KEY POINTS:
Forty-three patients face a lifetime of uncertainty, waiting to see if they have been infected with an inevitably fatal, incurable brain disease.
The patients - 11 of them children - had operations last month in Auckland City Hospital during which surgeons used instruments previously used in brain surgery
on a woman now thought to have Creutzfeldt-Jakob disease (CJD).
Once a person is infected with CJD, it can take years or decades before symptoms appear.
Gradually the affected cells die, leaving holes in the brain.
The disease destroys not only the brain but muscle control and movement, leaving victims with severe dementia, unable to walk properly or care for themselves.
Pneumonia is often the cause of death, which usually occurs within a year of symptoms appearing.
Tests for CJD are not definitive, unless a brain sample is examined, which is often not possible.
"It is fatal and there is no cure for it," the hospital's clinical director of neurology, Dr Barry Snow, said yesterday.
Doctors started to suspect the unnamed woman had the disease on March 23 after she did not recover as expected from a March 8 operation.
They say she has been having seizures and is "effectively" unconscious.
Scans of her brain indicate she has the disease and samples are being analysed, but it is not known when, or if, the diagnosis will be confirmed.
The instruments used on her had to be tracked and cross-referenced to find the 43 people, who were treated between March 9 and 28.
The instruments include scalpel blades and handles, scissors, drills, forceps, clamps, clips and bone saws.
Hospital officials said yesterday the risk that any of the 43 patients would develop the disease was extremely low.
Staff were contacting them to explain the situation.
Most had had brain surgery; some had head or neck operations.
"Patients have been very concerned initially," said neurosurgery clinical director Edward Mee.
"We've discussed it with them ... and I think they have gone away with a recognition that the chance of them contracting the disease is remote. It's not zero, but it is extremely unlikely."
The woman thought to have the disease does not have variant-CJD, which is linked to eating beef infected with "mad cow disease" (bovine spongiform encephalopathy, or BSE).
She had brain surgery in 1984 and this required a "dural graft", which may have been the source of her CJD infection.
The dura is tough, fibrous tissue, one of the three membrane layers covering the brain and spinal cord. Openings made for surgery can be sewn back together, but a patch is sometimes required.
At the time, dural grafts with the brand name Lyodura, processed from deceased patients, were common. Synthetic patches are increasingly used today.
Thousands of patients around the world received Lyodura grafts, supplied by a German company. They include about 500 in New Zealand.
In the late 1980s, Lyodura was linked with CJD, after which the company changed its processing techniques.
Auckland City Hospital's clinical director of infectious diseases, Dr Mark Thomas, said the company's subsequent dural grafts were unlikely to carry significant risk of CJD.
Two New Zealand CJD cases have been linked to Lyodura; the current case could be the third.
Mr Mee said the risk of patients with Lyodura grafts developing CJD was only 0.04 per cent to 0.2 per cent.
The risk to other patients is because the infective agent of CJD - an abnormal protein called a prion - is so hard to eradicate.
The hospital's chief medical officer, Dr David Sage, said repeated cycles of washing with a specialised enzyme and high-temperature sterilisation progressively destroyed CJD prions.
He acknowledged there was a risk to other patients from instruments used when the woman had the dural graft applied in 1984, but said it was only a "theoretical possibility".
None of the affected patients had donated blood or organs since their operations and would not be able to do so in the future.
The last reported case anywhere in the world of CJD being transmitted by surgical instruments was in the 1970s. Only eight cases have ever been reported.
Mr Mee said British experts had decided not to tell individual patients with the Lyodura dural grafts because it could cause great emotional distress, for a risk that was extremely low.
The Ministry of Health's deputy director-general for clinical services, Colin Feek, said the ministry would re-issue guidelines on CJD and infection control.
Creating a register of patients with Lyodura grafts had been considered 10 years ago, but there had been multiple importers of the material and hospital records were inadequate.
