well..
my thoughts about any possible TOS surgery would be that you need to know exactly where and what kind of TOS you have.
So that would mean seeing some kind of TOS specialist, to pin point what is the specific problem areas for you.

TOS compressions can be caused by -
any of the scalene muscles
clavicle/top rib
pec minor
oversize bones/ligaments or other structural anomalies
scar tissue

you didn't have any extra cervical ribs, correct?
should show on MRI and xray but sometimes they have been missed if the aren't checked for.

and the compressions can be on a nerve or on artery or vein.


The dr recommending the ulnar redo isn't the one who did it the first time is he?? --if so second or third opinion.
And if not - if you are considering the redo - find the highest rated top surgeon skilled in the area to do it - not a time to let just any surgeon practice on you.

I guess I would want to know for sure what is causing the curling before undergoing a surgery redo at the elbow.

Sounds like you would benefit from the MRA test- I don't know if a CT or other test could show specifics like what would be needed to get that knowledge...

some of the others have had more of the those tests than I did, so maybe they can tell more about them.