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Visual inspection.During the investigation, no significant deformations or damage of the valves was determned.Permeability test: a permeability test has shown that the shuntassistant is 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 valve is tested in both the horizontal as well as the vertical position.The results show that the shunt assistant is operating within the accepted tolerance in the horizontal position, but not within the specified tolerances in the vertical position.An accelerated outflow of shunt assistant in the vertical position could be determined.Internal inspection: after dismantling of the valve, deposits were found in the shuntassistant.Results: based on our test results, we can determine an accelerated outflow at the shuntassistant.The deposits visible in the valve may have led to the change in flow rate.Deposits caused by natural substances in the 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 proteins can impair 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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