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An adjustable CSF shunt: advices for clinical use
B Lundkvist1, A Eklund, L-O D Koskinen
1Department of Clinical Neuroscience, Umeå University, Umeå, Sweden. bo.lundkvist@neuro.umu.se
Acta Neurologica Scandinavica
|June 17, 2003
Summary
The new Strata shunt, featuring an adjustable differential pressure valve with an anti-siphoning device, demonstrates comparable performance to the Delta valve. Its consistent opening pressure and resistance allow for reliable in vivo testing of cerebrospinal fluid (CSF) shunt function.
Area of Science:
- Neurosurgery and Medical Device Engineering
- Hydrodynamics and Fluid Mechanics in Medical Devices
Background:
- Cerebrospinal fluid (CSF) shunts are critical for managing hydrocephalus, requiring precise control of opening pressure and resistance for effective clinical use.
- Validating manufacturer specifications for CSF shunts is essential to ensure reliable performance and patient safety.
- Adjustable differential pressure valves with anti-siphoning mechanisms are advancements in shunt technology aimed at improving hydrocephalus treatment.
Purpose of the Study:
- To compare the in vitro hydrodynamic properties of the new Strata adjustable differential pressure valve with its predecessor, the Delta valve.
- To validate and supplement the manufacturer's product description for the Strata valve, focusing on opening pressure, resistance, and anti-siphoning function.
- To assess the reproducibility of the Strata valve's performance characteristics.
Main Methods:
- An automated, computerized experimental setup was utilized within an incubator at 37°C to simulate physiological conditions.
- Key parameters including opening pressure, resistance, and anti-siphoning properties were systematically measured for both Strata and Delta valves.
- Six new shunts of each type, including catheters, were tested; Delta valves were set at performance level 1.5 for comparison.
Main Results:
- The Strata and Delta valves exhibited similar hydrodynamic properties and effective anti-siphoning functionality across all tested units.
- Mean resistance values were comparable: 2.6 ± 0.4 mmHg/ml/min for Delta and 2.2 ± 1.0 mmHg/ml/min for Strata shunts.
- The Strata shunt offered five performance levels for opening pressure (3.3, 5.1, 7.7, 10.7, and 13.1 mmHg), with noted variations between individual shunts.
Conclusions:
- The Strata shunt is a functional adjustable valve with an effective anti-siphoning device, demonstrating good reproducibility in opening pressure and resistance.
- At performance level 1.5, the Strata shunt's opening pressure and resistance were similar to those of the Delta valve.
- The established opening pressure and resistance values for the Strata shunt can guide in vivo testing using standard lumbar CSF infusion tests for clinical application.