Patient-Specific Fibula Malleolus Cap for Osteotomy Guide Alignment
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Solution Overview
Problem
Current methods for jaw reconstruction using fibula free flaps face challenges with sliding and rotational errors due to the geometric variations of the fibula and soft tissue interference, leading to inaccuracies in positioning the fibula harvest guide.
Innovation Solution
The development of patient-specific fibula malleolus caps connected to osteotomy guides via connecting bars, which are designed to fit the morphology of the lateral malleolus and reduce errors by providing precise alignment and angulation during fibula harvesting.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If traditional measurement methods from lateral malleolus are used to locate fibula harvest guide, then the surgical procedure is simple to perform, but sliding and rotational errors occur leading to positioning inaccuracy
Solution Approach 1:
The surgical device is segmented into distinct functional components: a malleolus cap that fits the lateral malleolus, a connecting bar for rigid attachment, and an osteotomy guide for precise cutting. This segmentation allows each component to perform its specific function optimally while maintaining overall positioning accuracy.
Solution Approach 2:
The malleolus cap acts as an intermediary element between the lateral malleolus and the osteotomy guide. It provides a stable reference point on the rounded malleolus surface, eliminating direct measurement errors from the irregular malleolus geometry while transmitting positional information accurately to the guide.
2Manufacturing precision
If fibula harvest guide is positioned without patient-specific morphology fitting, then the device is easier to manufacture, but sliding errors occur due to geometric variations of fibula
Solution Approach 1:
The malleolus cap is designed with local quality specific to each patient's anatomy. The inner surface morphology is customized to match the patient's lateral malleolus geometry, providing optimal fit and stability at the specific location while the rest of the device can be manufactured using standard processes.
Solution Approach 2:
The device incorporates patient-specific parameters obtained from preoperative imaging (CT or MRI scans). These parameters define the unique geometry of the lateral malleolus, allowing the malleolus cap to be customized for each patient while maintaining manufacturability through digital modeling and additive manufacturing technologies.
3Measurement precision
If conventional osteotomy guide positioning is used, then the surgical workflow is simpler, but rotational errors occur due to rounded shape of fibula cross-section
Solution Approach 1:
The malleolus cap is pre-positioned on the lateral malleolus to establish a stable reference frame before the osteotomy guide is attached. This preliminary action eliminates rotational degrees of freedom and ensures correct angular orientation of the subsequent osteotomy cuts according to the virtual surgical plan.
Solution Approach 2:
The connecting bar serves as a mediator that rigidly connects the pre-positioned malleolus cap to the osteotomy guide. This intermediary component ensures that the angular relationship established by the cap is accurately transmitted to the guide, preventing rotational errors during osteotomy while maintaining ease of operation.
Data Source
Figure 1A~1F
Figure 2A~2C
Figure 2D~2F
AI summary
Described are fibula malleolus caps and surgery devices with fibula malleolus caps. The fibula malleolus caps may be patient-specific fibula malleolus caps. The devices with patient-specific fibula malleolus caps overcome the sliding and rotational errors during fibula flap harvesting. A comparative clinical study demonstrates that the fibula malleolus cap enhances the accuracy of fibula flap harvesting, leading to accurate location and angulation of simultaneous dental implants.