Sacral Prosthesis Inverted V-Shape Stress Distribution
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Solution Overview
Problem
Current sacral prosthesis reconstruction methods face issues with unreliable supporting and easy fatigue break of the screw-rod system, leading to instability and potential damage to the lumbar vertebra and pelvis, especially after sacrectomy, which complicates stress conduction and long-term stability.
Innovation Solution
A sacral prosthesis with an 'inverted V-shaped' structure, incorporating a screw-rod system with a connecting seat and rotatable rod body, and an anti-dropping mechanism, along with a hollow truss structure and 3D printing for personalized fit, to enhance mechanical properties and stability, and promote bone fusion.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If a screw-rod system is used to support the lumbar vertebra onto iliums, then bearing effect is achieved in short time, but the screw rod is broken or loosed easily due to fatigue break in long term
Solution Approach 1:
A bone contact plate is introduced as an intermediary component between the screw-rod system and the bone. The plate distributes stress over a larger area and provides a broader contact surface, reducing stress concentration on the screw rod and preventing fatigue break while maintaining the bearing effect
Solution Approach 2:
The prosthesis combines different materials and structural forms (screw-rod system for immediate stability, bone contact plate for stress distribution, and bone graft for long-term fusion) to create a composite reconstruction system that addresses both short-term and long-term stability requirements
2Stability of the object's composition
If metal implant is used to provide early stability, then fixation effect is achieved, but the stress is mainly focused on the metal implant causing fatigue break
Solution Approach 1:
The bone contact plate is designed with specific local qualities including extended width to distribute stress, porous structure at contact surfaces to promote bone ingrowth, and strategic placement to transfer stress from the metal implant to the surrounding bone tissue, reducing stress concentration on the metal components
3Reliability
If bone graft methods are applied to reduce implant pulling, then long-term stability is improved, but the problem of fatigue break of metal implant still hasn't been solved
Solution Approach 1:
The bone contact plate is installed preliminarily to establish a stable framework before bone grafting. This preliminary structure provides immediate stress distribution capability, and when combined with bone graft materials, creates a composite structure that protects the metal implant from fatigue break while enabling long-term stability through biological fusion
Data Source
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AI summary
The present invention provides a sacral prosthesis, comprising: a prosthesis main body, the prosthesis main body including two first prosthesis bodies (11) and a second prosthesis body (12) connected between the two first prosthesis bodies (11), a first end of each of the first prosthesis bodies (11) being connected with the second prosthesis body (12), the two first prosthesis bodies (11) and the second prosthesis body (12) being of an integrally prototyped structure, a second end of each of the first prosthesis bodies (11) being extended along a direction far away from the second prosthesis body (12), and being contacted and matched with an ilium (1), and a top of the second prosthesis body (12) being contacted and matched with a lumbar vertebral body (2); and a screw-rod structure, the screw-rod structure including a connecting seat (22) and a rod body (23), the connecting seat (22) being connected with the prosthesis main body, and the rod body (23) being fixed on the connecting seat (22). The technical solutions of the present invention can effectively solve the problems of unreliable supporting and easy fatigue break of the screw-rod system in the related technology.