The other thing is people... AND dogs,, can just plain INJURE a disk without it being disk "disease". I ruptured 3 disks in an (over-use) accident many years ago. It was miserable. It took 3 years to heal. (there is no possible "crate rest" for a mother of an infant and a toddler!) But the doctors Assured me that it WOULD heal, and it did! I don't have any "disease". The disks healed, refilled with fluid, and on X-ray, look normal again. I do have some residual arthritis in that area now, from the period when the disks were collapsed, and I had no choice but to keep moving, and the joints were bone-on bone. But then, I am also 68 years old, so that's not unexpected either...Did Mia have an XRay? That would have shown if there was disc material in the spinal canal. My Hallie had only one big bout of IVDD in her life, age 7 never had it happen again so it still could have been IVDD. It's nice they have this test now, they didn't when I had my girls.