Modular Bone Screw Assembly with Biasing Pressure Element
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing polyaxial bone screws are often delivered in a pre-assembled condition, limiting the surgeon's ability to select and assemble components during surgery, which can result in undesirable pivoting of the screw head during procedures.
Innovation Solution
A modular bone anchoring device with a simplified design, allowing for assembly of separate parts at the operation site, featuring a pressure element with a snap-ring or resilient fingers to provide a biasing force on the screw head, enabling easy handling and selection of components based on clinical needs.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If polyaxial bone screws are delivered in a pre-assembled condition, then the manufacturing and inventory management is simplified, but the surgeon's ability to select and assemble components during surgery is limited
Solution Approach 1:
The bone screw system is divided into separate modular components: a receiving part, a screw element, and a pressure element. These segments can be manufactured independently and assembled during surgery, allowing both simplified manufacturing of individual components and flexible selection/assembly based on surgical needs.
2Ease of operation
If the pressure element is positioned to enable free pivoting of the head, then the anchoring device is easy to assemble, but undesirable pivoting occurs during surgery
Solution Approach 1:
The pressure element is designed with a resilient or spring-like characteristic that allows dynamic adjustment. During assembly, the pressure element can be positioned to allow free pivoting for ease of assembly, but during surgery, the spring force automatically provides the necessary biasing to stabilize the screw head and prevent undesirable pivoting, thus adapting to different operational phases.
3Adaptability or versatility
If a modular design with separate parts is used, then component selection and assembly during surgery is improved, but the device complexity increases
Solution Approach 1:
The receiving part is designed as a universal component that can accommodate different screw elements and pressure element configurations. This multi-functional design allows various components to be selected and assembled during surgery without requiring completely different receiving parts, thus providing component selection flexibility while limiting the overall number of unique parts needed.
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 solution allows for flexible assembly and upgrade of existing components, reducing costs and inventory, providing improved handling and reducing the need for pre-assembled screws, while allowing for precise control of the force applied to the screw head during surgery.
Implementation Method 1
a spring element withstands against removal of the pressure element through the top end once the pressure element is inserted
Data Source
AI summary
A bone anchoring device includes an anchoring element having a shaft and a head; a receiving part for receiving the head and a rod, the receiving part being formed in one piece and having a top end and a bottom end, a bore extending from the top end to the bottom end, an inner wall defined by the bore, a substantially U-shaped channel adjacent to the top end for receiving the rod and a seat adjacent to the bottom end for accommodating the head; a pressure element; and a spring element having a spring force. The anchoring element is inserted from the top end and is pivotable with respect to the receiving part. The pressure element is movable in the bore so as to be able to fix the anchoring element at an angle with respect to the receiving part by exerting pressure onto the head. The spring element acts between the pressure element and the receiving part and allows the pressure element to be introduced from the top end but withstands against removal of the pressure element through the top end.