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Visual inspection: during the investigation, no significant deformations or damage of the valves were determined.Permeability test: a permeability test has shown that the gav 2.0 is permeable and that the pediatric prechamber has a blockage.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 valve is tested in both the horizontal as well as the vertical positions.The results show that the gav 2.0 operates not within the accepted tolerance in both positions.An accelerated outflow in both positions could be determined.Internal inspection: after dismantling of the valve, deposits were found in the gav 2.0 and in the inlet of the pediatric prechamber.To make the deposits in the more visible, they were colored using a staining solution.Results: based on our investigation results, we can determine an accelerated outflow at the gav 2.0 and a blockage at the pediatric prechamber.The deposits visible in the valves may have led to this malfunctions.Deposits caused by substances naturally present in the patient's body, such as protein, blood or tissue particles, are among the known and unavoidable risks and side effects of hydrocephalus therapy.Even small amounts of organic material can affect the integrity of the valve.We can exclude a defect at the time of release.The valve 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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