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A deformation of the outer housing of the prosa valve and a fdamage oft he membrane of the reservoir were observed through the visual inspection.The prosa valve housing was subsequently measured and confirmed the presence of a deformation.The housing deformation measured at -0.055 mm, outside the tolerance of 0 ± 0.02 mm.Permeability test: a permeability test has shown that both valves are permeable.Adjustment test: the valves were tested and are adjustable to all specified pressures.Braking force and brake function test: the brake functionality test of both valves have shown that the brake functions are fully operational and the braking forces are 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.Neither valve is operating within acceptable tolerances.Results: first, we performed a visual inspection of the shunt system.A deformation of the outer housing of the prosa valve was observed through the visual inspection.The deformation was confirmed through a measurement of the parallelity of the valve housing.Additional was a damage/ cut of the reservoir membrane visible.Next, we tested the permeability and opening pressure of the valves.Both valves were shown to be permeable, but their opening pressures were not operating within the specifications.The opening pressure of both valves were significantly lower than expected, indicating a tendency towards over-drainage.Additionally, we tested the adjustability as well as the brake functionality and brake force of the valves.The valves operated as expected and met all specifications.Finally, we have dismantled the valves.Inside both valves we have found build-up of substances (likely protein).Based on our investigation, we are unable to substantiate the claim of under-drainage.At the time of our investigation, the valves were operating in over-drainage.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.The cause of the deformation of the prosa valve could not be determined through our investigation.Significant outside pressure, for example by too much force from the prosa 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.No further regulatory actions are required from our point of view.
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It was reported that there was a problem with a prosa shuntsystem with progav 2.0.The surgeon suspected that the shuntsystem operated in under-drainage.Patient information: age: (b)(6), height: unknown, weight: unknown, gender: male.Implantation: (b)(6) 2019, removal: (b)(6) 2020.
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