Rotary Impactor Damping for Stable Orthopedic Bone Reaming
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Solution Overview
Problem
Current surgical robots face challenges in orthopedic surgery due to high reactionary forces from tools like rotary reamers, leading to navigational errors, damage, and loss of registration, which hinder their effectiveness and safety.
Innovation Solution
A rotary impacting tool with a dampening mechanism and torque sensing system that reduces reactionary forces by spreading them over time and using a hammer mechanism to minimize torque and linear force requirements, allowing for both rotary and linear impacts.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional rotary reamers are used in orthopedic surgery, then bone preparation can be performed, but high reactionary torque is generated causing robot loss of registration and potential damage
Solution Approach 1:
The patent employs intermittent impacting action instead of continuous rotation. The impacting member delivers periodic blows to the bone during reaming, creating a pulsating cutting action that reduces continuous reactionary torque on the robot while maintaining effective bone preparation. This periodic impacting allows the robot to reset between impacts, preventing loss of registration.
Solution Approach 2:
The patent incorporates a dampening mechanism that absorbs and dissipates reactionary forces before they reach the robot. This cushioning system reduces peak torque values and smooths out force variations, protecting the robot from high instantaneous loads that would cause registration loss or damage.
2Productivity
If conventional rotary reamers are used, then bone cavity preparation is achieved, but significant linear force must be applied by the surgeon or robot
Solution Approach 1:
The impacting mechanism delivers repeated blows during the reaming process, creating efficient bone removal through impact forces. This periodic impacting action achieves effective bone preparation with reduced continuous linear force requirements compared to conventional rotary reamers that require constant pushing force.
Solution Approach 2:
The impacting member acts as an intermediary that transfers energy to the bone through controlled impacts. This mediator mechanism allows the robot or surgeon to apply force indirectly through the impacting sequence, reducing the need for direct continuous linear force application on the reamer.
3Ease of operation
If high reactionary forces are accepted, then conventional rotary tools can be used, but surgeon fatigue and navigational errors increase
Solution Approach 1:
The dampening mechanism is built into the tool design to absorb and reduce reactionary forces before they reach the surgeon or robot. This pre-cushioning allows for easier control and reduced fatigue while maintaining effective bone preparation capabilities.
Solution Approach 2:
The intermittent impacting action creates periods of lower force between impacts, allowing the surgeon or robot to recover and maintain better control. This rhythmic application of force reduces cumulative fatigue and improves operational ease compared to continuous high-force rotary reaming.
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 tool significantly reduces surgeon and robot fatigue and improves surgical precision by minimizing reactionary forces, enabling efficient and accurate bone preparation in orthopedic surgeries.
Implementation Method 1
a dampening mechanism that spreads reactionary forces over time
Implementation Method 2
using a hammer mechanism to minimize torque and linear force requirements, allowing for both rotary and linear impacts
Data Source
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AI summary
A rotary impactor for orthopedic surgery includes an output anvil and a hammer that is capable of imparting linear and rotary force on the anvil. The anvil may be moveable on a leadscrew element to alternately generate energy in an energy storage means and to move along the leadscrew element to impact the anvil. A viscoelastic mechanism or a dampening mechanism is used to reduce the reflected force and or torque during operation of the rotary impactor. High frequency linear impacts by the impactor obviate the need for a surgeon to provide an external push force on the impactor in order to perform a successful surgical operation.