Segmented Cerclage Wire Passer for Minimally Invasive Bone Fixation
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Solution Overview
Problem
Existing cerclage tools cause significant disruption and trauma to surrounding muscle tissue due to their rigid design and requirement for large incisions, which complicates and prolongs the bone fracture fixation procedure.
Innovation Solution
A cerclage wire passer comprising two members with J-shaped tubes that form a continuous tube when coupled, allowing for minimal incision and reduced musculature exposure by conforming to the bone circumference, enabling the passage of a wire or cable without excessive intrusion.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If rigid cerclage devices with C or S shaped portions are used to pass wires around bones, then the wire can be positioned around the bone, but significant spreading of incision and trauma to muscle tissue occurs
Solution Approach 1:
The cerclage device is divided into two separate members (first and second members) that can be independently inserted through the incision. Each member has a curved portion and a tube, and they couple together to form a complete circular configuration. This segmentation allows the device to be inserted through a small incision without requiring significant spreading, thereby reducing muscle tissue trauma while still achieving proper wire positioning around the bone.
Solution Approach 2:
The first and second members are designed to nest together when coupled, forming a complete circular cerclage device. The tubes of both members align to create a continuous pathway for the wire. This nesting configuration allows the device to achieve its full functional form only after insertion and coupling, minimizing the incision size required and reducing tissue trauma during insertion.
2Object-affected harmful factors
If flexible retractable tips are used to adapt to bone circumference, then incision spreading is reduced, but the device lacks sufficient strength to penetrate bone surrounding muscles
Solution Approach 1:
The device incorporates different material properties in different regions: the curved portions and tips are made flexible to adapt to bone circumference and reduce tissue trauma, while the central shafts and coupling mechanisms are made rigid to provide sufficient strength for penetration and wire passage. This local differentiation of material properties allows the device to simultaneously achieve both adaptability and strength requirements.
Solution Approach 2:
The cerclage device uses composite construction combining flexible materials for the curved adapting portions with rigid materials for the structural shafts and coupling elements. This composite approach enables the device to have both the flexibility needed to conform to bone shapes without excessive tissue spreading and the strength needed to penetrate through muscle tissue and guide the wire effectively.
3Ease of operation
If large incisions are made to allow device insertion and movement around bone, then the device can be properly positioned, but procedural time increases and tissue trauma worsens
Solution Approach 1:
By dividing the cerclage device into two insertable members that couple together inside the body, the invention enables insertion through a small incision. This eliminates the need for large incisions required by traditional single-piece devices, reducing both tissue trauma and procedural time while maintaining the ability to properly position the wire around the bone.
4Strength
If rigid cerclage devices are used, then structural strength is maintained, but significant spreading of incision is required for insertion
Solution Approach 1:
The rigid cerclage device is segmented into two separate members that can be independently inserted through a small incision. Each member contains rigid structural components for strength, but the segmented design allows them to pass through the small incision separately. Once inside, they couple together to form the complete rigid circular structure, achieving both small incision size and structural strength.
Solution Approach 2:
The device transitions from a static rigid structure to a dynamic insertion process where two separate rigid members are inserted individually through the incision, then coupled together in situ. This dynamic approach allows the rigid structure to be assembled after insertion rather than requiring pre-formed rigid structure to pass through the incision, thereby reducing incision size while maintaining structural strength.
Data Source
AI summary
A cerclage tool for placement of a wire around a bone for internal fixation of the bone comprising a first member having a handle portion, a central portion and a first bent tube portion and a second member having a handle portion, a central portion and a second bent tube portion. The first member and the second member are configured and adapted to be inserted separately through an incision into soft tissue surrounding the bone and subsequently joined together after insertion such that the first bent tube portion and the second bent tube portion form a continuous tube that encircles the bone.