Apparatus and method for sensing force

• US 8,083,691 B2
• Filed: 11/12/2008
• Issued: 12/27/2011
• Est. Priority Date: 11/12/2008
• Status: Active Grant

• Current Assignee: Auris Health, Inc. (Johnson & Johnson)
• Original Assignee: Hansen Medical Incorporated (Johnson & Johnson)
• Inventors: Goldenberg, Alex S., Schlesinger, Randall L., Schultheis, Eric A.
• Primary Examiner(s): Hindenburg, Max
• Assistant Examiner(s): Towa, Rene
• Application Number:
  US12/269,684
• Publication Number:
  US 20100121138A1
• Time in Patent Office: 1,140 Days
• Field of Search: 600587-595, 606/130
• US Class Current: 600/587
• CPC Class Codes: A61B 1/005 Flexible endoscopes
• CPC Class Codes: A61B 10/06 Biopsy forceps , e.g. with cup-shaped jaws
• CPC Class Codes: A61B 17/29 Forceps for use in minimally invasive surgery
• CPC Class Codes: A61B 18/1492 having a flexible, catheter-like structure, e.g. for heart ablation A61B18/1477 takes precedence
• CPC Class Codes: A61B 2017/00477 Coupling A61B2017/0046 takes precedence
• CPC Class Codes: A61B 2017/2902 characterized by features of the actuating rod
• CPC Class Codes: A61B 2018/00273 Anchoring means for temporary attachment of a device to tissue
• CPC Class Codes: A61B 2018/00702 Power or energy
• CPC Class Codes: A61B 2018/00791 Temperature
• CPC Class Codes: A61B 2018/00815 measured by a thermistor
• CPC Class Codes: A61B 2018/00839 Bioelectrical parameters, e.g. ECG, EEG
• CPC Class Codes: A61B 2034/301 for introducing or steering flexible instruments inserted into the body, e.g. catheters or endoscopes
• CPC Class Codes: A61B 2090/064 for measuring force, pressure or mechanical tension
• CPC Class Codes: A61B 2090/065 for measuring contact or contact pressure
• CPC Class Codes: A61B 2218/002 Irrigation
• CPC Class Codes: A61B 5/01 Measuring temperature of body parts ; Diagnostic temperature sensing, e.g. for malignant or inflamed tissue clinical contact thermometers G01K13/20
• CPC Class Codes: A61B 5/24 Detecting, measuring or recording bioelectric or biomagnetic signals of the body or parts thereof
• CPC Class Codes: A61B 5/6885 Monitoring or controlling sensor contact pressure
• CPC Class Codes: A61M 25/0105 Steering means as part of the catheter or advancing means; Markers for positioning systems for detection of markers A61B

Abstract

A medical system comprises a medical probe including an elongated probe body, a lumen extending within the probe body, an axially flexible section, and a push-pull rod slidably disposed within the lumen. The system comprises a ditherer mechanically coupled to the rod for cyclically displacing it axially back and forth within the lumen, such that the ends of the probe body are axially displaced relative to each other via the axially flexible section. The system further comprises a sensor for sensing a force axially applied to the distal end of the probe body. A method comprises introducing a medical probe into a patient, axially dithering the distal end of the medical probe back and forth relative to the proximal end of the medical probe, and sensing a force applied between tissue of the patient and the distal end of the medical probe while the distal end is axially dithered.

Claims

1. A medical system, comprising:

a medical probe including an elongated probe body having a proximal section , a distal section, and an axially translatable section disposed between the proximal and distal sections, a lumen axially extending within the probe body, and a push-pull rod slidably disposed within the lumen, the push-pull rod having a distal end that is affixed to the distal section of the probe body and a proximal end slidable within and extending from the proximal section of the probe body;

a dithering mechanism mechanically coupled to the proximal end of the push-pull rod, the dithering mechanism configured for cyclically displacing the push-pull rod axially back and forth within the lumen within the probe body, such that the displacement of the push-pull rod causes the distal section of the probe body to be axially dithered back and forth relative to the proximal section of the probe body via the axially translatable section of the probe body; and

at least one sensor configured for sensing an external force axially applied to a distal tip of the probe body.

2. The medical system of claim 1, wherein the probe body is an intravascular catheter body.

3. The medical system of claim 1, wherein the axially translatable section of the probe body comprises an axially flexible member.

4. The medical system of claim 3, wherein the axially flexible member is a bellows.

5. The medical system of claim 1, wherein the axially translatable section of the probe body comprises at least one seal that allows one of the proximal and distal sections of the probe body to slide within the other of the proximal and distal sections of the probe body.

6. The medical system of claim 1, wherein the medical probe further includes an operative medical element mounted to the distal tip of the probe body.

7. The medical system of claim 1, wherein the medical probe further comprises a coil wrapped around the push-pull rod, the coefficient of friction between the coil and the lumen being less than the coefficient of friction between the push-pull rod and the lumen.

8. The medical system of claim 1, wherein the at least one sensor is mounted on the dithering mechanism.

9. The medical system of claim 1, further comprising a drive mechanism affixed to the proximal section of the probe body for effecting movement of the probe body within at least one degree of freedom.

10. The medical system of claim 9, wherein the medical probe further includes at least one control element extending within the probe body, and wherein the drive mechanism includes an adapter coupled to the at least one control element for deflecting the distal tip of the probe body in at least one direction.

11. The medical system of claim 10, wherein the at least one control element is affixed to the probe body at a point proximal to the axially translatable section.

12. The medical system of claim 9, wherein the proximal end of the push-pull rod is configured for being axially displaced by the dithering mechanism relative to the drive mechanism.

13. The medical system of claim 9, further comprising an introducer sheath having a lumen in which the probe body is disposed, wherein the drive mechanism is configured for axially displacing the probe body and the introducer sheath relative to each other.

14. The medical system of claim 1, further comprising a computer configured for obtaining a baseline force measurement by receiving signals from the at least one sensor when the push-pull rod is dithered back and forth without an external axial force applied to the distal tip of the probe body, for obtaining a total force measurement by receiving signals from the at least one sensor when the push-pull rod is dithered back and forth with an external axial force applied to the distal tip of the probe body, and computing the external axial force applied to the distal tip of the probe body by subtracting the baseline force measurement from the total force measurement.