|
This complaint was reopened in reference to (b)(4).Investigation: visual inspection: no significant deformations or other damage of the valves were detected during the visual inspection.Permeability test: a permeability test has shown that the valve is permeable.Adjustment test: the progav 2.0 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 breaking force is within the given tolerances.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 results show that the valve operates within the acceptable tolerance in the horizontal position.Results: first, we performed a visual inspection of the progav®.No significant deformations or damage of the valve were detected during the visual inspection.Next, we tested the permeability, adjustability, and opening pressure of the valve, as well as the brake functionality and brake force.The valve operates as expected and met all specifications.The computer controlled test showed that the valve operates within the accepted tolerance in the horizontal position, although with a slight tendency to under drainage, which is probably due to deposits of cerebrospinal fluid.If the valve is implanted in a position that is not along the longitudinal under-drainage may occur, depending on how large the angular deviation actually is.With an angular deviation of 45° for example, a good 12 cmh2o is still effective, at a deviation of 30° almost 10 cmh2o.Finally, 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 clinical claim of under drainage.At the time of our investigation, the opening pressure of the valve was within the specified tolerances.However, it is possible that the deposits observed inside the valve could have caused the malfunction in the past.As described in scientific literature, the problem encountered is one of the known, inevitable risks of hg-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.No further regulatory actions are required from our point of view.
|