Craniovertebral Junction Instability: A Review of Facts about Facets

Abstract

Craniovertebral junction surgery involves an appropriate philosophical, biomechanical and anatomical understanding apart from high degree of technical skill and ability of controlling venous and arterial bleeding. The author presents his 30-year experience with treating complex craniovertebral junction instability related surgical issues. The facets of atlas and axis form the primary site of movements at the craniovertebral junction. All craniovertebral junction instability is essentially localized to the atlantoaxial facet joint. Direct manipulation and fixation of the facets forms the basis of treatment for instability.

Retrospective Study of Craniovertebral Junction (CVJ) Anomalies: A Clinical Profile and Outcome Analysis of Surgically Treated Patients

“…Direct atlantoaxial fi xation provides the biomechanically strongest method of stabilization and the treatment protocol should shift towards craniovertebral realignment and fi xation-arthrodesis rather than decompression and bone removal. 6,10…”

“…Direct atlantoaxial fi xation provides a segmental stabilization at the point of fulcrum of all movements, and hence the occipito cervical fusion may not be required in all cases to stabilize and decompress the cervicovertebral junction. 6 Limitation: This study has small sample size limiting adjusted regression analysis to establish statistical correlation of different variables with outcome. Because of fi nancial and logistic constrains, detail imaging studies like CT scan and MRI could not be done in follow up for proper evaluation of bony morphology and fusion and adequacy of neural decompression.…”

“…5 Inclusion of occiput in fi xation construct is also considered by some but craniovertebral junction stabilization techniques is now focusing more on atlantoaxial joint alone. 6 The purpose of this study was to analyse the clinical characteristics and outcome of patients with craniovertebral instability managed with posterior surgery with or without posterior decompression.…”

Degenerative Cervical Spondylosis- Is Instability the Primary Point of Pathogenesis?

“…In the entire spine, facets are the sites of movement [1]. Odontoid process in the craniovertebral junction and disc in the rest of the spine are the brain behind all the movements [2].…”

“…Odontoid process in the craniovertebral junction and disc in the rest of the spine are the brain behind all the movements [2]. Disc and odontoid process are like orchestra conductors wherein they direct the movements that are actually conducted by the facets [1]. In the year 2010, we speculated that instability of the spine manifested at the site of its maximal movements, namely the facets, is the primary site of pathogenesis in degenerative spinal disease [3,4].…”