Saw this posted on SSo. Note small sample size and that it only includes people fused to L3 or higher. This comports with what our surgeon said about no long term issues if you can stay above that level and explains why surgeons appear to stop there on kids with what appear to be frank L curves that include levels below.

"We wanted to see how the patients were doing ten years down the road, specifically focusing on the part of the spine that didn’t have surgery. The standard belief was that the area of the spine just below the surgery would wear out, because of the increased stress that the surgery or the fusion would put on that part of the spine," Dr. Green said. "That isn’t what we found. We found that the area of the spine adjacent to the fusion was pretty healthy and didn’t show any major degeneration ten years later. While mild degenerative changes were noted in almost every patient, the severe changes that we were concerned that we might find were not there at all."
The investigators say the study results are good news for patients. Dr. Green also said the results may cause worry for investigators and companies who are trying to develop surgeries for scoliosis that do not involve fusing the spine. "There is a lot of research and investment being done looking for new technologies that do not use fusion," Dr. Green said. "This study would suggest that there is a challenge for those trying to do that because the patients doing fusion are doing well."