Meningitis is dramatically higher among the 80,000 people who have had an implant since the 1980s, researchers have discovered. In most cases, the person has died.
There's been a marked increase in infections since 2002, which suggests that a particular design - which was withdrawn from the market that year - may be one of the causes of infection.
It may also be associated to the operation itself when the implant is inserted, as it involves fracturing the bony structures of the inner ear. People who suffer from the ear disease otitis media are especially at risk.
(Source: British Medical Journal, 2007; 335: 1058).