Method of forming an electromagnetic sensing coil in a medical instrument

• US 8,549,732 B2
• Filed: 07/01/2011
• Issued: 10/08/2013
• Est. Priority Date: 10/17/2003
• Status: Active Grant

• Current Assignee: Medtronic Navigation Incorporated (Medtronic Plc)
• Original Assignee: Medtronic Navigation Incorporated (Medtronic Plc)
• Inventors: Burg, Bruce M., Dukesherer, John H., Jascob, Bradley A., Kessman, Paul
• Primary Examiner(s): Kim, Paul D
• Application Number:
  US13/175,084
• Publication Number:
  US 20110258842A1
• Time in Patent Office: 830 Days
• Field of Search: 296/021, 296/05, 296/06, 298/32, 298/41, 298/55, 298/58, 298/83, 336/176, 336/200, 336/212, 336/229, 336/232, 336/233, 600/414, 600/424, 600/426, 600/431, 600/433
• US Class Current: 29/605
• CPC Class Codes: A61B 2034/105 Modelling of the patient, e.g. for ligaments or bones
• CPC Class Codes: A61B 2034/107 Visualisation of planned trajectories or target regions
• CPC Class Codes: A61B 2034/2051 Electromagnetic tracking systems
• CPC Class Codes: A61B 2034/2068 using pointers, e.g. pointers having reference marks for determining coordinates of body points
• CPC Class Codes: A61B 2034/207 Divots for calibration
• CPC Class Codes: A61B 2034/2072 Reference field transducer attached to an instrument or patient
• CPC Class Codes: A61B 2034/256 having a database of accessory information, e.g. including context sensitive help or scientific articles
• CPC Class Codes: A61B 2090/365 augmented reality, i.e. correlating a live optical image with another image
• CPC Class Codes: A61B 2090/367 creating a 3D dataset from 2D images using position information
• CPC Class Codes: A61B 2090/376 using X-rays, e.g. fluoroscopy
• CPC Class Codes: A61B 2090/378 using ultrasound
• CPC Class Codes: A61B 2090/3983 Reference marker arrangements for use with image guided surgery
• CPC Class Codes: A61B 34/20 Surgical navigation systems; Devices for tracking or guiding surgical instruments, e.g. for frameless stereotaxis
• CPC Class Codes: A61B 5/06 Devices, other than using radiation, for detecting or locating foreign bodies for removing same A61B17/50 ; determining position of probes within or on the body of the patient
• CPC Class Codes: A61B 5/062 using magnetic field
• CPC Class Codes: A61B 5/4528 Joints A61B5/4533, A61B5/4538 take precedence
• CPC Class Codes: A61B 5/7285 for synchronising or triggering a physiological measurement or image acquisition with a physiological event or waveform, e.g. an ECG signal A61B6/5205, A61B6/541, A61B8/5207, A61B8/543 take precedence
• CPC Class Codes: A61B 6/12 Arrangements for detecting or locating foreign bodies
• CPC Class Codes: A61B 6/4405 the apparatus being movable or portable, e.g. handheld or mounted on a trolley
• CPC Class Codes: A61B 6/4423 related to hygiene or sterilisation
• CPC Class Codes: A61B 6/4441 : the rigid structure being a C-arm or U-arm
• CPC Class Codes: A61B 6/541 : involving acquisition triggered by a physiological signal
• CPC Class Codes: A61B 8/4245 : involving determining the position of the probe, e.g. with respect to an external reference frame or to the patient
• CPC Class Codes: A61B 8/543 : involving acquisition triggered by a physiological signal
• CPC Class Codes: H01F 2005/027 : wound on formers for receiving several coils with perpendicular winding axes, e.g. for antennae or inductive power transfer
• CPC Class Codes: Y10T 29/4902 : Electromagnet, transformer or inductor
• CPC Class Codes: Y10T 29/49071 : by winding or coiling
• CPC Class Codes: Y10T 29/49073 : by assembling coil and core
• CPC Class Codes: Y10T 29/4913 : Assembling to base an electrical component, e.g., capacitor, etc.
• CPC Class Codes: Y10T 29/49146 : with encapsulating, e.g., potting, etc.
• CPC Class Codes: Y10T 29/49171 : with encapsulating

Abstract

A surgical navigation system for navigating a region of a patient includes a non-invasive dynamic reference frame and/or fiducial marker, sensor tipped instruments, and isolator circuits. The dynamic reference frame may be repeatably placed on the patient in a precise location for guiding the instruments. The instruments may be precisely guided by positioning sensors near moveable portions of the instruments. Electrical sources may be electrically isolated from the patient.

Claims

1. For a surgical navigation system, a method of forming an electromagnetic sensing coil in a medical instrument, comprising:

forming an elongated cylinder of the medical instrument having a distal end;

forming a coil about the elongated cylinder;

electrically isolating the coil from the elongated cylinder; and

covering a portion of the elongated cylinder and the coil with a first layer of a material without covering the distal end, said first layer being displaced a first distance from the distal end to protect the first layer from damage when the distal end touches a surface,

wherein the coil is substantially electrically isolated from an environment.

2. The method of claim 1, wherein electrically isolating the coil from the elongated cylinder includes covering the elongated cylinder with a second layer of a material.

3. The method of claim 2, wherein covering the elongated cylinder with the second layer occurs prior to forming the coil.

4. The method of claim 2, further comprising selecting a dielectric material for one of the first layer and the second layer.

5. The method of claim 1, wherein forming an elongated cylinder includes forming the elongated cylinder of an electro-magnetic permeable material.

6. The method of claim 1, wherein forming an elongated cylinder includes forming the elongated cylinder including a portion having a diameter of less than about 2 millimeters.

7. The method of claim 1, wherein forming the coil includes forming a first coil and forming a second coil of a wire around said elongated cylinder.

8. The method of claim 1, wherein covering the coil includes substantially covering the coil to isolate the coil from an exterior environment.

9. The method of claim 1, wherein forming the elongated cylinder includes forming a guidable portion of a stylet, a suction tube, a core for a probe, a core for a catheter, a core for an ablation tip, a core for a lens, and combinations thereof.

10. The method of claim 1, wherein covering the elongated cylinder with the first layer of material includes covering the formed elongated cylinder with at least about 0.0005 inches of the material.

11. For a surgical navigation system, a method of forming an electro-magnetic sensing coil in a medical instrument, comprising:

forming an elongated cylinder having a distal end;

forming a coil about the elongated cylinder a first distance from the distal end;

covering a portion of the elongated cylinder without covering the distal end with a first layer of material displaced a second distance from the distal end to protect the first layer of material; and

electrically isolating the coil from the elongated cylinder.

12. The method according to claim 11, wherein the first layer has a thickness between about 0.00025 inches and about 0.03 inches.

13. The method according to claim 11, wherein the first layer has a thickness of about 0.001 inches.

14. The method according to claim 11, wherein the first layer has a dielectric breakdown voltage of at least 4,000 volts per about 0.001 inches in thickness.

15. The method according to claim 11, further including covering the elongated cylinder and coil with a second material displaced a third distance from the distal end so the coil is electrically isolated from the environment.

16. The method of claim 11, wherein forming the elongated cylinder includes forming a guidable portion of a stylet, a suction tube, a core for a probe, a core for a catheter, a core for an ablation tip, a core for a lens, and combinations thereof.

17. The method according to claim 11, wherein the first layer is disposed between the deformable elongated cylinder and the coil.

18. For a surgical navigation system, a method of forming an electro-magnetic sensing coil in a medical instrument, comprising:

forming a deformable elongated cylinder having a distal end of the medical instrument;

forming a coil about the elongated cylinder a first distance from the distal end;

covering a portion of the elongated cylinder without covering the distal end of the elongated cylinder and the coil with a first layer of dielectric material, said first layer being disposed between the coil and the deformable elongated cylinder; and

electrically isolating the coil from an environment.

19. The method according to claim 18, wherein the first layer of dielectric material is displaced from the distal end a second distance.

20. The method according to claim 18, wherein the first layer of dielectric material has a thickness between about 0.00025 inches and about 0.03 inches.

21. The method according to claim 18, wherein the elongated cylinder forms one of a suction tube, a core of a probe, a core of a catheter, and a core of an ablation tip.

22. The method according to claim 18, further comprising covering the coil and deformable elongated cylinder with a second layer of material without covering the distal end.

23. The method according to claim 22, wherein forming a second layer is forming a second layer having a third distance from the distal end to protect the second layer from damage when the distal end touches a surface.