Nervous System

Abstract

Heterotopic ossification (HO) in the nervous system is a relatively rare phenomenon. It is differentiated from general heterotopic calcification by histopathological examination demonstrating differentiated bone tissue. HO also occurs in other parts of the body as a result of brain and spinal cord injury. Myositis ossificans (MO) is similar and shares etiological causes, whereas primary peripheral and central neuritis ossificans have been reported but remain rare entities. Ossification of the peripheral and central nervous system can have devastating effects. The most common form of HO affecting the nervous system is ossification of the posterior longitudinal ligament (OPLL). Trauma is suggested to be the most common cause of this pathological process which can have profound effects on the vertebral column and spinal cord. HO is additionally a clinical relative of diffuse skeletal hyperostosis (DISH) and has been associated with other forms of skeletal disorders; both inheritable and non-inheritable forms exist. This chapter will focus on the clinical diagnosis, radiologic examination, treatment and outcomes of HO within the nervous system. Additionally, current research and future directions in therapy will be presented to further the knowledge base of this rare yet debilitating pathology.