Methods and apparatus for imparting curves in elongated medical catheters

An elongated medical instrument configured to be inserted into a body, comprising:

• an elongated instrument body having an instrument body axis, an instrument body proximal segment, and an instrument body distal segment;
• a temperature-activated shape memory alloy actuator coupled to the distal segment of the elongated instrument body, the actuator comprising first and second elongated actuator members extending side-by-side in substantially a common plane in parallel with the instrument body axis to first and second elongated actuator member free ends;
• the first elongated actuator member further comprising a first elongated layer of shape memory alloy material that retains an elevated temperature shape memory effecting movement of the first elongated actuator member and the distal segment in a first direction;
• a first heating device comprising:
• a first plurality of heating elements in a first heating element array, each heating element spatially displaced from one another and disposed in operative relation to a respective spatially displaced portion of the first layer of shape memory alloy material;
• and
• means for selectively energizing one or more of the first plurality of heating elements to selectively heat one or more respective portion of the first layer of shape memory material and induce a deflection of the first actuator member free end in the first direction that is proportional to the number of the heated portions and the spatial relation of the heated portions;
• the second elongated actuator member comprises a second elongated layer of shape memory alloy material that retains an elevated temperature shape memory effecting movement in a second direction;
• and
• the second heating device comprises:
• a second plurality of heating elements in a second heating element array, each heating element spatially displaced from one another and disposed in operative relation to a respective spatially displaced portion of the second layer of shape memory alloy material;
• and
• means for selectively energizing one or more of the second plurality of heating elements to selectively heat one or more respective portion of the second layer of shape memory material and induce a deflection of the second actuator member free end in the second direction that is proportional to the number of the heated portions and the spatial relation of the heated portions.

A method of deflecting a distal segment of an elongated medical instrument within the body, comprising:

• providing an elongated instrument body having a proximal segment and a distal segment;
• mounting a temperature-activated actuator to the distal segment of the elongated instrument body, the actuator comprising first and second elongated actuator members extending side-by-side in substantially a common plane and each configured to move in opposite directions when independently activated;
• selectively heating the first elongated actuator member to activate the first elongated actuator member and cause the first elongated actuator member to move the distal segment in a first direction out of the common plane;
• and
• selectively heating the second elongated actuator member to activate the second elongated actuator member and cause the second elongated actuator member to move the distal segment in a second direction out of the common plane and opposed to the first direction.

An elongated medical instrument configured to be inserted into a body comprising:

• an elongated instrument body having a proximal segment and a distal segment that are aligned axially;
• a temperature-activated actuator coupled to the distal segment of the elongated instrument body, the actuator comprising first and second elongated actuator members extending side-by-side in substantially a common plane and each configured to move the distal segment out of axial alignment with the proximal segment when independently activated;
• means for delivering thermal energy to the first elongated actuator member to activate the first elongated actuator member and cause the first elongated actuator member to move the distal segment in a first direction out of the common plane;
• and
• means for delivering thermal energy to the second elongated actuator member to activate the second elongated actuator member and cause the second elongated actuator member to move the distal segment in a second direction out of the common plane and opposed to the first direction.

An elongated medical instrument to be advanced through the body comprising:

• an elongated instrument body having an instrument body sidewall extending between an instrument body proximal end and an instrument body distal end and having an instrument body proximal segment and an instrument body distal segment;
• the instrument body distal segment further comprising a shape memory alloy actuator supported by said catheter body sidewall along one side of the catheter body sidewall and extending longitudinally from the junction of the instrument body proximal section with the instrument body distal section through at least a portion of said instrument body distal segment;
• the shape memory alloy actuator comprising first and second elongated shape memory alloy members extending substantially in parallel with one another along the one side of the instrument body;
• the first shape memory alloy member is thermally trained to deflect the instrument body distal segment in a first direction when heated by application of energy thereto to a transition temperature;
• the second shape memory alloy member is thermally trained to deflect the instrument body distal segment in a second direction generally opposed to the first direction when heated by application of energy thereto to a transition temperature;
• and
• means for selectively conducting energy to at least portions of the first and second shape memory alloy members, whereby selective deflection of the distal segment in the first and second directions is effected.

An elongated medical instrument to be advanced through the body comprising:

• an elongated instrument body having an instrument body extending between an instrument body proximal end and an instrument body distal end and having axially aligned instrument body proximal and distal segments joined at a junction;
• the instrument body distal segment further comprising a shape memory alloy actuator supported by said catheter body extending longitudinally from the junction of the instrument body proximal section with the instrument body distal section through at least a portion of said instrument body distal segment;
• the shape memory alloy actuator comprising first and second elongated shape memory alloy members extending substantially in parallel with one another;
• the first shape memory alloy member is thermally trained to deflect the instrument body distal segment in a first direction when heated by application of energy thereto to a transition temperature;
• the second shape memory alloy member is formed to be more robust than the first shape memory alloy member and thermally trained to deflect the instrument body distal segment in a second direction generally opposed to the first direction when heated by application of energy thereto to a transition temperature;
• means for selectively conducting energy to at least portions of the second shape memory alloy member to effect selective deflection of the distal segment in the second direction out of axial alignment with the proximal segment and through a relatively wide range of motion;
• and
• means for selectively conducting energy to at least portions of the first shape memory alloy member to effect selective deflection of the distal segment in the second direction through a relatively narrow range of motion to substantially restore the axial alignment of the distal segment with the proximal segment.