Bone Screw Porous Surface Additive Manufacturing
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional surgical implant devices, such as pedicle screws, often lack adequate friction and surface area for bony fixation, ingrowth, and purchase, leading to instability and potential delamination of friction coatings over time.
Innovation Solution
A bone screw with a porous surface formed through additive manufacturing, such as 3D printing, which covers at least a portion of the threads, providing enhanced bony fixation, ingrowth, and purchase, and optionally includes needle-like protrusions or lattice structures for increased surface area and stability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of stationary object
If conventional subtractive manufacturing processes are used to create friction surfaces, then manufacturing is simpler, but the surface area for bony fixation is insufficient
Solution Approach 1:
The patent applies porous materials by creating a porous surface layer on the bone screw threads through additive manufacturing. This porous structure dramatically increases the surface area available for bony fixation and ingrowth, directly resolving the contradiction between needing more surface area and maintaining manufacturing simplicity. The porous structure is formed by selective deposition of material during the additive manufacturing process.
Solution Approach 2:
The patent transitions from conventional two-dimensional friction surfaces to a three-dimensional porous surface structure. By adding the vertical dimension through porous protrusions and lattice structures, the surface area for bone contact is exponentially increased without proportionally increasing the overall device complexity, as the porous structure is integrated into the manufacturing process.
2Reliability
If friction coatings are applied to enhance surface area, then bony fixation is improved, but the coatings may delaminate and fail over time
Solution Approach 1:
The patent merges the friction surface and the structural surface into a single integrated porous surface. Instead of applying a separate friction coating layer that could delaminate, the porous friction surface is created as an integral part of the bone screw through additive manufacturing. This eliminates the interface between coating and substrate that causes delamination, directly improving reliability.
Solution Approach 2:
The porous material structure provides mechanical interlocking with the bone, creating a reliable fixation that does not depend on adhesive coatings. The porous structure allows bone ingrowth and creates friction through its three-dimensional architecture, providing durable fixation without the risk of coating delamination.
3Reliability
If mechanically-manufactured friction surfaces with teeth or grooves are used, then some friction is provided, but they do little to promote bony fixation and ingrowth
Solution Approach 1:
The patent uses a porous surface structure with controlled pore sizes and distributions that actively promote bony fixation and ingrowth. Unlike smooth or mechanically grooved surfaces, the porous structure provides numerous nucleation sites for bone apposition and allows bone cells to infiltrate and grow into the structure, directly enhancing bony fixation reliability.
Solution Approach 2:
The patent applies local quality by creating regions of different porous structures on different portions of the bone screw. The porous surface is selectively applied to the threaded portion where bone contact occurs, while maintaining a smooth or different structure elsewhere. This localized porous structure optimizes bony fixation where needed without unnecessarily complicating the entire device.
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 porous surface enhances the stability and durability of the bone screw by promoting bony integration and reducing the risk of coating delamination, while being economical to manufacture.
Implementation Method 1
The porous surface is formed by a conventional or novel additive manufacturing process, such as three-dimensional (3D) printing or the like
Data Source
AI summary
The present invention provides a bone screw or bone anchor, such as a threaded pedicle screw or the like, incorporating a porous surface for enhancing bony fixation, ingrowth, and purchase when implanted in bone. Preferably, this porous surface covers at least a portion of the threads of the bone screw or bone anchor. The porous surface is formed by a conventional or novel additive manufacturing process, such as three-dimensional (3D) printing or the like, optionally as well as a prior and/or subsequent machining process. The porous surface may include novel needle-like protrusions and/or lattice structures, and/or any other protruding/depressed features, whether regular or irregular.