Migration patterns of herniated disc fragments: a study on 1,020 patients with extruded lumbar disc herniation.

Background Context: Herniated disc fragments are known to migrate in various directions within the spinal canal. To date, no comprehensive studies have been undertaken to examine the migration patterns of herniated disc material using a standard nomenclature and classification system.

Purpose: To report migration patterns of extruded lumbar disc fragments.

Disproportion of end plates and the lumbar intervertebral disc herniation.

Background Context: It is suggested that the shape of the vertebral end plates may play a role in the development of abnormalities in the intervertebral disc. On midsagittal magnetic resonance images of the spine in patients with lumbar intervertebral disc herniation, a notable disproportion frequently exists between the end plates of two vertebrae to which the disc is attached. There is apparently no study in the literature examining possible association of this disproportion with development of disc herniation.