Conclusions: Patients have good long-term health-related quality of life after surgery for idiopathic scoliosis and spondylolisthesis in adolescence. Patients who have surgery for idiopathic scoliosis are likely to have better long-term outcomes than are patients who have surgery for spondylolisthesis. It is possible that back pain in adolescence may affect quality of life more than spinal deformity does.