Heterotopic ossification - ectopic (myositis ossificans)

The term describes the formation of heterotopic ossification of bone in abnormal anatomical sites, usually in soft tissues. The term has been abandoned in favor of or ectopic ossification ossified miozitei used to describe the same pathology. The condition can affect the bones or joints. They described three types of disease: myositis ossificans progressive (a rare metabolic disease in which pediatric skeletal muscles to ossify), neurogenic heterotopic ossification (occurs as a result of burns or neurological damage) and traumatic form (which follows an injury to adjacent bone tissueand joints).
The disease can be defined histologically as follows: heterotopic ossification is the formation of mature lamellar bone tissue nonosos and myositis ossificans is a specific type of heterotopic ossification that occurs in inflamed muscles. Both processes are examples of ectopic ossification and may coexist, although they are different periarticular calcification, which is a storage tissue surrounding the pyrophosphates in the joints.
Traumatic ossification occurs in 20% of patients prone. After total hip arthroplasty and acetabular fracture surgery, the incidence is 2-63%. The disease seems to complicate nonoperative treatment of acetabular fractures. Hip arthroplasty with cement after the incidence is 8-90%, although many cases are asymptomatic. For fractures of the distal humerus and proximal humerus arthroplasty incidence is 10-90%.
Heterotopic ossification clinical impact depends on the extent of the disease. One injury caused by trauma is stable and can be reversed. Ossification related to brain injury or spinal meduvei not regress and cause pain and immobilization of the affected joints with complete ankylosis and severe disability. Among patients with neurological deficits, 10% had severe functional limitations with heterotopic ossification. Extension injury is associated with negative prognosis for recovery of patients with brain lesions. In patients with spinal cord injuries, large fossil ossification leading to inability to puncture the skin and orthostatic position of the column.Malignant degeneration has been reported but is very rare.
Causes and Risk FactorsThe etiology is determined by the type of heterotopic ossification.Rare condition of autosomal dominant progressive myositis ossificans is an inherited metabolic disease in children.Neurogenic heterotopic ossification occurs after head injury, spinal cord, multiple sclerosis and stroke. Traumatic heterotopic ossification is caused by local trauma.Etiology of traumatic heterotopic ossification:It is still uncertain. A number of theories have emerged. Cell migration was suggested as the cause of medullary bone osteogenesis in the connective tissue. Muscle lesions or interstitial hemorrhage was suspected as the cause of muscle degeneration, perivascular proliferation conjunctiva and bone metaplasia. It is considered a theory induce osteogenic differentiation of cells in the lesion periosteala periarticular.
There are three conditions that must be met for the development of traumatic ossification:Osteogenic progenitor cells, thisThis stimulus-inducingTissue-friendly environment must be favorable.The etiology of neurogenic heterotopic ossification:Patients with head injuries are at increased risk of developing heterotopic ossification shows if spasticity or increased muscle tone of the affected extremity, are unconscious for more than two weeks, shows the associated fractures of long bones.Fibrodisplazie ossificans progressive in patients with any trauma to soft tissues (biopsies, surgical procedures, injections) and viral infections induce episodes of ossification.
Risk factors for heterotopic ossification gained:-Trauma, burns, neurological damageHeterotopic ossification previous-And pelvic-hip surgery, after reimplantation arthroplasty-Male, advanced age, genetic predisposition.
Risk factors associated with surgical technique used:-Prolonged intervention, this pressure of pressure adjacent to the surgical approach-The amount of bone resected, the amount of soft tissue dissectedMuscle-ischemia, tissue trauma, bone traumaPersistence of debris-bone, prolonged tissue retraction, the presence of devitalized tissue-This hematoma, postoperative wound infection, Prolonged wound drainage.
Pathogenesis:Pathophysiology miozitei ossificans (fibrodisplazia ossificans progressive)The disease occurs in the first decade of life as spontaneous exacerbations or caused by trauma. Lesions are characterized by painful swelling of connective tissue, including tendons, ligaments, fascia and skeletal muscle. He showed an inflammatory component of the immune system in myositis ossificans. This macrophages, lymphocytes and mast cells in early lesions, macrophages and lymphocytes in skeletal muscle, viral infections and exacerbations by beneficial response to corticosteroids supports the immune system involvement in disease pathogenesis. Case miozitei ossified genetic mutation was identified through a morphogenetic protein receptor.
Pathophysiology of traumatic heterotopic ossification:Since the etiology is not fully understood, nor pathophysiology of this condition is uncertain. Once the osteogenic cells are stimulated to begin training soteoid mature heterotopic ossification turns. The basic process is considered to be one of the inflammatory response to local tissue trauma. Heterotopic bone is metabolically active and contains numerous osteoblasts from normal bone. Tissue will not form normal anatomical planes and is more diffuse than normal. This ectopic ossification around the joints and bones determine the functional abnormalities of soft tissues.Heterotopic ossification may be due to interaction between local factors (availability of calcium in the skeleton adjacent tissue edema, vascular stasis, tissue hypoxia, mesenchymal cells with osteoblastic activity) and some unknown factors. Substantive defect in this condition is abnormal differentiation of fibroblasts in bone-forming cells.
Pathophysiology of heterotopic ossification neurologicalIt involves an inflammatory process with increased blood flow in soft tissues. Bone matrix is ​​mineralized, and the sequence reaches the end of evolution in 6-18 months. Suspected cases were local, systemic, neural and hormonal ossification.