Sliding Plate Fixation Device for Head Immobilization
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Solution Overview
Problem
Current radiation therapy systems face challenges in accurately and repeatedly positioning a patient's head during fractionated therapy sessions, as existing fixation methods are invasive or not suitable for maintaining precise alignment over time.
Innovation Solution
A fixation device with a sliding plate and pivotally linked bite-block system that allows for precise and repeatable immobilization of the patient's head, using a Cartesian coordinate system for alignment and adjustable locking mechanisms to ensure accurate repositioning without tension, allowing for comfortable and artifact-free treatment.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a stereotactic frame with fixation pins is used for rigid fixation of the skull, then the head can be securely fixed, but the method is invasive and not suitable for fractionated therapy where the patient is docked in and out of the system at each session
Solution Approach 1:
The fixation device is divided into separate functional components: a head rest for head support, a bite block for jaw fixation, and a chin rest for chin support. These segmented components can be independently positioned and adjusted, allowing for precise head positioning without requiring invasive skull fixation pins. The segmentation enables the device to be easily assembled and disassembled for each therapy session.
Solution Approach 2:
The patent introduces an intermediary positioning system that uses a bite block as a mediator between the patient's jaw and the fixation device. The bite block engages with the mandible and connects to the head rest and chin rest through linking means, creating a chain of mechanical connections that securely fix the head without direct bone penetration. This intermediary approach maintains fixation reliability while eliminating the need for invasive pins.
2Productivity
If the patient is docked in and out of the radiation therapy system at each therapy session, then the patient can be treated in fractionated therapy, but it must be secured that the patient is positioned in exact the same way as in the session when the pictures were captured to create the therapy plan
Solution Approach 1:
The fixation device is designed with pre-configurable components that can be positioned before each therapy session. The head rest, bite block, and chin rest are arranged in a predetermined configuration that replicates the reference position established during image capture. This preliminary positioning ensures that when the patient is docked in and out for fractionated therapy, their head is positioned with exact precision relative to the treatment plan.
Solution Approach 2:
The device incorporates adjustable components with locking mechanisms that allow for fine-tuning and verification of positioning. The linking means connect the bite block to the head rest and chin rest, creating a mechanically linked system where adjustment of one component automatically positions other components accordingly. This feedback mechanism ensures consistent positioning across multiple therapy sessions.
3Ease of operation
If a bite block is used for head positioning, then the patient's head can be immobilized, but the bite block must be precisely linked to the sliding plate and interface unit to ensure accurate repositioning
Solution Approach 1:
The linking means is designed with pivot points that allow dynamic adjustment of the bite block's position relative to the sliding plate and interface unit. The pivot points enable the bite block to be positioned at different angles and locations, providing flexibility in accommodating various patient anatomies. This dynamic capability simplifies the overall device operation while maintaining positioning accuracy.
Solution Approach 2:
The pivot points act as intermediaries between the bite block, linking means, and sliding plate, allowing for controlled movement and precise positioning. The pivot points translate simple user actions into precise positional adjustments, reducing the complexity of the overall device while ensuring accurate repositioning. The intermediary pivot points make the device easier to operate by providing intuitive control mechanisms.
4Adaptability or versatility
If the fixation device uses a sliding plate mechanism for positioning, then the bite block can be adjusted in position, but the sliding plate must be locked securely to maintain fixation during treatment
Solution Approach 1:
The sliding plate mechanism provides dynamic positioning capability during setup, allowing the bite block to be adjusted to the optimal position for each patient. Once positioned, the locking mechanism secures the sliding plate to maintain fixation reliability during treatment. The dynamic-to-static transition is achieved through the locking mechanism that transforms the movable sliding plate into a fixed component during the therapy session.
Solution Approach 2:
The locking mechanism acts as an intermediary between the sliding plate and the fixation device structure. It securely connects the sliding plate to the head rest and chin rest, transferring the positioning adjustments to the overall fixation system. This intermediary locking mechanism ensures that the positioning adaptability achieved during setup is maintained as fixation reliability during treatment.
Data Source
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AI summary
This application relates to a fixation device (50) for immobilizing a head of a patient relative a treatment unit or medical device during treatment of the head. The fixation device is provided with an interface unit (54) adapted to be fixated in relation to an adaptor unit (52) for connection to the treatment unit, or to a frame for connection to the medical device. Furthermore, the fixation device is further provided with a sliding plate (56) being slidable in relation to said interface unit in an xz-plane of a coordinate system. The system is a Cartesian coordinate system defined by three orthogonal axis having an x-axis extending in the medial-lateral direction of the patient, an y-axis extending in the anterior-posterior direction, and a z-axis extending in the cranial-caudal direction. The fixation device is further provided with a plate locking means (58) for locking said sliding plate in relation to said interface unit, a bite-block (60) for being inserted into a mouth of the patient, a linking means (65) for linking said bite-block with said sliding plate, at least one pivot point (62,64) arranged such that the bite-block is movable at least in a plane orthogonal to the xz-plane; and a link locking means (66) for locking said at least one pivot point in a desired position in relation to said linking means so as to fixate the bite-block to the interface unit.