Coaxial Dual Component Locking Screw for Bone Fixation
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Solution Overview
Problem
Existing bone screws lack sufficient resistance to migration and pull-out after implantation, particularly in applications such as sacroiliac joint fusion and spine fusion surgery.
Innovation Solution
A coaxial dual component locking screw comprising a screw component with a thread extending from its tip to head, and a housing component with sidewalls featuring slits corresponding to the thread pitch, providing resistance to migration and pull-out by protruding thread through the slits.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a traditional single-component bone screw is used, then the implantation process is simple, but the resistance to migration and pull-out is insufficient
Solution Approach 1:
The bone screw is divided into two separate components: a screw component with external threads and a housing component with internal threads and slits. This segmentation allows each component to have specialized functions - the screw provides anchoring while the housing provides locking through slit engagement with protruding threads, thereby improving resistance to migration and pull-out without requiring a overly complex single-component design
Solution Approach 2:
The screw component is nested within the housing component, with the screw inserted through the housing. The housing contains the screw while allowing its thread to protrude through the slits. This nested configuration enables the smaller screw to provide anchoring function while the larger housing provides the locking mechanism, achieving enhanced reliability through coordinated action of nested components
2Reliability
If the thread protrudes through the slits to provide resistance, then pull-out resistance improves, but the risk of bone damage during insertion increases
Solution Approach 1:
The housing component is inserted into the bone void space first, establishing the external framework before the screw component is inserted. This preliminary action allows the housing to prepare the insertion path and provide structural support, enabling the subsequent screw insertion to proceed with reduced risk of bone damage while still achieving the desired thread protrusion for pull-out resistance
Solution Approach 2:
The housing component acts as an intermediary between the screw component and the bone. It receives the screw, allows controlled thread protrusion through its slits, and distributes mechanical stresses. This intermediary structure enables the thread to protrude for pull-out resistance while the housing protects the bone from direct damage during insertion and loading
Data Source
AI summary
A coaxial dual component locking screw includes a screw component and a housing component. The screw component includes a thread extending at least a portion of the length from the tip to the head and the housing component includes each having a plurality of wherein the slits of the housing component are adapted to correspond to a pitch of the thread of the screw component. When the screw component and the housing component are engaged, the thread of the screw component protrudes through the slits and provides resistance to migration and pull out of the coaxial dual component locking screw when implemented in a bone.