Manufacturing site evaluation: the shunt system was manufactured by a qualified employee; deviations during assembly did not occur.All parameters have been inspected and approved during the manufacturing process.All parameters have been assessed as meeting specifications.Investigation - the shunt system was received submersed.No significant deformations or damage of the valve were detected during the visual inspection.Permeability test- the test has shown that the valve is permeable.The flow rate was slower than expected.Adjustment test - this is a fixed pressure valve.An adjustment test was not applicable.Braking force and brake function test - this is a fixed pressure valve.A braking force and brake function test is not applicable.Computer controlled test - to investigate the claim of over-drainage, the opening pressure is measured using a testing apparatus which simulates a cerebrospinal fluid (csf) flow.The valve is tested in the vertical position and was tested twice.The first results showed that the valve was not operating within the acceptable tolerance.Upon a seond test, the opening pressure value moved just within tolerance.This was likely due to a clearing out of the valve due to the nature of the test.Results - after the tests, we have dismantled the valve.Inside the valve we have found a build-up of substances (likely protein).Based on our investigation, we confirm that the valve was operating in an over-drainage state, likely due to the deposits observed inside the valve.As described in our literature, the problem encountered is one of the known, inevitable risks of hydrocephalus therapy by shunt implants.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.
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