A British boy was saved from a life of severe disability by a pioneering medical technique that flushed out his brain to remove the toxic products of a deadly haemorrhage.

Isaac Walker-Cox was born 13 weeks premature and was given hours to live after a blood vessel burst in his brain, causing a condition known as hydrocephalus, which is often fatal.

The toxic fluids building up were generating pressures that threatened to poison his brain and deform his skull. However, two Bristol-based doctors used the new “brain washing” technique to pump them away and so minimise the damage.

Nine years later, Isaac is thriving, above average for his age at reading and afflicted only by a slight paralysis down his left side.

His father Steven, 35, said: “We are astonished by what he can do now. The doctors did tell us he would be left with severe physical and mental disabilities but that has not proved to be the case. He has no mental disability whatsoever. He is in a mainstream school. His physical disability does hold him back a bit but he is not the sort of boy to say no to a challenge.”

The technique could have wider applications, including possible new treatments for conditions such as brain haemorrhages and strokes in adults.

Ian Pople, paediatric neurosurgeon at North Bristol NHS trust, and Andrew Whitelaw, professor of neonatal medicine at the University of Bristol, devised the brain-flushing technique because of the growing number of children who survive very premature birth but then suffer brain haemorrhages.

Whitelaw said: “Premature babies are particularly at risk of bleeding because in the middle of pregnancy, the foetus has many fragile blood vessels in the centre of the brain.”

In Britain, several hundred children are affected by such haemorrhages each year. About half develop hydrocephalus.

Until now, the standard approach has been to insert needles repeatedly into the head to remove fluid, but this has never been proven to work. In fact, no treatment in these babies has been shown to reduce disability or improve any aspect of health.

In the new approach, babies suffering brain haemorrhages were anaesthetised and two tubes were inserted into the ventricles of the brain. One continuously drained the toxin-filled fluid generated by the haemorrhage, and the other was used to infuse an artificial version of the same fluid. By letting less fluid flow in than was drained out, the doctors reduced the pressure in the brain, allowing the bleeding to heal. Typically after three days, the tubes could be removed.

In a trial whose results will be published this week, a number of babies still died or suffered brain damage, but the proportion was significantly reduced. The trial involved 77 premature babies being treated for large brain haemorrhages in Bristol, Glasgow, Katowice in Poland and Bergen in Norway.

Thirty-eight babies were given the standard treatment, where their skulls were drained with needles. Of these 27 (71%), died or were left severely disabled. Of the 39 who underwent brain-flushing, only 21, or 54%, died or were left disabled.

Of the 35 survivors of the new technique only 11, or 31%, were left with severe mental disability. By contrast, 19 of the 32 survivors of the standard technique, or 59%, were left badly impaired.

Whitelaw said: “This is the first time that any treatment has been shown to benefit these very vulnerable babies.”

Isaac, who lives in Yate, south Gloucestershire, was treated in 2000 during an earlier pilot trial. Born at Southmead hospital in Bristol, weighing 2lb 10oz, he suffered a huge haemorrhage 48 hours later.