Adjustable Bone Anchor Assembly Angular Positioning
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Solution Overview
Problem
Current orthopedic surgical techniques for stabilizing and correcting spinal deformities lack a versatile and adjustable anchor system that allows for precise angular positioning and secure fixation of elongated members, such as spinal rods, to vertebrae, limiting the range of motion and stability in surgical corrections.
Innovation Solution
An adjustable bone anchor assembly comprising a receiver member, a bone anchor, a crown member, and a retaining member, which allows for the secure attachment and angular adjustment of elongated members to vertebrae, enabling precise alignment and stabilization by using a combination of threads, chamfers, and friction-enhancing surfaces to lock the anchor in place.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a fixed-angle bone anchor system is used, then the device complexity is reduced, but the adaptability to different spinal deformity corrections is limited
Solution Approach 1:
The bone anchor assembly incorporates a dynamic adjustment mechanism that allows the angle between the receiver member and crown member to be changed after implantation. The crown member can be rotated relative to the receiver member within a controlled range, enabling the system to adapt to different spinal deformity corrections without requiring multiple fixed-angle implants.
Solution Approach 2:
The bone anchor assembly is divided into separate functional components: a receiver member that engages the bone, a crown member that attaches the elongated member, and a retaining member that secures the crown. This segmentation allows independent optimization of each component and enables angular adjustment through relative movement between segments.
2Manufacturing precision
If an adjustable bone anchor system is implemented, then the precision of angular positioning is improved, but the device complexity increases
Solution Approach 1:
The receiver member and crown member are pre-configured with precisely engineered surfaces and geometric features that define the angular relationship. Chamfered surfaces and precision-machined interfaces ensure accurate angular positioning is achieved through the assembly process itself, rather than requiring complex adjustment mechanisms during surgery.
Solution Approach 2:
The system allows change in the angular parameter between the receiver member and crown member while maintaining precise control through geometric constraints. The adjustable angle is achieved through controlled rotation within defined limits, ensuring manufacturing precision is maintained across the range of motion.
3Adaptability or versatility
If a multi-component bone anchor assembly is used, then the adjustability is enhanced, but the ease of manufacture decreases
Solution Approach 1:
The receiver member is designed as a universal component that can accommodate different crown members and elongated members while maintaining the same engagement interface with the bone. This multi-functionality allows the same receiver design to be used across various configurations, simplifying manufacturing despite the multi-component nature of the assembly.
Solution Approach 2:
Certain components are combined into integrated units where appropriate. For example, the retaining member may be integrally formed with the crown member or receiver member in some configurations, reducing the total number of separate parts that need to be manufactured and assembled while preserving the necessary adjustability features.
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 assembly provides enhanced stability and adjustability, allowing for effective correction of spinal deformities by securely attaching elongated members to vertebrae, enabling precise angular positioning and limiting unwanted motion, thus facilitating better surgical outcomes in orthopedic procedures.
Implementation Method 1
using a combination of threads, chamfers, and friction-enhancing surfaces to lock the anchor in place
Implementation Method 2
using a combination of threads, chamfers, and friction-enhancing surfaces to lock the anchor in place
Data Source
AI summary
A medical implant device has in one embodiment a receiver member for receiving an elongated member, a crown member, an anchor member and a retaining member. An embodiment of the receiver member has an axial opening, a transverse channel, a chamber including at least one substantially flat wall, and a groove. An embodiment of the crown member has at least one substantially flat side. An embodiment of the anchor member has a head with at least one substantially flat surface that may be parallel to the anchor member's longitudinal axis, and an anchoring portion. An embodiment of the retaining member is a substantially flat clip. The crown member and anchor member are inserted into the chamber, and the retaining member is inserted into the groove beneath them. The anchor member may be pivoted substantially in one plane with respect to the receiver member until locked.