DMLS Bone Screw With Porous Threads for Bone Integration
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Solution Overview
Problem
Existing bone screws lack effective structures and manufacturing methods to promote bone growth and are not optimally designed for fixation at the sacroiliac joint.
Innovation Solution
A bone screw manufactured via Direct Metal Laser Sintering (DMLS) using Titanium Alloy (Ti-6Al-4V) with a roughened surface, porous structures, and features like overhanging threads, windows, and permeable fills to enhance bone integration and growth, suitable for 3-D printing without post-printing machining.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If traditional manufacturing methods are used for bone screws, then manufacturing processes are simpler, but bone growth promotion and integration are insufficient
Solution Approach 1:
The bone screw incorporates porous structures and permeable fills within its threaded body to promote bone ingrowth and integration. These porous features allow bone cells to migrate through and onto the screw surface, enhancing biological fixation and long-term reliability of the implant.
Solution Approach 2:
The manufacturing process utilizes Direct Metal Laser Sintering (DMLS) with specific parameters (laser power, scan speed, layer thickness) to create a roughened surface texture and controlled porous structure. These parameter changes during manufacturing directly influence bone growth promotion while maintaining structural integrity.
2Strength
If conventional bone screw designs are used, then manufacturing is easier, but bone integration and growth are limited
Solution Approach 1:
The screw body incorporates porous structures and permeable fills that enable bone cells to penetrate and integrate with the implant. This porous architecture significantly enhances bone integration strength while being manufacturable through additive processes.
Solution Approach 2:
The patent introduces internal permeable fills and porous structures within the threaded body, adding a third dimension (internal porosity) beyond the traditional external threading. This dimensional addition promotes bone growth from multiple directions simultaneously, enhancing overall bone integration.
3Reliability
If traditional manufacturing methods are used, then production costs are lower, but quality consistency and surgical performance are reduced
Solution Approach 1:
The patent replaces traditional mechanical manufacturing processes (machining, milling) with Direct Metal Laser Sintering (DMLS), a additive manufacturing process. This substitution enables complex porous structures and consistent surface roughness to be built-in during manufacturing, improving surgical performance while reducing post-processing costs.
Solution Approach 2:
By controlling DMLS parameters (laser power, scan speed, layer thickness, support structure design), the manufacturing process achieves consistent surface roughness and porous structure characteristics. This parameter control ensures quality consistency across production batches while maintaining cost-effectiveness through automated additive manufacturing.
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 bone screw facilitates enhanced bone growth and integration, reduces manufacturing costs, and ensures consistent quality with improved surgical performance.
Implementation Method 1
manufactured via Direct Metal Laser Sintering (DMLS) using Titanium Alloy (Ti-6Al-4V)
Implementation Method 2
porous structures, and features like overhanging threads, windows, and permeable fills to enhance bone integration and growth
Data Source
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AI summary
A bone screw includes a screw body having a head at one end of the screw and a tip at an opposite end of the screw; head threads directly attached to the screw body and continuous around the head of the screw; tip threads directly attached to the screw body and continuous around the tip of the screw; and overhanging thread portions between the head threads and the tip threads, the overhanging thread portions spaced apart, with unthreaded channels between the overhanging thread portions and the overhanging thread portions overhanging a portion of the unthreaded channels.