Flexible Bone Screw Curved Path Fixation
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Solution Overview
Problem
Conventional orthopedic bone plates require extensive surgical exposure and carry a high risk of infection due to protruding elements, necessitating a solution that minimizes exposure and reduces infection risk during bone healing.
Innovation Solution
A bone screw with a distal threaded portion and a mid-proximal portion of varying bending stiffness, allowing the screw to follow a curved path within the bone, thereby reducing the need for extensive exposure and minimizing the risk of infection, while providing stable fixation of bone fragments.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If bone plates are used to repair fractures, then bone stabilization is achieved, but extensive surgical exposure is required and infection risk increases
Solution Approach 1:
The bone screw utilizes a flexible threaded distal portion that can navigate curved intramedullary canal paths without requiring extensive surgical exposure. This flexibility allows the device to be implanted through minimal incisions, eliminating the need for large exposure windows required by traditional bone plates, thereby reducing infection risk while maintaining stabilization reliability
2Reliability
If bone plates are used to repair fractures, then bone stabilization is achieved, but surgical exposure time and healing duration increase
Solution Approach 1:
The flexible threaded portion allows the screw to be inserted through the intramedullary canal following curved paths without requiring extensive surgical exposure or bone resection. This minimizes surgical time and allows for quicker patient recovery compared to traditional bone plate fixation that requires wide exposure of the fracture site
3Strength
If a rigid screw is used for bone fixation, then strong fixation is provided, but the screw cannot accommodate curved bone paths
Solution Approach 1:
The bone screw is divided into distinct functional segments: a flexible threaded distal portion for navigating curved intramedullary paths and a stiffer proximal portion for providing stable fixation in the proximal bone. This segmentation allows each portion to perform its specific function optimally while working together as a unified fixation device
Solution Approach 2:
Different portions of the screw have different mechanical properties tailored to their specific functions. The distal portion has lower bending stiffness to accommodate curved paths, while the proximal portion has higher stiffness to provide strong fixation. This local variation in material properties resolves the contradiction between flexibility and strength
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 effectively stabilizes bone fragments with reduced surgical exposure and lower infection risk, allowing for efficient healing by accommodating curved bone paths and providing solid support without causing bone failure under torsional loads.
Implementation Method 1
The bending stiffness of the distal threaded portion is lower than the bending stiffness of the mid-portion. The threaded distal portion is responsive to rotation of the implant to thread into a bone and advance the bone implant into the bone
Implementation Method 2
The threaded distal portion is responsive to rotation of the implant to thread into a bone and advance the bone implant into the bone
Data Source
AI summary
Examples of devices and methods for stabilizing a fracture in a bone include a body having an elongate distal portion having an outer surface defining a screw thread and an elongate proximal portion having a non-threaded outer surface. In one example, a passage is formed through the proximal portion transverse to the longitudinal axis from a first opening on the surface of the proximal portion to a second opening on the surface of the proximal portion.