Pott Disease — Spinal Tuberculosis

A 42-year-old man from rural India presents with a 6-month history of progressive back pain, low-grade fever, and night sweats. Plain radiograph of the thoracolumbar spine shows a sharp angular kyphotic deformity. MRI reveals marrow edema in two adjacent vertebral bodies with preservation of the intervertebral disc space and a paravertebral collection. The structure marked **A** in the diagram (anterior wedging/collapse of vertebral bodies) is the result of which pathophysiologic mechanism in Pott disease?