A combination of gravitational and differential pressure valve

for the treatment of HC in adults


  • a gravitational valve for the treatment of hydrocephalus in adults
  • more protection against overdrainage complications due to position-dependent function
  • MRT compatible up to 3 Tesla
  • slim, cylindrical design for easy implantation in the retroauricular region
  • precise precision engineering
  • robust and durable due to the use of titanium


The GAV - gravitation-assisted valve - operates according to the position of the patient's body and thus offers more protection against overdrainage complications.

The GAV is manufactured from a solid and stable titanium housing. The proximal side consists of a ball-cone unit. A spiral spring controls the valve opening pressure here. The functioning of the gravitational unit on the distal side of the valve is ensured by a tantalum and a sapphire ball. The slim and cylindrical design makes implantation comparatively easy. Due to the integrated gravitational technology it is important to implant the valve parallel to the body axis.

Horizontal Position

As long as the patient is lying down, the intraventricular pressure is controlled exclusively by the ball-cone unit of the GRAVITY ASSISTED VALVE. The freely movable balls of the gravity unit do not provide any additional resistance when the patient is lying down and automatically keep the flow channel open at this point. In the upper illustration, the ball-and-cone unit is closed and prevents any liquor drainage. If the intraventricular pressure increases, this force acts on the ball-and-cone unit and finally causes the spring to give way and a gap to form between the cone and the ball, which now allows the cerebrospinal fluid to flow. In the illustration below, the GAV is open.


Vertikale Position

In the upright position, the gravitational unit is automatically activated when the balls fall down. A higher valve opening pressure is established, since the opening pressures of both valve mechanisms (differential pressure and gravitational unit) must now be overcome. If the patient therefore straightens up, the gravitational unit closes and the risk of overdrainage is reduced. If the sum of both valve units is exceeded by the increasing intraventricular pressure, the valve opens and thus enables the necessary drainage of the cerebral fluid.



Each preset pressure stage is specially coded and can be recognized post-operatively in imaging. The lower illustrations show the X-ray images of all available pressure stages of the GAV (5/30, 5/35, 4/40, 10/30, 10/40 and 10/50 cmH2O):


pressure stage 5/30 cmH2O



pressure stage 5/35 cmH2O



pressure stage 5/40 cmH2O



pressure stage 10/30 cmH2O



pressure stage 10/40 cmH2O



pressure stage 10/50 cmH2O


For detailed information on the optimum pressure stage setting, please refer to our pressure stage recommendation.




The MIETHKE App shows clearly and quickly understandable how our valves work:

+ Influence of the body position on the opening pressure: The motion sensor of the smartphone simulates the body position of the patient: upright - inclined - lying.

+ Pressure stage recognition in the X-ray image: Every set or preset pressure stage is shown here and can be easily recognized by means of templates.

+ Simulation of adjustability: Valves can be easily adjusted with the finger and thus help to understand what is happening inside the valve.

+ View into the inside of MIETHKE valves: All valves allow a view of their construction and thus the influence of the cerebrospinal fluid flow on the functioning can be shown in an easily understandable way.

+ free for Apple and Android




Download Information


GAV Brochure


Instructions for use


Patient Manual


Thoralf Knitter

Head of Research & Development

Roland Schulz

Head of Product Management

Thammo Weise

Product Management

Andreas Bunge

Product Management

Michaela Funk-Neubarth

Head of Marketing & HR

Jan Mügel

Product Management

Josefine Kehl

Press & Public Relations

August von Hardenberg

Product Management

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B. Braun and MIETHKE - Together for a better life with hydrocephalus

We have a long and intensive partnership with B. Braun in the field of neurosurgery. We are driven by a common vision: to improve the lives of hydrocephalus patients around the world with innovative solutions.

Our partnership is an exciting combination of B. Braun's nearly 180 years of expertise as one of the world's leading medical device and pharmaceutical companies and our agility as an innovative company and technology leader in gravitation-based shunt technology. 


Our strong partner in neurosurgery: