Surgical Instrument Coupling Interface for Repeatable 6-DOF Alignment
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Solution Overview
Problem
Current surgical navigation systems face precision issues due to overdetermined geometries in instrument-navigations array interfaces, leading to inconsistent and repeatable attachment challenges, which can result in navigational inaccuracies and increased costs.
Innovation Solution
A coupling assembly with a cylindrical surface and a prismatic surface, featuring a screw and pin configuration that restricts movement in all six degrees of freedom, ensuring a secure, repeatable, and precise relative position and orientation between the surgical instrument and the navigation array.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If overdetermined geometries with multiple contacting surfaces are used to connect the navigation array to the instrument, then the connection provides structural stability, but manufacturing tolerances and variations prevent perfect mating, leading to inconsistent and non-repeatable attachment precision
Solution Approach 1:
The coupling interface is segmented into two distinct components: a cylindrical surface component and a prismatic surface component. This segmentation allows each component to be manufactured with simpler, more controllable geometries that can be precisely mated without the complexity of overdetermined multi-surface contacts, thereby achieving repeatable attachment precision while maintaining structural stability.
Solution Approach 2:
The invention transitions from a planar multi-surface contact geometry to a three-dimensional cylindrical-prismatic interface. The cylindrical surface provides rotational symmetry and the prismatic surface provides linear constraint, creating a fully constrained rigid-body connection that eliminates the tolerance accumulation problems of overdetermined two-dimensional surface contacts.
2Manufacturing precision
If welding or integrally-forming the navigation array to the instrument is done, then high precision navigation is achieved, but the capability to decouple the array or couple it to other instruments is lost
Solution Approach 1:
The coupling interface is designed to be dynamically adjustable between coupled and decoupled states. The cylindrical-prismatic interface allows for repeated attachment and detachment operations while maintaining precise relative positioning when coupled, providing both the precision of a permanent connection and the versatility of a removable connection.
Solution Approach 2:
The cylindrical-prismatic coupling interface serves multiple functions: it provides precise positioning, allows decoupling and recoupling, and can accommodate different instruments. This universal interface replaces the need for separate dedicated instruments for standard and navigation use, thereby improving adaptability while maintaining precision.
3Adaptability or versatility
If dovetail or v-groove geometries are used for interchangeable connections, then the navigation array can be interchangeably attached with instruments, but the larger number of contacting surfaces compounds the risk of mechanical deformation and reduces navigation precision
Solution Approach 1:
The invention employs a cylindrical surface (curved geometry) instead of planar dovetail or v-groove surfaces. The cylindrical-prismatic interface reduces the number of contacting surfaces to essential constraint points, minimizing the areas susceptible to mechanical deformation while maintaining full interchangeability and high navigation precision through the curved-flat mating geometry.
Data Source
AI summary
Couplings disclosed herein can include a first coupling component having a cylindrical surface with a screw and a pin extending therefrom and a second coupling component having a prismatic surface with a first and a second through-hole. The first coupling component and the second coupling component can be configured such that relative motion between the first coupling component and the second coupling component can be restricted in all six degrees of freedom when the screw is engaged with the first through-hole to secure the cylindrical surface of the first component against the prismatic surface of the second component.