for determining nerve proximity, direction, and pathology during surgery
US8068912Jan 9, 2004Nov 29, 2011Nuvasive, Inc.System and methods for determining nerve proximity, direction, and pathology during surgery
US8092455Feb 7, 2005Jan 10, 2012Warsaw Orthopedic, Inc.Device and method for operating a tool relative to bone tissue and detecting neural elements
US8114019Dec 30, 2009Feb 14, 2012Nuvasive, Inc.Surgical access system and related methods
US8133173Dec 30, 2009Mar 13, 2012Nuvasive, Inc.Surgical access system and related methods
US8137284Oct 8, 2003Mar 20, 2012Nuvasive, Inc.Surgical access system and related methods
US8147421Jul 15, 2005Apr 3, 2012Nuvasive, Inc.System and methods for determining nerve direction to a surgical instrument
US8165653Jun 14, 2011Apr 24, 2012Nuvasive, Inc.Surgical access and nerve surveillance
US8172750Mar 17, 2010May 8, 2012Nuvasive, Inc.Surgical access system and related methods
US8182423Dec 30, 2009May 22, 2012Nuvasive, Inc.Surgical access system and related methods
US8187179Dec 30, 2009May 29, 2012Nuvasive, Inc.Surgical access system and related methods
US8192356Dec 10, 2009Jun 5, 2012Nuvasive, Inc.Surgical access system and related methods
US8192357Dec 30, 2009Jun 5, 2012Nuvasive, Inc.Surgical access system and related methods
US8206312Sep 22, 2006Jun 26, 2012Nuvasive, Inc.Multi-channel stimulation threshold detection algorithm for use in neurophysiology monitoring
US8244343Aug 14, 2012Nuvasive, Inc.System and methods for performing surgical procedures and assessments
US8255044Feb 2, 2010Aug 28, 2012Nuvasive, Inc.System and methods for performing dynamic pedicle integrity assessments
US8255045 *Aug 28, 2012Nuvasive, Inc.Neurophysiologic monitoring system
US8262683Sep 13, 2011Sep 11, 2012Medtronic Xomed, Inc.Micro-resecting and evoked potential monitoring system and method
US8265744Aug 16, 2011Sep 11, 2012Nuvasive, Inc.Systems and methods for performing surgical procedures and assessments
US8287597Oct 16, 2012Nuvasive, Inc.Method and apparatus for performing spine surgery
US8303498Feb 18, 2011Nov 6, 2012Nuvasive, Inc.Surgical access system and related methods
US8303515Dec 11, 2009Nov 6, 2012Nuvasive, Inc.Surgical access system and related methods
US8313430Jan 11, 2007Nov 20, 2012Nuvasive, Inc.Surgical access system and related methods
US8323208May 6, 2010Dec 4, 2012Timothy Taylor DavisNeurologic monitoring system and method
US8328851Jul 28, 2006Dec 11, 2012Nuvasive, Inc.Total disc replacement system and related methods
US8337410Aug 2, 2011Dec 25, 2012Nu Vasive, Inc.Electromyography system
US8343046Mar 12, 2012Jan 1, 2013Nuvasive, Inc.Surgical access system and related methods
US8355780Nov 20, 2009Jan 15, 2013Nuvasive, Inc.Surgical access system and related methods
US8374673Jan 25, 2007Feb 12, 2013Warsaw Orthopedic, Inc.Integrated surgical navigational and neuromonitoring system having automated surgical assistance and control
US8388527Dec 31, 2009Mar 5, 2013Nuvasive, Inc.Surgical access system and related method
US8403841Mar 26, 2013Nuvasive, Inc.Surgical access system and related methods
US8439832Jan 4, 2011May 14, 2013Nuvasive, Inc.Surgical access system and related methods
US8465513Sep 11, 2012Jun 18, 2013Medtronic Xomed, Inc.Micro-resecting and evoked potential monitoring system and method
US8500634Jan 17, 2013Aug 6, 2013Nuvasive, Inc.Surgical access system and related methods
US8500653Jun 26, 2012Aug 6, 2013Nuvasive, Inc.Neurophysiology monitoring system configured for rapid stimulation threshold acquisition
US8512235Jun 1, 2012Aug 20, 2013Nuvasive, Inc.Surgical access system and related methods
US8523768May 8, 2012Sep 3, 2013Nuvasive, Inc.Surgical access system and related methods
US8523873 *Apr 8, 2010Sep 3, 2013Warsaw Orthopedic, Inc.Neural-monitoring enabled sleeves for surgical instruments
US8548579Aug 7, 2012Oct 1, 2013Nuvasive, Inc.System and methods for performing surgical procedures and assessments
US8550994Nov 5, 2012Oct 8, 2013Nuvasive, Inc.Surgical access system and related methods
US8556808Jan 15, 2013Oct 15, 2013Nuvasive, Inc.Surgical access system and related methods
US8562521Feb 1, 2013Oct 22, 2013Nuvasive, Inc.Surgical access system and related methods
US8562539Aug 21, 2007Oct 22, 2013Nuvasive, Inc.Electromyography system
US8568317Sep 27, 2006Oct 29, 2013Nuvasive, Inc.System and methods for nerve monitoring
US8568331Feb 2, 2006Oct 29, 2013Nuvasive, Inc.System and methods for monitoring during anterior surgery
US8591431 *Sep 22, 2006Nov 26, 2013Nuvasive, Inc.System and methods for performing pedicle integrity assessments of the thoracic spine
US8591432Jan 3, 2011Nov 26, 2013Nuvasive, Inc.Surgical access system and related methods
US8602982Apr 4, 2013Dec 10, 2013Nuvasive, Inc.Surgical access system and related methods
US8628469Jul 30, 2013Jan 14, 2014Nuvasive, Inc.Surgical access system and related methods
US8634904Nov 8, 2011Jan 21, 2014Nuvasive, Inc.System and methods for determining nerve proximity, direction, and pathology during surgery
US8641638Oct 31, 2007Feb 4, 2014Nuvasive, Inc.Electromyography system
US8652140Jan 3, 2012Feb 18, 2014Warsaw Orthopedic, Inc.Device and method for operating a tool relative to bone tissue and detecting neural elements
US8663100Sep 4, 2013Mar 4, 2014Nuvasive, Inc.Surgical access system and related methods
US8672840May 8, 2012Mar 18, 2014Nuvasive, Inc.Surgical access system and related methods
US8679006Feb 1, 2013Mar 25, 2014Nuvasive, Inc.Surgical access system and related methods
US8696559Feb 1, 2013Apr 15, 2014Nuvasive, Inc.Surgical access system and related methods
US8708899Feb 1, 2013Apr 29, 2014Nuvasive, Inc.Surgical access system and related methods
US8738123Feb 11, 2013May 27, 2014Nuvasive, Inc.System and methods for performing surgical procedures and assessments
US8740783 *Jul 20, 2006Jun 3, 2014Nuvasive, Inc.System and methods for performing neurophysiologic assessments with pressure monitoring
US8747307Sep 4, 2013Jun 10, 2014Nuvasive, Inc.Surgical access system and related methods
US8753270Jul 31, 2013Jun 17, 2014Nuvasive, Inc.Surgical access system and related methods
US8753271Jan 13, 2014Jun 17, 2014Nuvasive, Inc.Surgical access system and related methods
US8758378Jun 18, 2013Jun 24, 2014Medtronic Xomed, Inc.Micro-resecting and evoked potential monitoring system and method
US8764649Oct 11, 2013Jul 1, 2014Nuvasive, Inc.Surgical access system and related methods
US8768450Feb 8, 2013Jul 1, 2014Nuvasive, Inc.System and methods for performing surgical procedures and assessments
US8784330May 17, 2011Jul 22, 2014Nu Vasive, Inc.Insulated pedicle access system and related methods
US8790406Apr 2, 2012Jul 29, 2014William D. SmithSystems and methods for performing spine surgery
US8812116May 7, 2012Aug 19, 2014Nuvasive, Inc.System and methods for determining nerve proximity, direction, and pathology during surgery
US8821396Jun 9, 2014Sep 2, 2014Nuvasive, Inc.Surgical access system and related methods
US8827900Nov 20, 2012Sep 9, 2014Nuvasive, Inc.Surgical access system and related methods
US8870960Dec 11, 2012Oct 28, 2014Nuvasive, Inc.Total disc replacement system and related methods
US8915846Apr 18, 2013Dec 23, 2014Nuvasive, Inc.Surgical access system and related methods
US8920500Oct 16, 2012Dec 30, 2014Nuvasive, Inc.Methods and apparatus for performing spine surgery
US8942801Jun 9, 2014Jan 27, 2015Nuvasive, Inc.Surgical access system and related methods
US8945004Aug 1, 2014Feb 3, 2015Nuvasive, Inc.Surgical access system and related methods
US8956283Mar 3, 2014Feb 17, 2015Nuvasive, Inc.Surgical access system and related methods
US8958869Dec 22, 2012Feb 17, 2015Nuvasive, Inc.Electromyography system
US8977352May 15, 2014Mar 10, 2015Nuvasive, Inc.Systems and methods for performing surgical procedures and assessments
US8979748 *Oct 23, 2009Mar 17, 2015James L. ChappuisDevices and methods for temporarily retaining spinal rootlets within dural sac
US9014776Jul 16, 2013Apr 21, 2015Nuvasive, Inc.Surgical access and nerve surveillance
US9037250Feb 14, 2013May 19, 2015Nuvasive, Inc.System and methods for determining nerve proximity, direction and pathology during surgery
US9131947Jan 23, 2009Sep 15, 2015Nuvasive, Inc.Neurophysiological apparatus and procedures
US9168149Oct 28, 2014Oct 27, 2015NaVasive, Inc.Total disc replacement system and related methods
US9192482Dec 19, 2014Nov 24, 2015Nuvasive, Inc.Methods and apparatus for performing spine surgery
US9198765Oct 31, 2012Dec 1, 2015Nuvasive, Inc.Expandable spinal fusion implants and related methods
US9204871Jan 16, 2015Dec 8, 2015Nuvasive, Inc.Surgical access system and related methods
US20050004623 *Apr 30, 2004Jan 6, 2005Patrick MilesSystem and methods for performing percutaneous pedicle integrity assessments
US20060200023 *Mar 4, 2005Sep 7, 2006Sdgi Holdings, Inc.Instruments and methods for nerve monitoring in spinal surgical procedures
US20070198062 *Apr 23, 2007Aug 23, 2007Nuvasive, Inc.Surgical access system and related methods
US20070293782 *Aug 21, 2007Dec 20, 2007Nu Vasive, Inc.Electromyography system
US20080064976 *Oct 31, 2007Mar 13, 2008Nuvasive, Inc.Electromyography system
US20080064977 *Oct 31, 2007Mar 13, 2008Nuvasive, Inc.Electromyography system
US20080221473 *Sep 22, 2006Sep 11, 2008Blair CalancieSystem and Methods for Performing Pedicle Integrity Assessments of the Thoracic Spine
US20090221153 *Mar 2, 2009Sep 3, 2009Pioneer Surgical Technology, Inc.Electrical Connector for Surgical Systems
US20100286554 *May 6, 2010Nov 11, 2010Timothy Taylor DavisNeurologic monitoring system and method
US20100317989 *Jun 16, 2010Dec 16, 2010Nuvasive Inc.Systems and Methods for Performing Neurophysiologic Assesments With Pressure Monitoring
US20110098705 *Oct 23, 2009Apr 28, 2011Chappuis James LDevices and Methods for Temporarily Retaining Spinal Rootlets within Dural Sac
US20110251597 *Apr 8, 2010Oct 13, 2011Warsaw Orthopedic, Inc.Neural-monitoring enabled sleeves for surgical instruments
EP2249914A2 *Feb 21, 2008Nov 17, 2010Integrity Intellect, Inc.Implant equipped for nerve location and method of use
WO2006086367A1Feb 6, 2006Aug 17, 2006Sdgi Holdings IncDevice and method for operating a tool relative to bone tissue and detecting neural elements
WO2007051143A1 *Oct 26, 2006May 3, 2007Medtronic Xomed IncInstrument for surgical cutting
WO2011127413A3 *Apr 8, 2011Apr 19, 2012Warsaw Orthopedic, Inc.Neural-monitoring enabled sleeves for surgical instruments
Classifications
U.S. Classification600/554
International ClassificationA61B17/16, A61N1/08
Cooperative ClassificationA61N1/08, A61B17/1626, A61B17/1671
European ClassificationA61B17/16S4, A61B17/16D8
Legal Events
DateCodeEventDescription
Sep 7, 2004ASAssignment
Owner name: NUVASIVE, INC., CALIFORNIA
Free format text: ASSIGNMENT OF ASSIGNORS INTEREST;ASSIGNOR:FERREE, BRET A., M.D.;REEL/FRAME:015761/0781
Effective date: 20040902