Hydrodynamics of the Certas™ programmable valve for the treatment of hydrocephalus

Fluids and Barriers of the CNS

Jan Malm⁴  Stephen M Dombrowski²  Mark G Luciano²  Michael A Williams³  Lars-Owe D Koskinen⁴  Anders Eklund¹ 

[1] Department of Radiation Sciences, Umeå University, Umeå, S-901 85, Sweden;Department of Neurosurgery, Cleveland Clinic, Cleveland, US;Department of Neurology, The Sandra and Malcolm Berman Brain & Spine Institute, Sinai Hospital, Baltimore, US;Department of Clinical Neuroscience, Umeå University, Umeå, Sweden

关键词: Conductance;    Outflow resistance;    Intracranial pressure;    Shunt;    Cerebrospinal fluid;    CSF;    Normal pressure hydrocephalus;    Hydrocephalus;   

Others  :  807232
DOI  :  10.1186/2045-8118-9-12

 received in 2012-03-23, accepted in 2012-05-29,  发布年份 2012

【 摘 要 】

Background

The new Certas™ shunt for the treatment of hydrocephalus has seven standard pressure settings that according to the manufacturer range from 36 to 238 mmH₂O, and an additional “Virtual Off” setting with an opening pressure >400 mmH₂O. Information on actual pressure response and reliability of shunt performance is important in clinical application, especially the “Virtual Off” setting as a non-surgical replacement for shunt ligation. The objective of this study was to evaluate the in-vitro hydrodynamic performance of the Certas™ shunt.

Methods

Six new Certas™ shunts with proximal and distal catheters were tested with an automated, computerized test system that raised the pressure from zero to a maximum pressure and back to zero at each valve setting. Opening pressure and flow resistance were determined.

Results

For settings 1–7 the measured opening pressure range was 26 to 247 mmH₂O, and the mean change in opening pressure for a one-step adjustment was between 33 and 38 mmH₂O. For setting 8 (“Virtual Off”) the measured mean opening pressure was 494 ± 34 mmH₂O (range 451 to 556 mmH₂O). The mean outflow resistance was 7.0 mmHg/ml/min (outflow conductance 17.9 μl/s/kPa).

Conclusions

The six shunts had similar characteristics and closely matched the manufacturer’s specifications for opening pressure at settings 1–7. The opening pressure for the “Virtual Off” setting was nearly 500 mmH₂O, which is 100 mmH₂O higher than the manufacturer’s specification of “>400” and should be functionally off for most patients with communicating hydrocephalus. Clinical studies are needed to evaluate if the CSF dynamic profile persists after implantation in patients.

【 授权许可】

   
2012 Eklund et al.; licensee BioMed Central Ltd.

【 图 表 】

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