designed
by
Sam

Pathfinder

Company
  • JEB Technologies Ltd
Category
  • Industrial Design
  • Usability
  • Prototyping
  • Design Engineering
  • CAD/SolidWorks
  • DFMA
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Project Summary

Pathfinder is a Class IIb medical device I worked on during my time at JEB. The current state of the art for fistula treatment is the "Lockhart Mummery Probe" which is over 100 years old. The idea for this device was conceived by a clinician who we worked closely with. The main function of the device is to deploy a seton which allows the fistula to drain fluid and therefore promote healing. The main components to Pathfinder are the seton, the probeshaft which pulls the seton through the fistula, and the handle which helps the clinician to guide the probeshaft along the fistula tract. The probeshaft has 3 internal bores - one to carry hydrogen peroxide which bubbles at the internal fistula opening, and the other two for the insertion of 'd-wires' which can be withdrawn and reinserted to adjust the flexibility of the probeshaft, aiding tract navigation.

I joined the project part way through its development and worked to overcome some major usability and performance issues with the device at the time. As the primary interface for the user, the handle was completely redesigned from something that was unreliable and allowed for subjectivity to a design that is intuitive and that provides confidence to the user.

Sketches of some handle design ideas with alternative locking mechanisms.
Further sketches of handle design ideas focusing on a hinge and button release mechanism with a flexible insert to grip the probeshaft.
Development sketches considering alternative ways to grip the probeshaft. The main challenge to overcome was providing enough torsional grip whilst accomodating two different probeshaft diameters.
Further development and detailed design sketches with a brief exploration of alternative forms.
Utilising surface and parametric modelling in SolidWorks allowed for a design where form complimented function.
Sketches of the final handle design idea. The hexagonal outer profile of the probeshaft sitting in the v-shaped slot and the elastic deformation of the handle's bottom surface both work together to provide plenty of torsional grip, aiding fistula negotiation.
The wire hubs are the main interface by which the user removes and reinserts the d-wires to adjust the flexibility of the probeshaft. The sketches show some of the form exploration for the wire hubs.
The wire hub was surface modelled to achieve an organic and comfortable to grip shape.
3D printing iterations enabled early stage user studies to be conducted and the handle design to be continually improved.
Render of the handle from the top. Features include surface texture to optimise grip in an operating theatre environment, lock/unlock symbols, and a simple button release mechanism.
Render of the handle from the bottom. Features include matching surface texture, cut-outs for all undercuts to keep the injection mould tooling simple, and a flexible bottom surface that automatically grips the probeshaft and also allows the user to squeeze and provide additional grip.
Render of the handle from the side showing how it opens and closes. Pushing the button forwards unlocks the handle. Pushing the top of the handle down locks it and an audible click provides user confidence.