Sentence:  When the goal is to provide postural support, slow progression, or postpone (but not prevent) surgery, a polypropylene <WSD>body jacket</WSD>, or “clam-shell brace,” may suffice for waking or sitting hours. 
Meaning of the word marked with <WSD> tags:  A rigid brace that fits around the torso (but does not cover the neck, arms or legs) to immobilize the spine, reduce curvature, etc.