Rod Reducer Instrument Threaded Shaft Mechanism
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Solution Overview
Problem
Current rod reduction instruments in orthopedic surgery, such as those using pliers, require significant hand strength and can be difficult to use, especially in minimally invasive procedures where access is limited and angles are awkward, making it challenging to efficiently and safely engage orthopedic rods with fixation elements like screws.
Innovation Solution
A rod reducer instrument featuring a pliers mechanism with a pushing member and threaded shaft, allowing for the conversion of circular handle rotations into linear motion to force the rod into engagement with orthopedic screws, combined with a locking mechanism to secure the pliers in place, facilitating easier and more precise rod reduction.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Force
If traditional pliers are used for rod reduction, then the surgeon can apply direct force to the rod and fixation element, but the procedure requires excessive hand strength and is difficult to perform from awkward angles
Solution Approach 1:
The patent introduces a rod reducer instrument as an intermediary device between the surgeon's hand and the rod-fixation element assembly. This instrument includes a pushing member that contacts the rod, a gripping member that contacts the fixation element, and a threaded shaft with handle that converts rotational motion into linear pushing force. The intermediary instrument amplifies the surgeon's input force through mechanical advantage provided by the threaded shaft mechanism, eliminating the need for excessive direct hand strength while enabling precise control during rod reduction from various angles including minimally invasive approaches
2Object-affected harmful factors
If minimally invasive surgical approaches are used, then patient trauma is reduced, but access to the rod and fixation element is limited and angles are awkward
Solution Approach 1:
The rod reducer instrument incorporates dynamic elements including a rotatable handle connected to a threaded shaft that converts rotational motion into linear motion of the pushing member. The instrument also features movable gripping and pushing members that can be positioned and adjusted along the instrument's body. This dynamic design allows the surgeon to operate the instrument from various angles and positions, accommodating the limited and awkward access conditions of minimally invasive surgery while maintaining effective force application to the rod
3Force
If rigid tools like pliers are used, then direct force can be applied to the rod, but precise control over the rod reduction process is difficult to achieve
Solution Approach 1:
The rod reducer instrument provides mechanical feedback through its threaded shaft mechanism, where each rotation of the handle produces a controlled linear displacement of the pushing member. The gripping member is designed to engage the fixation element securely while allowing the pushing member to apply gradual, controlled force to the rod. As the rod is reduced into the fixation element, the surgeon can feel the progression through the instrument's mechanical structure, enabling precise control over the reduction process and detection of when proper engagement is achieved
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The instrument enables efficient and secure engagement of rods with fixation elements, reducing the need for excessive hand strength and improving accessibility in both minimally invasive and open surgical approaches by providing a mechanical advantage and precise control over the rod reduction process.
Implementation Method 1
A rod reducer instrument featuring a pliers mechanism with a pushing member and threaded shaft, allowing for the conversion of circular handle rotations into linear motion to force the rod into engagement with orthopedic screws
Data Source
AI summary
A rod reducer instrument is configured to be secured to a fixation element and to force a rod into engagement with the fixation element. The rod reducer instrument can have a pliers to secure the rod reducer to the fixation element and a threaded shaft with a handle and a pusher member. The pliers can form a threaded channel that engages the threaded shaft and directs a movement of the shaft. The threaded shaft can translate a rotational movement at the handle into a linear movement at the pusher member and in this way force a rod into engagement with a fixation element.