Acta Neurochirurgica

, Volume 159, Issue 8, pp 1389–1397

Comparison of anti-siphon devices—how do they affect CSF dynamics in supine and upright posture?

  • Manuel Gehlen
  • Anders Eklund
  • Vartan Kurtcuoglu
  • Jan Malm
  • Marianne Schmid Daners
Original Article - Neurosurgical Techniques



Three different types of anti-siphon devices (ASDs) have been developed to counteract siphoning-induced overdrainage in upright posture. However, it is not known how the different ASDs affect CSF dynamics under the complex pressure environment seen in clinic due to postural changes. We investigated which ASDs can avoid overdrainage in upright posture best without leading to CSF accumulation.


Three shunts each of the types Codman Hakim with SiphonGuard (flow-regulated), Miethke miniNAV with proSA (gravitational), and Medtronic Delta (membrane controlled) were tested. The shunts were compared on a novel in vitro setup that actively emulates the physiology of a shunted patient. This testing method allows determining the CSF drainage rates, resulting CSF volume, and intracranial pressure in the supine, sitting, and standing posture.


The flow-regulated ASDs avoided increased drainage by closing their primary flow path when drainage exceeded 1.39 ± 0.42 mL/min. However, with intraperitoneal pressure increased in standing posture, we observed reopening of the ASD in 3 out of 18 experiment repetitions. The adjustable gravitational ASDs allow independent opening pressures in horizontal and vertical orientation, but they did not provide constant drainage in upright posture (0.37 ± 0.03 mL/min and 0.26 ± 0.03 mL/min in sitting and standing posture, respectively). Consequently, adaptation to the individual patient is critical. The membrane-controlled ASDs stopped drainage in upright posture. This eliminates the risk of overdrainage, but leads to CSF accumulation up to the volume observed without shunting when the patient is upright.


While all tested ASDs reduced overdrainage, their actual performance will depend on a patient’s specific needs because of the large variation in the way the ASDs influence CSF dynamics: while the flow-regulated shunts provide continuous drainage in upright posture, the gravitational ASDs allow and require additional adaptation, and the membrane-controlled ASDs show robust siphon prevention by a total stop of drainage.


Animal testing alternatives Anti-siphon device Cerebrospinal fluid shunt In vitro Overdrainage Posture 

Copyright information

© Springer-Verlag GmbH Austria 2017

Authors and Affiliations

  • Manuel Gehlen
    • 1
    • 2
  • Anders Eklund
    • 3
  • Vartan Kurtcuoglu
    • 2
    • 4
    • 5
  • Jan Malm
    • 6
  • Marianne Schmid Daners
    • 7
  1. 1.Institute for Dynamic Systems and Control, Department of Mechanical and Process EngineeringETH ZurichZurichSwitzerland
  2. 2.The Interface Group, Institute of PhysiologyUniversity of ZurichZurichSwitzerland
  3. 3.Department of Radiation SciencesUmeå UniversityUmeåSweden
  4. 4.Neuroscience Center ZurichUniversity of ZurichZurichSwitzerland
  5. 5.Zurich Center for Integrative Human PhysiologyUniversity of ZurichZurichSwitzerland
  6. 6.Department of Pharmacology and Clinical NeuroscienceUmeå UniversityUmeåSweden
  7. 7.Product Development Group Zurich, Department of Mechanical and Process EngineeringETH ZurichZürichSwitzerland

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