Spinal Plate Fastener Retention via Nested Spring Blocking
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Solution Overview
Problem
Existing spinal orthopedic fastener retention systems face issues with fastener loosening due to vibrations and improper insertion angles, which compromise fixation integrity and increase manufacturing complexity, leading to discomfort and potential trauma.
Innovation Solution
A fastener retention system featuring a spring mechanism with a blocking member and pockets in the spinal plate, where the spring expands to fill a cavity formed between the pockets, biasing the blocking member to protrude into apertures and prevent fastener back-out, while allowing for top-loading and self-limiting compression to maintain secure fixation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a retention mechanism is added to prevent fastener loosening, then fastener retention reliability is improved, but device complexity and manufacturing difficulty increase
Solution Approach 1:
The blocking member is nested within the plate structure, with pockets formed directly in the plate body. The spring is housed within the blocking member's cavity, creating a compact integrated assembly that prevents fastener loosening without adding external components
Solution Approach 2:
The retention mechanism is merged with the plate structure by forming pockets directly in the plate. The blocking member and spring are combined into a single functional unit that can be pre-assembled and installed as one component, reducing overall device complexity
2Reliability
If additional openings are added to the plate for retention mechanism assembly, then fastener retention is improved, but structural integrity of the plate decreases
Solution Approach 1:
The blocking member and spring are nested within existing plate geometry, utilizing pockets formed in the plate body rather than requiring additional through-openings. This approach minimizes disruption to the plate's structural continuity
Solution Approach 2:
The retention mechanism utilizes the thickness dimension of the plate by forming pockets within the plate body volume. This allows the mechanism to be housed within the existing plate footprint without requiring additional openings that would compromise structural integrity
3Reliability
If the retention mechanism requires springs and compression members, then fastener retention is improved, but manufacturing and assembly complexity increases
Solution Approach 1:
The blocking member and spring are merged into a pre-assembled unit that can be manufactured and tested separately, then installed as one component. This reduces assembly steps and ensures proper pre-assembly of the spring mechanism
Solution Approach 2:
The spring is pre-compressed within the blocking member cavity during manufacturing, and the blocking member is designed to be pre-assembled with the spring in the correct configuration. This preliminary preparation simplifies the final installation process and ensures proper function
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 system effectively prevents fastener loosening and maintains structural integrity by ensuring proper alignment and secure engagement of fasteners, reducing discomfort and trauma risks, and simplifying manufacturing by integrating the retention mechanism within the plate design.
Implementation Method 1
a spring that expands from a compressed configuration within the first pocket to a decompressed configuration within the cavity
Data Source
AI summary
A fastener retention system for retaining fasteners within apertures of an orthopedic plate includes a first pocket disposed between two of the apertures in the plate, a blocking member disposed between the two apertures and including a second pocket that forms a cavity with the first pocket, and a spring that expands from a compressed configuration within the first pocket to a decompressed configuration within the cavity.