Roald Dahl's contribution to neurosurgery: The Wade-Dahl-Till shunt

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LETTER TO THE EDITOR
Roald Dahl’s contribution to neurosurgery:
the Wade-Dahl-Till shunt
Dennis R. Buis &Ellen S. Mandl
Received: 28 September 2010 / Accepted: 29 September 2010 / Published online: 12 October 2010
#The Author(s) 2010. This article is published with open access at Springerlink.com
Although most physicians know Roald Dahl (1916–1990)
for the many wonderful novels and short stories he wrote,
due to a personal tragedy, he is also one of the inventors of
the modern ventricular catheters and shunt valves.
In 1960, while living in New York, his then 4-month-old
son Theo was hit by a New York taxi and suffered
traumatic brain injury with multiple skull fractures and
cerebral damage [2]. Theo survived, but developed second-
ary hydrocephalus. When his condition stabilized after
implantation of a ventriculo-atrial shunt, the Dahl family
moved back to the United Kingdom in January 1961 [2].
Back in the UK, Theo suffered from hydrocephalus due to
multiple shunt obstructions with debris clogging the
silicone slits of his Holter valve [2,5].
Dahl was determined to find a solution to this
problem. He contacted Stanley Wade, a toymaker who
specialized in making small hydraulic pumps that
supplied fuel to model aeroplane engines [2]. Meanwhile
Theo’s treatment was taken over by pediatric neurosur-
geon Kenneth Till at the Hospital for Sick Children at
Great Ormond Street in London, who invited both Dahl
and Wade in his operating room so they could see how the
shunts were used in clinical practice [2]. Together, they
designed a new introducer device for the ventricular
catheter and a valve for the treatment of hydrocephalus
in young children [3,4].
The inventors had observed that the valve became
obstructed by cerebral debris, which was introduced
through the slits of the ventricular catheter when the
catheter was inserted through the brain into the ventricles.
In order to prevent this, the openings (slits) of the
ventricular shunt should not come in contact with brain
during the initial placement [4]. A cannula (A) carrying a
hollow tube (B) or trocar (D) was inserted through a small
dural opening into the ventricles (Fig. 1). The “plug of
brain”inside the hollow tube should be removed by the
release of cerebrospinal fluid (CSF) or by withdrawal of the
tube [4]. With the cannula in place, the hollow tube or
trocar was removed, and the ventricular catheter with a
stilette (C) was placed into the ventricles (Fig. 1). The
cannula was then removed over the ventricular drain with
the stilette holding the catheter in place. After removal of
the stilette, the ventricular shunt was in place without ever
having touched brain [4].
The commercially available valves had another problem:
they were expensive and often had plastic components that
could not be sterilized [3]. The Wade–Dahl–Till (WDT) valve
was made of stainless steel, and patients were only charged
the costs to produce the valve [2,3]. Therefore, the WDT
valve cost less than a third of its predecessors [2,3].
In order to prevent obstruction of the valve, no non-
return slits, such as were used in the Holter valve [1], but a
moving steel disk was used, therefore CSF could be drained
through the widest possible surface. The valve consisted of
only six moving parts: a steel disk (E) placed in a four-
pronged cage (D) topped with a seat (B) placed in a
D. R. Buis
Neurosurgical Center Amsterdam, VU University Medical Center,
Amsterdam, The Netherlands
E. S. Mandl
Department of Neurosurgery, St. Elisabeth Hospital,
Tilburg, The Netherlands
D. R. Buis (*):E. S. Mandl (*)
Department of Neurosurgery, St. Elisabeth Ziekenhuis Tilburg,
P.O. Box 90151, 5000 LC Tilburg, The Netherlands
e-mail: drbuis@gmail.com
E. S. Mandl
e-mail: ellensmandl@gmail.com
Acta Neurochir (2011) 153:429–430
DOI 10.1007/s00701-010-0834-z

cylinder (A) (Fig. 2). On the side of the seat, the steel disk
had a knife-edge round its rim to prevent backflow.
The valve was designed to shunt CSF into a cerebral
sinus and thus had an extremely low opening pressure of
0.2–0.5 cm water. When necessary, CSF could be pumped
out of the ventricles by applying digital pressure on the
valve through the scalp. The inventors explicitly mention
the risk of causing subdural hematomas when doing this in
older children with a closed fontanel [3].
The WDT valve was taken into production in 1962, and
the first patient was treated around June 1962. The WDT
valve was estimated to have been used in two to 3,000
children worldwide in the next couple of years, before it
became superseded by novel types of valve. Fortunately for
Roald Dahl, in 1962, Theo’s hydrocephalus turned into an
arrested state, and he never received the carefully designed
WDT shunt.
Conflicts of interest None.
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References
1. Drake JM, Sainte-Rose C (1995) History of cerebrospinal fluid
shunts. In: Drake JM, Sainte-Rose C (eds) The shunt book.
Blackwell Science, Cambridge, pp 3–12
2. Sturrock D (2010) A tornado of troubles. Storyteller. The life of
Roald Dahl. Harper Press, London, pp 356–385
3. Till K (1964) A valve for the treatment of hydrocephalus. Lancet
283:202
4. Till K (1964) Introducer for intraventricular catheter used in
treatment of hydrocephalus. Lancet 1:202
5. Treglown J (1995) Punishment and pain, unhappiness and despair.
Roald Dahl: a biography. Harvest/HBJ Book, Orlando, pp 136–157
Fig. 2 The Wade–Dahl–Till valve: Anarrow exit, Bseat, Ccylinder,
Dfour-pronged cage, Esteeldisk(takenfromTill[4], with
permission). The bottom arrow represents the direction of flow
Fig. 1 Introducer system for intraventricular catheter placement. A
cannula, Bhollow tube, Crigid stilette, Dtrocar (taken from Till [4],
with permission)
430 Acta Neurochir (2011) 153:429–430