Degenerative conditions of the spine represent a group of most common lifestyle associated diseases with significant medical and important social impact. Clinical symptoms and syndromes of surgically considerable degenerative diseases of the spine mostly result from nerve root or spinal cord compression caused by a herniated intervertebral disc or a dorsal osteophyte. Therefore, the main goal of the surgical treatment is decompression of the neural structures by complete removal of the intervertebral disc and the osteophytes followed by insertion of an artificial disc spacer into the remaining space. The most frequently used procedure for treating such findings is called anterior cervical discectomy. Since its first introduction in 1950, several modifications of the original technique have been introduced. Their common feature is that removal of the degenerated intervertebral disc or the osteophytes requires stabilization of the adjacent segments by fusion. Thus, implantation of an interbody spacer results not only in intervertebral space reconstruction, but by immobilizing the adjacent vertebral bodies also in forming a firm bony bridging between them--and ultimately a solid bony block. Our paper provides a review of cervical interbody spacers in the order of their evolution from auto- and allografts, through compact materials, cages and dynamic artificial disks. Furthermore, different types of cage filling materials used for fusion augmentation are also discussed.