Implantable CSF Valve With Gravity Compensation Against Overdrainage
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Solution Overview
Problem
Existing shunt systems for treating normal pressure hydrocephalus (NPH) face challenges in setting the threshold pressure due to non-pathologically increased mean pressure and wave-like pressure fluctuations, leading to complications like hydrostatic overdrainage and inadequate treatment results.
Innovation Solution
A valve system with a movable valve body assembly and a spring mechanism that ensures drainage only at low pressures in the horizontal position and prevents backflow, closing at higher pressures in the vertical position, using the weight of the valve body to adjust based on body position.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If a fixed threshold pressure valve is used, then drainage control is simple, but it cannot adapt to body position changes leading to hydrostatic overdrainage
Solution Approach 1:
The valve transitions from a static fixed threshold pressure design to a dynamic adaptive threshold pressure design that automatically adjusts based on body position. The valve incorporates a gravity-compensated mechanism with a movable valve body that responds to changes in gravitational force orientation, allowing the threshold pressure to vary dynamically between upright and horizontal positions to prevent overdrainage while maintaining simple operation.
Solution Approach 2:
The valve changes the threshold pressure parameter automatically based on body position. In the upright position, a higher threshold pressure is maintained to prevent overdrainage, while in the horizontal position, a lower threshold pressure allows adequate drainage. This parameter change is achieved through the interaction of gravitational force with the movable valve body and spring mechanism, eliminating the need for manual adjustment.
2Productivity
If threshold pressure is set low for adequate drainage in horizontal position, then drainage is sufficient, but overdrainage occurs in upright position
Solution Approach 1:
The valve employs dynamic threshold pressure adjustment based on body position. The movable valve body responds to gravitational force changes, automatically setting appropriate threshold pressures: lower threshold in horizontal position for adequate drainage efficiency, and higher threshold in upright position to prevent hydrostatic overdrainage. This dynamic adaptation eliminates the harmful effects of fixed threshold pressure settings.
Solution Approach 2:
The valve uses a spring mechanism that counteracts gravitational force on the movable valve body. The spring force is calibrated to balance gravity in the upright position, maintaining a higher threshold pressure to prevent overdrainage. When the patient lies horizontal, the gravitational component along the valve axis changes, allowing the spring to permit drainage at lower pressures, thus achieving adequate drainage without overdrainage risks.
3Adaptability or versatility
If gravity-compensated system is used, then adaptation to body position is improved, but threshold pressure settings remain critical and narrow
Solution Approach 1:
The valve is designed to be self-adjusting based on body position without requiring complex manual threshold pressure settings. The movable valve body automatically responds to gravitational force changes, and the spring mechanism self-calibrates the threshold pressure according to the patient's position. This self-service design simplifies the setting process while maintaining excellent adaptability to different body positions, reducing the criticality of precise manual adjustments.
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 valve effectively prevents unphysiologically high drainage quantities, reducing the risk of overdrainage and ensuring efficient drainage with improved safety for NPH patients.
Implementation Method 1
a spring device arranged in the interior space and exerting a spring force on the valve body assembly in the direction of the first valve seat
Implementation Method 2
the weight of the valve body assembly acts in the direction of the second valve seat when the valve housing is in a vertical position
Data Source
AI summary
The invention relates to an implantable valve (1) for a drainage system for discharging cerebrospinal fluid, comprising: a valve housing (10) extending along a valve axis (A), an inlet (2) and an outlet (3) as well as a valve housing (10) surrounding an interior space (4), a valve body assembly (600) arranged in the interior (4) and movably arranged in the interior space (4), a first valve seat (5), wherein the valve body assembly (600) is configured to abut the first valve seat (5) to close a flow connection between the inlet (2) and the interior space (4) of the valve housing (10), a second valve seat (7) which faces the first valve seat (5), wherein the valve body assembly (600) is configured to abut the second valve seat (7) to close a flow connection between the outlet (3) and the interior space (4) of the valve housing (10), and a spring device (800) arranged in the interior space (4) which exerts a spring force on the valve body assembly (600) in the direction of the first valve seat (5).