Wade-Dahl-Till valve

The Wade-Dahl-Till (WDT) valve is a cerebral shunt developed in 1962 by hydraulic engineer Stanley Wade, author Roald Dahl, and neurosurgeon Kenneth Till.

Dahl knew Wade to be an expert in precision hydraulic engineering, from their shared hobby of flying model aircraft.

(In addition to building his own model aircraft engines, Wade ran a factory at High Wycombe for producing precision hydraulic pumps.

)[3] With Dahl coordinating the efforts of the neurosurgeon and the hydraulic engineer, the team developed a new mechanism using two metal discs, each in a restrictive housing at the end of a short silicone rubber tube.

[2] As Till reported in The Lancet, the invention was characterized by “low resistance, ease of sterilisation, no reflux, robust construction, and negligible risk of blockage”.