Rotatable Cochlear Implant Magnet for MRI Compatibility
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional cochlear implants are susceptible to demagnetization and tissue damage during MRI procedures due to misalignment of magnetic fields, and their magnets are prone to fracture and deformation from impact forces, leading to compromised alignment and retention issues.
Innovation Solution
A cochlear implant with a magnet apparatus featuring a spine-protected, rotatable magnet assembly that aligns with both the external headpiece magnet and MRI magnetic field, utilizing a disk-shaped case and linearly magnetized magnets to prevent damage from impact forces and ensure stable rotation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If a disk-shaped magnet with axial magnetic dipoles is used in conventional cochlear implants, then the magnet structure is simple and easy to manufacture, but the magnet is not compatible with MRI systems and may be demagnetized or generate significant torque
Solution Approach 1:
The patent introduces a rotatable magnet assembly that can dynamically change its orientation. The magnet is mounted on a rotation mechanism allowing it to align with the MRI magnetic field during scanning, thereby reducing torque and preventing demagnetization. This dynamic adjustment resolves the contradiction by making the magnet MRI-compatible while maintaining manufacturing simplicity.
Solution Approach 2:
The patent changes the magnetic field orientation parameter by allowing the magnet to rotate. During MRI procedures, the magnet rotates to align with the external magnetic field, changing its magnetic dipole orientation from axial to radial relative to the skin surface. This parameter change enables MRI compatibility while keeping the original disk-shaped structure easy to manufacture.
2Force
If the magnet strength is increased to improve headpiece retention, then the retention force is sufficient for typical activities, but the pressure on the skin flap causes discomfort and tissue necrosis
Solution Approach 1:
The rotatable magnet assembly allows dynamic adjustment of magnetic field direction. The magnet can rotate to optimize the retention force vector, directing it more tangentially along the skin surface rather than perpendicularly into the skin flap. This reduces pressure-induced tissue damage while maintaining adequate retention for headpiece stability.
Solution Approach 2:
By changing the orientation parameter of the magnetic field through rotation, the patent alters how the retention force is distributed. The magnetic force vector can be adjusted to reduce the perpendicular component that causes skin flap pressure, while maintaining sufficient total force for headpiece retention during typical activities.
3Reliability
If the magnet is made rotatable to align with MRI magnetic field, then MRI compatibility is improved, but the magnet becomes susceptible to impact forces that may fracture it or deform the housing
Solution Approach 1:
The patent incorporates a shock-absorbing mechanism in the magnet assembly housing. The housing includes cushioning elements positioned to protect the rotatable magnet from impact forces. This beforehand cushioning prevents fracture or deformation from accidental impacts while allowing the magnet to rotate freely for MRI alignment.
Solution Approach 2:
The patent introduces an intermediary protective structure between the external environment and the magnet. The magnet assembly housing acts as a mediator that absorbs and distributes impact forces, protecting the fragile rotatable magnet mechanism from direct impact while allowing rotational movement for MRI compatibility.
4Reliability
If a rotatable magnet assembly is implemented, then alignment with MRI field and headpiece magnet is improved, but the device complexity increases
Solution Approach 1:
The patent implements a rotatable magnet assembly with a simple rotation mechanism that allows the magnet to align with both the headpiece magnet and MRI magnetic field. This dynamic alignment capability improves reliability during MRI procedures while the rotation mechanism is designed to be as simple as possible, minimizing the increase in overall device complexity.
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 magnet apparatus effectively protects the magnets from impact forces, maintains alignment with the external headpiece and MRI field, reducing the risk of demagnetization and tissue damage, while ensuring secure retention of the headpiece.
Implementation Method 1
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.
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.
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 and a magnet assembly, having a spine and at least one magnet that is secured to the spine, that is located within the case and is rotatable relative to the case.