Modern hydrocephalus treatment started in 1949, when the surgeons Frank Nulsen and Eugene Spitz had showed that shunts, which lead the cerebrospinal fluid to the blood veins, were effective in reducing the pressure in the ventricles.
In 1955 Charles Case (Casey) Holter was born with Arnold-Chiari malformation and a myelomeningocele. The after surgery, the inter-cranial pressure continued to raise despite ventricular taps temporarily relieving the pressure.
Shunt operation were attempted, using ventriculoperitoneal shunts constructed with polythene tubing, but they failed.
While visiting his son in hospital John Holter, Casey Holter's father, noticed a how the valve in an inter-venous line allowed a needle to be inserted and withdrawn, without any leakage of fluid. He suggested, to Dr. Spitz, that the usage of this type of one-way valve could prevent blockage of the shunt.
Using criteria specified by Spitz, Holter quickly began to design an model of a shunt valve using his experience as a hydraulics technician. Holter's design was simple and impressed the doctors, but further development was required. A material which could be easily sterilized, and wouldn't be rejected by the body was still needed.
Silicone which had been successfully used in other surgical procedures was found to have the characteristics required, so after switching from polyethylene to silicone catheters there was a significant decrease in shunt failure.
Further development was made to create a valve which could reliably maintain pressure, and also to design valves with different pressure characteristics.
Holter continued manufacturing the shunts by hand, and supplied over 500 per year.
The Spitz-Holter valve was patented, and a company was formed to manufacture the valves. The basic design from their valve can still used in today's hydrocephalus treatment.