A musician from South Africa had a tumour in his brain, so doctors opened a hole in his skull to remove it. But they had a crucial request: He must play his acoustic guitar during the surgery.

The musician, Musa Manzini, a jazz bassist, was awake when the doctors performed the surgery last week, and video footage from the local media site News24 shows him strumming an acoustic guitar slowly as they operated.

The technique, known as “awake craniotomy”, allows doctors to operate on delicate areas of the brain — like the right frontal lobe, the site of Manzini’s tumour — without causing damage. Presumably, had he hit a wrong note, it would have been an immediate signal for the surgeons to probe elsewhere.

“It can be very difficult to tell the difference between the tumour and normal brain tissue,” said Basil Enicker, a specialist neurosurgeon who led the operation at Inkosi Albert Luthuli Central Hospital, in the coastal city of Durban. “Once you’re near a critical area, you can pick it up early, because he will tell you.”

The doctors who treated Manzini were concerned about the motor function of his left hand, said Rohen Harrichandparsad, another surgeon on the team. “We wanted to make sure we took as much of the tumour as we safely could, but preserve his dexterity,” he said.

For a professional musician like Manzini, whose work requires coordinated activity across multiple regions of the brain, there were further complications.

“We had to ensure that whatever pathways he was using for music were preserved,” Harrichandparsad said. “There’s no single pathway, but a multitude that interact.” It would have been “impossible to do this”, he added, without Manzini’s remaining awake.

First, the doctors placed Manzini under intravenous anaesthetic, gently waking him once they had exposed his brain. Sensitive nerves in the surrounding skin, muscles and membranes were dulled by injections of local anaesthetic. But “once we’re in the brain, there’s no pain”, Enicker said, as the brain has no pain receptors of its own.

Using small electrodes, the surgeons stimulated different parts of Manzini’s cortex, testing which areas were functional in a process known as cortical mapping.

“The hand would sort of move automatically by itself,” Manzini recalled in a phone interview on Friday. “It’s very funny and strange.”

Next, the doctors handed Manzini a guitar and asked him to play while they excised the tumour, ensuring that they were not removing any critical tissue. It was difficult to concentrate, Manzini said, with what felt like a “blowtorch” inside his head.

“There’s this loud sucking sound and stuff, yet I don’t feel no pain at all,” Manzini said, referring to the vacuuming device used to remove blood while the surgeons operated. “It’s like you’re in between being dead and being alive.”

“I watched quite a lot of YouTube videos to prepare myself mentally,” Manzini said.

Before operating on Manzini, neither Enicker nor Harrichandparsad had come across his music.

“I’ll be looking forward to being invited to his first concert after surgery,” Harrichandparsad said.