Spinal Cage Electrode Layout for Targeted Bone Growth Control
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Solution Overview
Problem
Current spinal fusion technologies face challenges in controlling electrical stimulation for precise osteoinduction and osteolysis, leading to complications such as heterotopic ossification and non-fusions, with limited effectiveness and potential side effects from biologics like rhBMP-2, and lack of precise control over electrical stimulation regions.
Innovation Solution
A system and method for calibrated electrical stimulation and monitoring using orthopedic implants, specifically spinal cages, with customizable electrode placement, geometry, and impedance sensing to promote targeted bone growth or breakdown, utilizing a dose response curve for optimal stimulation conditions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If recombinant human bone morphogenetic protein (rhBMP-2) is used to increase bone formation, then non-fusion rates are reduced, but heterotopic ossification and other side effects occur
Solution Approach 1:
The patent applies local quality by creating spatially differentiated electrical stimulation zones around the implant. Different regions receive different electrical field intensities and polarities: the fusion space receives osteoinductive stimulation to promote bone growth, while surrounding regions receive osteolytic stimulation to prevent heterotopic ossification. This localized control of electrical field properties enables selective bone formation only where desired.
Solution Approach 2:
The patent utilizes parameter changes by dynamically adjusting electrical stimulation parameters including current density, voltage, frequency, and polarity. The system varies these parameters across different spatial zones and time periods to achieve osteoinduction in the fusion space while preventing unwanted bone growth elsewhere. The electrical field parameters are tuned to specific thresholds that differentiate between desired and undesired bone formation.
2Reliability
If electrical stimulation is applied to promote bone growth, then fusion rates improve, but precise control over stimulation regions is lacking
Solution Approach 1:
The patent implements segmentation by dividing the electrical stimulation field into distinct zones using multiple independently controllable electrodes. The system segments the stimulation regions into an osteoinductive zone (fusion space) and an osteolytic zone (surrounding tissue), with each zone controlled by specific electrode configurations. This segmentation enables precise spatial control over where bone growth is promoted or inhibited.
Solution Approach 2:
The patent incorporates feedback mechanisms through impedance sensing that monitors bone growth progress and tissue conditions. The system uses this feedback information to dynamically adjust electrical stimulation parameters, ensuring precise control over stimulation regions. The feedback loop allows the system to adapt to actual tissue responses and maintain accurate spatial control of bone formation and resorption zones.
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
Enables precise control over bone growth and breakdown regions, enhancing fusion rates while minimizing complications, allowing for faster and safer spinal fusion procedures with reduced patient testing time.
Implementation Method 1
When mechanical stress is exerted on bone, an electric field is created. In the body, this electrical field constitutes a signal causing a physiological response resulting in osteoinduction or osteolysis. Consequently, it is possible to cause osteoinduction or osteolysis by introducing an electrical field in the volume within and surrounding a segment of bone.
Implementation Method 2
the biologic represents an illustrating example of how, nonspecific, unguided osteoinduction can be harmful to a patient
Data Source
AI summary
A system and method for spinal fusion that can include: a spinal cage body that includes at least one defined graft window cavity; a plurality of electrodes exposed on the surface of the spinal cage body; control circuitry configured to drive the plurality of electrodes in a stimulation mode; wherein there is at least a targeted osteoinduction region and a targeted non-osteoinduction region that are immediately adjacent to the spinal cage body; and wherein the control circuitry includes configuration to excite the plurality of electrodes during the stimulation mode for generation of a current density in the targeted osteoinduction region and targeted non-osteoinduction region according to targeted levels of bone growth.