Spinal Deformity Correction Instrument with Integrated Derotation and Rod Reduction
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Solution Overview
Problem
Current spinal surgery instruments and methods are inadequate for simultaneously performing segmental vertebral body alignment, en bloc derotation of multiple vertebral levels, reduction of fixation rods, and stabilization of corrected alignment, which are essential for effectively treating spinal deformities like scoliosis.
Innovation Solution
The development of an instrument system comprising inner and outer members with threaded sleeves and reduction blades that allow for controlled force application and rod reduction, along with alignment and derotation capabilities, enabling shared corrective forces across multiple vertebrae and segments, and stabilization through a system of brackets and cross-links.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If traditional spinal surgery instruments are used for segmental vertebral body alignment and derotation, then alignment can be achieved, but the surgical procedure becomes time-consuming and complex requiring multiple separate instruments
Solution Approach 1:
The patent combines multiple separate surgical instruments into a single integrated instrument system that performs segmental vertebral body alignment, derotation, and rod reduction functions. The instrument includes a derotation tube with alignment features and rod reduction capabilities integrated into one device, eliminating the need for multiple separate tools and reducing surgical time.
Solution Approach 2:
The instrument is designed with multi-functionality to perform various spinal deformity correction tasks including alignment, derotation, and rod reduction. The derotation tube incorporates alignment members, rod reduction mechanisms, and coupling features that enable it to serve multiple purposes in a single surgical procedure.
2Ease of operation
If multiple separate instruments are used for alignment and derotation, then specific functions can be performed, but the surgical procedure becomes more time-consuming
Solution Approach 1:
The patent merges alignment, derotation, and rod reduction functions into a single instrument system. The derotation tube integrates alignment members that guide vertebral positioning with rod reduction mechanisms, allowing all functions to be performed with one device rather than multiple separate instruments.
Solution Approach 2:
The instrument includes pre-configured alignment members and derotation features that are prepared in advance within the derotation tube. This preliminary arrangement of functional elements allows the surgeon to perform alignment and derotation operations sequentially without switching instruments, reducing procedural time.
3Ease of manufacture
If traditional instruments are used for rod reduction, then fixation rods can be reduced, but the risk of damage to implants and vertebrae increases due to high stresses
Solution Approach 1:
The patent introduces an intermediary reduction tube that facilitates rod reduction by distributing forces more evenly. The reduction tube includes a threaded sleeve and reduction blade mechanism that gradually reduces the rod diameter through controlled engagement, acting as a mediator between the rod and the vertebral implants to minimize stress concentration and damage risk.
4Productivity
If en bloc derotation of multiple vertebral levels is performed, then deformity correction is achieved, but control of corrective forces becomes more difficult
Solution Approach 1:
The instrument divides the derotation process into segmental vertebral levels while maintaining en bloc capability. The derotation tube includes multiple coupling portions that can engage with different vertebral levels independently, allowing the surgeon to control and apply corrective forces to each segment while achieving overall derotation of the spinal column.
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
This system simplifies spinal deformity correction by enabling en bloc derotation and positioning of vertebrae, reducing the complexity and risk of damage during surgery, while effectively maintaining corrected alignment and reducing fixation rods, thus improving surgical efficiency and post-operative stability.
Implementation Method 1
A threaded sleeve with an external thread and a thru-bore slides relative to the proximal portion of the inner member. The outer member couples with the proximal portion of the inner member and engages with the external thread to apply a reduction force to the threaded sleeve as the outer member rotates relative to the inner member.
Implementation Method 2
A reduction blade includes a proximal interlocking portion that removably couples with the threaded sleeve and a distal rod engagement feature configured to engage the fixation rod and transfer the reduction force to reduce the fixation rod into the spinal implant.
Implementation Method 3
A slot extends transversely through the coupling portion and is configured to guide a fixation rod into the spinal implant.
Data Source
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AI summary
An instrument for correction of spinal deformities includes an inner member with a proximal portion configured to receive a corrective force and a distal coupling portion configured to transfer the corrective force to a spinal implant in a vertebra. A slot extends transversely through the coupling portion and is configured to guide a fixation rod into the spinal implant. A threaded sleeve includes an external thread and a thru-bore that slides relative to the proximal portion. An outer member couples with the proximal portion and threadably engages the external thread to apply a reduction force as the outer member rotates relative to the inner member. A reduction blade includes a proximal interlocking portion that removably couples with the threaded sleeve and a distal rod engagement feature configured to engage the fixation rod and transfer the reduction force to reduce the fixation rod into the spinal implant.