Artificial discs in the cervical spine. Coloured lateral X-rays of a human head and neck, showing the cervical spine in flexion (left) and extension (right), with artificial discs (dark blue). These artificial implants have been surgically inserted to replace the original intervertebral discs. These implants are also known as disc replacements, disc prostheses or spine arthroplasty devices. They are usually used in cases where the existing intervertebral discs have degenerated. They are an alternative to spinal fusion, and allow retention of full movement of the spine.