Unilateral osseous bridging between the arches of atlas and axis after trauma

Study Design. This is a case report. Objective. To present a case of osseou s bridging between C1 and C2 of posttraumatic origin and with an associated closed head injury and to discuss its pathogenesis and clinical outcome af ter surgical resection. Summary of Background Data. Heterotopic ossifications of posttraumatic orig in in the spine are rare. To the authors' knowledge, no cases have been rep orted of spontaneous bony bridging between C1 and C2 with a posttraumatic o rigin. Methods. Heterotopic ossifications were detected when pain and limited axia l rotation (left/right 10 degrees/0 degrees/20 degrees) were persistent, de spite intensive physical therapy. Be cause heterotopic ossifications were a nkylosing C1 and C2, the decision was to resect the osseous bridge in combi nation with a careful mobilization of the cervical spine. Functional comput ed tomography was performed for analysis of the postoperative results. Results. Four months after surgery, clinical examination showed asymptomati c increased axial rotation. Functional computed tomography indicated that l eft C1-C2 axial rotation was reduced, possibly related to impingement cause d by residual bony spurs. Pathologic changes in the surrounding soft tissue may be another important factor in the persistent limitation of rotation. Conclusions. Osseous bridging between C1 and C2 may be considered when pers istent pain and limited axial rotation are observed after trauma. Operative resection, together with careful intraoperative and postoperative mobiliza tion, may be the treatment of choice.