Navigation-assisted Excision of Heterotopic Ossification in Bilateral Hips of a Paraplegic Patient: A Case Report with Technical Note

REPORTphases, namely the early (inflammatory) phase, which presents as localized pain, tenderness, and swelling, and the late phase in which there is gradual maturation into bony tissue and deformed joints.The characteristic clinical features include limitation of range of motion adjacent to the joint involved, complete bony ankylosis (in severe form), deformity in the affected areas like hip, elbow, IntroductIonIn heterotopic ossification (HO), abnormal ossification of lamellar bone in the extraskeletal soft tissue is observed, which is most often seen as a complication in rehabilitation settings. 1Heterotopic ossification was first coined as paraosteoarthropathy by two French physicians, Dejerne and Ceilier, who described them as a consequence of traumatic paraplegic patients of the First World War. 2 There is a broad age distribution in HO from infancy to late adulthood, showing male predilection with a male-to-female ratio of 3:2.Individuals are prone to develop HO if traumainduced or due to repetitive mechanical stress from unrecognized microtrauma, especially after a head injury or other categories. 2,3cute rehabilitation and transfer activities of bedbound patients or repeated microtrauma during activities of daily living may predispose them to HO. Tissue expression of bone morphogenic proteins stimulates mesenchymal spindle stem cells, aka satellite cells, to migrate to the injured areas and metamorphose into fibroblasts, and eventually transform into osteoblasts.Heterotopic ossification consists of two main etiology-traumatic, which includes fracture, muscular trauma, joint dislocation, burns, arthroplasty, and neurogenic, which includes stroke, spinal cord injury, traumatic brain injury, and brain tumors. 1 Nongenetic forms of HO are the most common, but rare genetic forms such as fibrodysplasia ossificans progressiva and progressive osseous heteroplasia are also reported.The severity and clinical presentation of the genetic form will differ from that of the nongenetic form of HO. 1,3 The clinical presentation depends on the temporal stage of nongenetic HO, which has two 1,4-