How does spondylolysis show up on an xray long after it has healed? i had fractures at l1, 2 and 3 in 1985 but my last mri said it showed nothing?

CT scans: Ct scans are better for showing fractures, particularly older fractures. They will show up as areas of increased density or callous on the ct scans and reflect the healing process that most likely occured and has "bridged" the fracture line. Mri scans don't show this as well as they are best for imaging soft tissues rather than boney structures, particularly old healed structures.

Technique: Different technique showing different structures. As a rule of thumb, xrays show bone best, MRI shows soft tissues best. So you may see a thin-ness in the bone where the MRI does not pick it up. The fractures you had 30 years ago may long be healed up and the bone remodeled.

Sponylolysis is hard: Spondylolyis is hard to see on x-rays since it is so deep and the pictures have overlapping shadows related to bowel gas. Best way to see an acute process is with bone scan. Best way to assess for healing at long term follow up s thin sliced ct scan. However, almost half heal with scar tissue and never go on to bone healing. If no symptoms or mild, then no worries.....If severe, then surgery.