Percutaneous Interspinous Distractor with Rotating Stabilizers
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Solution Overview
Problem
Existing interspinous vertebral distractors face challenges with percutaneous implantation due to excessive size and complex mechanical structures, which hinder their effectiveness and ease of use, especially in lumbar-sacral regions and for patients with varying degrees of disc degeneration or scoliosis.
Innovation Solution
A percutaneously implantable interspinous distractor with mobile stabilizers that rotate from a closed to a spread apart position, allowing for easy insertion and stabilization within the interspinous gap, featuring a cam-shaped mechanism for adjustment and a compact design to accommodate different spinal deformities, enabling mini-invasive implantation and extraction.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the fixed portion of the stop members is made large to provide stable support, then the stability of the distractor is improved, but the device cannot be implanted percutaneously due to excessive size
Solution Approach 1:
The stop members are designed to be movable rather than fixed, allowing them to rotate between a closed position for percutaneous implantation and an open position for providing stable support. This dynamic transformation resolves the contradiction by enabling the same component to satisfy both size constraints during implantation and stability requirements during operation.
Solution Approach 2:
The distractor is divided into a central body and separate stop members that can be independently positioned. The stop members are initially retracted during implantation and then deployed after positioning, allowing the central body to remain compact while the stop members provide stability when needed.
2Volume of moving object
If the stop members are housed in a cylindrical body to reduce radial size, then the overall device size is reduced, but the mechanical complexity increases due to rotation mechanisms and slits
Solution Approach 1:
The stop members utilize a simple rotation mechanism about a pivot point, which is mechanically simpler than the complex slits and rotation mechanisms required by cylindrical housing. The dynamic opening and closing action is achieved through a straightforward hinge joint rather than complex mechanical constraints.
3Length of moving object
If the stabilizers are kept closed to maintain a compact profile, then the device can be percutaneously implanted, but the distractor cannot be stabilized within the interspinous gap
Solution Approach 1:
The stabilizers are designed as mobile components that can dynamically change their configuration from a closed, compact state during implantation to an open, spread-apart state for stabilization. This dynamic transformation allows the same component to satisfy both the size constraints for percutaneous access and the stability requirements for maintaining distraction.
Solution Approach 2:
The distractor is segmented into a central body and separate stabilizer components that can be independently positioned. The stabilizers are initially retracted along the longitudinal axis during implantation and then deployed laterally after positioning, allowing the central body to remain compact while the stabilizers provide stabilization when needed.
Data Source
AI summary
Interspinous distractor for percutaneous implantation comprising a central body (10) and two couples of stabilizears (14a, 14b; 14c, 14d), hinged at the end of the body (10) in order to rotate from a closed position, which assists the percutaneous implantation of the distractor, to a spread apart position, which limits its movement stabilizing it in the interspinous gap. Means are provided for causing the rotation of the stabilizears that can be operated percutaneously, in particular, by means of cam shaped elements sliding axially and adapted to engage a cam-shaped surface, or by a system of tie members, and special tools. With respect to the known distractors it can implanted end extracted percutaneously and in a much easier way.