Review Question - QID 214130

A 74-year-old female presents with complaints of persistent back pain for the past 2 months. She reports sustaining a fall down the stairs 10 months prior and was initially seen in the Emergency Department where imaging was obtained (Figure A). She was managed with rest and physical therapy. Following initial conservative management, she reported improvement in symptoms until the past 2 months. She denies any new injury. Figures B-D represent the MRI images obtained one week ago. What is the most likely etiology for her persistent back pain?