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Visual inspection: during the investigation, no significant deformations or damages of the valves were determined.Permeability test: a permeability test has shown that both valves are permeable.Computer controlled test: to investigate the claim of under-drainage, the opening pressure is measured using a miethke computer controlled testing apparatus which simulates a cerebrospinal fluid flow.The valves are tested in both the horizontal as well as the vertical position.The results show that the valves are operating within the specified tolerances in their respective relevant position.Adjustment test: the valves were tested and the progav 2.0 is adjustable, but the m.Blue is not adjustable to all pressure settings.Braking force and brake function test: the brake functionality test has shown that the brake function operates as expected for both valves.However, the braking force cannot be measured in the m.Blue due to the non-adjustability of the valve.Internal inspection: after dismantling of the valves, organic deposits were found in both valves.To make the deposits in the valves more visible, they were colored with a staining solution.Results: based on our investigation results, we can determine adjustment difficulties in the m.Blue.The determined organic deposits can be named as the cause for the functional deviation.Organic matter in the cerebrospinal fluid can influence the function temporarily and are known inherent side effects in hydrocephalus therapy.Furthermore, we can determine organic deposits in the progav 2.0.The deposits had no effect to the technical properties at the time of the investigation.We can exclude a defect at the time of release.The shunt system met all specifications of the final inspection when released from christoph miethke gmbh & co.Kg.No further regulatory actions are required from our point of view.
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