Guided intravascular catheter sheath having bi-directional steering assembly

1. A steerable intravascular catheter, comprising:

a) an elongated sheath having a tubular body wall defining a central lumen and a deflectable distal end portion;

b) a pair of laterally opposed elongated pull wires extending through the tubular body wall of the sheath and terminating within the distal end portion thereof;

c) a handle assembly having a longitudinal axis and operatively associated with a proximal end portion of the sheath, the handle assembly including a rotatable control knob for controlling bi-directional deflection of the distal end portion of the sheath, wherein bi-directional angular rotation of the control knob about the longitudinal axis of the handle assembly effectuates corresponding reciprocal axial movement of the laterally opposed pull wires in opposed axial directions and corresponding bi-directional angular deflection of the distal end portion of the sheath; and

d) a drive mechanism associated with the handle assembly for actuating the laterally opposed elongated pull wires in response to the bi-directional angular rotation of the control knob, the drive mechanism having a distal drive gear mounted for angular rotation about the longitudinal axis of the handle assembly, the distal drive gear having a threaded bore and a cooperating threaded distal drive sleeve positioned within the threaded bore of the distal drive gear and supported for reciprocal axial movement therein, the drive mechanism further having a proximal drive gear mounted for angular rotation about the longitudinal axis of the handle assembly, the proximal drive gear having a threaded bore and a cooperating threaded proximal drive sleeve positioned within the threaded bore of the proximal drive gear and supported for reciprocal axial movement therein, wherein the proximal and distal drive gears have fixed axial positions relative to the longitudinal axis of the handle assembly and the proximal and distal drive sleeves have fixed angular positions relative to the longitudinal axis of the handle assembly, and wherein the proximal and distal drive sleeves are supported for reciprocal axial movement along a pair of laterally opposed cylindrical guide rods that extend parallel to the longitudinal axis of the handle assembly through corresponding circular apertures formed in each of the proximal and distal drive sleeves.

2. A steerable intravascular catheter as recited in claim 1 , wherein the proximal and distal drive gears are interlocked end to end with one another.

3. A steerable intravascular catheter as recited in claim 2 , wherein the distal drive gear has a polygonal belt extending about the circumference thereof for engaging a complementary shaped recess formed in an interior wall of the control knob.

4. A steerable intravascular catheter as recited in claim 1 , wherein the threaded bore of the proximal drive gear has a first thread pitch and the threaded bore of the distal drive gear has a second thread pitch that runs in a direction opposite the first thread pitch.

5. A steerable intravascular catheter as recited in claim 1 , wherein a proximal end of one of the pull wires is anchored to the proximal drive sleeve and a proximal end of the other pull wire is anchored to the distal drive sleeve.

6. A steerable intravascular catheter as recited in claim 1 , wherein the proximal end portion of the sheath extends entirely through the handle assembly and terminates at a sealed access port communicating with the central lumen defined by the tubular body.

7. A steerable intravascular catheter, comprising:

a) an elongated sheath having a tubular body wall defining a central lumen and a deflectable distal end portion;

b) a pair of laterally opposed elongated pull wires extending through the tubular body wall of the sheath and terminating within the distal end portion thereof;

c) a handle assembly having a longitudinal axis and operatively associated with a proximal end portion of the sheath, the handle assembly including a control knob configured for bi-directional angular rotation about the longitudinal axis of the handle assembly to control bi-directional angular deflection of the distal end portion of the sheath; and

d) a drive mechanism housed within the handle assembly for actuating the laterally opposed elongated pull wires in response to the bi-directional angular rotation of the control knob, the drive mechanism including a distal drive gear mounted for angular rotation about the longitudinal axis of the handle assembly, the distal drive gear having a threaded bore and a cooperating threaded distal drive sleeve positioned within the threaded bore of the distal drive gear and supported for reciprocal axial movement therein, the drive mechanism further including a proximal drive gear mounted for angular rotation about the longitudinal axis of the handle assembly, the proximal drive gear having a threaded bore and a cooperating threaded proximal drive sleeve positioned within the threaded bore of the proximal drive gear and supported for reciprocal axial movement therein, wherein the proximal and distal drive sleeves are supported for reciprocal axial movement on a pair of laterally opposed cylindrical guide rods that extend parallel to the longitudinal axis of the handle assembly through corresponding circular apertures formed in each of the proximal and distal drive sleeves.

8. A steerable intravascular catheter as recited in claim 7 , wherein the proximal and distal drive gears are interlocked end to end with one another, and the distal drive gear has a polygonal belt extending about the circumference thereof for engaging a complementary shaped recess formed in an interior wall of the control knob.

9. A steerable intravascular catheter as recited in claim 8 , wherein the threaded bore of the proximal drive gear has a first thread pitch and the threaded bore of the distal drive gear has a second thread pitch that runs in a direction opposite the first thread pitch.

10. A steerable intravascular catheter as recited in claim 9 , wherein a proximal end of one of the pull wires is anchored to the proximal drive sleeve and a proximal end of the other pull wire is anchored to the distal drive sleeve.

11. A steerable intravascular catheter as recited in claim 7 , wherein the proximal end portion of the sheath extends entirely through the handle assembly and terminates at a sealed access port communicating with the central lumen defined by the tubular body.