Linear Actuator Disc Spacer for Vertebral Body Separation
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Solution Overview
Problem
Current disc spreaders for adjusting vertebral body spacing are limited by large delivery cannulas, increased surgical trauma, and risk of nerve damage due to rotating edges that can gouge endplates, requiring multiple tool exchanges and compromising fusion processes.
Innovation Solution
A sizing device with a distraction member and actuator system that allows for linear movement to adjust spacing between vertebral bodies, minimizing the need for large cannulas and reducing trauma by using a larger surface area contact and uniform force application, featuring a distraction member that moves between a first and second configuration with a constant force requirement.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Length of stationary object
If traditional manual spreaders with larger height are used to achieve proper vertebral body separation, then the spacing between adjacent vertebral bodies is improved, but the delivery cannula size must be increased and surgical trauma is worsened
Solution Approach 1:
The spreader is designed with a dynamic height adjustment mechanism that allows it to expand from a compressed delivery profile to a full working height after insertion. The actuator system enables the spreader height to be changed from a first configuration during delivery to a second configuration for vertebral separation, eliminating the need for large delivery cannulas while maintaining adequate separation capability
Solution Approach 2:
The spreader components are nested within each other during the delivery phase, with the distraction member and actuator components arranged in a compact configuration that fits through smaller cannulas. Once positioned, the nested components are deployed to achieve the full spreader height needed for vertebral body separation
2Length of stationary object
If traditional spreaders are rotated 90 degrees to re-orient the height dimension perpendicular to endplates, then proper spacing is achieved, but the rotating edge causes gouging and damage to endplates
Solution Approach 1:
Instead of rotating the spreader height dimension into contact with the endplates as in traditional designs, the invention inverts the approach by having the distraction member contact the endplates through its top and bottom surfaces in a non-rotated orientation. The height adjustment occurs through linear actuation rather than rotation, eliminating the gouging effect on endplates
Solution Approach 2:
The distraction member is designed with contact surfaces that are pre-configured to engage the endplates in a non-rotated orientation, eliminating the need for the damaging rotation maneuver. The actuator is pre-positioned to enable direct linear actuation that brings the distraction member into contact with endplates through their top and bottom surfaces
3Adaptability or versatility
If multiple spreaders with different heights are used to accommodate different spacing situations, then adaptability is improved, but the number of tool exchanges increases and risk of nerve damage is worsened
Solution Approach 1:
The spreader is designed as a universal device that can accommodate different spacing requirements through a single actuator system. The actuator can be adjusted to provide different distraction forces and distances, allowing one spreader to perform the function of multiple fixed-height spreaders, thereby eliminating repeated tool exchanges and reducing the risk of nerve root damage
Solution Approach 2:
The spreader incorporates a dynamic actuator system that can be adjusted during the procedure to provide different distraction amounts. This dynamic adjustability allows the single spreader to adapt to various spacing situations that would otherwise require multiple fixed-height spreaders, reducing tool exchanges and improving patient safety
4Length of stationary object
If larger spreaders are used to achieve adequate vertebral body separation, then spacing is improved, but the access site size must be increased and resection is worsened
Solution Approach 1:
The spreader employs a dynamic compression mechanism that allows it to be delivered through a smaller access site in a compressed state and then expanded to a larger working size after insertion. The actuator system enables the spreader to transition from a compact delivery profile to a full-size separation device, eliminating the need for a large access site while achieving adequate vertebral body separation
Solution Approach 2:
The spreader components are nested within each other during delivery, allowing the device to pass through a smaller access site. Once positioned between the vertebral bodies, the nested components are deployed to achieve the full spreader dimensions needed for adequate separation, thus reducing the required access site size
Data Source
AI summary
Devices are provided for measuring and/or adjusting the distance between two opposing surfaces of a work space, such as two vertebral bodies separated by a disc space. A sizing device may include at least one distraction member, an actuator, and an actuator controller. The actuator controller is movable to move the actuator, with movement of the actuator changing the height dimension of the distraction member. The amount of movement of the actuator controller is generally linearly related to the change of the height dimension of the distraction member throughout the entire range of motion of the actuator controller. The amount of expansion force applied by the distraction member is also generally linearly related to the amount of movement of the actuator controller.