Quote Originally Posted by Concerneddad View Post
I just had to jump in here. Kids who hit maturity with curves in the 30s don't progress at "maybe 2 degrees per year" as adults. Kids below 35 degrees or so usually don't progress, or if they do, it's well under half a degree per year. Kids over 45 degrees do progress, normally in the 0.5-1.0 degree range. Most will probably need surgery at some point, but that point could be twenty years down the road. Kids between 35 and 45 are a huge gray area. It's probably safe to say that most (not all) will progress as adults, but it's a math problem at that point. If they're say 38 degrees at maturity and are progressing a third of a degree per year, that puts them hitting 50 degrees when they're in their early 50s, and a lot of docs wouldn't recommend surgery at that point unless the curves are very symptomatic. (On the other hand, if they're progressing at 2/3 of a degree per year, that puts them hitting 50 in their early 30s, and most docs probably would recommend surgery then. Though I've been talking to people lately, and apparently the thinking with some docs now is that well-balanced S-curves just shouldn't be operated on after maturity unless they are causing symptoms, even if they are above 50 or even 60 degrees, because they tend to be pretty stable and any adult progression is slow and intermittent.)
Stuart L. Weinstein, M.D.
Professor of Orthopaedic Surgery
University of Iowa
Iowa City, Iowa

This is the study with the most extensive look at curve progression after skeletal maturity that I have found. Weinstein looked at progression over a 40-year period and broke it down by curve types. Looks like less-than-30 degree curves generally did not progress except for thoracolumbar curves. Looks like no one in the study progressed much more than half a degree per year over 40 years, but the average progression was around 1 degree per year for the first 20-30 years in some categories. So, yeah, my saying up to 2 degrees/year seems to be pushing it according to this study. This study still seems to indicate somewhat of a rough "cut-off" around 30 degrees - less than 30 and no progression, over 30 and some level of progression somewhere between 1/4 degree and 1 degree on average. Of course there is a range of variable outcomes to get a average or mean, so there probably are some that did not progress at all and a few that progressed by multiple degrees per year.