Trackwork rider Kate Nipperess has undergone spinal surgery after an accident at Warwick Farm.
A riderless horse crashed head-on with the horse Nipperess was riding on Thursday morning.
Nipperess was taken to Royal North Shore Hospital with multiple injuries.
Her partner, trainer Craig Ritchie, told Racing NSW the main concern related to pressure being placed on her spinal cord by a displaced vertebra which required surgery.
He said it would be some time before they would know if Thursday night’s operation was successful because of swelling and trauma around the injury.
Ritchie said Nipperess also had a small fracture in her lower neck, multiple fractured ribs and lung damage but those injuries were not causing doctors too much concern.