Heterotopic ossification after brain and spinal cord injury

Heterotopic ossification (HO) is a soft tissue ossification commonly found after SCI and TBI. The incidence of HO after SCI is about 50%, after TBI is 20%. The etiology is unknown. The pathology of HO is characterized by an extra-articular localization in paralyzed extremities. In the acute stage of HO microscopic evaluation reveals edema, woven bone, numerous small vessels and fibroblasts. In the later stage HO contains lamellar bone with cortical and trabecular architecture. Clinically, in the acute stage of HO most common findings are swelling of soft tissue, reduction of ROM in affected joint and fever. In the chronic stage HO may limit functional status of patients. In the early stage the diagnosis of HO is based on three-phase bone scintigraphy with 99m-Tc diphosphonate. In the chronic stages when HO contains mature bone the radiographic examination is a diagnostic test. Prevention of HO in patients with TBI and SCI is effective if started early after injury. Etidronate in doses of 20 mg/kg/day for 3 months will significantly reduce the incidence of HO in both groups of patients. Treatment of HO in acute phase is etidronate therapy and physical therapy, at the stage of mature bone the management of HO is in the domain of orthopedic surgery.