What does it mean when it says there is a mile "dextroconvex Thoracic scoliosis"?

You have a slight curvature of your spine, it is very common.
Dextro means to the right and convex means it bulges in that direction.
Doctors love jargon, there are treatments and exercises available to correct this kind of Scoliosis.
(instead of "mile" I think the Dr. meant mild.)