Ocular Shunt Segmentation for Pressure Control and Migration Resistance
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Solution Overview
Problem
Current medical and surgical treatments for glaucoma and idiopathic intracranial hypertension face challenges such as unpredictable outcomes, high complication rates, and failure due to the inability to effectively regulate intraocular and intracranial pressure, leading to irreversible vision loss and eye damage.
Innovation Solution
A shunt system with a two-part construction, comprising a flexible distal tube and a rigid proximal tube, is implanted to connect the ocular anterior chamber with the subarachnoid space, featuring enlarged stop formations to prevent migration and erosion, and a shunt inserting device for precise placement, allowing controlled fluid drainage and pressure regulation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If a glaucoma drainage device is inserted into the subtenon's space, then fluid drainage is achieved, but an inflammatory response occurs resulting in fibrovascular bleb formation and high complication rates
Solution Approach 1:
The patent introduces the subarachnoid space as an intermediary drainage site between the anterior chamber and external space. Cerebrospinal fluid in the subarachnoid space serves as a mediator that receives aqueous humor without triggering inflammation, as it is already a physiological fluid present in the orbital space. This resolves the contradiction by providing a drainage pathway that achieves fluid removal without the harmful inflammatory response associated with subtenon's space drainage.
2Strength
If a shunt is made rigid to maintain structural integrity, then strength is improved, but the shunt cannot conform to the curvature of the ocular globe increasing erosion risk
Solution Approach 1:
The shunt is divided into multiple segments: a rigid proximal portion for structural integrity and strength, a flexible intermediate portion for conforming to curvature, and a distal portion for drainage. This segmentation allows each segment to fulfill its specific function - the rigid proximal segment maintains structural integrity while the flexible intermediate segment conforms to the ocular globe curvature, eliminating erosion risk.
Solution Approach 2:
Different portions of the shunt have different mechanical properties tailored to their specific functions. The proximal portion has high rigidity for structural support, the intermediate portion has graded flexibility to match tissue curvature, and the distal portion has appropriate compliance for drainage. This local differentiation of material properties resolves the contradiction between overall strength and local conformability.
3Reliability
If the distal stop formation is made large to prevent shunt withdrawal, then shunt stability is improved, but the shunt may become blocked by iris tissue
Solution Approach 1:
The stop formation is designed with a specific geometric configuration where its primary dimension for preventing withdrawal (radial extent) is separated from its dimension that could cause blockage (lumen obstruction). The stop formation extends radially to engage with surrounding tissues for stability, while the lumen remains clear and unobstructed. This dimensional separation allows the stop formation to provide stability without compromising fluid flow.
4Ease of operation
If the proximal shunt portion is made rigid to facilitate advancement through sclera, then ease of implantation is improved, but migration resistance after implantation is reduced
Solution Approach 1:
The shunt is segmented into a rigid proximal portion for easy advancement through scleral tissue during implantation, and a flexible intermediate portion that can be secured with fixation elements after implantation. The rigid segment provides the necessary stiffness for surgical manipulation and insertion, while the flexible segment allows for secure anchoring and resistance to migration forces once implanted.
Solution Approach 2:
The shunt transitions from a static rigid structure to a dynamic system where the rigid proximal portion remains fixed during implantation, while the flexible intermediate portion can be actively secured using fixation elements such as sutures or tissue engagement features. This dynamic approach allows the shunt to achieve both ease of implantation and migration resistance through different phases of the implantation process.
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 shunt system provides immediate, predictable, and long-term pressure control, reducing complications and the risk of bleeding, while preventing irreversible eye damage by maintaining balanced intraocular and intracranial pressures.
Implementation Method 1
the shunt having an enlarged distal stop formation near the distal end of the shunt, which is disposed in the subarachnoid space after implantation of a distal end region of the shunt in the subarachnoid space, for resisting withdrawal of the shunt
Implementation Method 2
the proximal shunt portion includes at least one outwardly-projecting ridge formation for resisting migration of the proximal shunt portion after implantation thereof in the ocular anterior chamber
Implementation Method 3
being flexible along a portion of a length of the shunt so as to conform to an outer anatomical curvature of the ocular globe
Data Source
Figure 1
Figure 2
Figure 2A
AI summary
A shunt 10 for implantation in the human body for treating ocular disorders related to disorders of intraocular or intracranial pressure by providing for flow of aqueous fluid in the anterior chamber A of the eye and cerebrospinal fluid in the subarachnoid space B surrounding the optic nerve C. The shunt has a proximal end 12 which is implanted in the ocular anterior chamber and a distal end 14 which is implanted in the subarachnoid space. The shunt has a two-part construction, including a flexible distal tube 18 and a rigid proximal tube 20. The distal tube has a distal stop formation 26 near the distal end 14 which is located in the subarachnoid space upon implantation of the distal end, resisting withdrawal of the shunt. The proximal tube has a curved portion which conforms to the anatomical curvature of the ocular globe.