The reporter indicated that a 3 year 2 month post-operative valve cannot be adjusted.Per the reporter, according to the physician the patient's shunt insertion in 2016.The patient's general condition was stable under the initial pressure setting control; the adjustable pressure was 10.However, two weeks ago, the physician ordered to change the adjustable pressure from 10 to 5.It was then noticed that the valve couldn't be adjusted.The physician also reviewed the skull x-ray, which revealed the pressure of the valve, remained at 10.As a result, shunt explantation was done.
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Investigation: visual inspection a slight deformation of the outer housing of the progav valve was observed through the visual inspection.The progav valve housing was subsequently measured and confirmed the presence of a deformation.The housing deformation measure at -0.048mm, outside the tolerance of 0 =/- 0.02mm.Permeability test a permeability test has shown that both valves are permeable.Adjustment test the progav 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.Finally, we have dismantled the valves.Inside both valves, we have found significant build-up of substances (likely protein).Based on our investigation, we confirm that the progav valve was non-adjustable at the time of our investigation.This is likely due to the significant deposits observed inside the valves.As described in our literature, the problem encountered is one of the known, inevitable risks of hc-therapy by shunt implants.The cause of the deformation of the progav valve could not be determined through our investigation.But we like to point out that significant outside pressure, for example by too much force from the progav adjustment tool or by a fall or impact to the head of the patient, can compromise the integrity of the valve.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 gmbh & co.Kg.
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