In Pott disease, which of the following best describes the characteristic pattern of vertebral body destruction?

Explanation

## Pathological Pattern of Vertebral Destruction in Pott Disease **Key Point:** Tuberculosis of the spine characteristically affects the anterior vertebral body while relatively sparing the posterior vertebral wall and posterior elements (pedicles, laminae, spinous processes). ### Mechanism of Anterior Vertebral Body Involvement 1. **Hematogenous seeding** — *Mycobacterium tuberculosis* spreads via the vertebral venous plexus (Batson's plexus) to the anterior metaphyseal region of the vertebral body. 2. **Granulomatous inflammation** — Caseating granulomas develop in the cancellous bone, leading to progressive necrosis and destruction. 3. **Anterior spread** — The infection spreads anteriorly beneath the anterior longitudinal ligament, creating a paravertebral abscess. 4. **Posterior sparing** — The posterior cortex and posterior elements remain relatively intact due to the initial site of bacterial lodgment and the direction of spread. ### Radiological Features | Feature | Characteristic | | --- | --- | | **Vertebral body involvement** | Anterior > posterior ("anterior vertebral body collapse") | | **Disc involvement** | Occurs late; disc space may be preserved initially | | **Posterior elements** | Relatively spared in early disease | | **Kyphotic deformity** | Develops due to anterior vertebral body collapse | | **Paravertebral shadow** | Indicates abscess formation | **High-Yield:** This anterior pattern of destruction distinguishes Pott disease from pyogenic spondylitis (which often involves the disc space early) and from metastatic disease (which may show posterior element involvement). **Clinical Pearl:** The relative preservation of the posterior vertebral wall is crucial clinically — it may provide some inherent stability even as the anterior body collapses, though kyphotic deformity and potential spinal cord compression remain serious complications.