Non-Cylindrical Guide Sleeve for Spinal Intervention
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Solution Overview
Problem
Conventional percutaneous spinal surgery methods using cylindrical guide sleeves result in increased tissue stress and risk of nerve damage due to large lateral cross-sectional dimensions and sharp edges, which are not adequately addressed by existing technologies.
Innovation Solution
A non-cylindrical guide sleeve with a convexly curved broad side and narrow sides, along with a set of dilators, is designed to reduce the height and stress on the patient, featuring a radius of curvature of 11 to 12.5 mm and an angle of curvature transition between 3 and 4.5 mm, with projections and rounded edges to minimize tissue trauma and improve grip.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of stationary object
If a conventional cylindrical guide sleeve is used to enable percutaneous access for intervertebral basket insertion, then the lateral cross-sectional dimensions are sufficient for instrument passage, but the height and tissue stress increase significantly
Solution Approach 1:
The guide sleeve employs a non-cylindrical design with convexly curved broad sides and rounded edges instead of sharp corners. This curvature reduces the height requirement while maintaining sufficient lateral cross-sectional area for instrument passage, thereby reducing tissue stress and the risk of nerve root compression.
Solution Approach 2:
The guide sleeve features an asymmetric cross-section with distinct broad sides and narrow sides, where the broad sides are convexly curved and separated by rounded corners. This asymmetric geometry optimizes the distribution of tissue stress and allows for reduced height while maintaining adequate lateral dimensions for basket insertion.
2Manufacturing precision
If a rectangular cannula with sharp outer edges is used, then the inner contour can be precisely defined, but the risk of damaging blood vessels and nerve tracts increases
Solution Approach 1:
The sharp outer edges of the cannula are replaced with rounded edges having a specified radius of curvature. This rounding maintains precise contour definition while eliminating the harmful sharp edges that could damage blood vessels and nerve tracts during insertion and manipulation.
3Reliability
If the guide sleeve height is reduced to minimize tissue stress, then patient safety improves, but the complexity of achieving precise geometric parameters increases
Solution Approach 1:
The guide sleeve design specifies precise geometric parameters including radius of curvature of 11 to 12.5 mm for convexly curved broad sides and angle of curvature transition of 3 to 4.5 mm. These parameter changes enable reduced height while maintaining functional requirements, balancing patient safety with manufacturable precision.
Data Source
Figure 1.1~1.2
Figure 1.3~2
Figure 3~4.1
AI summary
To reduce as far as possible the strain placed on a patient during a percutaneous spinal column intervention for insertion of an interbody cage between two vertebrae between which the intervertebral disc has been damaged and has therefore been removed, the invention proposes in the first instance a guide sleeve (3) which is used for the spinal column intervention and which has a non-cylindrical jacket (3.1). To achieve the stated object, the invention further proposes a set for spinal column interventions comprising at least one guide sleeve of the above-mentioned type and an expander (4), of which the outer contour is adapted to the contour of the lumen of the guide sleeve. Finally, the invention proposes a kit for the spinal column intervention consisting of a guide sleeve and of an interbody cage which is to be inserted through the guide sleeve, in which the lumen of the guide sleeve is adapted to the maximum cross-sectional contour of the interbody cage.