RF-Controlled Bone Cement for Vertebral Height Restoration
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Solution Overview
Problem
Current methods for treating vertebral compression fractures, such as vertebroplasty and kyphoplasty, lack control over bone cement flow and distribution, leading to complications like leakage, inadequate height restoration, and risk of new fractures due to high pressure injection and uncontrolled expansion forces.
Innovation Solution
A system utilizing RF energy with conductive bone cement and a controller to control cement flow parameters and energy delivery, allowing for selective polymerization and controlled geometry of the cement flow to prevent leakage and optimize vertebral height restoration by increasing cement viscosity and distributing forces effectively.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If high pressure injection is used to introduce bone cement into the vertebra, then the cement can be forced into the cancellous bone, but this causes uncontrolled expansion forces that may lead to new fractures and inadequate height restoration
Solution Approach 1:
The system dynamically adjusts cement injection parameters (flow rate, pressure, temperature) in real-time based on feedback from pressure sensors and temperature sensors, allowing the cement to be introduced at controlled rates that prevent uncontrolled expansion while ensuring adequate penetration into cancellous bone
Solution Approach 2:
The system changes physical parameters of the cement during injection, including temperature (to control viscosity), pressure (to control flow rate), and flow velocity (to control penetration depth), enabling precise control over cement distribution and expansion forces to avoid new fractures
2Manufacturing precision
If bone cement is injected at high pressure to restore vertebral height, then expansion forces are applied to the endplates, but this may cause cement leakage and cortical bone damage
Solution Approach 1:
The system uses pressure sensors and temperature sensors to provide real-time feedback during cement injection, allowing the controller to adjust injection parameters to maintain optimal pressure levels that restore vertebral height without exceeding thresholds that would cause cement leakage or cortical bone damage
Solution Approach 2:
The system performs preliminary actions including pre-heating the cement to control its viscosity before injection, and using aspiration to remove excess marrow and fat from the vertebra before cement introduction, which prepares the site for controlled cement placement and reduces the risk of leakage
3Productivity
If rapid cement injection is used to quickly restore vertebral height, then productivity is improved, but this results in uncontrolled cement flow and poor geometry control
Solution Approach 1:
The system uses periodic or pulsed injection patterns where cement is introduced in controlled bursts rather than continuous high-speed flow, allowing each pulse to set partially before the next, which maintains productivity while improving geometric control and preventing runaway expansion
Solution Approach 2:
The system replaces purely mechanical high-pressure injection with a controlled thermal-field approach, using RF energy to heat and polymerize the cement in situ, which allows faster overall treatment while maintaining precise geometric control through thermal field management rather than mechanical force
4Reliability
If the vertebra is aspirated to remove marrow and fat before cement injection, then the risk of emboli is reduced, but this adds time to the procedure
Solution Approach 1:
The system merges the aspiration step with the cement injection step by using the same introducer needle for both procedures, and by coordinating the aspiration and injection operations to occur in close succession, which maintains emboli prevention benefits while minimizing the time added to the procedure
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 system provides controlled introduction and distribution of bone cement, reducing leakage and improving vertebral height restoration, while sealing tissues to prevent emboli and distributing forces over the endplates for enhanced support and reduced risk of new fractures.
Implementation Method 1
A computer controller controls cement inflow parameters and energy delivery parameters for selectively polymerizing the cement inflow plume
Implementation Method 2
An exemplary system utilizes Rf energy in combination a conductive bone cement
Implementation Method 3
controlling cement flow parameters and energy delivery parameters to provide pulsed cement flows with high acceleration rates for applying expansion forces to the bone
Data Source
AI summary
The present invention relates in certain embodiments to medical devices for treating vertebral compression fractures. More particularly, embodiments of the invention relate to instruments and methods for controllably restoring vertebral body height by controlling the flow of bone cement into the interior of a vertebra and the application of forces causes by the cement flow. An exemplary system utilizes Rf energy in combination a conductive bone cement for selectively polymerizing the inflow plume to increase the viscosity of the cement. In one aspect of the invention, the system utilizes a controller to control bone cement flow parameters to either allow or disallow cement interdigitation into cancellous bone. A method of the invention includes pulsing the flows of bone cement wherein high acceleration of the flow pulses can apply expansion forces across the surface of the cement plume to reduce a vertebral fracture.