Trintignant was filming a series about French author Collette

Doctors say the operation was carried out at the request of her family, in a "last chance" attempt to relieve pressure caused by brain haemorrhaging.

They say she remains in a deep coma, and the chances of her survival are minimal.

Ms Trintignant's boyfriend, rock singer Bertrand Cantat, is being questioned by police.

The 41-year-old actress suffered the injuries on Sunday at the Lithuanian hotel where the couple were staying.

Her family, including her film star father Jean-Louis Trintignant, has flown to Vilnius to be at her bedside.

It was a last chance operation because the patient's condition was very complicated... Unfortunately, I think her days are numbered Stephane Delajoux French brain surgeon

Her 17-year-old son Roman, and her mother, film director Nadine Trintignant, are also in Vilnius.

Doctor Robertas Kvascevicius, among the doctors treating her at Vilnius University Hospital, said the second operation had produced no change in her condition.

He said French brain surgeon Stephane Delajoux, who flew to Lithuania on Monday, helped perform the operation.

"We have done an operation at the request of the patient's relatives and it was a last chance operation because the patient's condition was very complicated," he said.

"Unfortunately, I think her days are numbered now because she is in a deep coma, and the surgical decompression that was performed wasn't enough."

'Very grave'

Elvidius Jarvensgas, the head of the Vilnius hospital neurosurgery department, said: "The patient's condition remains very grave."

Cantat, who is lead singer with French rock band Noir Desir, was taken to the same hospital on Sunday after heavy alcohol use, police say.

Investigator Juozas Kandzezauskas said police had started questioning him about what happened at the hotel.