Patient Head Fixation Sleeve with Interchangeable Lengths
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Solution Overview
Problem
Existing fixation devices for neurological diagnosis and surgery, such as stereotactic frames, often have protruding fixation pins that interfere with equipment and require multiple lengths to accommodate different head sizes, leading to instability and increased costs due to excessive bending moments and potential displacement of the head during treatment.
Innovation Solution
The device incorporates a sleeve member that extends inward from the pin support member, allowing the fixation pin to be fully threaded and preventing protrusion, with interchangeable sleeve members of varying lengths to adapt to different head sizes, and internal engagement means to reduce interference and enhance stability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If fixation pins are made long to reach peripheral target areas and accommodate different head sizes, then adaptability is improved, but stability deteriorates due to large bending moments causing deflection
Solution Approach 1:
The fixation device is segmented into modular components: a reusable frame, interchangeable pin support members with different lengths, and standardized fixation pins. This segmentation allows adaptation to different head sizes by selecting appropriate pin support member lengths while keeping the fixation pin length standardized and short, thereby maintaining stability.
Solution Approach 2:
The device employs dynamic adaptability through interchangeable pin support members that can be selected based on the patient's head size and treatment requirements. This dynamic configuration allows the system to optimize the distance from the frame to the target area, using the minimum necessary length for each case, thus reducing bending moments and improving stability.
2Ease of operation
If fixation pins protrude beyond pin support members to provide engagement means, then ease of operation is improved, but device complexity increases due to interference with equipment
Solution Approach 1:
The fixation pin is nested within the pin support member, with the pin inserted through a longitudinal opening in the pin support member. The engagement means (such as a drive slot or hexagonal recess) is formed at the distal end of the fixation pin while the pin remains substantially contained within the pin support member's length, eliminating protrusion and interference with equipment.
Solution Approach 2:
The pin support member acts as an intermediary structure that provides the engagement interface for threading the fixation pin. The longitudinal opening in the pin support member allows insertion and engagement of the pin while keeping the pin within the bounds of the pin support member, thus maintaining ease of operation without protrusion.
3Adaptability or versatility
If multiple lengths of fixation pins are provided to accommodate different head sizes, then adaptability is improved, but manufacturing precision requirements increase
Solution Approach 1:
The length adaptation function is segmented from the fixation pin to the pin support member. Only the pin support members are manufactured in multiple standardized lengths, while the fixation pins maintain a single standardized length. This reduces the manufacturing precision requirements compared to producing fixation pins in many different lengths.
Solution Approach 2:
The fixation pin is designed as a universal component with a single length that can be used with pin support members of different lengths. The pin support member serves multiple functions: providing structural support, defining the insertion path through its longitudinal opening, and adapting the overall device length to different head sizes.
Data Source
AI summary
The present invention relates to a device for fixation to a head of a patient during neurological diagnosis, therapy or surgery, in particular during MRI diagnosis. The device comprises at least one fixation pin for fixation to the head, a sleeve member (5) having an internal threaded through bore to at least partly receive and hold said fixation pin, and a pin support member for supporting said fixation pin and sleeve member. The sleeve member is exchangeable and provided in at least two different lengths in order to allow adaptation of the sleeve member to the size of the head to improve the fixation of the head and avoid the fixation pin to protrude beyond the outer boundary of the pin support member. The invention also relates to a method for fixation of a head.