A prosthetic vertebral body for use in a cavity left by the removal of a defective vertebral body located between two adjoining healthy vertebral bodies is disclosed. A method of replacing the defective vertebral body with the disclosed prosthetic vertebral body is also disclosed. The prosthetic vertebral body includes an adjustable support device which is located within the cavity between the two adjoining vertebral bodies for supporting and adjusting the axial spacing of the adjoining vertebral bodies. A castable material is poured into the cavity and hardens so that the adjustable support device is embedded therein. An attaching device is also provided for rigidly attaching the spinous process of the defective vertebral body to the spinous processes of the adjoining vertebral bodies. Preferably, the adjustable support device includes a pair of elongate struts whose longitudinal dimensions are adjustable. The castable material is preferably acrylic cement and the attaching device for the spinous processes are preferably a pair of elongate plates which are secured to one another and to the spinous processes.