Investigation result: visual inspection: no significant deformations or damage of the valves were detected during the visual inspection.
Permeability test: a permeability test has indicated that the progav 2.
0 valve has a blockage and that the shunt assistant is permeable.
Adjustment test: the progav 2.
0 valve was tested and is not adjustable throughout the normal range.
Braking force and brake function test: the brake functionality test has shown that the brake function is operational, however the braking force cannot be measured due to the non-adjustability of the valve.
Computer controlled test: to investigate the claim of blockage of the valves, the opening pressure is measured using a miethke computer controlled testing apparatus which simulates a cerebrospinal fluid flow.
Because the progav 2.
0 valve is not permeable, a computer controlled test was not possible.
The shunt assistant operates within the accepted tolerance.
Results: first we performed a visual inspection of the progav 2.
0 shunt system.
No significant deformations or damage of the valves were detected during the visual inspection.
Next we tested the permeability and opening pressure of the valves.
The progav 2.
0 valve was not permeable, therefore the claim of over/under-drainage could not be further investigated.
The shunt assistant was permeable and operating within specifications.
Additionally, we tested the adjustability as well as the brake functionality and brake force of the progav 2.
0 valve.
The valve was not adjustable to all settings.
The brake functionality was fully operational, however due to the inability of the valve to hold a set pressure, it was not possible to measure the brake force.
Finally, we have dismantled the valves.
Inside both valves we have found significantly build-up of substances (likely protein).
Based on our investigations, we confirm the presence of occlusion in the system at the time of investigation.
This is likely due to the deposits observed inside the valves.
As described in scientific literature, the problem encountered is one of the known, inevitable risks of hc-therapy by shunt implants.
We can exclude a defect at the time of release.
The shunt system met all specifications of the final inspection when released from christoph miethke (b)(4).
From our point of view, no further regulatory actions are required.
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