Control handle for a contact force ablation catheter
A control handle for a steerable catheter body for navigation of the catheter body through a biological lumen and manipulation at a treatment site. The control handle includes a housing assembly that houses a piston assembly and a resistance adjusting assembly. The resistance adjusting assembly can be adjusted to provide the desired frictional characteristics of the user for control of the resistance between the piston assembly and the housing assembly. In one embodiment, the piston assembly is configured to provide a frictional resistance that varies dynamically to substantially match the restorative force across the range of catheter tip deflection. Other embodiments include a vibrating member that provides tactile feedback to the operator to indicate conditions at the distal end of the catheter, such as contact force.
1. A control handle for a steerable catheter, comprising:
a housing assembly having a proximal portion and a distal portion and defining a central axis, said proximal portion defining a central bore concentric with said central axis, said central bore including radial step that defines a shoulder concentric about said central axis;
a resistance adjusting assembly including a threaded member that is threadably engaged with said housing assembly, said resistance adjusting assembly having a bearing surface that cooperates with said shoulder of said central bore to define a gland that is concentric about said central axis, said gland having a volume that varies with a position of said resistance adjusting assembly;
a deformable gasket disposed in said gland; and
a piston assembly disposed within said housing assembly, said piston assembly extending distally from said distal portion of said housing assembly, said piston assembly including a glide assembly within said central bore of said proximal portion and having an axial length along said central axis, said glide assembly being positioned so that said gland is radially adjacent said axial length of said glide assembly and in contact with said deformable gasket that causes a friction force on said glide assembly when said piston assembly is translated relative to said housing assembly, said friction force being variable with said volume of said gland.
2. The control handle of claim 1 , further comprising structure that defines a port on a proximal end of said proximal portion of said housing assembly, said port being concentric with said central axis and extending proximal to said shoulder of said central bore, said resistance adjusting assembly being disposed in said port.
3. The control handle of claim 2 , wherein said port includes a threaded portion that engages said resistance adjusting assembly.
4. The control handle of claim 1 wherein said gland is continuous.
5. The control handle of claim 1 , wherein said bearing surface of said resistance adjusting assembly is defined by a bushing, said bushing being operatively coupled with said threaded member.
6. The control handle of claim 5 , wherein said bushing is a washer.
7. The control handle of claim 1 , wherein said resistance adjusting assembly includes a bushing, said bushing defining said bearing surface.
8. The control handle of claim 1 , wherein said glide assembly includes an angled glide surface that is in contact with said deformable gasket.
9. The control handle of claim 8 , wherein said angled glide surface is defined by a frustum having a proximal end and a distal end, a said proximal end being of greater diameter than said distal end.
10. The control handle of claim 1 further comprising a tactile feedback device that generates a tactile sensation when energized.
11. The control handle of claim 10 wherein said tactile feedback device is a vibrating motor.