Investigation results: visual inspection: no deviations are detected.Measurement of surface of the housing: the measured value of -0.054 mm lies not within the given tolerance (0 ± 0.02mm).Permeability test: the test showed that the prosa is permeable.Computer controlled test: the computer controlled test has shown the opening pressure of the prosa, at a reference flow rate of 20 ml/hr in a horizontal position, to be 0.97 cmh2o.This is within the specified tolerance of 2 cmh2o ± 2 cmh2o.Additionally, the prosa was tested according to standard procedure in the vertical position.At an opening pressure of 0 cmh2o in the vertical position, a pressure of 0 cmh2o ± 7 cmh2o is expected.The results indicated that at a reference flow of 20 ml/hr in the vertical position, the prosa had a pressure of 1.93 cmh2o.This is within the specified tolerance of 0 cmh2o ± 7 cmh2o.Adjustability test: the prosa was found to be adjustable to all pressure settings.Braking force and brake function test: the braking force of the prosa® was within the specified tolerance and the brake function operated as expected.Internal inspection of product: in order to verify whether the investigated valve was compromised by the known risks of hydrocephalus therapy, e.G.By a build-up of natural substances (protein, blood, or tissue particles) in the cerebrospinal fluid, we have dismantled the valve.After dismantling of the valve, some deposits were found in prosa.Results: based on our investigation, we are not able to substantiate the claim of "under-drainage." however, we assume that the significant deposits found within the valve may have temporarily caused the functional impairment.Deposits caused by natural substances in the cerebrospinal fluid, such as protein, blood or tissue particles, are among the known and unavoidable risks and side effects of hydrocephalus therapy.We can exclude a defect at the time of release.The valve met all specifications of the final inspection when released from christoph miethke (b)(4).No further regulatory actions are required from our point of view.
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