Investigation: visual inspection: scratches on the outer housing of the valves were observed through the visual inspection.No significant deformations or damage were detected.Permeability test: a permeability test has shown that both valves are permeable.Adjustment test: the progav 2.0 valve was tested and is adjustable to all specified pressures.Braking force and brake function test: the brake functionality test has shown that the brake function is fully operational and the braking force is within the given tolerances.Computer controlled test: to test the opening pressure, we use a miethke computer controlled testing apparatus which simulates a cerebrospinal fluid flow.Both valves are operating within acceptable tolerances.Results: finally, we have dismantled the valves.There were no visible deposits inside the valves.Based on our investigation, we are unable to substantiate the claim of underdrainage.The valves operate within the specified tolerances.Despite no visible deposits being observed, it is possible that even a small amount of non-visible blood or protein can lead to a temporary blockage and could be responsible for the suspected malfunction in the past.As described in our literature, the problem described is one of the known, inevitable risks of hc-therapy by shunt implants.
|