EP1682026A2 - Navigation magnetique de dispositifs medicaux dans des champs magnetiques - Google Patents

Navigation magnetique de dispositifs medicaux dans des champs magnetiques

Info

Publication number
EP1682026A2
EP1682026A2 EP04796484A EP04796484A EP1682026A2 EP 1682026 A2 EP1682026 A2 EP 1682026A2 EP 04796484 A EP04796484 A EP 04796484A EP 04796484 A EP04796484 A EP 04796484A EP 1682026 A2 EP1682026 A2 EP 1682026A2
Authority
EP
European Patent Office
Prior art keywords
medical device
distal end
magnetic field
torque
coils
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Withdrawn
Application number
EP04796484A
Other languages
German (de)
English (en)
Other versions
EP1682026A4 (fr
Inventor
Rogers C. Ritter
Raju R. Viwanathan
Roger N. Hastings
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Stereotaxis Inc
Original Assignee
Stereotaxis Inc
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Stereotaxis Inc filed Critical Stereotaxis Inc
Publication of EP1682026A2 publication Critical patent/EP1682026A2/fr
Publication of EP1682026A4 publication Critical patent/EP1682026A4/fr
Withdrawn legal-status Critical Current

Links

Classifications

    • A—HUMAN NECESSITIES
    • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
    • A61B—DIAGNOSIS; SURGERY; IDENTIFICATION
    • A61B34/00—Computer-aided surgery; Manipulators or robots specially adapted for use in surgery
    • A61B34/70—Manipulators specially adapted for use in surgery
    • A61B34/73—Manipulators for magnetic surgery
    • A—HUMAN NECESSITIES
    • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
    • A61B—DIAGNOSIS; SURGERY; IDENTIFICATION
    • A61B34/00—Computer-aided surgery; Manipulators or robots specially adapted for use in surgery
    • A61B34/70—Manipulators specially adapted for use in surgery
    • A—HUMAN NECESSITIES
    • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
    • A61M—DEVICES FOR INTRODUCING MEDIA INTO, OR ONTO, THE BODY; DEVICES FOR TRANSDUCING BODY MEDIA OR FOR TAKING MEDIA FROM THE BODY; DEVICES FOR PRODUCING OR ENDING SLEEP OR STUPOR
    • A61M25/00—Catheters; Hollow probes
    • A61M25/01—Introducing, guiding, advancing, emplacing or holding catheters
    • A61M25/0105—Steering means as part of the catheter or advancing means; Markers for positioning
    • A61M25/0127—Magnetic means; Magnetic markers

Definitions

  • This invention relates to the navigation of medical devices in magnetic fields, and in particular to the navigation of medical devices in magnetic fields created by magnetic resonance imaging equipment.
  • Systems have been developed for navigating medical devices in externally applied static magnetic fields, such as those created by magnetic resonance imaging equipment. Examples of such systems are disclosed in Kuhn, U.S Patent No. 6,216,026, Arenson, U.S. Patent No. 6,304,769, and Hastings et al., U.S. Patent No. 6,401,723, the disclosures of all of which are incorporated herein by reference. These systems employ a controllable variable magnetic moment in the medical device to orient the magnetic medical device relative to the externally applied magnetic field.
  • One way of creating a controllable variable magnetic moment is with one or more coils in the distal end which can be selectively energized.
  • magnetic navigation of a medical device in a static magnetic field is constrained by the nature of the interaction between the magnetic moments and the external field.
  • In navigation it is generally possible to completely vary the direction of m relative to the catheter tip, but in fixed field navigation, such as in an MRI, B cannot be changed.
  • the present invention provides for the navigation of medical devices in the plane perpendicular to an applied magnetic field, and more specifically turning a medical device with the assistance of an externally applied magnetic field or other means, or a combination thereof, in a direction with a component in a plane perpendicular to the direction of the externally applied magnetic field.
  • the method comprises applying a first torque to the distal end of the medical device by creating a magnetic moment at the distal end of the medical device; and applying a second torque to the distal end of the medical device. This second torque can be applied by creating a second magnetic moment at the distal end of the medical device, spaced from the first.
  • the second torque can be applied by the reaction of the distal end portion itself to the axial rotation caused by the first torque.
  • Figure 1 is a schematic view of a medical device C being navigated in a static applied magnetic field B, lying in a plane P perpendicular to the applied magnetic field;
  • Figure 2 is a schematic view of a medical device C in a vessel V that lies in a plane perpendicular to the applied magnetic field.
  • Figure 3A is a longitudinal cross-sectional view of a first embodiment of a medical device constructed according to the principles of this invention
  • Figure 3B are views of a first alternate construction of a device constructed according to the principles of this invention
  • Figure 3C are views of the first alternate construction after the distal end has been twisted for cause the distal end portion to assume a helical configuration
  • Figure 3D is a longitudinal cross-sectional view of an alternate construction of a medical device constructed according to the principles of this invention
  • Figure 4 is a longitudinal cross-sectional view of a second embodiment of a medical device constructed according to the principles of this invention
  • Figure 5 is a longitudinal cross-sectional view of a third embodiment of a medical device constructed according to the principles of this invention
  • Figure 6 is a longitudinal cross-sectional view of a fourth embodiment of a medical device constructed according to the principles of this invention
  • Figure 7 is a side elevation view of a fifth embodiment
  • the present invention provides a method for navigating a medical device in an operating region in a subject's body to which a static magnetic field is applied.
  • a medical device means any medical device that is navigated in the body, including but not limited to guide wires, catheters, endoscopes, etc.
  • the static magnetic field can be applied with a source magnet that is part of a dedicated magnetic navigation system, or the magnetic field can be applied with a magnet from a magnetic resonance imaging system.
  • the magnetic field direction B is into the paper, as represented by the X's.
  • the turn in direction R is in the plane perpendicular to the magnetic field direction, and cannot be accomplished simply by changing the magnetic moment at the distal end of the device C.
  • the magnetic moment interacting with the external magnetic field generally causes the device tip to move out of the plane P defined by V and D.
  • Means to accomplish effective turns of the tip within the plane P require that the tip be moved, however slightly, back into the plane, at which point there will be at least a small component of the bent tip that is along the field direction. The requisite change in m and tip orientation or displacement can then be calculated (by computer).
  • a first embodiment of a medical device for navigation in a static magnetic field constructed in accordance with the principles of this invention is indicated generally as 20 in Figure 3A.
  • the device 20 is preferably an elongate device having a proximal end 22, a distal end 24, and comprising a generally tubular sidewall 26 with a lumen 28 extending therethrough.
  • the distal end 24 of the medical device 20 preferably includes at least one element 30 for selectively creating a magnetic moment at the distal end of the medical device to orient the distal end of the medical device relative to a static magnetic field applied to the operating region in which the device 20 is being navigated by an external source magnet or magnets.
  • the element 30 may be any of a variety of elements for selectively creating a magnetic moment, but in this preferred embodiment the element 30 comprises at least one electromagnetic coil, and more preferably at least three mutually perpendicular coils. These coils can be arranged on a cubic substrate or simply embedded in the wall of the medical device.
  • the coils can be powered via leads 32, which preferably comprise a pair of leads for separately powering each coil.
  • the distal end 24 of the medical device 20 may include a second element 34, spaced a distance d from first element 30, for selectively creating a second magnetic moment at the distal end of the medical device 20 to orient the distal end of the medical device relative to a static magnetic field applied to the operating region by the external source magnet or magnets.
  • the element many be any of a variety of elements for selectively creating a magnetic moment, but in this preferred embodiment the element comprises electromagnetic coils, and in particular an electromagnetic coil unit.
  • the coil unit preferably comprises at least three mutually perpendicular coils. These coils can be arranged on a cubic substrate or simply embedded in the wall of the medical device.
  • the coils can be powered via leads 36, which preferably comprise a pair of leads for separately powering each coil.
  • the leads 32 and 36 can either extend through the lumen 28 as shown, extend through a separate lumen (not shown), or be embedded in the wall 26.
  • the distance d between the elements 30 and 34 is preferably sufficient, given the properties of the medical device, to allow the device to flex between the elements.
  • the two elements 30 and 34 allow the distal end portion 24 of the medical device 20 to be turned out of the plane perpendicular to the field B, and then turned in the desired direction.
  • the operation of the elements 30 and 34 can be controlled by computer to optimize the efficiency of the turn according to the physical properties of the device (the wall stiffness and the spacing d) and the particular turn that is desired.
  • L is the supported length of device (this depends on the particular medical application) where the device freely extends (measured back from the distal tip);
  • d is the spacing between the elements 30 and 34;
  • E is the Young's modulus of the material of the device;
  • I is the bending moment of area; and a magnetic moment of magnitude m produced by the most distal element 30 causes the device tip to move out of the plane P shown in Fig. 1 by an amount z.
  • the second element 34 is preferably controlled so as to produce a magnetic moment whose magnitude is ni !
  • the elements 30 and 34 can be mechanically move the elements 30 and 34 by advancing, retracting or turning the proximal end of the medical device, measuring the effect on the coils of element 30, and thereby determine the orientation of the element 30, and thus the orientation of the distal end portion of the device surrounding the element 30.
  • the movement of the element can be a small single impulse or a small repetitive "dithering" of the element.
  • the coils are not provided on a substrate, but are instead laminated on, or embedded in, the distal end portion of the medical device, in addition to creating a moment at the distal end of device, and magnetically sensing orientation, the coils can also function as strain gauges, measuring the bend of the device, and thus facilitating the determination of the configuration of the distal end portion of the device.
  • the bending of the device can be measured, and the configuration of the device determined.
  • This position information can be used to provide automated closed loop navigation. Once the components of the static magnetic field along the axes of the three orthogonal coils adjacent the tip of the device are determined, the orientation of the coils relative to the static field can be computed. The currents required to change the orientation of the coils can be calculated and applied to the coils. The catheter can be advanced, and the process repeated until the catheter tip reaches its desired destination.
  • Another method to determine the orientation is to place a series of MR- visible markers along the device in known orientations relative to one or more of the elements 30 and 34, and to extract the device orientation from appropriate image processing [0033] Rather than using two elements 30 and 34, it should also be possible to apply an axial twist to the distal end portion of the device with just element 30 (or a plurality of coils if not provided as a single element). In this case, the portion of the device adjacent the distal end is constructed to assume the shape of a helix upon axial twisting of the distal end of the device.
  • a deformable element 40 can be provided in the distal end of the device.
  • the element 40 is preferably sufficiently flexible, that it readily bends under the torques that can be created by the elements 30 and 34, yet is sufficiently stiff that it substantially resists bending under the resilience of the device itself.
  • the element 30 or the elements 30 and 34 can be used to create a bend in the element 40 and when the elements are deenergized, the element 40 can retain the distal end portion of the device in its bent configuration mechanically straightened out or straightened out by the application of appropriate currents in the element 30 or elements 30 and 34 to straighten the distal end of the device and thus the element 40.
  • a heating element or other device can be provided to facilitate returning the element 40 to its unbent configuration.
  • the user can temporarily fix the configuration of the distal end of the device, and use this configuration in navigation, including navigation in the "forbidden” plane, and then readily reshape the distal end of the device.
  • the element 40 can be incorporated into any of the embodiments of this invention, if desired.
  • a second embodiment of a medical device for navigation in a static magnetic field constructed in accordance with the principles of this invention is indicated generally as 120 in Figure 4.
  • the device 120 is preferably an elongate device having a proximal end 122, a distal end 124, and comprising a generally tubular sidewall 126 with a lumen 128 extending therethrough.
  • the distal end 124 of the medical device 120 preferably includes at least one element 130 for selectively creating a magnetic moment at the distal end of the medical device to orient the distal end of the medical device relative to a static magnetic field applied to the operating region in which the device 120 is being navigated by an external source magnet or magnets.
  • the element 130 may be any of a variety of elements for selectively creating a magnetic moment, but in this preferred embodiment the element 130 comprises at least one electromagnetic coil, and more preferably at least three mutually perpendicular coils. These coils can be arranged on a cubic substrate or simply embedded in the wall of the medical device.
  • the coils can be powered via leads 132, which preferably comprise a pair of leads for separately powering each coil.
  • the leads 232 can either extend through the lumen 228 as shown, extend through a separate lumen (not shown), or be embedded in the wall 226.
  • the element 130 is powered via leads 132 to turn the distal end 124 of the medical device 120 out of the "forbidden" plane perpendicular to the direction of the applied magnetic field.
  • the proximal end 122 of the medical device 120 is then rotated as indicated by arrow 134 (about the axis of 120) to turn the distal end 124 of the device in the desired direction.
  • This rotation can be either manually performed or implemented and driven by computer control.
  • the operation of the element 130 can be controlled by computer. It is desirable to know the orientation of the element 130 prior to energizing its coils.
  • the element 130 it is also possible to mechanically move the element 130 by advancing, retracting or turning the proximal end of the medical device, measuring the effect on the coils of element 130, and thereby determine the orientation of the element 130, and thus the orientation of the distal end portion of the device surrounding the element 130.
  • the movement of the element can be a small single impulse or a small repetitive "dithering" of the element.
  • the coils are not provided on element 130, but are instead laminated on, or embedded in, the distal end portion of the medical device, in addition to creating a moment at the distal end of device, and magnetically sensing orientation, the coils can also function as strain gauges, measuring the bend of the device, and thus facilitating the determination of the configuration of the distal end portion of the device.
  • a third embodiment of a medical device for navigation in a static magnetic field constructed in accordance with the principles of this invention is indicated generally as 220 in Figure 5.
  • the device 220 is preferably an elongate device having a proximal end 222, a distal end 224, and comprising a generally tubular sidewall 226 with a lumen 228 extending therethrough.
  • the distal end 224 of the medical device 220 preferably includes at least one element 230 for selectively creating a magnetic moment at the distal end of the medical device to orient the distal end of the medical device relative to a static magnetic field applied to the operating region in which the device 220 is being navigated by an external source magnet or magnets.
  • the element 230 many be any of a variety of elements for selectively creating a magnetic moment, but in this preferred embodiment the element 230 comprises at least one electromagnetic coil, and more preferably at least three mutually perpendicular coils. These coils can be arranged on a cubic substrate or simply embedded in the wall of the medical device.
  • the coils can be powered via leads 232, which preferably comprise a pair of leads for separately powering each coil.
  • a flexible cable 234 preferably extends through the lumen 228, and is anchored adjacent the distal end 224 of the medical device 220.
  • the cable 234 is preferably sufficiently flexible so as not to unduly interfere with the flexing and navigation of the medical device 220, but has sufficient torsional stiffness so that rotation of the cable 234 rotates the distal end 224 of the medical device.
  • the element 230 is energized via the leads 232 and turned out of the forbidden plane, and then the cable 234 can be turned to turn the distal end 224 of the medical device 220 in the desired direction.
  • the operation of the element 230 can be controlled by computer. It is desirable to know the orientation of the element 230 prior to energizing its coils. This can be conveniently done by moving the distal end of the medical device, and using the coils comprising the element 230 to measure the static field B and thereby determine their orientation relative to the known orientation of the field B. Likewise the turning of cable 234 may also be computer-controlled, with or without the use of feedback-control methods. [0042] The orientation of the element 230 can be conveniently determined by moving the distal end of the medical device, and using the coils comprising the element 230 to measure the static field B and thereby determine their orientation relative to the know orientation of the field B.
  • the element 230 For example it is possible to temporarily energize one of the coils in the element 230 and measure the response of the other two coils, and repeat this for each of the other coils, and thereby determine the orientation of the element 230, and thus the orientation of the distal end portion of the device surrounding the element 230. It is also possible to mechanically move the element 230 by advancing, retracting or turning the proximal end of the medical device, measuring the effect on the coils of element 230, and thereby determine the orientation of the element 230, and thus the orientation of the distal end portion of the device surrounding the element 230.
  • the movement of the element can be a small single impulse or a small repetitive "dithering" of the element.
  • the coils are not provided on element 230, but are instead laminated on, or embedded in, the distal end portion of the medical device, in addition to creating a moment at the distal end of device, and magnetically sensing orientation, the coils can also function as strain gauges, measuring the bend of the device, and thus facilitating the determination of the configuration of the distal end portion of the device.
  • strain gauges measuring the bend of the device, and thus facilitating the determination of the configuration of the distal end portion of the device.
  • a fourth embodiment of a medical device for navigation in a static magnetic field constructed in accordance with the principles of this invention is indicated generally as 320 in Figure 6.
  • the device 320 is preferably an elongate device having a proximal end 322, a distal end 324, and comprising a generally tubular sidewall 326 with a lumen 328 extending therethrough.
  • the distal end 324 of the medical device 320 preferably includes at least one element 330 for selectively creating a magnetic moment at the distal end of the medical device to orient the distal end of the medical device relative to a static magnetic field applied to the operating region in which the device 320 by an external source magnet or magnets.
  • the element 330 many be any of a variety of elements for selectively creating a magnetic moment, but in this preferred embodiment the element 330 comprises at least one electromagnetic/ coil, and more preferably at least three mutually perpendicular coils. These coils can be arranged on a cubic substrate or simply embedded in the wall of the medical device.
  • the coils can be powered via leads 332, which preferably comprise a pair of leads for separately powering each coil.
  • the leads 332 can either extend through the lumen 328 as shown, extend through a separate lumen (not shown), or be embedded in the wall 326.
  • the distal end 324 of the medical device 320 preferably includes at least one bending element, such as electrostrictive bending elements 334, connected by leads 336.
  • the electrostrictive elements may be piezoelectric materials which change shape upon the application of a potential, or electrostrictive polymers which change length, or any other element which creates mechanical action upon application of electrical current or potential.
  • the elements can be used individually or in groups to achieve the desired configuration. These elements can also be used in opposed pairs for example one element on one side of the device 320 constricting and one element on the other side of the device expanding to bend the device 320 in the desired direction.
  • the element 330 allows the distal end portion 324 of the medical device 20 to be turned out of the plane perpendicular to the field B, and then the electrostrictive elements 334 used to turn the distal end 324 in the desired direction.
  • the distal end 324 of the medical device 320 can be bent using one or more of the elements 324, and then the element 330 can be operated to turn the distal end 324 in the desired direction.
  • the operation of the elements 330 can be controlled by computer.
  • the electrostrictive elements 334 can also be computer-controlled. It is desirable to know the orientation of the elements 330 prior to energizing their coils. This can be conveniently done by moving the distal end of the medical device, and using the coils comprising the element 330 to measure the static field B and thereby determine their orientation relative to the known orientation of the field B. An alternate method can be based on the use of suitable MR-visible markers in the device together with image processing. [0048] The orientation of the element 330 can be conveniently determined by moving the distal end of the medical device, and using the coils comprising the element 330 to measure the static field B and thereby determine their orientation relative to the known orientation of the field B.
  • the element 330 For example it is possible to temporarily energize one of the coils in the element 330 and measure the response of the other two coils, and repeat this for each of the other coils, and thereby determine the orientation of the element 330, and thus the orientation of the distal end portion of the device surrounding the element 330. It is also possible to mechanically move the element 330 by advancing, retracting or turning the proximal end of the medical device or actuating the electrostrictive elements 334, measuring the effect on the coils of element 330, and thereby determine the orientation of the element 330, and thus the orientation of the distal end portion of the device surrounding the element 330.
  • the movement of the element can be a small single impulse or a small repetitive "dithering" of the element.
  • the coils are not provided on element 330, but are instead laminated on, or embedded in, the distal end portion of the medical device, in addition to creating a moment at the distal end of device, and magnetically sensing orientation, the coils can also function as strain gauges, measuring the bend of the device, and thus facilitating the determination of the configuration of the distal end portion of the device. Thus, by measuring changes in the resistance of coils, the bending of the device can be measured, and the configuration of the device determined. [0050] Another method to determine the orientation is to place a series of MR-visible markers along the device in known orientations relative to the element 330, and to extract the device orientation from appropriate image processing.
  • a fifth embodiment of a medical device for navigation in a static magnetic field constructed in accordance with the principles of this invention is indicated generally as 420 in Figure 7.
  • the device 420 is preferably an elongate device having a proximal end 422, a distal end 424, and comprising a generally tubular sidewall 426 with a lumen 428 extending therethrough.
  • the distal end 424 of the medical device 420 preferably includes at least one element 430 for selectively creating a magnetic moment at the distal end of the medical device to orient the distal end of the medical device relative to a static magnetic field applied to the operating region in which the device 420 is being navigated by an external source magnet or magnets.
  • the element 430 may be any of a variety of elements for selectively creating a magnetic moment, but in this preferred embodiment the element 330 comprises at least one electromagnetic coil, and more preferably at least three mutually perpendicular coils. These coils can be arranged on a cubic substrate or simply embedded in the wall of the medical device.
  • the coils can be powered via leads 332, which preferably comprise a pair of leads for separately powering each coil.
  • the leads 432 can either extend through the lumen 428 as shown, extend through a separate lumen (not shown), or be embedded in the wall 426.
  • the distal end 424 of the medical device 420 preferably includes at least one bending element, such as electrostrictive twisting elements 434, connected by leads 436.
  • electrostrictive torsional elements 434 and corresponding leads 436 disposed circumferentially around the distal end of the medical device 420.
  • the element 430 allows the distal end portion 324 of the medical device 420 to be turned out of the plane perpendicular to the field B, and then the electrostrictive elements 434 used to turn the distal end 424 in the desired direction.
  • the distal end 424 of the medical device 420 can be bent using one or more of the elements 424, and then the element 430 can be operated to turn the distal end 424 in the desired direction.
  • the operation of the elements 430 and that of the electrostrictive torsional elements 434 can be controlled by computer. It is desirable to know the orientation of the elements 430 prior to energizing their coils. This can be conveniently done by moving the distal end of the medical device, and using the coils comprising the element 430 to measure the static field B and thereby determine their orientation relative to the know orientation of the field B. An alternate method of orientation determination can be based on the use of suitable MR-visible markers in the device together with image processing.
  • the orientation of the element 430 can be conveniently determined by moving the distal end of the medical device, and using the coils comprising the element 430 to measure the static field B and thereby determine their orientation relative to the know orientation of the field B. For example it is possible to temporarily energize one of the coils in the element 430 and measure the response of the other two coils, and repeat this for each of the other coils, and thereby determine the orientation of the element 430, and thus the orientation of the distal end portion of the device surrounding the element 430.
  • the element 430 it is also possible to mechanically move the element 430 by advancing, retracting or turning the proximal end of the medical device or actuating the electrostrictive elements 434, measuring the effect on the coils of element 430, and thereby determine the orientation of the element 430, and thus the orientation of the distal end portion of the device surrounding the element 430.
  • the movement of the element can be a small single impulse or a small repetitive "dithering" of the element.
  • the coils are not provided on element 430, but are instead laminated on, or embedded in, the distal end portion of the medical device, in addition to creating a moment at the distal end of device, and magnetically sensing orientation, the coils can also function as strain gauges, measuring the bend of the device, and thus facilitating the determination of the configuration of the distal end portion of the device. Thus, by measuring changes in the resistance of coils, the bending of the device can be measured, and the configuration of the device determined. [0057] Another method to determine the orientation is to place a series of MR-visible markers along the device in known orientations relative to the element 430, and to extract the device orientation from appropriate image processing.
  • a sixth embodiment of a medical device for navigation in a static magnetic field constructed in accordance with the principles of this invention is indicated generally as 520 in Figure 8.
  • the device 520 is preferably an elongate device having a proximal end 522, a distal end 524, and comprising a generally tubular sidewall 526 with a lumen 528 extending therethrough.
  • the distal end 524 of the medical device 520 preferably includes at least one element 530 for selectively creating a magnetic moment at the distal end of the medical device to orient the distal end of the medical device relative to a static magnetic field applied to the operating region in which the device 520 is being navigated by an external source magnet or magnets.
  • the element 530 many be any of a variety of elements for selectively creating a magnetic moment, but in this preferred embodiment the element 530 comprises at least one electromagnetic coil, and more preferably at least three mutually perpendicular coils. These coils can be arranged on a cubic substrate or simply embedded in the wall of the medical device.
  • the coils can be powered via leads 532, which preferably comprise a pair of leads for separately powering each coil.
  • the leads 532 can either extend through the lumen 528 as shown, extend through a separate lumen (not shown), or be embedded in the wall 526.
  • the medical device 520 preferably includes at least one two sections 534 and 536 of differing flexibility. The more proximal section 534 is preferably stiffer than the more distal section 536.
  • the medical device 520 is adapted for use with a stylette, such as stylette 538, which has a specially shaped, resilient distal tip 540.
  • the stylette 538 is adapted to be inserted into the lumen 528, but because of the greater stiffness of the proximal end, as the shaped tip 540 of the stylette 538 passes through the proximal portion of the lumen, the shape remains unchanged. However, as the tip 540 of the stylette 538 passes through the distal portion of the lumen 528 in distal section 536, the distal portion of the medical device 520 bends to generally conform to the shaped tip 540.
  • the element 530 allows the distal end portion 524 of the medical device 520 to be turned out of the plane perpendicular to the field B, and then the stylette 538 can be used to turn the distal end 524 in the desired direction.
  • the distal end 324 of the medical device 320 can be bent using the stylette 538, and then the element 530 can be operated to turn the distal end 524 in the desired direction.
  • the operation of the elements 530 can be controlled by computer. It is desirable to know the orientation of the elements 530 prior to energizing its coils.
  • the orientation of the element 530 can be conveniently determined by moving the distal end of the medical device, and using the coils comprising the element 530 to measure the static field B and thereby determine their orientation relative to the know orientation of the field B. For example it is possible to temporarily energize one of the coils in the element 530 and measure the response of the other two coils, and repeat this for each of the other coils, and thereby determine the orientation of the element 530, and thus the orientation of the distal end portion of the device surrounding the element 530.
  • the element 530 it is also possible to mechanically move the element 530 by advancing, retracting or turning the proximal end of the medical device or inserting the stylette, measuring the effect on the coils of element 530, and thereby determine the orientation of the element 530, and thus the orientation of the distal end portion of the device surrounding the element 530.
  • the movement of the element can be a small single impulse or a small repetitive "dithering" of the element.
  • the coils are not provided on element 530, but are instead laminated on, or embedded in, the distal end portion of the medical device, in addition to creating a moment at the distal end of device, and magnetically sensing orientation, the coils can also function as strain gauges, measuring the bend of the device, and thus facilitating the determination of the configuration of the distal end portion of the device. Thus, by measuring changes in the resistance of coils, the bending of the device can be measured, and the configuration of the device determined. [0063] Another method to determine the orientation is to place a series of MR-visible markers along the device in known orientations relative to the element 530, and to extract the device orientation from appropriate image processing.
  • a seventh embodiment of a medical device for navigation in a static magnetic field constructed in accordance with the principles of this invention is indicated generally as 620 in Figure 9.
  • the device 620 is preferably an elongate device having a proximal end 622, a distal end 624, and comprising a generally tubular sidewall 626 with a lumen 628 extending therethrough.
  • the distal end 624 of the medical device 620 preferably includes at least one element 630 for selectively creating a magnetic moment at the distal end of the medical device to orient the distal end of the medical device relative to a static magnetic field applied to the operating region in which the device is being navigated by an external source magnet or magnets.
  • the element 630 may be any of a variety of elements for selectively creating a magnetic moment, but in this preferred embodiment the element 630 comprises at least one electromagnetic coil, and more preferably at least three mutually perpendicular coils. These coils can be arranged on a cubic substrate or simply embedded in the wall of the medical device.
  • the coils can be powered via leads 632, which preferably comprise a pair of leads for separately powering each coil.
  • the leads 632 can either extend through the lumen 628 as shown, extend through a separate lumen (not shown), or be embedded in the wall 626.
  • An expansible tube 634 (similar to a Bourdon tube pressure gauge) extends through the lumen 228, and is anchored adjacent the distal end 224 of the medical device 620.
  • the tube has a wound configuration, and upon changes in the applied fluid pressure the wound portion 636 can wind or unwind, changing the shaped of distal end portion of the medical device 620.
  • the element 630 is energized via the leads 632 and turned out of the forbidden plane, and then the expansible tube 634 is pressurized or depressurized to turn the distal end 624 of the medical device 620 in the desired direction.
  • the operation of pressure turning the tip is that of a bending (pressure release) or unbending (pressure increase) of a Bourdon tube.
  • the expansible tube 634 is pressurized or depressurized to turn the distal end 624 of the medical device 620 out of the "forbidden" plane, and then the element 630 is energized via the leads 632 to turn the device in the desired direction.
  • the operation of the element 630 can be controlled by computer. It is desirable to know the orientation of the element 630 prior to energizing its coils. The orientation of the element 630 can be conveniently determined by moving the distal end of the medical device, and using the coils comprising the element 630 to measure the static field B and thereby determine their orientation relative to the know orientation of the field B.
  • the element 630 For example it is possible to temporarily energize one of the coils in the element 630 and measure the voltage induced in the other two coils as they move through the static field B, and repeat this for each of the other coils, and thereby determine the orientation of the element 630, and thus the orientation of the distal end portion of the device surrounding the element 630. Furthermore, it is possible to determine the voltage induced in the energized coil by comparing the measured coil voltage to the TR drip across the known resistance of the coil. Thus, one or more coils may be energized, while the voltages induced in all three coils due to movement of the catheter tip in the static field B is determined.
  • the static field in an MRI is sufficiently large that only small, "virtual" movements of the tip are required to induce a measurable voltage in the coils. It is also possible to mechanically move the element 630 by advancing, retracting or turning the proximal end of the medical device or actuating the tube 634, measuring the voltage induced in the coils of element 630, and thereby determine the orientation of the element 630, and thus the orientation of the distal end portion of the device surrounding the element 630. In addition to using the coils in element 630 as induction sensors, a variety of other magnetic sensor structures can be added adjacent element 630 to measure the three components of the static field B along the three orthogonal axes of the coils in element 630.
  • miniature Hall Effect solid state magnetic sensors may be used to measure the static field.
  • Giant Magneto-Resistance (GMR) sensors available for example from Honeywell Solid State Electronic Center, Plymouth MN 55441, can be used to measure the three components of the static field B along the three coil axes. It is noted that the magnetic fields generated by currents flowing in coils is much smaller than the static field B, so that the field sensors can be co-located with the coils, or displaced a small distance from the coils, without significant influence on the static field measurement.
  • the static field B may have magnitude of 3 Tesla, while the energized coils will produce a field less than about 0.1 Tesla at the center of these coils.
  • the movement of the element can be a small single impulse or a small repetitive "dithering" of the element.
  • the coils are not provided on element 630, but are instead laminated on, or embedded in, the distal end portion of the medical device, in addition to creating a moment at the distal end of device, and magnetically sensing orientation, the coils can also function as strain gauges, measuring the bend of the device, and thus facilitating the determination of the configuration of the distal end portion of the device.
  • strain gauges measuring the bend of the device, and thus facilitating the determination of the configuration of the distal end portion of the device.
  • FIG. 10 An eighth embodiment of a medical device for navigation in a static magnetic field constructed in accordance with the principles of this invention is indicated generally as 720 in Figure 10.
  • the device 720 is preferably an elongate device having a proximal end 722, a distal end 724, and comprising a generally tubular sidewall 726 with a lumen 728 extending therethrough.
  • the distal end 724 of the medical device 720 preferably includes at least one element 730 for selectively creating a magnetic moment at the distal end of the medical device to orient the distal end of the medical device relative to a static magnetic field applied to the operating region in which the device 720 is being navigated by an external source magnet or magnets.
  • the element 730 many be any of a variety of elements for selectively creating a magnetic moment, but in this preferred embodiment the element 730 comprises at least one electromagnetic coil, and more preferably at least three mutually perpendicular coils. These coils can be arranged on a cubic substrate or simply embedded in the wall of the medical device.
  • the coils can be powered via a fiber optic lead 732, which conducts high energy light to a photovoltaic converter cell 734 to create electric power for the coils which is conducted to the coils via short lead 736.
  • the use of a fiber optic lead 732 and photovoltaic cell 734 eliminates the need for long wire lead, which are sometimes subject to heating in the rf field of an MRI system.
  • the fiber optic lead 732 can either extend through the lumen 728 as shown, extend through a separate lumen (not shown), or be embedded in the wall 726. This construction can be applied to any of the preceding embodiments one through seven.
  • a single fiber optic line can be provided that provides optic signals and optic power to control the distribution of light among a plurality of photovoltaic cells, or which controls the distribution of electric power among a plurality of electrical elements.
  • the fiber optic can conduct information signals to operate an optical or electrical switch.
  • a distribution device such as a filter can be used to distribute light based upon wavelength.

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  • Health & Medical Sciences (AREA)
  • Surgery (AREA)
  • Engineering & Computer Science (AREA)
  • Life Sciences & Earth Sciences (AREA)
  • Medical Informatics (AREA)
  • Robotics (AREA)
  • Biomedical Technology (AREA)
  • Heart & Thoracic Surgery (AREA)
  • Nuclear Medicine, Radiotherapy & Molecular Imaging (AREA)
  • Molecular Biology (AREA)
  • Animal Behavior & Ethology (AREA)
  • General Health & Medical Sciences (AREA)
  • Public Health (AREA)
  • Veterinary Medicine (AREA)
  • Media Introduction/Drainage Providing Device (AREA)
  • Magnetic Resonance Imaging Apparatus (AREA)

Abstract

L'invention concerne une méthode permettant de mettre en rotation un dispositif médical à l'aide d'un champ magnétique extérieurement appliqué, dans une direction avec un composant, dans un plan perpendiculaire à la direction du champ magnétique extérieurement appliqué. Cette méthode consiste à appliquer un premier couple sur l'extrémité distale du dispositif médical, en créant un moment magnétique, à l'extrémité distale du dispositif médical, et à appliquer un second couple sur l'extrémité distale du dispositif médical. Le second couple peut être créé en créant un second moment magnétique dans la partie distale du dispositif séparée du premier, au moyen d'un dispositif électrostrictif, au moyen d'un stylet inséré dans le dispositif, à l'aide d'un tube formé à entraînement fluidique, ou analogue.
EP04796484A 2003-10-27 2004-10-26 Navigation magnetique de dispositifs medicaux dans des champs magnetiques Withdrawn EP1682026A4 (fr)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
US51515403P 2003-10-27 2003-10-27
PCT/US2004/035545 WO2005044081A2 (fr) 2003-10-27 2004-10-26 Navigation magnetique de dispositifs medicaux dans des champs magnetiques

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EP1682026A2 true EP1682026A2 (fr) 2006-07-26
EP1682026A4 EP1682026A4 (fr) 2009-01-07

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US10258285B2 (en) 2004-05-28 2019-04-16 St. Jude Medical, Atrial Fibrillation Division, Inc. Robotic surgical system and method for automated creation of ablation lesions
US7632265B2 (en) 2004-05-28 2009-12-15 St. Jude Medical, Atrial Fibrillation Division, Inc. Radio frequency ablation servo catheter and method
US9782130B2 (en) 2004-05-28 2017-10-10 St. Jude Medical, Atrial Fibrillation Division, Inc. Robotic surgical system
US8528565B2 (en) 2004-05-28 2013-09-10 St. Jude Medical, Atrial Fibrillation Division, Inc. Robotic surgical system and method for automated therapy delivery
US8755864B2 (en) 2004-05-28 2014-06-17 St. Jude Medical, Atrial Fibrillation Division, Inc. Robotic surgical system and method for diagnostic data mapping
US10863945B2 (en) 2004-05-28 2020-12-15 St. Jude Medical, Atrial Fibrillation Division, Inc. Robotic surgical system with contact sensing feature
US8155910B2 (en) * 2005-05-27 2012-04-10 St. Jude Medical, Atrial Fibrillation Divison, Inc. Robotically controlled catheter and method of its calibration
US8862200B2 (en) 2005-12-30 2014-10-14 DePuy Synthes Products, LLC Method for determining a position of a magnetic source
US7525309B2 (en) 2005-12-30 2009-04-28 Depuy Products, Inc. Magnetic sensor array
US8068648B2 (en) 2006-12-21 2011-11-29 Depuy Products, Inc. Method and system for registering a bone of a patient with a computer assisted orthopaedic surgery system

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US6385472B1 (en) * 1999-09-10 2002-05-07 Stereotaxis, Inc. Magnetically navigable telescoping catheter and method of navigating telescoping catheter
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WO2005044081A3 (fr) 2005-07-14
EP1682026A4 (fr) 2009-01-07
WO2005044081A2 (fr) 2005-05-19

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