Ceramic Cranial Access Bolt With MRI Artifact Reduction
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Solution Overview
Problem
Current cranial access devices made from conductive materials induce imaging artifacts during procedures like MRI, affecting the visualization of medical devices and image-guided therapy, especially for shallow brain targets.
Innovation Solution
A cranial access device using a non-conductive material, such as ceramic, with a self-tapping threaded portion and a drive adapter to minimize imaging artifacts, and a drive adapter that acts as a torque limiter to prevent fracture during insertion.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If cranial access devices are made from conductive materials like metals (e.g., titanium), then the device provides sufficient strength and structural integrity, but it induces imaging artifacts during MRI and other imaging procedures
Solution Approach 1:
The cranial access device employs a composite construction combining a non-conductive ceramic cranial bolt with a conductive metal drive adapter. The ceramic portion (alumina or zirconia) eliminates imaging artifacts during MRI while the metal adapter provides sufficient torque interface for installation. This composite approach resolves the contradiction by assigning different material properties to different functional sections of the device.
Solution Approach 2:
The device is divided into two distinct segments: a non-conductive ceramic cranial bolt that interfaces with the skull and provides artifact-free imaging, and a separate conductive metal drive adapter that interfaces with the driver tool during installation. This segmentation allows each component to be optimized for its specific function without compromising the other.
2Object-generated harmful factors
If the cranial bolt is made from non-conductive material like ceramic, then imaging artifacts are reduced, but the material may be more prone to fracture during insertion
Solution Approach 1:
The metal drive adapter serves as an intermediary component between the driver tool and the ceramic cranial bolt. It provides a torque interface for installation while protecting the brittle ceramic material from direct mechanical stress during insertion. The adapter absorbs and distributes insertion forces, preventing fracture of the ceramic bolt.
Solution Approach 2:
The drive adapter is designed with torque-limiting features that prevent excessive force from being applied to the ceramic cranial bolt during installation. By cushioning against over-torquing beforehand, the design protects the fracture-prone ceramic material while ensuring proper installation.
3Object-generated harmful factors
If the cranial access device uses a non-conductive material, then artifact formation during MRI is reduced, but the ease of manufacture compared to metals is reduced
Solution Approach 1:
The device is manufactured as two separate components - a ceramic cranial bolt and a metal drive adapter - allowing each to be fabricated using optimal processes for its material. The ceramic bolt can be manufactured via precision ceramic machining or molding, while the metal adapter uses conventional metal manufacturing techniques. This segmentation simplifies the overall manufacturing challenge compared to creating a monolithic device from difficult-to-machine ceramic material.
Data Source
AI summary
The disclosure provides a cranial access device that reduces or eliminates artifacts during imaging. The cranial access device includes a cranial bolt and a drive adapter. The cranial bolt includes a distal threaded portion, a proximal drive portion comprising a plurality of protrusions that form an external drive geometry, and a central passageway configured for receiving a neurosurgical tool. The drive adapter includes a distal end configured to receive and interface with the external drive geometry of the proximal drive portion, and a proximal end configured to receive a driver tool.