RE: "Has anyone had their Sagittal Band rupture?"
Yes, Susan Ellen, I was diagnosed with, in his words, "Radial Sagittal Band Rupture with dislocation of Extensor Tendon" by a hand surgeon May 24. When it was first, say, "developing", I could "see" (under the skin) the extensor tendon slipping off the top of the knuckle down into the "valley" between the, in my case, ring and small fingers.

Oddly I can only figure it may have happened as a result of normal age degeneration – I'm 80 – coupled with my being, for a year now, on a immunosuppressive drug (tocilizumab, a monoclonal antibody designed to impair an immune system inflammation response) and my daily washing a tall, thin ceramic mug (which involves stretching my fist into a kind of arc that'll fit deep into the bottom of the mug).

This may not be a helpful 'comment' w.r.t. your situation. CTS isn't something I've had to deal with and it sounds difficult to handle! There's some interesting basic information here: https://plasticsurgerykey.com/sagittal-band-injuries-primary-and-secondary-management/