Expandable Intervertebral Implant with Actuator Screw
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Current intervertebral implants lack the ability to adjust height dynamically to accommodate varying spinal needs, which can lead to inadequate support and stability in degenerative conditions or spinal injuries.
Innovation Solution
An adjustable intervertebral implant with a design featuring moveable endplates connected by a frame and an actuator screw, allowing for expansion and contraction by rotating the screw, which moves a carriage relative to the endplates along ramps, enabling precise height adjustment.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a fixed-height intervertebral implant is used, then the implant structure is simple, but the implant cannot accommodate varying spinal needs and anatomical variations
Solution Approach 1:
The implant transitions from a fixed structure to a dynamic adjustable structure through the actuator screw mechanism that enables continuous height adjustment between minimum and maximum heights, allowing adaptation to varying spinal needs while maintaining structural integrity
Solution Approach 2:
The implant is divided into separable components including endplates, frame, actuator screw, and carriage, allowing the height adjustment function to be achieved through relative movement of these segments while keeping each component relatively simple in design
2Adaptability or versatility
If an adjustable height mechanism is added to the implant, then the implant can accommodate anatomical variations, but the device complexity increases
Solution Approach 1:
The complex multi-component actuation systems found in prior art are replaced with a simplified mechanical screw-thread mechanism that provides continuous height adjustment through rotation of the actuator screw, reducing the number of parts and simplifying the overall mechanism while maintaining adjustability functionality
Solution Approach 2:
The implant incorporates a dynamic adjustment capability through the actuator screw and carriage system that allows continuous height modification from minimum to maximum height, enabling adaptation to anatomical variations without requiring multiple fixed-size implants
3Ease of operation
If the actuator screw crosses between proximal and distal carriage sides, then the screw can be shorter, but the ramps cannot engage properly with ramped surfaces
Solution Approach 1:
The actuator screw is positioned in the transverse dimension (side-to-side) rather than extending longitudinally between proximal and distal ends, allowing the screw to engage the carriage through the transverse dimension while ramps engage ramped surfaces in the longitudinal dimension, effectively using a different spatial dimension to resolve the conflict between screw length and ramp engagement
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The implant provides continuous expansion and retraction capabilities, allowing for customized fit and support to restore disc space height, stabilize adjacent vertebrae, and accommodate anatomical variations, enhancing spinal stability and lordosis correction.
Implementation Method 1
an actuator screw rotatably connected to the frame; and a carriage (a) forming an open area aligned with the openings in the first and second endplates... (b) threadably connected to the actuator screw, whereby rotation of the actuator screw moves the carriage with respect to the frame and the first and second endplates
Implementation Method 2
including a plurality of ramps each mateable with at least one of the at least one ramped surfaces of the first and second endplates, wherein when the carriage is moved by rotation of the actuator screw, at least one of the at least one ramped surface of the first endplate and at least one of the at least one ramped surface of the second endplate each slide along at least one of the plurality of ramps of the carriage to cause the endplates to move relative to each other
Implementation Method 3
the implant further includes a polymeric material configured to press against the actuator screw to reduce a potential for unintended rotation of the actuator screw
Data Source
Figure 1~3
Figure 4~6B
Figure 7A~8
AI summary
An implant for therapeutically separating bones of a joint has two endplates each having an opening through the endplate, and at least one ramped surface on a side opposite a bone engaging side. A frame is slideably connected to the endplates to enable the endplates to move relative to each other at an angle with respect to the longitudinal axis of the implant, in sliding connection with the frame. An actuator screw is rotatably connected to the frame. A carriage forms an open area aligned with the openings in the endplates. The openings in the endplates pass through the carriage to form an unimpeded passage from bone to bone of the joint. The carriage has ramps which mate with the ramped surfaces of the endplates, wherein when the carriage is moved by rotation of the actuator screw, the endplates move closer or farther apart.