sequestra

Sequestra (singular sequestrum) are fragments of necrotic bone that have become separated from living bone tissue. They most commonly arise in osteomyelitis but may occur in other settings such as fracture nonunion, avascular necrosis, radiation-induced bone damage, or extensive inflammatory infection. A sequestrum is often surrounded by inflamed or proliferative new bone called an involucrum.

Clinical features include chronic pain, sinus tract formation, discharge containing foul odor, and persistent swelling. In the mandible and maxilla, sequestra may present after dental infection or trauma and can complicate osteomyelitis or osteoradionecrosis. Diagnosis relies on imaging and clinical assessment: plain radiographs may show a dense, fragmented radiopaque piece within a radiolucent lesion; CT clarifies extent; MRI can assess marrow involvement; histology confirms necrosis if tissue is obtained.

Management centers on removing the sequestrum and controlling infection. This typically requires surgical debridement or sequestrectomy, combined with targeted antibiotics and treatment of any underlying condition (dental source, vascular insufficiency, or radiation damage). In radiation osteitis or osteomyelitis, adjunctive therapies such as hyperbaric oxygen may be used in selected cases. Prognosis improves after removal of dead bone and adequate infection control, but recurrence is possible if the underlying pathology is not addressed.

Etymology: Sequestrum derives from Latin sequestrare, meaning to set apart.