Expandable Spinal Jack With Stepped Pins for Post-Implant Adjustment
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Solution Overview
Problem
Existing spinal jack designs lack the ability to adjust and secure positioning support between succeeding spinal vertebrae in a minimally invasive manner, especially for future re-adjustment to compensate for vertebral complications post-implantation.
Innovation Solution
An adjustable spinal jack with gripping portions and spring-actuated pins or gears that allow for telescopic expansion and adjustment between vertebral processes, using medical-grade materials and optional screw fixation or crimping for secure attachment, enabling repositioning without invasive procedures.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a fixed spinal jack design is used, then the structure is simple and easy to manufacture, but it cannot be adjusted post-implantation to compensate for vertebral complications
Solution Approach 1:
The spinal jack is divided into multiple segments including upper and lower bodies, stems, sleeves, and adjustable components. This segmentation allows independent adjustment of each segment while maintaining overall structural integrity, enabling post-implantation adaptability without requiring complete device replacement
Solution Approach 2:
The spinal jack incorporates dynamic adjustment mechanisms including spring-actuated pins, threaded stems, and gear systems that allow the device to transition from a fixed state during implantation to an adjustable state post-implantation. The ratcheting mechanism enables one-way adjustment while maintaining position, providing both flexibility and stability
2Ease of operation
If traditional spinal jack designs are used, then the implantation procedure is straightforward, but re-adjustment requires invasive procedures
Solution Approach 1:
The spinal jack incorporates self-adjustment mechanisms where the device can be re-positioned using its own integrated adjustment mechanisms. The external adjustment tool interfaces with the gear system to rotate stems and reposition the jack, allowing the device to serve itself for re-adjustment without requiring surgical exposure or invasive procedures
Solution Approach 2:
An external adjustment tool acts as an intermediary between the surgeon and the spinal jack's internal adjustment mechanisms. This tool transmits rotational force to the gear system, enabling non-invasive adjustment of the jack's position and configuration while maintaining secure engagement with the vertebral processes
3Strength
If the gripping portions are made smooth for easy insertion, then the insertion is easier, but the gripping strength and stability are reduced
Solution Approach 1:
The gripping portions feature localized textured surfaces with increased friction characteristics applied only to the specific areas that contact the vertebral processes. This local application of texture provides enhanced gripping strength exactly where needed while maintaining smoother surfaces in other areas for easier insertion and reduced tissue irritation
Solution Approach 2:
The gripping portions incorporate curved and contoured surfaces that conform to the natural geometry of vertebral processes. These curved surfaces increase contact area and distribute pressure evenly, enhancing gripping strength through geometric adaptation rather than relying solely on surface roughness
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
Provides stable and adjustable inter-vertebral support that can be reconfigured post-implantation to accommodate spinal changes, ensuring effective stabilization and alignment.
Implementation Method 1
A pair of spring actuated and stepped pins are incorporated into the lower jack body and, when inwardly actuated, engage recessed locations configured along the stems
Implementation Method 2
One or more outward biasing springs are seated within pockets in the lower body for upwardly displacing the stems and upper jack body
Implementation Method 3
The pockets each further include textured surfaces for providing additional gripping of the vertebral processes
Implementation Method 4
Additional gears are actuated by the outer bevel gears and in turn engage any of opposing teeth or threads configured into the extending stems
Data Source
AI summary
A spinal jack adapted for installation between first and second vertebral processes and including an upper spinal jack body and a lower spinal jack body having gripping portions adapted for engaging the vertebral processes. A pair of upwardly extending sleeves are integrated into the lower spinal body and coaxially receive a pair of downwardly extending stems integrated into the upper spinal body. A pair of spring actuated and stepped pins are incorporated into the lower jack body and, when inwardly actuated, engage recessed locations configured along the stems in order to define an adjusted separation distance between the bodies. In a second variant, a rotatable gear is incorporated into one of the bodies and engages a pair of outer beveled gears, with additional gears actuated by the outer bevel gears and in turn engaging any of opposing teeth or threads configured into the extending stems in order to define an adjusted separation distance between the bodies.