Spinal Interbody Plate Polyaxial Attachment Mechanism
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Solution Overview
Problem
Current spinal implant systems face challenges in stabilizing interbody devices between vertebrae, particularly in preventing expulsion and managing movement impacts, which can lead to bone screw backout and suboptimal plate positioning.
Innovation Solution
A spinal implant system featuring a rotatable attachment member coupled to a plate, allowing polyaxial rotation and adjustable positioning relative to the interbody device, which can be inserted at a desired depth and angle to minimize movement and prevent expulsion, using biocompatible materials like titanium and PEEK.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If a rigid plate is used to stabilize the spine, then the spine is stabilized, but movement of the interbody device asserts impact forces on the plate causing bone screws to back out
Solution Approach 1:
The attachment member incorporates a polyaxial rotation mechanism that allows dynamic adjustment of the interbody device relative to the plate. This dynamic capability absorbs impact forces through controlled movement about three axes, preventing force transmission to the bone screws while maintaining overall spinal stabilization.
Solution Approach 2:
The attachment member serves as an intermediary element between the rigid plate and the interbody device. It mediates the interaction by providing a rotationally compliant connection that decouples the rigid plate from the potentially moving interbody device, thereby protecting the bone screws from impact forces.
2Stability of the object's composition
If the interbody device is firmly attached to the plate, then the interbody device is stabilized, but the plate cannot be positioned optimally after insertion
Solution Approach 1:
The attachment member enables dynamic positioning by allowing polyaxial rotation after the interbody device is inserted. The surgeon can adjust the plate's position and orientation relative to the interbody device by rotating the attachment member about multiple axes, achieving optimal positioning while maintaining firm attachment.
Solution Approach 2:
The attachment member is designed with pre-configured rotational degrees of freedom that are activated after interbody device insertion. This preliminary design allows the surgeon to perform positioning adjustments post-insertion without requiring additional fixation steps or complex assembly procedures.
3Reliability
If bone screws are used to attach the interbody device to the vertebrae from the back, then the interbody device is secured, but the patient must be opened on both anterior and posterior sides
Solution Approach 1:
The system merges the functions of anterior interbody device placement with posterior plate stabilization into a single integrated construct. The attachment member couples the anteriorly placed interbody device to the posterior plate, allowing both functions to be achieved through one surgical approach rather than requiring separate anterior and posterior procedures.
Solution Approach 2:
The attachment member serves multiple functions: it secures the interbody device to the plate, provides polyaxial rotation capability, and enables positioning adjustment. This multi-functionality eliminates the need for separate bone screws to attach the interbody device to the vertebrae from the posterior side, simplifying the surgical approach.
4Volume of moving object
If the interbody device is placed close to the plate, then the construct is compact, but the interbody device may be expelled
Solution Approach 1:
The polyaxial rotation mechanism allows the interbody device to move dynamically relative to the plate within controlled boundaries. This dynamic capability accommodates physiological movements and prevents stress concentration that could lead to expulsion, while the attachment member's structural design maintains adequate spacing to prevent direct contact and potential expulsion.
Data Source
AI summary
Embodiments of the present invention provide spinal implant systems and methods. According to one embodiment, a plate attached to one or more vertebrae can prevent expulsion of an interbody device from a disc space. The plate and interbody device can be coupled by an attachment member. According to one embodiment, the attachment member is coupled to the plate and includes a portion inserted in a threaded or non-threaded cavity. Preferably, the coupling between the plate and attachment member allows rotation in three dimensions thereby allowing the plate to rotate relative to the interbody device. This allows the plate to be better positioned for attachment to the spine during an operation.