You and I are very similar. My Harrington rod is still in though. I had a fusion 22 years ago for scolios, I was 23. Had great results from my harrington rod. The body cast was fun back then, huh?
Anyway I was fused from T5 to T12. I developed "flatback" too. I also had hyperlordosis in the lumbar area and minor spondylolisthesis, and a disc bulge at L4/5. I started having referred back pain (in my sacro iliac joint) a couple of years ago. It kept gettin worse despite PT. I decided not to live on vicodin anymore.
I'm 5 weeks post op from a poster/anterior fusion L4 - S1. They replaced the discs with cadeaver bone and use something called BMP to help fusion.
It's all supposed to fuse into one mass of solid bone for a stable base for the rest of my spine. Below T5 I only have 3 unfused vertabrae.
I'm feeling pretty good. No cast or brace this time. But the home recovery time is longer. 7 weeks. Went back to work after 3 weeks last time. But heck, I'm 22 years older too
That's my story for what's it's worth. If you have any questions, let me know. Nice to hear from an old harrington rod person.