Tiger Woods' former mistress, Rachel Uchitel, reportedly is undergoing major brain surgery to correct Chiari malformations, in which the cerebellum and brain stem are pushed downward into the upper spinal canal.
TMZ.com said that the operation will take place in two weeks. The condition is often genetic but can also manifest later in life.
Former nightclub hostess and party planner Uchitel, who was born in 1975, made headlines in December 2009 when her affair with golfing star Woods became public.
The twice-divorced Uchitel now owns a Manhattan children's boutique named for her young daughter, Wyatt Lily.