The Hospital Authority (HA) said on Monday that it has suspended the use of 12 operating theatres across its public hospitals, after screws were found to have come loose on their surgical lights.

The comprehensive checks came after a light fell from the ceiling of an operating theatre at United Christian Hospital on Saturday, injuring an anaesthetic assistant.

A senior manager with the authority, Yuen Pak-leung, told a radio programme that the case was unprecedented, adding that loose screws might be to blame for the fall.

He said officials have already checked all 29 lights of the same model across all public hospitals, and found that screws were also loose on 12 of these lights.

The affected operating theatres won’t be used until the screws are replaced, he stressed.

Yuen also noted that the HA is aiming to finish checking some 200 lights from the same supplier as soon as possible.

"The light can move up and down. So as it is hung on the ceiling by the screws, they will be stretched. If you move it a lot, it may become a little loose, this does happen usually," he said.

"So as part of the established procedure, we have annual checks, and if we find that the lights are loose, we will tighten them again."

He said the surgical lights at United Christian Hospital were last checked in December, and this particular model – which weighs around 200 pounds – had been in use for more than a decade.

To avoid a repeat of the incident, Yuen said the HA will step up inspections and check the lights every two weeks, adding that the supplier will also conduct its own probe into the incident.

Meanwhile, the head of the Hong Kong Public Doctors' Association, Tony Ling, described the case as shocking, and urged the HA to look into whether there’s a need to conduct a thorough review of the relevant maintenance mechanism.