Sternal Closure with Deployable Bone Plate Anchors
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Solution Overview
Problem
Existing sternal closure techniques, such as those using cerclage wires and bone plates, are inefficient and lack effective mechanisms for securely reapproximating and rejoining sternum bone sections post-surgery.
Innovation Solution
A sternal closure system comprising bone plates with integrated fixation devices, including molly anchors and deployment pins, that transition between relaxed and deployed positions to securely fasten the sternum sections, utilizing cerclages and sutures for reinforcement.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If traditional cerclage wires and bone plates are used for sternal closure, then the sternum can be closed, but the closure is inefficient and lacks secure reapproximation mechanism
Solution Approach 1:
The fixation device incorporates a deployable leg mechanism that transitions from a compressed delivery state to an expanded fixation state. The deployable legs expand within the bone plate opening to engage with the sternum, providing dynamic adaptation from insertion to final fixation, thereby achieving secure reapproximation efficiently.
Solution Approach 2:
The fixation device is divided into separate functional components: a bone plate for structural support, deployable legs for bone engagement, and a delivery mechanism for insertion. This segmentation allows each component to be optimized for its specific function while enabling efficient assembly and deployment during surgery.
2Reliability
If a fixation device with deployable legs is used, then secure sternum reapproximation is achieved, but the device complexity increases
Solution Approach 1:
The deployable legs are nested within the bone plate opening during delivery, with the legs positioned inside the opening and the delivery mechanism inside the legs. This nested configuration allows the complex fixation device to be delivered through a minimal incision and then deployed to its full functional configuration, managing complexity through compact storage.
Solution Approach 2:
A delivery mechanism acts as an intermediary tool to insert and deploy the fixation device. The delivery mechanism includes a pusher that advances the bone plate through tissue and a deployment pin that triggers leg expansion. This intermediary simplifies the surgical procedure by providing a controlled method to manage the complex device deployment.
3Strength
If the molly anchor is inserted through the bone plate opening, then the bone plate can be fixed to the sternum, but the insertion process becomes more difficult
Solution Approach 1:
The bone plate is pre-formed with openings positioned to align with the sternum anatomy, and the deployable legs are pre-configured within the plate. This preliminary preparation ensures that when the device is inserted, the openings are already in the correct position to receive the molly anchor and engage with the sternum, simplifying the insertion process while maintaining strong fixation.
Data Source
AI summary
Sternal closure systems are provided for closing a separated sternum following a surgery that requires accessing a patient's chest cavity. An exemplary sternal closure system may utilize a combination of one or more bone plates, cerclages, and fixation devices.