Bi-directional Fixating Transvertebral Screws for Spinal Fusion
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Solution Overview
Problem
Current spinal fusion techniques, particularly those using pedicle screw fixation and anterior vertical plating, are associated with complications such as pseudoarthroses, neural and vascular injuries, excessive blood loss, prolonged recovery, and increased risk of adjacent segment disease, due to their rigidity and invasive nature.
Innovation Solution
The use of bi-directional fixating transvertebral (BDFT) screws, which can be strategically inserted to link vertebral bodies across the intervertebral space, providing strong segmental fusion while preserving posterior joint mobility, combined with novel zero-profile mini-plates and calibrated facet stapling to enhance stability and flexibility.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If pedicle screw fixation and anterior vertical plating are used to achieve strong spinal fusion, then fusion strength and stability are improved, but the risk of neural and vascular injuries, excessive blood loss, and prolonged recovery increases
Solution Approach 1:
The invention divides the fixation system into multiple components: BDFT screws for vertebral body anchoring, zero-profile miniplates for lateral stabilization, and facet stapling devices for posterior joint fixation. This segmentation allows each component to perform its specific function with minimized invasive impact on neural and vascular structures.
Solution Approach 2:
Instead of using traditional anterior vertical plating that requires extensive dissection and carries high risk of vascular injury, the invention inverts the approach by using BDFT screws inserted through safer trajectories combined with zero-profile miniplates that provide equivalent or superior stabilization without the harmful side effects.
2Stability of the object's composition
If traditional anterior vertical plating is used for cervical fusion, then anterior column stability is improved, but esophageal compression and vascular injuries occur
Solution Approach 1:
The invention replaces traditional anterior vertical plating with BDFT screws and zero-profile miniplates, inverting the conventional approach to achieve anterior column stability without the need for large anterior plates that compress the esophagus and risk vascular injury.
Solution Approach 2:
The zero-profile miniplates are designed to be locally adapted to the vertebral anatomy, providing stabilization only where needed without creating global anterior compression that would affect the esophagus. The plates conform to the lateral vertebral surfaces without protruding into the anterior spinal space.
3Reliability
If rigid fixation systems are used to prevent pseudoarthroses, then fusion reliability is improved, but adjacent segment disease and need for re-operations increase
Solution Approach 1:
The BDFT screw system incorporates dynamic elements that allow controlled micromotion at the fusion interface while maintaining overall stability. The facet stapling device provides calibrated motion restriction rather than complete rigid fixation, allowing physiological movement that prevents stress concentration at adjacent segments.
Solution Approach 2:
The invention changes the fixation parameters from rigid, high-stiffness constructs to a more compliant system with controlled flexibility. The facet stapling device allows calibrated degrees of motion, and the BDFT screws provide stable but not overly rigid anchoring, creating a balance that protects adjacent segments while ensuring fusion reliability.
4Ease of operation
If extensive muscle retraction is performed to access vertebral structures, then surgical exposure is improved, but blood loss and recovery time increase
Solution Approach 1:
The invention extracts the need for extensive muscle retraction by using percutaneous or minimally invasive approaches to insert BDFT screws and apply zero-profile miniplates. The surgical exposure is minimized to only what is necessary for safe screw insertion, eliminating the need for large muscle dissections required by traditional plating systems.
Data Source
AI summary
An apparatus and method for joining members together using a self-drilling screw apparatus or stapling apparatus are disclosed. The screw apparatus includes a shell and first and second first screw members having tapered ends and threaded bodies that are disposed within the shell. A drive mechanism rotatably drives the first and second screw members from the shell in opposite directions and causes the screw members to embed themselves in the members to be joined. The screw apparatus can be used to join members such as bones, portions of the spinal column, vertebral bodies, wood, building materials, metals, masonry, or plastics. The stapling apparatus includes first and second lever arms rotatably joined together at a fulcrum, and the lever arms rotate in opposite directions. First and second cartridges are disposed at the ends of the lever arms. Each cartridge is capable of holding a staple including a bracket, a nail member and an alignment slot. When the ends of the lever arms are rotated towards each other the staples from the cartridges are interlocked. The staples can be also be used to join members such as bones, portions of the spinal column, or vertebral bodies.