Spine of Ish Sah's rulings appear to say it can't be sacrificed:
Spine of Ish Sah’s last ability doesn’t allow you to sacrifice it. You must find another way to get Spine of Ish Sah into the graveyard.
Does that mean it can't be sacrificed to Breya, Etherium Shaper or Emrakul, the Aeons Torn?