Pars Fracture Fixation via Needle Guide Docking
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Solution Overview
Problem
Repairing a pars interarticularis fracture is challenging due to the damaged lamina's undulating shape, making it difficult to access and stabilize the fracture effectively in orthopedic surgery.
Innovation Solution
A fixation system and method involving a needle guide, needle, guidewire, screw assembly, and surgical instrument are used to dock on the lamina, insert and position a screw assembly coaxially with the guidewire, and approximate the fractured ends to facilitate healing through a minimally invasive procedure.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If traditional open surgery methods are used to access and stabilize the pars fracture, then the fracture can be stabilized, but the tissue disruption and invasiveness increase significantly
Solution Approach 1:
The surgical procedure is segmented into distinct steps using separate instruments: needle guide for positioning, needle for creating the pathway, guidewire for establishing the trajectory, and screw assembly for fixation. This segmentation allows each component to be optimized for its specific function while maintaining minimal invasiveness throughout the procedure.
Solution Approach 2:
The needle guide acts as an intermediary device that bridges the external access point and the internal fracture site. It provides a stable platform for inserting the needle and guidewire through the pars interarticularis, enabling precise stabilization without requiring extensive surgical exposure or tissue disruption.
2Reliability
If the screw assembly is inserted through the pars interarticularis to stabilize the fracture, then the fracture stabilization is achieved, but the complexity of the surgical procedure increases
Solution Approach 1:
The needle guide is positioned and secured on the lamina before the needle insertion step. This preliminary action establishes a stable reference framework that guides subsequent steps (needle insertion, guidewire placement, screw assembly insertion) along the correct trajectory, reducing the need for complex real-time adjustments and simplifying the overall procedure.
Solution Approach 2:
The instruments are nested within each other during the procedure: the guidewire is inserted through the needle, the needle is removed leaving the guidewire in place, and the screw assembly is then inserted over the guidewire. This nesting approach allows for sequential placement of components through the same access point, reducing the number of separate incisions and surgical steps required.
3Object-affected harmful factors
If a single-incision approach is used to minimize tissue disruption, then the invasiveness is reduced, but the precision of screw assembly placement becomes more difficult
Solution Approach 1:
The needle guide serves as a precision intermediary device that is docked on the lamina and provides a stable, pre-positioned pathway for the screw assembly. It includes alignment features and guides that ensure the needle, guidewire, and screw assembly follow the exact desired trajectory through the pars interarticularis, achieving precise placement without requiring multiple incisions or complex external guidance systems.
Data Source
AI summary
A fixation system for repairing a pars fracture includes a needle guide configured to be docked on a lamina of the pars, a needle, a guidewire, and a screw assembly. A portion of the needle is configured for insertion through a passage of the needle guide. A portion of the guidewire is configured for insertion through a passage of the needle. The screw assembly includes a collar and an elongated portion, the collar being movable with respect to the elongated portion. A portion of the screw assembly is configured to contact the lamina co-axially with the guidewire.