Threadless Spinal Implant for Stable Fixation Without Tissue Damage
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Solution Overview
Problem
Existing threaded spinal implants risk damaging nerves, blood vessels, and other tissues during implantation due to thread engagement, and can be improperly positioned, leading to implant malposition and instability.
Innovation Solution
A threadless friction fit surgical implant with roughened or porous surfaces for bone ingrowth, utilizing frictional pressure for immediate stabilization and bone growth for long-term stability, without the need for threads, and featuring varying cross-sectional areas, conical segments, and regions with graduated slopes to guide precise implantation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If threaded implants are used for spinal fixation, then immediate mechanical stability is achieved through thread engagement, but tissue damage to nerves, blood vessels and other structures occurs during implantation
Solution Approach 1:
The patent removes the threaded portion from the implant design entirely. Instead of using threads to achieve mechanical stability, the implant relies on a smooth cylindrical shaft that achieves fixation through friction fit and bone ingrowth into porous surfaces, thereby eliminating the harmful cutting action of threads on surrounding tissues.
Solution Approach 2:
The patent replaces the mechanical thread-engagement system with a friction-based fixation system. The smooth cylindrical surface creates frictional forces against the bone, while porous coatings enable biological bonding, substituting the traditional mechanical threading mechanism that causes tissue damage.
2Strength
If threaded implants are used for spinal fixation, then immediate mechanical stability is achieved, but implant malposition occurs due to thread engagement causing misdirection
Solution Approach 1:
By removing the threads entirely, the implant eliminates the directional forcing effect that threads have on insertion trajectory. The smooth cylindrical design allows the implant to follow the intended surgical path without being deflected by thread engagement with cortical bone, thereby improving positioning accuracy.
3Reliability
If roughened or porous surfaces are added to the implant, then long-term stabilization through bone ingrowth is achieved, but device complexity increases
Solution Approach 1:
The patent applies porous or roughened surface coatings to the cylindrical implant shaft. These porous structures provide pathways for bone ingrowth while maintaining the overall simple cylindrical geometry of the implant, achieving biological fixation without significantly increasing device complexity.
Solution Approach 2:
The patent applies different surface characteristics to different regions of the implant. The cylindrical shaft may have porous or roughened surfaces for bone ingrowth, while other regions maintain smooth surfaces for friction fit, creating localized functional zones without overall structural complexity.
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
The threadless implant achieves stable fixation by minimizing tissue damage and malposition risks, enhancing biomechanical strength through bone ingrowth and surface contact area, reducing the need for revision surgery.
Implementation Method 1
Long-term stabilization is achieved by either bone growth into the porous surface of the implant
Implementation Method 2
Immediate stabilization of the implant is achieved by frictional pressure
Implementation Method 3
addition of an adhesive, such as Polymethylmethacrylate, which interdigitates the porous surface of the implant with the subcortical bone
Data Source
AI summary
A threadless spinal implant suited for implantation or use in a mammalian spinal or other boney tissue.