I just saw a little bit of the interview. Apparently she needed surgery on a nerve in her back as she had no feeling in her feet.
The back surgery could well be to repair a fractured vertebral body with fragments impinging the cord. Loss of feeling in the legs is ominous, and in cases of cord impingement, progressive. So the timing of surgery can be critical. That's why they would fix the back first and the extremities later.
If she has a fractured vertebral body in the thoracic or lumbar region it usually comes, in a young healthy person, from a fall from a height.
Discs rupture, they don't fracture. Though an acute ruptured disc can impinge the cord, too.