Surgical Instrument Guide With Core Support for Thin-Wall Molding
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Solution Overview
Problem
Existing instrument guides for minimally invasive surgery, particularly those designed for single port access, face challenges in achieving sufficient length and thin walls while being suitable for injection molding, leading to issues like deformations, warp, and the need for larger cannula diameters.
Innovation Solution
The design incorporates a thick central core with symmetrically supported radial walls and varying wall thicknesses to facilitate injection molding, allowing for a smaller diameter instrument guide with channels for insufflation gas, ensuring structural integrity and manufacturability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If the walls of the instrument guide are made thin to reduce cannula diameter, then the cannula size is reduced and tissue trauma is minimized, but the plastic material hardens quickly within the thin wall during injection molding, making manufacturing difficult
Solution Approach 1:
The instrument guide employs varying wall thicknesses throughout its structure, with thinner walls in non-critical areas and thicker walls in areas requiring structural support or longer flow paths during injection molding. This local variation in thickness allows the part to be manufactured by injection molding while maintaining a small overall cannula diameter.
2Length of moving object
If the instrument guide is made long to support multiple instruments through a single cannula, then single port access is enabled, but the walls must be made thick to prevent deformations and warp during injection molding, which increases the required cannula diameter
Solution Approach 1:
The instrument guide uses non-uniform wall thickness distribution, with thicker sections strategically placed at critical locations prone to deformation or warp during cooling, while other sections maintain thinner walls to minimize overall diameter.
Solution Approach 2:
The design incorporates a thick central core that provides structural support along the length of the instrument guide, allowing the radial walls to be thinner while maintaining overall structural integrity. This dimensional approach separates the support function (core) from the guiding function (radial walls).
3Volume of moving object
If the walls of the instrument guide are made thin to reduce cannula diameter, then the incision size is reduced, but deformations such as shrinkage, warp, and surface irregularities occur during injection molding
Solution Approach 1:
The instrument guide employs varying wall thicknesses throughout its structure, with thinner walls in non-critical areas and thicker walls in areas requiring structural support or longer flow paths during injection molding. This local variation in thickness allows the part to be manufactured by injection molding while maintaining a small overall cannula diameter.
Data Source
AI summary
An instrument guide is removably inserted into a proximal portion of a cannula and extends to a distal end of the cannula to guide and support multiple surgical instruments within the cannula. The instrument guide is designed to be manufactured by injection molding of plastic material. The instrument guide includes a tube and several radial walls connected to the tube to form passageways within the tube. The radial walls are joined to a core where they intersect. The tube and radial walls have substantially the same wall thickness and the core has a minimum diameter that is substantially larger than the wall thickness to facilitate delivery of plastic material. Portions of the tube and radial walls are thinner than the general wall and rib thickness to form guideways that support surgical instruments within the passageways. Channels may be formed on an outside of the tube to deliver insufflation gas.