Articulated magnetic guidance systems and devices and methods for using same for magnetically-assisted surgery

• US 6,459,924 B1
• Filed: 11/10/1998
• Issued: 10/01/2002
• Est. Priority Date: 11/12/1997
• Status: Expired due to Fees

• Current Assignee: Stereotaxis, Inc.
• Original Assignee: Stereotaxis, Inc.
• Inventors: Ritter, Rogers C., Creighton, Francis M. IV, Werp, Peter R.
• Primary Examiner(s): Jeffery, John A.
• Application Number:
  US09/189,633
• Time in Patent Office: 1,421 Days
• Field of Search: 600/427, 600/114, 600/424, 128/899, 248/324
• US Class Current: 600/427
• CPC Class Codes: A61B 1/00158 using magnetic field
• CPC Class Codes: A61B 2034/733 arranged only on one side of the patient, e.g. under a table
• CPC Class Codes: A61B 2090/376 using X-rays, e.g. fluoroscopy
• CPC Class Codes: A61B 34/70 Manipulators specially adapted for use in surgery
• CPC Class Codes: A61B 34/73 Manipulators for magnetic surgery
• CPC Class Codes: A61B 90/10 for stereotaxic surgery, e.g. frame-based stereotaxis
• CPC Class Codes: A61M 25/0127 Magnetic means; Magnetic markers

Abstract

An articulated magnet assembly optionally includes one or two additional fixed magnets to guide or move such as by pulling or pushing a magnetic structure in the body. The magnetic structure may be a magnetic tip of a catheter or a magnetic seed, or other such magnetic assembly, implant or device. The device is arranged to facilitate biplanar, real-time, X-ray imaging of the patient. The moved magnet can be a large, strong permanent magnet or a cored solenoid. The added, fixed electromagnets may have either normally conducting or superconducting coils. The magnet on the articulated magnet assembly can move radially, along a polar direction, and at an azimuthal angle, and may also pivot in place to direct an opposite pole of the magnet in the direction of the patient. Magnetically-assisted surgery can be performed, in some instances, by pivoting the magnet on one or two axes without withdrawing it from the vicinity of the patient to control the direction and/or orientation of a temporarily or permanently implanted magnetic surgical device. If the magnet is an electromagnetic coil, this pivoting may or may not have to be accompanied by a ramping of current in the coil.

Claims

1. A device for directing a magnetic structure in living tissue positioned within an operating region, comprising:

an articulated arm having one end mounted on a base and a second end; and

a magnet, comprising a pair of oppositely oriented permanent magnets, pivotably mounted at the second end of the articulated arm, wherein the magnet is pivotable about each of at least two mutually perpendicular axes of the magnet to provide, in any location in the operating region, varying directions of at least one of magnetic field lines and magnetic gradient in said operating region.

2. A method of directing a magnetic structure within living tissue located within an operating region, comprising the steps of:

embedding a magnetic structure in the living tissue;

positioning an electromagnet to provide an effective magnetic field in the operating region;

pivoting the magnet on at least one of at least two axes of the magnet as desired to change at least one of either the direction of movement or orientation of the magnetic structure;

ramping a magnitude of current in the electromagnet down to a low value between the positioning and the pivoting steps, and

ramping a magnitude of current in the electromagnet up to a selected value after moving the magnet.

3. The method of claim 2 and further comprising the step of withdrawing the magnet from the vicinity of the operating region between the positioning and pivoting steps, and repositioning the magnet to provide an effective magnetic field in the operating region after the pivoting step.

4. A device for directing a magnetic structure in living tissue positioned within an operating region, the device comprising:

(a) a magnet assembly comprising at least two permanent magnets sufficient to generate two magnetic fields of opposite polarities, and configured to rotate about at least two of its axes to provide a magnetic field in said operating region; and

(b) a magnet support assembly, said magnet support assembly being controllably, mechanically re-positionable about the operating region to thereby desirably change either or both of the magnetic field strength and direction to thereby direct the magnetic structure.

5. A method of directing a magnetic structure within living tissue located within an operating region, comprising the steps of:

embedding a magnetic structure in the living tissue;

positioning an electromagnet to provide an effective magnetic field in the operating region;

moving the electromagnet as desired to change at least one of either the direction of movement or orientation of the magnetic structure;

ramping a magnitude of current in the electromagnet down to a low value between the positioning step and a pivoting step; and

ramping a magnitude of current in the electromagnet up to a selected value after moving the magnet.

6. A method of directing a magnetic structure within living tissue located within an operating region, comprising the steps of:

embedding a magnetic structure in the living tissue;

positioning a magnet to provide an effective magnetic field in the operating region;

pivoting the magnet as desired to change at least one of either the direction of movement or orientation of the magnetic structure;

withdrawing the magnet from the vicinity of the operating region between the positioning step and the pivoting step; and

repositioning the magnet to provide an effective magnetic field in the operating region after the pivoting step.

7. A device for directing a magnetic structure in living tissue positioned within an operating region, the device comprising:

(a) a magnet assembly comprising a magnet means sufficient to generate a quadrupole magnetic field and configured to rotate about at least two of its axes to provide a magnetic field in said operating region; and

(b) a magnet support assembly, said magnet support assembly being controllably, mechanically re-positionable about the operating region to thereby desirably change either or both of the magnetic field strength and direction to thereby direct the magnetic structure.

8. A method of directing a magnetic structure within living tissue located within an operating region, comprising the steps of:

embedding a magnetic structure in the living tissue;

positioning a magnet to provide an effective magnetic field in the operating region;

pivoting the magnet on at least one of at least two axes of the magnet as desired to change at least one of either the direction of movement or orientation of the magnetic structure; and

withdrawing the magnet from the vicinity of the operating region between the positioning and pivoting steps, and repositioning the magnet to provide an effective magnetic field in the operating region after the pivoting step.