Flexible Pubic Symphysis Implant With Guided Cable Fixation
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Solution Overview
Problem
Existing implant devices for re-joining a disjoined pubic symphysis suffer from mechanical complications such as screw loosening and plate breakage, necessitating revision surgeries.
Innovation Solution
A flexible implant system comprising a bent body with lateral arms and guiding elements for a tensioning element, allowing secure fixation of disjoined pubic symphysis without damaging bone or tissue, using a tensioning element guided along the implant's guiding paths.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If a rigid implant plate with screws is used to fixate the pubic symphysis, then stable fixation is achieved, but mechanical complications occur including screw loosening and plate breakage
Solution Approach 1:
The implant uses a flexible cable instead of a rigid plate to stabilize the pubic symphysis. The cable can be tensioned to provide stable fixation while its flexibility prevents the mechanical failures (screw loosening and plate breakage) associated with rigid structures. The cable passes through guiding elements and can be secured with friction locks or knots to maintain tension without the stress concentration points that cause rigid plate failures.
Solution Approach 2:
The implant system changes the mechanical parameter from rigid to flexible by using a tensionable cable. The cable's flexibility allows it to adapt to the anatomical structure and distribute forces more evenly, preventing the localized stress that leads to screw loosening and plate breakage. The tensioning mechanism allows adjustment of the fixation force to optimal levels.
2Force
If a tensioning element is applied directly to bone without guiding elements, then fixation force is transmitted, but bone or tissue damage occurs
Solution Approach 1:
The implant introduces guiding elements (such as channels or tracks) as intermediaries between the tensioning cable and the bone. These guiding elements distribute the fixation force over a larger area and guide the cable in a controlled manner, preventing direct concentration of force on small areas of bone or soft tissue that would cause damage. The guiding elements act as a mediator that transforms the point-load cable tension into a distributed force pattern.
3Reliability
If a flexible cable system is used instead of rigid plate, then mechanical failure risk is reduced, but fixation stability may be compromised
Solution Approach 1:
The implant system employs a dynamic tensioning mechanism where the cable can be adjusted and locked at optimal tension levels. The flexibility of the cable allows it to dynamically adapt to movement and loading conditions while maintaining stable fixation. The tensioning system can incorporate friction locks or knot mechanisms that maintain constant tension despite positional changes, providing stability comparable to rigid plates without their mechanical failure risks.
Data Source
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AI summary
The invention refers to an implant device (10), in particular to a pubic symphysis implant device, and to an implant system (50) comprising two such implant devices (10-1, 10-2). The implant device (10) of the invention comprises a bent body (11) comprising a curved middle portion (12) and two lateral arms (14a, 14b) extending away from the middle portion (12) and being mutually joined by the middle portion (12), and at least one guiding element defining at least one guiding path along which a tensioning element (40) can be guided. The invention further refers to method of fixating together a first bone or bone part and a second bone or bone part, for example for re-joining a disjoined pubic symphysis, using such an implant system (50), in particular by placing each of the two implant devices (10-1, 10-2) on corresponding bones or bone parts and by pulling the two implant devices (10-1, 10-2) towards each other by tensioning a tensioning element (40) guided along the at least one guiding path of each of the two implant devices (10-1, 10-2).