Lumbar spine segmental instability in degenerative spine conditions

12–40% of people with low back pain have spinal instability in degenerative-dystrophic diseases of the spine. The paper highlights the biomechanical basis for the development of segmental instability and discusses various hypotheses for the development of this condition. The authors describe the modern methods of neuroimaging used in the diagnosis of segmental instability, such as radiography, functional spondylography, CT, functional CT, MRI. Further, the paper presents provocative tests used in the diagnosis of instability: passive extension of the lumbar spine, standing, sitting, pron-instability, "scissors", compression of spinous processes, forward lean in standing position, and some others. The authors shared their experience in diagnosing segmental instability. However, the discrepancy between the data of instrumental examinations and patient complaints, poorly studied rotational and lateral instability in osteochondrosis indicate the need for a more detailed study of the instability of the spine as a whole.