Spinal Implant Attachment System Preventing Screw Backout
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Solution Overview
Problem
Spinal implants often experience screw loosening or backout over time due to subsidence, leading to improper fusion, loss of stability, and the need for costly and painful revision surgeries.
Innovation Solution
A spinal implant assembly with an attachment system featuring fixation screws and a locking plate with pins or plugs that secure the screws, allowing for toggle and nutation to prevent backout and accommodate subsidence, while providing rigid fixation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If rigid fixation is provided to ensure immediate stability, then stability is improved, but screw loosening or backout occurs over time due to subsidence
Solution Approach 1:
The fixation element incorporates a toggle mechanism that allows dynamic adjustment. The fixation element can toggle between different positions within the bone cavity, enabling it to adapt to subsidence while maintaining secure fixation. This dynamic capability prevents screw loosening by allowing controlled movement rather than rigid constraint.
Solution Approach 2:
The system changes the state of fixation from rigid to controlled-movable. The fixation element is designed to change its position parameter within the bone cavity, allowing it to accommodate subsidence through controlled toggling rather than maintaining a fixed position. This parameter change enables the system to adapt to changing conditions over time.
2Stability of the object's composition
If fixation elements are rigidly fixed to the implant, then immediate stability is achieved, but the implant cannot accommodate subsidence without causing loosening or damage
Solution Approach 1:
The fixation element provides immediate stability through initial rigid fixation, then transitions to a dynamic state where it can toggle within the bone cavity. This allows the system to accommodate subsidence while maintaining overall stability, resolving the contradiction between immediate stability and long-term adaptability.
3Strength
If screws are securely locked in place, then fixation strength is improved, but the system cannot accommodate implant settling without risking loosening
Solution Approach 1:
The fixation element maintains strong fixation through secure engagement with the bone cavity while incorporating the ability to dynamically toggle to different positions. This allows the system to accommodate implant settling and subsidence while maintaining fixation strength, as the element can adjust its position rather than being locked in a single rigid position.
Data Source
AI summary
The embodiments of the present disclosure relate to a spinal implant assembly having features to prevent or minimize fixation elements, such as screws, from being dislodged, or from backing out over time and with use. The spinal implant assembly may comprise an implantable body having first apertures for receiving fixation elements. A plate configured to nest against the posterior portion of the implantable body and comprising one or more second apertures can be provided. These second apertures permit access to the head portions of the fixation elements. One or more locking elements are then passed through the second apertures and engage the head portions of the fixation elements. In addition, the plate may comprise an adjustable arm to allow the plate to be used with implantable bodies of different size.