Not many people have. Scoliosis surgery in adulthood is not common for obvious reason scoliosis is growing skeleton disease, some ignore that so they have problem in adulthood, and another reason some congenital scoliosis also could have surgery in this age. Traumatic scoliosis could happen in adulthood.
Yes. Some people have surgery as adults. If curve is 50 degrees or larger, risk & rate of it worsening is 75% at 1 degree/ year. As curve gets larger, rate can progress especially if the bones get less dense. Sometimes, a scoliosis occurs as a new finding in the lower back in older individuals due to degenerative changes that may require surgery usually seen with stenosis or spondylolisthesis.