He and his team at East Shore Hospital spent just over four hours on the operation.

The eight-year-old girl, whose formerly conjoined twin Ganga died in July, needed the operation to fix a relatively rare problem called a chiari malformation.

Part of her brain was blocking the normal flow of fluid from the brain down the spinal column; the fluid was instead forcing its way into her spinal cord, damaging the nerves and tissues there.

This may well have been the reason she has not been able to use her right arm and leg despite intensive physiotherapy. The problem was also at the root of her headaches.

Doctors yesterday removed a piece of bone about 3cm in diameter from the base of her skull.

The plan was to insert a pair of heated forceps through this gap to shrink the cerebellum, the bottom part of her brain, so space would be freed up to allow the fluid to flow normally down her spinal column.

But on removing the bone, Dr Goh and his team found a mass of scar tissue; it was impossible to separate the brain from the spinal cord.

He therefore did not attempt to use the heated forceps in case it damaged the spinal cord. He proceeded instead to remove as much of the fibrous tissue as possible to create space.

After this, he closed up the hole with skin. The bone was not replaced in case it constricted the brain. Many centres in the United States do this routinely, and this procedure alone is often enough to allow the brain fluid to flow normally, he said.

Jamuna's mother, Madam Sandhya Shrestha, who had appeared composed the whole day, burst into tears when told that Jamuna was out of danger and awake following the operation.

She had been told before the operation that there was a risk Jamuna could die bleeding on the table if any of the many blood vessels at the base of her skull ruptured.

The maze of blood vessels is a legacy of the way she and Ganga were born joined at the top of their heads.

They came through the risky operation to separate them at the Singapore General Hospital seven years ago, but it left them with their brains unprotected by bone on the tops of their heads. This exposed their brains to external air pressure, retarding their growth in the past seven years.

Jamuna's trip here was to create a covering for that gap on her head, but the more urgent problem of the blocked fluids had to be fixed first.

Yesterday, the little girl took what was at stake in her stride. She told her grandfather over the phone before the operation: 'Don't worry, no tension.'

But when the hospital trolley came for her, she looked glum. On waking up after the operation, one of the first things she asked for was dinner.

salma@sph.com.sg

But when the hospital trolley came for her, she looked glum. On waking up after the operation, one of the first things she asked for was dinner.