Anyone ever had or know anyone who needed spinal fusion surgery?

My sister has to have spinal fusion surgery. She is only 42 years old and she has a 70% chance of a successful surgery in which she will not wind up in a wheelchair. She was recently diagnosed with Degenerative Disc Disease, Scoliosis, Sciatica, herniated discs in the lumbar spine, fractures and cysts in the lumbar spine, Lumbar Spine Stenosis, and Spondylosis, and there are pieces of her vertebrae floating inside her spine. Basically her spine is crumbling like a cracker. They say this is hereditary, but we know of no one in our family ever having anything like this. I really worry about back surgery of any sort, because I have never heard of a successful back surgery. She has no choice, the surgery is not an option. She must have it or she will definitely be in a wheelchair.