MIETHKE proGAV 2.0 Manuel Du Patient page 25

proGAV 2.0 mechanism of action
The proGAV 2.0 is a position-dependent valve. It consists of an adjustable
differential pressure unit and a gravitational unit. In this way it can be en-
sured that optimal CSF drainage is maintained for every individual patient,
independent of the body position of the patient.
Adjustable differential pressure unit
The adjustable differential pressure unit operates the same in all body posi-
tions; for that reason, it has generally got a low opening pressure set for the
horizontal position to ensure that in case of increasing intracranial pressure
the valve permits the timely drainage of cerebrospinal fl uid particularly in the
horizontal position. This opening pressure can be changed post-operative
through the skin, without necessitating any further surgical intervention.
Gravitational unit
The gravitational unit makes use of the principle of gravity. As soon as the
patient moves to an upright position, a tantalum ball is activated, which,
by its weight, sets the opening pressure of the valve to a higher value. The
closer the upperbody of the patient is to the vertical position, the higher the
total opening pressure of the proGAV 2.0.
Adjustment mechanism
The proGAV 2.0 is an adjustable valve. Unintended readjustments by exter-
nal magnet fi elds are protected by the brake of the rotor. The adjustable diffe-
rential pressure unit of proGAV 2.0 is equipped with a feedback mechanism.
Due to the unique construction of the valve housing, pressuring on the valve
produces an acoustic signal (a clicking sound) which is audible or noticeable
as an tacticle resistance, so the brake of the rotor is now released. The valve
indicates acousticly and haptically that the brake of the rotor is released and
the pressure is suffi cient to decoupling. The clicking sound is well recogniz-
able before implantation. However after implantation, once the valve is fi lled
up, depending on place and texture of the surrounding area of the implant,
the acoustic signal could be considerably muted. The clicking sound should
generally be audible by the patient itself or via a stethoscope.
Warning note: Applying pressure on the feedback-mechanism
is restricted to the physician.
Warning note: The shunt system may be fi tted with a pumpa-
ble reservoir. As too frequent pumping can result in an excessive
drainage (overdrainage) and thus unfavourable pressure condi-
tions, this process should only be performed by a physician.
®
EN // proGAV 2.0 PATIENT MANUAL //
25