Spinal Rod Assembly for Distributed Pedicle Force Correction
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Solution Overview
Problem
Existing spinal fixation techniques often concentrate stress on a single pedicle, limiting manual adjustments and distribution of force across multiple pedicles, making it difficult to treat spinal deformities effectively.
Innovation Solution
A spinal correction assembly with lateral rods and cross-couplers that distribute force across multiple pedicles, allowing for manual adjustments and realignment of vertebrae through manipulation of cross-couplers and pedicle screws.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If a single rod is retained by only one pedicle screw per vertebra, then the rod can be easily retained and manipulated, but all force applied in reducing the rod is transferred mostly or entirely to one pedicle, limiting stress distribution
Solution Approach 1:
The patent divides the rod retention system into multiple independent pedicle screws, each capable of retaining the rod independently. This segmentation allows force to be distributed across multiple pedicles rather than concentrated on one, resolving the contradiction between ease of rod retention and stress distribution.
Solution Approach 2:
The patent combines multiple rod retention mechanisms (multiple pedicle screws) to work together in supporting the rod. By merging the retention function across multiple pedicles, the system achieves both ease of operation and improved stress distribution simultaneously.
2Stress or pressure
If two separate rods are used on opposite sides of the spine, then stress is distributed across multiple pedicles, but manual adjustments to individual vertebrae are inhibited
Solution Approach 1:
The patent introduces dynamic retention features that allow the rod to be manipulated and adjusted manually while maintaining stress distribution. The retention mechanism is designed to be movable and adjustable, enabling dynamic manipulation of individual vertebrae without compromising the stress-distributing architecture of multiple pedicle screws.
3Device complexity
If force is concentrated on one pedicle for rod retention, then the retention mechanism is simple, but the spinal deformity correction is less effective due to limited adjustment capability
Solution Approach 1:
The patent segments the retention function across multiple pedicle screws, creating a distributed system that maintains relative simplicity while significantly improving the effectiveness of spinal deformity correction through enhanced adjustment capabilities.
Solution Approach 2:
The patent changes the parameters of the retention mechanism by introducing multiple pedicle screws instead of a single screw, thereby altering the force distribution parameters and improving correction effectiveness without excessively increasing system complexity.
Data Source
AI summary
An assembly for correcting spinal deformities may include at least lateral rods extending across adjacent vertebrae to be retained at either end by pedicle screws. A cross-coupler may be coupled to each lateral rod, and a longitudinal rod may run along the spine and be coupled to the lateral rods by the cross-couplers. The assembly may be used to correct spinal deformities by manipulating the pedicle screws or cross-couplers to rotate about the lateral rods or the longitudinal rod.