The number of shunt systems used over time in neurosurgery has grown to a considerable number. Thus, it is quite possible to encounter a patient with an implanted shunt system that is unknown and cannot be identified on the radiograph either.
This article is intended to help distinguish between the various commonly used shunt valves and their properties. The collection of shunt valves described in this article is not exhaustive, but should represent the systems most frequently implanted.
Overview table
Shunt valve | Adjustable opening pressure | MRI compatibility |
proGAV 2.0 | Yes | Yes |
Polaris Sophysa | Yes | Yes, up to 3 Tesla[^2] |
Codman Hakim | Yes | Conditional. Verification of the shunt valve setting is required. |
proGAV 2.0
The proGAV 2.0 valves are distributed by Miethke and can be adjusted using a magnet between an opening pressure of 0-20 cmH20. The shunt setting can also be read using a magnetic indicator directly on the patient or by radiographic imaging of the shunt valve. Determination on the radiograph provides more reliable information about the current setting, since reading it with the aid of the magnet depends on the orientation of the shunt valve beneath the skin and is more difficult in patients with pronounced subcutaneous adipose tissue.
proGAV 1.0
The proGAV 1.0 shunt valves are predecessors of the proGAV 2.0 valves and are also distributed by the same company, Miethke.
Sophysa Polaris shunt valve
The Polaris® Shunt System is distributed by Sophysa and is an adjustable shunt valve compatible with MRI up to 3 Tesla[^2].
The Polaris® shunt valve has an adjustable pressure setting of 30-200mmHg in the standard model, and there are three additional models that can be differentiated on radiographs by a marker and offer further pressure-setting options.
Codman Hakim shunt valve
The Codman Hakim shunt valve is manufactured by Codman Inc and can be adjusted to 18 different pressure settings ranging from 30-200 mm H2O.
Spitz-Holter shunt valve
The Spitz-Holter shunt valve was developed in Philadelphia in the 1950s and was the first functioning shunt valve for the treatment of hydrocephalus[^1]. Spitz-Holter shunt valves are no longer implanted in Europe and have been replaced by more modern shunt valves. The pressure setting of Spitz-Holter shunt valves cannot be determined from radiographs.
