Apparatus and method for sensing force on a robotically controlled medical instrument

• US 8,372,019 B2
• Filed: 12/17/2009
• Issued: 02/12/2013
• 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): TOWA, RENE T
• Application Number:
  US12/641,145
• Publication Number:
  US 20100121269A1
• Time in Patent Office: 1,153 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 member slidably disposed within the lumen. The system comprises a ditherer mechanically coupled to the member 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 method for sensing force on a robotically controlled medical instrument, the method comprising:

introducing a medical probe into a patient, the medical probe having an elongated probe body comprising a central lumen, and a push-pull member extending axially through the central lumen, a distal end of the push-pull member being attached to a distal end portion of the probe body;

mechanically displacing a proximal end of the push-pull member back and forth in a cyclical manner without any external force applied to the distal end portion of the probe body;

mechanically displacing the proximal end of the push-pull member back and forth in a cyclical manner with external force axially applied between internal body tissue of the patient and the distal end portion of the probe body; and

determining the external force applied between the internal body tissue of the patient and the distal end portion of the probe body, wherein the external force applied between the internal body tissue of the patient and the distal end portion of the probe body is determined by

obtaining a baseline force measurement when the distal end portion of the probe body is axially dithered back and forth without any external axial force applied to the distal end portion of the probe body,

obtaining a total force measurement when the distal end portion of the probe body is dithered back and forth with the external axial force axially applied between the tissue and the distal end portion of the probe body, and

subtracting the baseline force measurement from the total force measurement.

2. The medical method of claim 1, the probe body further comprising an axially variable-length portion interposed between the respective distal end and more proximal portions of the probe body.

3. The medical method of claim 2, wherein the push-pull member comprises a fluid delivery tube having an open distal end coupled to the distal end portion of the probe body.

4. The medical method of claim 2, wherein the axially variable-length portion of the probe body comprises a spring.

5. The medical method of claim 2, wherein the probe body is robotically controlled by an instrument driver having an adapter configured to be operatively coupled to one or more steering wires extending through the probe body for controllable bending of a bendable portion of the probe body in at least one direction, the one or more steering wires having distal ends affixed to the probe body at a steering wire anchor member located at a distal end of the bendable portion, the push-pull member extending distally past the anchor member to the distal end portion of the probe body.