Adjustable Bone Implant Transcutaneous Spacing Mechanism
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Solution Overview
Problem
Current surgical techniques for decompressive hemi-craniectomy, such as 'free floating' or 'hinged' bone flaps, fail to securely decompress the swollen brain, expose the brain to atmospheric pressure, and pose risks of infection and poor cosmetic outcomes, while synthetic implants are biomechanically inferior and costly.
Innovation Solution
An adjustable bone implant with a body secured to the skull, an anchoring member for the bone flap, and a spacing member that can be adjusted transcutaneously using a magnetic tool to raise and lower the bone flap, eliminating the need for further invasive surgery.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a bone flap is completely removed during decompressive hemi-craniectomy, then intracranial pressure is reduced and brain swelling is allowed, but the patient is exposed to risks of infection, atmospheric pressure on the brain, and requires a second surgery for reconstruction
Solution Approach 1:
The bone flap is made dynamically adjustable through a spacing member with threaded engagement, allowing it to be positioned at different heights relative to the skull. This enables the bone flap to be raised during decompression to reduce intracranial pressure, then lowered later to restore skull integrity without requiring complete removal or second surgery
Solution Approach 2:
The implant is divided into separate functional components: a body secured to the skull, an anchoring member attached to the bone flap, and a spacing member connecting them. This segmentation allows independent adjustment of the bone flap position while maintaining secure attachment to both the skull and bone flap
2Reliability
If a bone flap is held in a raised position during swelling, then brain decompression is achieved, but the bone flap may be driven into the brain or expose the brain to atmospheric pressure
Solution Approach 1:
The adjustable spacing member allows the bone flap to be dynamically positioned at an optimal height that maintains decompression while preventing excessive exposure to atmospheric pressure or compression into the brain tissue
Solution Approach 2:
The system allows for monitoring and adjustment of the bone flap position based on patient condition, enabling the surgeon to optimize the balance between decompression benefits and protection from harmful atmospheric pressure or tissue compression
3Reliability
If a second cranioplasty surgery is performed to reconstruct the skull defect, then skull integrity is restored, but surgical risks increase due to scar tissue and wound breakdown
Solution Approach 1:
The adjustable bone flap implant is implanted during the initial decompressive hemi-craniectomy, performing the skull reconstruction function in advance. This eliminates the need for a separate second cranioplasty surgery by incorporating the reconstruction capability into the first surgery
Solution Approach 2:
The implant serves multiple functions: it provides skull decomposition during the first surgery, maintains brain protection during swelling, and enables skull reconstruction during the same procedure through adjustment of the spacing member, eliminating the need for a separate second surgery
4Reliability
If synthetic cranioplasty implants are used instead of bone flaps, then skull reconstruction is achieved, but biomechanical performance is inferior and cost increases
Solution Approach 1:
The patent preserves and reuses the patient's own bone flap material rather than discarding it during the initial decompression. The bone flap is secured to the adjustable implant and can be repositioned or reattached, maintaining the original bone's superior biomechanical properties without requiring synthetic substitutes
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 adjustable bone implant securely holds the bone flap in a raised position during swelling, protecting the brain and allowing for non-invasive lowering once swelling subsides, reducing surgical risks and improving cosmetic outcomes without the need for a second surgery.
Implementation Method 1
The external tool comprises a magnetic head and the spacing member comprises a magnetic portion, and the magnetic head and the magnetic portion are magnetically coupleable transcutaneously, whereby rotation of the external tool causes a rotation of the spacing member for adjustment thereof
Data Source
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AI summary
An adjustable bone implant having a body configured to be secured to a first bone surface; an anchoring member configured to be secured to a second bone surface held at a raised position offset from the first bone surface, and a spacing member connecting the anchoring member to the body in an adjustable manner, to selectively space the anchoring member from the body, where the spacing member is located subcutaneously, where the spacing member is configured to receive an input via a transcutaneoustransmission from an external tool, and where the spacing member is configured to lower the first bone surface from a raised position upon receipt of the input and secure the first bone surface at the lowered position.