Significance of Atlantoaxial and Subaxial Spinal Instability in Cervical Spinal Spondylosis: Commentary on “Clinical Impact and Correlations of Odontoid Parameters Following Multilevel Posterior Cervical Fusion Surgery”

Standing posture has unique implications for human spine. Facetal articulation forms the fulcrum of activity for a large part of muscle bulk of the nape of neck and back that main-tains the erect spinal posture. On the other hand, only a relatively few strands of muscles are associated with the vertebral body and intervertebral disc. Our articles discuss that the disc (and the odontoid process) is the brain of spinal movements, whilst the brawn of the movements are the muscles. 1 Intervertebral disc regulates spinal movements and mimic in actions an opera conductor who plays all music without holding any instruments in hand. The conductor of an orchestra (the disc) doesn’t make a sound. He depends, for his power on his ability to make other people (muscles) powerful – Benjamin Zander For several decades ‘old’ age or injury related affection of the disc, reduction in its water content and its herniation has been incriminated as the nodal point of genesis of cascade of secondary events that are grouped under the term spinal degeneration. ‘Pathological’ issues related to spinal degeneration include bulging of the disc into the spinal canal, osteophyte formation, ligamentum flavum hypertrophy, bone fusion, and listhesis of the facets. The eventual outcome is reduction in the spinal canal and neural foraminal dimensions that results in neural compression and related symptoms of radiculopathy and/or myelopathy. In 2010, we proposed that muscle weakness related to their injury, disuse or abuse results in telescoping or listhesis of the facets or in ‘vertical’ spinal instability and forms the point of genesis of