Manufacturing and qualtiy control data: all parameters have been inspected and approved during the manufacturing process.All parameters have been assessed as meeting specification.Investigation: visual inspection: no significant deformations or damages of the valve were detected during the visual inspection.Permeability test: a permeability test has indicated that the valve has a blockage.Computer controlled test: to test the opening pressure, we use a miethke computer controlled testing apparatus which simulates a cerebrospinal fluid flow.Because the valve is not permeable, a computer controlled test is not possible.Results: we have dismantled the valve.Inside the valve we have found a build-up of substances (likely protein).Based on our investigation, we are unable to substantiate the claim of over-drainage or malfunction.However, it is possible that the deposits observed inside the valve could have caused the malfunctions in the past.As described in our literature, the problem encountered is one of the known inevitable risks of hc therapy by shunt implants.
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