Abstract
Shunt testing independent of manufacturers provides knowledge that can significantly improve the management of patients with hydrocephalus. The Cambridge Shunt Evaluation Laboratory was created 20 years ago. Thanks to financial support from the Department of Health (1993–1998), all shunts in use in the UK were systematically evaluated, with “blue reports” being published. Later new devices were tested as they appeared in public domain.
Twenty-six models have been evaluated. The majority of the valves had a non-physiologically low hydrodynamic resistance that may result in over-drainage, both related to posture and during nocturnal cerebral vasogenic waves. A long distal catheter increases the resistance of these valves by 100–200 %. Drainage through valves without a siphon-preventing mechanism is very sensitive to body posture. Shunts with siphon-preventing accessories offer a reasonable resistance to negative outlet pressure. Bench parameters were used to test shunt performance in vivo using infusion tests. A criterion for correctly performing a shunt procedure was established. Pressure measured in the shunt prechamber during the plateau phase of infusion should not remain more than 5 mmHg above the le shunt’s operating pressure plus hydrodynamic resistance of the valve multiplied by the infusion rate. “Critical levels” for every shunt and every performance level have been used in the shunt testing wizard of ICM+ software.
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References
Albeck MJ, Børgesen SE, Gjerris F, Schmidt JF, Sørensen PS (1991) Intracranial pressure and cerebrospinal fluid outflow conductance in healthy subjects. J Neurosurg 74(4):597–600
Aschoff A, Kremer P, Benesch C, Fruh K, Klank A, Kunze S (1995) Overdrainage and shunt technology. A critical comparison of programmable, hydrostatic and variable-resistance valves and flow-reducing devices. Childs Nerv Syst 11(4):193–202
Chari A, Czosnyka M, Richards HK, Pickard JD, Czosnyka ZH (2014) Hydrocephalus shunt technology: 20 years of experience from the Cambridge Shunt Evaluation Laboratory. J Neurosurg 120(3):697–707
Chhabra DK, Agrawal GD, Mittal P (1993) “Z” flow hydrocephalus shunt, a new approach to the problem of hydrocephalus, the rationale behind its design and the initial results of pressure monitoring after “Z” flow shunt implantation. Acta Neurochir (Wien) 121(1–2):43–47
Czosnyka Z, Czosnyka M, Richards HK, Pickard JD (1998) Posture-related overdrainage: comparison of the performance of 10 hydrocephalus shunts in vitro. Neurosurgery 42(2):327–333
Czosnyka ZH, Czosnyka M, Pickard JD (2002) Shunt testing in-vivo: a method based on the data from the UK Shunt Evaluation Laboratory. Acta Neurochir Suppl 81:27–30
Disclosure
Cambridge Shunt Lab had R-D agreements (short term) with various shunt manufacturers (J&J, Medtronic, Integra, Miethke, Sophysa etc.) to cover the costs of shunt testing.
MC has a consultancy agreement with Codman J&J and lecture contracts with Integra.
JDP was a member of the Scientific Advisory Board for Medtronic and Codman J&J.
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We declare that we have no conflict of interest.
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© 2016 Springer International Publishing Switzerland
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Czosnyka, Z., Czosnyka, M., Pickard, J.D., Chari, A. (2016). Who Needs a Revision? 20 Years of Cambridge Shunt Lab. In: Ang, BT. (eds) Intracranial Pressure and Brain Monitoring XV. Acta Neurochirurgica Supplement, vol 122. Springer, Cham. https://doi.org/10.1007/978-3-319-22533-3_68
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DOI: https://doi.org/10.1007/978-3-319-22533-3_68
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