Catheter with bendable tip
A medical probe includes a flexible insertion tube, having a distal end for insertion into a body cavity of a patient, and a distal tip, which is disposed at the distal end of the insertion tube and is configured to be brought into contact with tissue in the body cavity. A coupling member couples the distal tip to the distal end of the insertion tube and includes a tubular piece of an elastic material having a helical cut therethrough along a portion of a length of the piece.
1. A medical probe, comprising:
a flexible insertion tube, having a distal end for insertion into a body cavity of a patient;
a distal tip, which is disposed at the distal end of the insertion tube and is configured to be brought into contact with tissue in the body cavity;
a coupling member, which couples the distal tip to the distal end of the insertion tube and comprises a tubular piece of a superelastic alloy having a helical cut therethrough along a portion of a length of the piece;
a position sensor within the distal tip, the position sensor being configured to generate a signal in response to a magnetic field, and wherein the signal is indicative of a position of the distal tip; and
a magnetic field generator within the distal end of the insertion tube for generating the magnetic field.
2. The probe according to claim 1 , wherein the tubular piece of superelastic alloy has a length of approximately 10 mm with an outer diameter of approximately 2.0 mm and a wall thickness of approximately 0.05 mm.
3. The probe according to claim 1 , wherein the helical cut subtends an angle between 360° and 720° about an axis of the tubular piece.
4. The probe according to claim 1 , wherein the coupling member is configured to bend in response to pressure exerted on the distal tip when the distal tip engages the tissue, and wherein the helical cut has a width chosen so as to inhibit bending of the distal tip beyond a predetermined angular limit.
5. The probe according to claim 1 , wherein the position sensor is configured to sense a position of the distal tip relative to the distal end of the insertion tube, which changes in response to deformation of the coupling member.
6. The probe according to claim 1 , and comprising an electrical conductor, which is coupled to a distal side of the position sensor and is curved to pass in a proximal direction around the position sensor and through the insertion tube so as to convey position signals from the position sensor to a proximal end of the insertion tube.
7. The probe according to claim 1 , and comprising a pull-wire for use by an operator of the probe in steering the probe, wherein the pull-wire passes through the insertion tube and is anchored at a point in the distal end of the insertion tube that is proximal to the helical cut in the coupling member.
8. The probe according to claim 1 , and comprising a heat-resistant plastic sheath covering at least the coupling member.
9. The probe according to claim 1 , wherein the insertion tube, distal tip and coupling member are configured for insertion through a blood vessel into the heart of the patient.
10. The probe according to claim 1 wherein the superelastic alloy is a nickel titanium alloy.