Orthopedic Fixation Devices Bottom-Loading Tulip Assembly
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Solution Overview
Problem
Current orthopedic fixation devices for spinal stabilization often require larger tulip elements to accommodate larger bone fasteners, increasing inventory costs and complicating surgical procedures, while also limiting visualization and ease of surgery due to the need for top-loading bone fasteners.
Innovation Solution
The orthopedic fixation device features a bottom-loading mechanism with a locking clamp assembly that allows for the use of larger bone fasteners without increasing the tulip element size, enabling easier site preparation and improved visualization during surgery by allowing the tulip element to be attached to the bone fastener in situ, and facilitating more accurate pedicle decortication.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If larger tulip elements are used to accommodate larger bone fasteners, then the bone fastener can be securely retained, but the inventory costs increase and the tulip element size becomes unnecessarily large
Solution Approach 1:
The retention mechanism is segmented into multiple functional components: the tulip element provides the basic retention structure, while the locking clamp assembly (comprising clamp portions and a wedge element) provides the securing function. This segmentation allows the tulip element to remain compact while the locking mechanism ensures reliable bone fastener retention.
Solution Approach 2:
The locking clamp assembly introduces a new dimensional aspect to the retention system by adding radial clamping action through the wedge element. Instead of relying solely on the tulip element's internal diameter, the system uses the wedge element to apply radial force that secures the bone fastener head, effectively adding a second dimension of retention control.
2Ease of operation
If bone fasteners are top-loaded into the tulip element, then the assembly is straightforward, but the visualization and ease of surgery are reduced
Solution Approach 1:
The loading sequence is inverted: instead of inserting the bone fastener into the tulip element from above, the tulip element is placed over the bone fastener from below. This bottom-loading approach allows the surgical site to remain visible and accessible from the top, improving visualization while still achieving secure assembly through the subsequent locking clamp application.
Solution Approach 2:
The tulip element is preliminarily positioned on the bone fastener before the locking clamp assembly is applied. This preliminary action allows the surgeon to verify proper placement and alignment while maintaining full visualization of the surgical site, and then the locking mechanism is applied to secure the assembly.
3Device complexity
If a single tulip member is used in the fixation device, then the device is simpler, but it cannot accommodate multiple elongated rods for increased stability
Solution Approach 1:
The locking clamp assembly serves multiple functions: it secures the bone fastener to the tulip element, provides a platform for attaching one or more elongated rods, and allows for future expansion to accommodate additional rods. This multi-functional design enables a single tulip member to support both single-rod and multi-rod configurations, enhancing versatility without requiring fundamentally different device architectures.
Data Source
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AI summary
The present application is generally directed to orthopedic fixation devices that comprise a pre-assembled double headed tulip assembly (700), having two tulip elements (710) to receive rods (14), wherein the assembly is configured to receive a bone fastener (704) in at least one of the tulip elements. At least one of the tulip elements comprises a saddle (706) and a ring (708) to attach the double headed tulip to a bone fastener.