Seve Ballesteros is in a stable condition after undergoing a fourth brain operation.
The Spaniard is back in the intensive care unit at Madrid's La Paz hospital following scheduled surgery for the placement of a valve to drain fluid from his brain.
At the same time, the surgical team treating the 51-year-old performed a cranioplasty to repair a bone defect.
His condition is reported as stable and he will remain in the intensive care unit.
Ballesteros was diagnosed with a brain tumour after losing consciousness at Madrid Airport in October.
Tumour removed
He underwent a lengthy operation on October 24 to reduce pressure on his brain and remove remaining tumour tissues following two previous operations.
On November 18 he had recovered sufficiently to leave intensive care, although a hospital statement did warn there was a long way to go.
Ballesteros is one of the most influential figures in the history of European golf, he won five majors - the Open three times and Masters twice - during a decorated playing career that ended in 2007 due to knee and back problems.
He also compiled an impressive Ryder Cup record, winning 20 points in eight appearances as a player and captaining Europe to victory at Valderrama in 1997.
