Facet Fixation Guide With Wire Collet Segmentation
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Solution Overview
Problem
Conventional facet joint fixation devices, such as screws, often loosen or fracture and can be difficult to place optimally, limiting their effectiveness in stabilizing spinal facet joints during surgical procedures.
Innovation Solution
A facet fixation device featuring an anchor screw secured to a pedicle with a wire drawn through an adjacent pedicle and attached using a collet assembly, allowing for dynamic stabilization and motion preservation, and optionally combined with a threaded screw for cannulated guidance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional facet screws are used for fixation, then the facet joint can be immobilized, but the screws may loosen or fracture and are difficult to place optimally
Solution Approach 1:
The fixation system is divided into separate components: an anchor screw that provides stable purchase in the pedicle, and a separate wire that can be independently directed through the facet joint. This segmentation allows each component to be optimized for its specific function - the anchor for stability and the wire for precise joint targeting.
Solution Approach 2:
A wire is introduced as an intermediary element that connects the anchor screw to the facet joint. The wire serves as a mediator that can be precisely directed through bone tunnels to achieve optimal facet joint fixation, overcoming the trajectory limitations of direct screw placement.
2Stability of the object's composition
If conventional facet screws are used, then immobilization is achieved, but the device complexity increases due to trajectory requirements
Solution Approach 1:
By separating the anchoring function (anchor screw in pedicle) from the joint fixation function (wire through facet), the system simplifies the trajectory requirements. The anchor screw follows a straightforward pedicle trajectory, while the wire can be independently directed through bone tunnels to the facet joint, reducing overall procedural complexity.
3Productivity
If minimally invasive approach is used, then surgery time and hospitalization are reduced, but placement precision may be compromised
Solution Approach 1:
Bone tunnels are pre-formed through the pedicles before wire insertion. This preliminary action creates predetermined pathways that guide the wire to the facet joint, ensuring precise placement while maintaining the minimally invasive nature of the procedure. The pre-prepared tunnels eliminate the need for complex real-time trajectory adjustment.
Data Source
AI summary
A facet fixation device formed from an anchor screw and a collet or facet screw that is secured to adjacent pedicles. The anchor screw has an aperture for receipt of a first end of a guide wire or polyaxial based facet screw. The collet includes a unidirectional attachment mechanism wherein a wire can be drawn to a desired position to fix the distance between the anchor screw and the collet. Excess wire can then be removed.