Rotatable Magnet Apparatus for MRI-Compatible Cochlear Implants
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional cochlear implants are susceptible to demagnetization and torque-induced dislocation when exposed to MRI magnetic fields due to misalignment of magnetic fields, requiring surgical removal and replacement of the implant magnet, which can cause tissue damage.
Innovation Solution
A cochlear implant with a magnet apparatus featuring a case with a rotatable magnet frame and diametrically magnetized magnets biased to a predetermined orientation, allowing the magnetic field to align with strong external fields like MRI, preventing demagnetization and torque-induced dislocation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a conventional disk-shaped magnet with axial N-S alignment is used in the cochlear implant, then the magnet provides stable magnetic attraction for headpiece alignment, but the magnet is susceptible to demagnetization and torque-induced dislocation when exposed to MRI magnetic fields
Solution Approach 1:
The magnet is designed to be freely rotatable about its longitudinal axis, allowing it to dynamically adjust its orientation in response to external magnetic fields. This rotational freedom enables the magnet to align with strong external MRI fields, preventing demagnetization and torque-induced dislocation while maintaining stable magnetic attraction for headpiece alignment during normal operation
Solution Approach 2:
The magnet's operational parameters change based on external field conditions. In the absence of strong external fields, the magnet maintains a predetermined N-S orientation for stable headpiece alignment. When exposed to strong MRI fields, the magnet rotates to align with the external field, changing its orientation parameter to prevent demagnetization and torque damage
2Object-affected harmful factors
If the magnet is made freely rotatable to align with MRI fields, then demagnetization and torque damage are prevented, but the magnetic attraction force for headpiece alignment may be reduced
Solution Approach 1:
The magnet's rotational freedom allows it to adapt to different magnetic field conditions. During normal operation without strong external fields, the magnet maintains a predetermined N-S orientation that provides optimal magnetic attraction for headpiece alignment. When exposed to strong MRI fields, the magnet rotates to align with the external field, preventing torque-induced dislocation while the overall system maintains functional integrity
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 solution ensures that the cochlear implant remains stable and functional during MRI procedures without the need for surgical magnet removal and replacement, maintaining proper magnetic attraction for headpiece alignment.
Implementation Method 1
a plurality of diametrically magnetized magnets that are located in the magnet frame, the magnets defining a longitudinal axis and a N-S direction and being rotatable about the longitudinal axis relative to the magnet frame and biased by the magnet frame to a predetermined N-S rotational orientation
Implementation Method 2
The dominant MRI magnetic field B (typically 1.5 Tesla or more) may demagnetize the implant magnet 14 or generate a significant amount of torque T on the implant magnet 14
Implementation Method 3
a magnet frame within the case and rotatable about the central axis of the case
Implementation Method 4
the headpiece and the cochlear implant may include respective positioning magnets that are attracted to one another, and that maintain the position of the headpiece transmitter over the implant receiver
Data Source
AI summary
A cochlear implant including a cochlear lead, an antenna, a stimulation processor, and a magnet apparatus, associated with the antenna, including a case defining a central axis, a magnet frame within the case and rotatable about the central axis of the case, and a plurality of diametrically magnetized magnets that are located in the magnet frame, the magnets defining a longitudinal axis and a N-S direction and being rotatable about the longitudinal axis relative to the magnet frame and biased by the magnet frame to a predetermined N-S rotational orientation.