Spinal Correction Device Using Ratchet Mechanism
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Solution Overview
Problem
Current surgical methods for correcting spinal deformities often result in limited correction during the procedure, permanent fusion of the spinal column, and subsequent loss of spinal motion, leading to increased mechanical loads on adjacent segments and wear.
Innovation Solution
A surgical device that allows relative rotation of adjacent vertebrae about a common axis in opposite directions, using a ratchet mechanism and bone fixing elements to gradually correct spinal deformities over time without fusion, allowing for progressive correction through daily activities and exercises.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If fixation implant devices with rigid rods are used to achieve permanent stabilisation, then the spinal deformity correction is achieved, but the spinal motion is permanently lost and mechanical loads increase on adjacent segments
Solution Approach 1:
The patent applies a dynamic ratchet mechanism that allows the spinal column to evolve from a fixed rigid structure to a dynamic system with controlled mobility. The ratchet permits rotation in one direction (corrective motion) while blocking the opposite direction, enabling the spine to adapt and move gradually during recovery while maintaining stability during correction.
Solution Approach 2:
The spinal column is divided into multiple segments with individual bone screws and rods, allowing each segment to move independently. This segmentation enables progressive correction of deformity at different levels while preserving overall spinal stability, avoiding the need for complete fusion of the entire spinal column.
2Productivity
If the entire correction is achieved during the surgical procedure, then the deformity is corrected, but no further degree of correction is possible thereafter
Solution Approach 1:
The ratchet mechanism enables the spinal column to transition from a static postoperative state to a dynamic recovery phase. The mechanism allows progressive correction to continue over time as the patient engages in daily activities, with the ratchet ensuring that corrective motion is permitted while preventing reversal of the correction.
Solution Approach 2:
The device enables continuous correction action to extend beyond the surgical procedure. The ratchet mechanism maintains the capacity for correction throughout the recovery period, allowing the spinal column to gradually achieve full correction through ongoing motion and loading during daily life activities.
3Force
If passive devices with springs or flexible rods are used, then corrective forces are generated, but the devices cannot provide for progressive correction assisted by active movements of the human body
Solution Approach 1:
The ratchet mechanism enables the spinal column to be self-correcting through the patient's own daily activities and movements. The mechanism allows the natural motions of walking, sitting, and other daily activities to contribute to progressive correction, eliminating the need for external active correction devices or procedures.
Solution Approach 2:
The device transitions from passive corrective forces (springs, flexible rods) to an active dynamic system where the ratchet mechanism responds to and utilizes the patient's natural movements. The ratchet allows corrective motion to occur spontaneously during daily activities while blocking reversal, enabling the body's own active movements to drive the correction process.
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
Enables gradual correction of spinal deformities while preserving spinal mobility, preventing the return of the spine to its curved form and distributing mechanical loads effectively to prevent device failure.
Implementation Method 1
a ratchet mechanism and bone fixing elements to gradually correct spinal deformities over time
Data Source
AI summary
The present invention relates generally to a surgical device for the correction of deformities of the spinal column and finds particular, although not exclusive, utility in devices which are surgically implantable. Presently known implantable surgical devices are unable to provide for the progressive correction of spinal deformities assisted by active movements of the human body without fusion of the involved part of the spinal column. The present surgical device comprises a spinal column straightening means for permitting the relative rotation of two substantially adjacent vertebrae about a common axis substantially only in opposite rotational directions.