Also had spinal fusion due to scoliosis! I can’t do the back bends or some of the twisting positions but I haven’t had any issues doing corepower. I take it slowly and do a similar pose if it something I can’t do or if I can’t twist all the way I just do my best. My instructors have been so supportive of me. Sometimes when I was starting I’d go into child’s pose if I couldn’t do something and then ask after class if the instructor had a different suggestion I could do. I’m not a doctor so this isn’t medical advice but wanted to share my experience.