Teaching the singer with scoliosis...

I have personal experience with this one, as I have scoliosis from a childhood injury and have had to learn to work with it in my own singing.  The path of support deviates from normal, as does the path of resonance.  For instance, my core support is to the right of center, because that's the direction of curve in the lumbar spine region.  I can access support better if I put a little more of my weight on my right foot, than my left.  Similarly, my path to head resonance is to the right of center, also, because the cervical spine is also curved to the right, as is the atlanto-occipital joint between the top of the spine and the base of the skull.  I can access more head vibration on the right side of my face/skull than the left.

I found initially that the core spinal muscles on the interior side of the curves, both lumbar and cervical, responded  less quickly and strongly than the muscles on the exterior side of the curves, so I had to mentally encourage both sides to activate equally. This proved easier to do than I thought.  Internal muscle systems are, of course, not managed directly, but by clear understanding and thought-commands.  The results tell you if you are achieving anything.  In my case, the results displayed in my singing tone as greater core support became available.

I have students in the studio with some similar challenges.  One student is a pro-actor who had a severe injury to her neck in a car accident less than 5 years ago.  There is major scar tissue along her cervical spine, limiting  some of her movement.  When she found a clear pathway to her head resonance, her head/spine relationship went to a different place than a "normal" singer's would have.  I have another student, a community singer, and when she breathes in fully and deeply, her rib-cage opens to the left more easily than the right and her entire hip structure moves to the left by several inches.  This is a movement she is not aware of.   We experimented with her thinking her inhalation more down and to the right, looking particularly to a more even response between left- and right-side ribcage movement: she could do it, but the right side was quite slow to respond.  It will take time...

In general, I have found that you have to work with what's there, curves, tweaks and all.  And nobody has a "perfect" structure :).