Bone Plate Captive Clips for Post-Operative Angulation
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Solution Overview
Problem
Current orthopaedic fixation systems, particularly for the spine, lack the ability to allow post-operative angulation and movement, such as translational and rotational settling, while resisting fastener back-out, which is crucial for effective compression and stability post-surgery.
Innovation Solution
A fixation system comprising a plate with undercut fixation holes and resilient clips that permit fastener toggling and sliding, utilizing a perimetral groove on the fastener head to secure the clip and prevent back-out, while allowing for limited angular movement.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If a fastener is rigidly secured to the bone plate through threading, then the fastener is firmly fixed to the plate, but the fastener cannot allow post-operative angulation or movement
Solution Approach 1:
The fixation system transitions from a static rigid connection to a dynamic adjustable connection. The fastener head can rotate within the fixation hole and the clip can slide along the fastener shaft, allowing the system to adapt to post-operative settling and angulation requirements while maintaining secure fixation.
Solution Approach 2:
The system allows changes in angular parameters and positional parameters after surgery. The fastener can be angulated at different angles relative to the plate, and the clip position can be adjusted along the shaft, enabling the fixation construct to accommodate physiological changes during healing.
2Adaptability or versatility
If a bushing is used to permit polyaxial movement of the fastener, then post-operative angulation is allowed, but the fastener cannot be secured against back-out
Solution Approach 1:
The resilient clip acts as an intermediary component between the fastener and the bone plate. It provides the locking function that was missing in pure polyaxial bushing systems, while still allowing the fastener to be inserted and angled before final securing.
Solution Approach 2:
The fixation system is divided into functional segments: the bushing handles polyaxial movement and angulation, while the resilient clip handles securement and back-out prevention. This segmentation allows each component to optimize its specific function without compromising the other.
3Reliability
If a resilient clip is used to secure the fastener, then back-out is prevented, but the fastener cannot slide or toggle within the plate hole
Solution Approach 1:
The clip design incorporates dynamic elements that allow movement during insertion and adjustment, then provide stability during final fixation. The clip can slide along the fastener shaft during insertion but engages the perimetral groove to prevent back-out during the healing process.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
Enables post-operative angulation and movement of fasteners, facilitating vertebral body compression and stability by allowing translational and rotational settling while preventing fastener back-out, thus enhancing surgical outcomes.
Implementation Method 1
At least one resilient clip is disposed in at least a portion of the undercut, with the at least one clip having a pair of generally parallel sides and an end tab
Data Source
AI summary
A fixation system includes a plate comprising a top surface, a bottom surface, a central longitudinal axis, at least one fixation hole extending between the top and bottom surfaces and comprising an undercut therein, and at least one passage intersecting one of the undercuts. At least one resilient clip is disposed in at least a portion of the undercut, with the at least one clip having a pair of generally parallel sides and an end tab. At least one fastener is provided and comprises a head and a threaded shaft, with the head comprising a perimetral groove extending around at least a portion thereof and an instrument receiving portion. The at least one clip is configured and dimensioned to seat in the undercut with the end tab extending within the passage, and the at least one fastener is configured and dimensioned to be received in the at least one fixation hole and securable therein when the at least one clip abuts the perimetral groove of the head.