US20070021731A1 - Method of and apparatus for navigating medical devices in body lumens - Google Patents

Abstract

A guide wire combined with a catheter or medical device for moving through a body lumen to a desired position in the body with the aid of an applied magnetic field. The guide wire is provided with a magnet on its distal end that can be oriented or oriented and moved by the application of a magnetic field to the magnet. A catheter or other medical device can be advanced over the guide wire. Once the medical device is in its desired position, the magnet can be withdrawn through the lumen of the catheter. Alternatively, a guide wire with a magnet on its distal end can be docked at the distal end of a catheter or medical device and can be oriented, or oriented and moved by the application of a magnetic field.

Description

CROSS REFERENCE TO RELATED APPLICATION
• This application is a continuation in part of PCT application Serial No. PCT/US98/02835 filed Feb. 17, 1998.
FIELD OF THE INVENTION
• This invention relates to a method of, and apparatus for, navigating medical devices in body lumens, such as in blood vessels, the trachea, the gastrointestinal tract, or the urinary tract.
BACKGROUND OF THE INVENTION
• Many diagnostic and therapeutic medical procedures require navigating a medical device to a particular location through lumens in the body. For example, procedures such as cardiac catheterizations and interventional neuroradiology procedures involve the introduction of medical devices through the arteries; bronchoscopies involve the introduction of medical devices through the trachea; endoscopies and colonoscopies involve the introduction of instruments through the gastrointestinal tract; and urethroscopies involve the introduction of medical devices through the urinary tract.
• Numerous methods and apparatus have been developed for introducing medical devices in the body. Many of these methods employ guide wires for remotely controlling the orientation of the tip of the medical device as it is advanced in the body lumen. These guide wires typically have a bend in their distal ends, the tip is rotated until the tip is properly oriented, and the wire is then advanced. It is a difficult and tedious process to steer a medical device remotely with a guide wire since the orientation of the guide wire is difficult to control. Thus, these procedures can be prolonged, which increases the risk to the patient and fatigues the physician.
• It has been proposed to guide medical devices in the body with magnets, see Yodh, Pierce, Weggel, and Montgomery, A New Magnetic System, for ‘Intravascular Navigation’, Medical & Biological Engineering, Vol. 6, No. 2, pp. 143-147 (March 1968), incorporated herein by reference. This article proposes a magnetically tipped catheter that is steered within the body by an externally applied magnetic field. However, the magnet in this proposed device is attached to the catheter which can impair the ability to control the magnet. Moreover, there is no provision for removing the magnet and leaving the catheter or other medical device in place. Thus, only one such catheter can be directed to a given position because the magnetic field acting on one magnet will also act on the other magnets in the vicinity.
SUMMARY OF THE INVENTION
• The methods and apparatuses of the present invention involve magnetically guiding a medical device through a lumen in the body. Generally, according to the method of this invention, a magnet is provided on the end of a guide wire and an externally applied magnetic field orients the magnet in the body lumen. The magnet can be advanced through the body lumen by manipulating the magnetic field or by pushing the guide wire.
• According to a first embodiment of this invention, a catheter may be disposed over a guide wire having a magnet on its distal end. The guide wire and catheter combination is introduced into a body lumen through a natural or surgically formed opening. Once in the body the guide wire and catheter combination is navigated through the body lumen by applying a magnetic field, which acts on the distal end of the guide wire, orienting it. Typically, the guide wire is advanced slightly ahead of the catheter at a branch in the body lumen, and a magnetic field is applied to orient the tip of the guide wire, and the guide wire is advanced in the direction of the tip which is oriented into the selected branch. The guide wire can be advanced by the application of the magnetic field, by pushing at the proximal end, or by both. The catheter is then advanced over the guide wire. This process is repeated until the distal end of the catheter is at its desired location. Once the distal end of the catheter is in the desired position, the magnet can be withdrawn through the lumen of the catheter by pulling on the tether. Treatment, such as drug therapy or embolizing agents, can then be passed through the catheter.
• According to a second embodiment of this invention, a guide wire with a magnet on the tip may be docked at the distal end of the lumen inside a catheter or other medical device. The guide wire and catheter combination is introduced into a body lumen through a natural or surgically formed opening. Once in the body lumen, the guide wire and catheter combination is navigated through the body lumen by applying a magnetic field, which acts upon the magnet-tipped guide wire in the catheter, orienting it. The catheter is advanced by pushing the guide wire. Once the distal end of the catheter is in the desired location, the guide wire can be withdrawn through the lumen of the catheter by pulling on the guide wire. Treatment, such as drug therapy or embolizing agents, can then be passed through the catheter.
• The methods of the various embodiments of this invention, and the guide wire of the various embodiments of this invention, facilitate quick, easy and accurate positioning of a catheter or other medical device via a body lumen. Once the catheter is properly positioned, it can be used during a diagnostic or therapeutic procedure, either directly or as a passage for other medical devices.
• These and other features and advantages will be in part apparent and in part pointed out hereinafter.
BRIEF DESCRIPTION OF THE DRAWINGS
• FIG. 1 is a longitudinal cross-sectional view of a guide wire and catheter combination constructed according to the principles of a first embodiment this invention;
• FIG. 2 is a plan view of the guide wire of the first embodiment;
• FIG. 3 is an enlarged cross-sectional view of the distal tip of the guide wire;
• FIG. 4 is an enlarged cross sectional view the distal end of a first alternate construction of the guide wire of the first embodiment, using a socket to secure the magnet;
• FIG. 5 is an enlarged cross sectional view of the distal end of a second alternate construction of the guide wire of the first embodiment, using a collar to secure the magnet.
• FIG. 6 is an enlarged cross-sectional view of a third alternate construction of the distal section of the guide wire;
• FIG. 7 is an enlarged cross-sectional view of a fourth alternate construction of the distal section of the guide wire;
• FIG. 8 is a side elevation view of the distal section of a fifth alternate construction of the guide wire of the first embodiment with a portion broken away to show details of the construction;
• FIG. 9 is a side elevation view of the distal end section of a sixth alternate construction of the guide wire of the first embodiment;
• FIG. 10 is a side elevation view of the distal end section of a seventh alternate construction of the guide wire of the first embodiment;
• FIG. 11 is a side elevation view of the distal section of an eighth alternate construction of the guide wire of the first embodiment;
• FIG. 11ais an enlarged side elevation view of the eighth alternate construction of the distal end section, with a portion broken away to show details of the construction;
• FIG. 12 is a side elevation view of the distal section of a ninth alternate construction of the guide wire of the first embodiment;
• FIG. 12ais a side elevation view of the distal section of the third alternate construction of the guide wire, in a magnetic field;
• FIG. 13 is a side elevation view of a tenth alternate construction of the distal section of the guide wire;
• FIG. 13ais a side elevation view of a tenth alternate construction of the distal tip of the guide wire, in a magnetic field;
• FIG. 14 is a longitudinal cross-sectional view of the guide wire and endoscope combination constructed according to the principles of the first embodiment of this invention;
• FIG. 15 is a longitudinal cross-sectional view of a guide wire and catheter combination according a second embodiment of this invention;
• FIG. 16 is a longitudinal cross-sectional view of a guide wire and catheter combination with the guide wire partially withdrawn from the lumen of the catheter; and
• FIG. 17 is a side elevation view of a guide wire and biopsy device according to the principles of the present invention.
• Corresponding reference numbers indicate corresponding parts throughout the several views of the drawings.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
• A guide wire and magnet combination constructed according to the principles of a first embodiment of this invention is indicated generally as20 inFIG. 1. The guide wire andcatheter combination20 comprises aguide wire22 and acatheter24. Theguide wire22 comprises awire26, which is preferably made of nitinol, which is highly flexible and resists kinking, although the guide wire could be made of some other suitable material. Amagnet28 is mounted on thedistal end30 of thewire26. This magnet may either be a permanent magnet or a permeable magnetic material. A permanent magnet is easier to orient under the application of a magnetic field, as described below, but a permeable magnetic material is easier to pull under the application of a magnetic field.
• In the preferred embodiment, themagnet28 is made of NdFeB (neodymium-iron-boron) or samarium cobalt and is sized to respond to the magnetic field that will be applied to orient theguide wire22 in the body lumen and to be retracted through thecatheter24. Themagnet28 is preferably elongate so that it can orient the tip of theguide wire22 in the presence of an applied magnetic field. Magnets of about 0.3 mm (0.02 inches) to about 0.7 mm (0.03 inches) in diameter, and about 1 mm (0.04 inches) to 1.5 mm (0.06 inches) long are sufficiently large for use in navigating a guide wire.
• As shown inFIGS. 2 and 3, themagnet28 is preferably acylindrical body34 with anaxial bore36 therethrough. The distal end of thewire26 extends through thebore36, and is secured with abead38 of adhesive on the distal side of themagnet28. Thebead38 also provides a rounded head on thedistal end30 of theguide wire22.
• A first alternate construction of theguide wire22 of the first embodiment is indicated generally as40 inFIG. 4. Theguide wire40 is similar in construction to guidewire22, comprisingwire42, having a proximal end (not shown) and adistal end44. A mountingbody46, having asocket48 therein, is attached to thedistal end44 of the wire. Amagnet50 is mounted in the mounting body. The magnet can be secured in the mounting body with adhesive, or thesocket48 can be crimped to secure the proximal end of themagnet50 in thesocket48.
• A second alternate construction of theguide wire22 of the first embodiment is indicated generally as60 inFIG. 5. Theguide wire60 is similar in construction to guide22, comprising awire62 having a proximal end (not shown) and adistal end64. A mountingcollar66 is attached to thedistal end64 of thewire62. A magnet68 is mounted on the mountingcollar66. The magnet68 can be secured to the mountingcollar66 by adhesive or by fusion.
• A third alternate construction of theguide wire22 is indicated generally as70 inFIG. 6. Theguide wire70 is similar in construction to guide22, comprising awire72 having a proximal end (not shown) and adistal end74, and amagnet76 mounted on the distal end of thewire72. Themagnet76 is preferably a cylindrical body with anaxial bore78 therethrough. The distal end of thewire24 extends through thebore78, and is secured with abead80 of adhesive on the distal side of themagnet76. Thebead80 also provides a rounded head on the distal end of theguide wire22. There is a taperingcollar82 on thewire26 proximal to themagnet76. Thecollar82 facilitates withdrawing themagnet76 through the distal end of thecatheter24. The collar can be made of a platinum or some other non-magnetic radio opaque material so that the position of the end of the guide wire can be easily located with x-ray or fluoroscopic imaging equipment.
• A fourth alternative construction of aguide wire22 is indicated generally as90 inFIG. 7. Theguide wire90 is similar in construction to guidewire22, comprising awire92 having a proximal end (not shown) and adistal end94, and amagnet96 on the distal end of thewire92. Themagnet96 is preferably a cylindrical body with anaxial bore98 therethrough. The distal end of thewire24 extends through thebore98, and is secured with abead100 of adhesive on the distal side of themagnet96. Thebead100 also provides a rounded head on the distal end of theguide wire90. Theguide wire90 includes asheath102, made of flexible polyurethane tubing, extending over thewire92. Thesheath102 preferably has the same outside diameter as themagnet96, to smoothly slide in the lumen of the catheter, and to help prevent excessive movement of theguide wire90 within the lumen. Thesheath102 is preferably secured to the proximal end of themagnet96 with an adhesive, such as SICOMET40 available from Tracon.
• A fifth alternate construction of the guide wire of the first embodiment is indicated generally as110 inFIG. 8.Guide wire110 comprises awire112 having a proximal end (not shown) and adistal end114. Thewire112 is preferably made of nitinol, which is highly flexible and resists kinking, although it could be made of some other suitable material. Amagnet116, which can either be a permeable magnet or a permanent magnet, is secured on thedistal end114. A permanent magnet is easier to orient under the application of a magnetic field, as described below, but a permeable magnetic material is easier to pull under the application of a magnetic field.
• Themagnet116 is preferably made of NdFeB (neodymium-iron-boron) or samarium cobalt and is sized to respond to the magnetic field that will be applied to orient the distal tip of theguide wire110 in the body lumen and to be retracted through the lumen of the catheter or other medical device. Themagnet116 is preferably elongate so that it can orient the distal tip of theguide wire110 in the presence of an applied magnetic field. Magnets of about 0.3 mm (0.02 inches) to about 0.7 mm (0.03 inches) in diameter, and about 1 mm (0.04 inches) to 1.5 mm (0.06 inches) long are sufficiently large for use in navigating a guide wire.
• As shown inFIG. 8, themagnet116 is preferably a cylindrical body. A magnetic or non-magnetic sleeve118, made of a suitable sheet material or wire, covers themagnet76 and extends over thedistal end114 of theguide wire110, securing the magnet on the wire. In this preferred embodiment shown inFIG. 8 the sleeve118 is made from a thin plastic tube, which is can be secured over the magnet and the distal end of the guide wire, with an adhesive, or more preferably, by heat shrinking.
• A sixth alternate construction of the guide wire of the first embodiment is indicated generally as120 inFIG. 9.Guide wire120 comprises awire122 having a proximal end (not shown) and adistal end124. Thewire122 is preferably made of nitinol, which is highly flexible and resists kinking, although it could be made of some other suitable material. Amagnet126, which can either be a permeable magnet or a permanent magnet, is secured on thedistal end124, for example with adhesive. A permanent magnet is easier to orient under the application of a magnetic field, as described below, but a permeable magnetic material is easier to pull under the application of a magnetic field.
• Themagnet126 is preferably made of NdFeB (neodymium-iron-boron) or samarium cobalt and is sized to respond to the magnetic field that will be applied to orient the distaltip guide wire120 in the body lumen and to be retracted through the lumen of the catheter or other medical device. Themagnet126 is preferably elongate so that it can orient the distal tip of theguide wire120 in the presence of an applied magnetic field. Magnets of about 0.3 mm (0.02 inches) to about 0.7 mm (0.03 inches) in diameter, and about 1 mm (0.04 inches) to 1.5 mm (0.06 inches) long are sufficiently large for use in navigating a guide wire.
• As shown inFIG. 9, themagnet126 is preferably a cylindrical body. Asleeve128, made of wire, covers themagnet126 and extends over thedistal end124 of thewire122, helping to secure the magnet on the wire. In this preferred embodiment shown inFIG. 9, thesleeve128 is a coil of platinum wire, the proximal end of which is secured to thewire122 proximal to thedistal end124, and the distal end of which is secured to themagnet126. The coil improves the axial stiffness of the distal end while leaving the guide wire flexible in other directions to permit magnetic navigation. The coil also improves the radiopacity of the end of the guide wire so that it can be seen on x-ray and fluoroscopic images. The coil is secured to thewire122 and to themagnet126 with adhesive. The adhesive preferably fills the spaces between the turns of the coil around themagnet126, so that the surface is smooth.
• A seventh alternate construction of the guide wire of the first embodiment is indicated generally as130 inFIG. 10.Guide wire130 comprises awire132 having a proximal end (not shown) and adistal end134. Thewire132 is preferably made of nitinol, which is highly flexible and resists kinking, although it could be made of some other suitable material. Amagnet136, which can either be a permeable magnet or a permanent magnet, is secured on thedistal end132, for example with adhesive. A permanent magnet is easier to orient under the application of a magnetic field, as described below, but a permeable magnetic material is easier to pull under the application of a magnetic field.
• Themagnet136 is preferably made of NdFeB (neodymium-iron-boron) or samarium cobalt and is sized to respond to the magnetic field that will be applied to orient the distaltip guide wire130 in the body lumen and to be retracted through the lumen of the catheter or other medical device. Themagnet136 is preferably elongate so that it can orient the distal tip of theguide wire130 in the presence of an applied magnetic field. Magnets of about 0.3 mm (0.02 inches) to about 0.7 mm (0.03 inches) in diameter, and about 1 mm (0.04 inches) to 1.5 mm (0.06 inches) long are sufficiently large for use in navigating a guide wire.
• As shown inFIG. 10, themagnet136 is preferably a cylindrical body. Acoil138 of platinum wire is disposed over the distal end portion of thewire132. The proximal end of the coil is attached to thewire132 proximal to the distal end, and the distal end of the coil is attached to the proximal end of themagnet136. The coil improves the axial stiffness of the distal end while leaving the guide wire flexible in other directions to permit magnetic navigation. The coil also improves the radiopacity of the end of the guide wire so that it can be seen on x-ray and fluoroscopic images. Thecoil98 is secured to thewire92 and to themagnet96 with adhesive. A sleeve covers themagnet136 and extends over thecoil138 an thedistal end134 of thewire130, helping to secure the magnet and the coil on the wire. In this preferred embodiment shown inFIG. 10, the sleeve140 is a tube of a flexible plastic material, that is secured with an adhesive, or more preferably by heat shrinking.
• An eighth alternate construction of the guide wire of the first embodiment is indicated generally as150 inFIGS. 11 and 11a.Guide wire150 comprises awire152, having a proximal end (not shown) and adistal end154. Thewire152 is preferably made of nitinol, which is highly flexible and resists kinking, although it could be made of some other suitable material. Thewire152 tapers toward thedistal end154. The portion of thewire152 adjacent the distal end is surrounded by amagnetic coil156.
• A ninth alternate construction of the first embodiment of a guide wire according to the principles of this invention is indicated generally as160 inFIGS. 12 and 12a.Guide wire160 comprises awire162 having a proximal end (not shown) and adistal end164. Instead of a single magnet on the distal end of the wire, as in the first embodiment,guide wire160 has a series of spacedmagnets166 on thedistal end portion168 of thewire162. Themagnets166 each preferably have a generally cylindrical body, with anaxial bore170 extending therethrough. The distal portion54 of the wire56 extends through thebores60, and the magnets52 are secured to the wire56 in spaced apart relation with adhesive.
• Themagnets166 are preferably made from NdFeB, and have a diameter of 2 mm (0.08 inches) and are 4 mm (0.16 inches) long. Themagnets166 are preferably spaced over the distal 5 cm (2 inches) of theguide wire160, and are spaced 1 cm (0.4 inches) on center. Of course some other size magnets and/or different magnet spacing could be used. Moreover the spacing of the magnets does not have to be equal. This third alternate construction is particularly useful for an electrophysiology catheter where the magnetic fields could pull or shape theguide wire160 to the heart wall, thereby guiding the electrophysiology catheter over the guide wire against the heart wall.
• As shown inFIG. 12a, upon the application of a magnetic field, themagnets166 on thedistal end portion164 of theguide wire160 cause the guide wire to assume a particular shape dictated by the field. Thus by controlling the applied magnetic field, the shape of the distal portion of the guide wire can be controlled, facilitating the navigation through, or shaping to, the body lumen. Theguide wire160 can be advanced by pulling with a magnetic force on themagnets166, or the proximal end can be manually pushed. A magnetic pulling force could also be used to hold the catheter with guide wire to the wall of a body lumen.
• A tenth alternate construction of the first embodiment of a guide wire constructed according to the principles of the present invention is indicated generally as180 inFIGS. 13 and 13a. Theguide wire180 comprises awire182, having a proximal end (not shown) and adistal end184. Instead of the single magnet on the distal end of the wire, or a plurality of magnets on the distal end portion of the wire, thedistal end portion186 ofguide wire180 is made from a magnetic material.
• Thedistal end portion186 is preferably about 0.25 mm (0.01 inches) in diameter, and about 1 cm (0.4 inches) long. The distal end portion can be made of a permeable magnetic material such as a steel or a magnetic stainless steel wire, or a steel or a magnetic stainless steel braid.
• As shown inFIG. 13a, upon the application of a magnetic field, thedistal end portion186 of theguide wire180 assumes a particular orientation dictated by the field. Thus by controlling the applied magnetic field, the orientation and/or shape of thedistal portion186 of theguide wire180 can be controlled, facilitating the navigation through the body lumen. Theguide wire180 can be advanced by magnet force on thedistal end portion186, or the proximal end can be pushed. The magnetic field can also function to selectively stiffen thedistal end portion186 of the guide wire, to facilitate navigation through the body lumen. This allows theguide wire182 to be designed with the minimum amount of stiffness to overcome static friction when applying an axial pushing force on at the proximal end. Sufficient stiffness for navigation can be provided by applying a magnetic field to the distal tip.
• As shown inFIG. 1, thecatheter24 is preferably of conventional construction, having aproximal end100, adistal end202, and alumen204 extending therebetween. Thecatheter24 can be made of polyurethane tubing, or some other suitable material. The size of thecatheter24 depends upon where in the body it will be introduced, and how it will be used. For example, for use in the blood vessels in the brain, the catheter might have an outside diameter of about 0.7 mm (0.03 inches), an inside diameter of about 0.6 mm (0.02 inches), and a length of about 2 m (6.6 feet). Of course, medical devices other than catheters can be used with the guide wire, for example an endoscope where the guide wire is inserted through its working channel. These devices would typically include a lumen extending all or partly along the length of the device that passes over the guide wire so that the device follows the guide wire. One of the guide wires of the present invention can be introduced into a body lumen, such as a blood vessel, and navigated to its desired location by the controlled application of magnetic fields. The application of a magnetic field allows the operator to steer the distal end of the guide wire by orienting the distal end of the guide wire to the desired direction of travel. The guide wire can be advanced using the magnetic field to pull the magnet on the distal end of the guide wire, or the guide wire can be advanced by pushing the proximal end. As the guide wire advances, thecatheter24 or other medical device can be advanced over the guide wire, until the catheter or medical device is in its desired location.
• Once thedistal end202 of thecatheter24 has been placed in its desired location, the guide wire can be left in place, or if the magnet is sufficiently small, the guide wire can be withdrawn through thelumen204 of the catheter and out theproximal end200.
• The magnetic articulation of the distal end of the guide wire eliminates the need to provide a permanent bend in the guide wire in order to navigate through branches in body lumens. The straight configuration of the guide wires permitted by the present invention permits faster and easier navigation in straight sections of the body lumen and reduces unintentional diversion down branches of the lumen.
• As shown inFIG. 14, one of the guide wires of this invention can be used to navigate anendoscope300 through a body lumen, such as a colon. Theendoscope300 has alumen302 extending therethrough. A magnetic field is applied to orient the magnet on the distal end of the guide wire with the magnetic field. Theendoscope300 can then be advanced over the guide wire, thelumen302 sliding over the guide wire. The guide wire is preferably incrementally advanced, and the endoscope is then advanced over the guide wire, until the distal end of theendoscope300 reaches its desired location.
• A guide wire and catheter combination constructed according to a second embodiment of this invention is indicated generally as400 inFIGS. 15 and 16. The guide wire andcatheter combination400 comprisesguide wire402 andcatheter404. Theguide wire402 comprises awire406, preferably made of nitinol, which is highly flexible and resists kinking, although the guide wire could be made of some other suitable material. Amagnet408 is mounted on thedistal end410 of thewire406. This magnet may either be a permanent magnet or a permeable magnetic material. A permanent magnet is easier to orient under the application of a magnetic field, as described below, but a permeable magnetic material is easier to pull under the application of a magnetic field.
• In the preferred embodiment, themagnet408 is made of NdFeB (neodymium-iron-boron) or samarium cobalt and is sized to respond to the magnetic field that will be applied to move theguide wire402 through the body lumen. Themagnet408 is preferably elongate so that it can orient the tip of theguide wire402 in the presence of an applied magnetic field. Magnets of about 0.3 mm (0.02 inches) to about 0.7 mm (0.03 inches) in diameter, and about 1 mm (0.04 inches) to 1.5 mm (0.06 inches) long are sufficiently large for use in navigating a guide wire.
• As shown inFIG. 16, the magnet is preferably a cylindrical body with anaxial bore412 therethrough. The distal end of thewire410 extends through thebore412, and is secured with abead414 of adhesive on the distal side of themagnet408. Thebead414 also provides a rounded head on the distal end of theguide wire402. Of course instead ofmagnet408, theguide wire402 could have a plurality of spaced magnets on the distal end portion similar to guidewire160, described above, or the distal end portion of the guide wire could be made of a flexible magnetic material similar to guidewire180.
• Thecatheter404 is preferably of conventional construction, having aproximal end416, adistal end418, and alumen420 extending therebetween. Thecatheter404 can be made of polyurethane tubing, or some other suitable material. The size of thecatheter404 depends upon where in the body it will be introduced, and how it will be used. For example, for use in the blood vessels in the brain, the catheter might have an outside diameter of about 0.7 mm (0.13 inches), an inside diameter of about 0.6 mm (0.11 inches), and a length of about 2 m (6.5 feet).
• Theguide wire402 is adapted to fit inside thelumen420, and “dock” with thecatheter404. To facilitate this, the distal end of thelumen420 has a restriction orstricture422 for engaging the distal end of theguide wire422. This restriction or stricture is preferably formed by a annular flange924 on ring426 provided on the distal end of the catheter, although it could be some other reduction in the lumen that can be engaged by the guide wire. The ring426 can be made of tantalum.
• The guide wire andcatheter combination400 can be introduced into a body lumen, such as a blood vessel, and navigated to its desired position by the controlled application of magnetic fields. The application of a magnetic field allows the operator to steer the distal end of theguide wire402 by orienting the distal end of the guide wire to the desired direction of travel. Theguide wire402 can be advanced using the magnetic field to pull the magnets on the distal end or the guide wire can be advanced by pushing the proximal end. As theguide wire402 advances, thecatheter404 can be advanced.
• Once thedistal end418 of thecatheter404 has been placed in its desired location, theguide wire402 can be withdrawn through thelumen420, and out theproximal end416.
• As shown inFIG. 17, theguide wire412 can be used to navigate abiopsy tool428 through a body lumen such as a kidney. Thebiopsy tool428 has alumen430 therein. The distal end of theguide wire402 is adapted to fit into thelumen430 and “dock” with the biopsy tool. A magnetic field is applied to orient themagnet408 inside thelumen430 of thebiopsy tool428. Thebiopsy tool428 can then be advanced, in the desired direction either by pushing the proximal end of theguide wire402, or pulling the distal end of the guide wire with the magnetic field. When thebiopsy tool428 has been advanced to its desired location, theguide wire402 can be withdrawn.
• The guide wires of either embodiment can be used to deliver catheter or other medical devices to locations within the body accessible via a body lumen. For example the guide wire could be used to navigate a device for retrieval of man made objects stents, or body made objects e.g. stones. The high degree of articulation of the tip provides the control needed to capture and recover such objects.
• Operation
• In operation, one of theguide wires22,40,50,60,70,90,110,120,130,150,160, or180 of the first embodiment and an associated catheter or other medical device is introduced through a natural or surgically formed opening in a body lumen. A magnetic field is applied to orient the distal tip within the body lumen. The magnetic field can also be used to advance the distal tip of the guide wire, or the guide wire can be pushed to advance the guide wire in the body lumen. As the guide wire is incrementally advanced the catheter can be advanced over the guide wire. Once the distal end of the catheter is in its desired position, the magnet is removed from the catheter by pulling the guide wire to withdraw the magnet through the lumen of the catheter.
• Because the magnet on the guide wire can be removed from the treatment site, multiple catheters can be directed in the same general area to facilitate a medical procedure with independent control of the catheters.
• In operation, theguide wire402 is inserted into the lumen of the catheter404 (or other medical device) and the guide wire andcatheter combination400 of the second embodiment is introduced through an opening in a natural or surgically formed opening in a body lumen. A magnetic field is applied to orient themagnet408 on the proximal end of theguide wire402, inside thecatheter404. The guide wire and catheter are then advanced, either by applying a magnetic field, or by pushing the distal end of the guide wire. Once thedistal end418 of the catheter is in its desired position, theguide wire402 is removed from thecatheter404 by pulling theguide wire402 to withdraw it from thelumen420 of the catheter.
• Once thecatheter24 or404 is in position it can be used for the administration of drug therapy or to perform a medical procedure or it can be used as a guide to insert medical devices to the area surrounding the distal end of the catheter to perform a medical procedure.
• Because the magnet on the guide wire can be removed from the treatment site, multiple catheters can be directed in the same general area to facilitate a medical procedure with independent control of the catheters. Of course, the magnet could be left in place within the catheter, if desired.

Claims (21)

1.-20. (canceled)

21. A method of navigating a medical device having a proximal end portion, a distal end portion, and a magnetically responsive element disposed on the distal end portion of the medical device, the method comprising:

introducing the distal end portion of the medical device having the magnetically responsive element into a subject's body;

applying a magnetic field to the area of the subject in which the medical device is located, the magnetic field being effective for orienting the magnetically responsive element on the distal end portion of the medical device with the magnetic field, wherein the application of the magnetic field is controlled to allow an operator to guide the distal end portion of the medical device in a desired direction; and

applying a subsequent magnetic field to the area of the subject in which the medical device is located, the subsequent magnetic field being effective for pulling the magnetically responsive element on the distal end portion of the medical device to advance the medical device in the desired direction.

22. The method ofclaim 21 further comprising the steps of iteratively applying a magnetic field effective for orienting the magnetically responsive element on the distal end portion of the medical device with the magnetic field to re-orient the distal end in a desired direction, and a subsequent magnetic field effective for pulling the magnetically responsive element on the distal end portion of the medical device to advance the medical device in the desired direction, to incrementally guide the medical device to a desired location within a subject's body.

23. The method ofclaim 21 further comprising the steps of advancing a catheter over the medical device, the catheter having a passage therethrough in which the medical device is received, such that the catheter may be advanced over the medical device to guide the catheter to where the distal end portion of the medical device is located within the subject's body.

24. The method ofclaim 21 further comprising the steps of advancing an endoscope over the medical device, the catheter having a passage therethrough in which the medical device is received, such that the endoscope may be advanced over the medical device to guide the endoscope to where the distal end portion of the medical device is located within the subject's body.

25. The method ofclaim 21 further comprising the step of pushing the proximal end portion of the medical device to assist in advancing the medical device in the desired direction.

26. The method ofclaim 23 further comprising the step of retracting the medical device from the catheter once the catheter has been guided to a desired location within the subject's body.

27. The method ofclaim 24 further comprising the step of retracting the medical device from the endoscope once the endoscope has been guided to a desired location within the subject's body.

28. The method ofclaim 22 wherein the medical device is inserted within the vasculature of a subject's body.

29. The method ofclaim 22 wherein the magnetic field is applied from a location external to the subject.

30. A method of navigating a catheter device having a passageway therein through a subject's body, the method comprising:

introducing the distal end portion of the catheter device into a subject's body;

introducing the distal end portion of a medical device into the passage in the catheter device, the medical device having a proximal end portion, a distal end portion, and a magnetically responsive element disposed on the distal end portion of the medical device;

applying a magnetic field to the area of the subject in which the medical device is located, the magnetic field being effective for orienting the magnetically responsive element on the distal end portion of the medical device with the magnetic field, wherein the application of the magnetic field is controlled to allow an operator to guide the distal end portion of the medical device in a desired direction;

applying a subsequent magnetic field to the area of the subject in which the medical device is located, the subsequent magnetic field being effective for pulling the magnetically responsive element on the distal end portion of the medical device to advance the medical device in the desired direction; and

advancing the catheter device, if necessary, over the medical device received within the passage in the catheter device.

31. The method ofclaim 30 further comprising the steps of iteratively applying a magnetic field effective for orienting the magnetically responsive element on the distal end portion of the medical device with the magnetic field to re-orient the distal end in a desired direction, and a subsequent magnetic field effective for pulling the magnetically responsive element on the distal end portion of the medical device to advance the medical device in the desired direction, to incrementally guide the medical device to a desired location within a subject's body.

32. The method ofclaim 30 further comprising the step of pushing the proximal end portion of the medical device to assist the subsequent magnetic field in advancing the medical device in the desired direction.

33. The method ofclaim 30 wherein the catheter device is advanced over the medical device by pushing the proximal end portion of the catheter device to advance the catheter device towards the distal end portion of the medical device.

34. The method ofclaim 31 further comprising the step of retracting the medical device from the catheter once the catheter device has been guided to a desired location within the subject's body.

35. The method ofclaim 30 wherein the medical device is inserted within the vasculature of a subject's body.

36. The method ofclaim 34 wherein the medical device comprises a guide wire having a distal end portion including a core wire on which the magnetically responsive element is disposed, the distal end portion being sufficiently flexible adjacent the magnetically responsive element to allow the wire to flex in response to a magnetic field applied to the magnetically responsive element.

37. The method ofclaim 30 wherein the magnetic field is applied from a location external to the subject.

38. A method of navigating a medical device having a proximal end portion, a distal end portion, and a magnetically responsive element disposed on the distal end portion of the medical device, the method comprising:

introducing the distal end portion of the medical device having the magnetically responsive element into a subject's body;

applying a magnetic field to the area of the subject in which the medical device is located, the magnetic field being effective for orienting the magnetically responsive element on the distal end portion of the medical device with the magnetic field, wherein the application of the magnetic field is controlled to allow an operator to guide the distal end portion of the medical device in a desired direction; and

pushing the proximal end of the medical device, while the magnetic field is being applied to orient the magnetically responsive element on the distal end portion of the medical device with the magnetic field, to advance the medical device in the desired direction.

39. The method ofclaim 38 further comprising the steps of iteratively applying a magnetic field effective for orienting the magnetically responsive element on the distal end portion of the medical device with the magnetic field to re-orient the distal end in a desired direction, and pushing the proximal end of the medical device to advance the medical device in the desired direction, to incrementally guide the medical device to a desired location within a subject's body.

40. The method ofclaim 39 further comprising the steps of advancing a catheter over the medical device, the catheter having a passage therethrough in which the medical device is received, such that the catheter may be advanced over the medical device to guide the catheter to where the distal end portion of the medical device is located within the subject's body.

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