The concept of bypassing the impaired CSF circulation in the existence of a hydrocephalus
was introduced by Gardner in 1895. This concept underwent different evolutionary modifications
of its components. There is an evolution of the approaches to the ventricular system,
an evolution of the targets of the CSF (normally a preformed hole of the body) and
an evolution of the tube systems and the interposed valves. While, in the meantime,
the approach to the ventricular system has been established to transcortical frontal
or transcortical parietodorsal, and the CSF is normally is drained into the peritoneal
cavity, the ideal tube system and the ideal valve are still a matter of debate. The
main problems are still the lack of a material which is resistant to colonisation
of bacteria, adhesion of immunocompetent cells, and kinking or rupture of the tube.
The other main problem is inadequate drainage because the valve does not adapt to
the body position. Consequences of these deficits are infections, hydrocephal situations
and overdrainage with bleedings or slit ventricle syndromes. Special modifications
of the tube surface, mechanisms for neutralisation of the gravitation effect and adjustable
valves are actual inventions. The goal is a valve system, which adapts to the continuously
changing physiological situation automatically.
