[Lumbar intervertebral herniation. The composition of free sequesters--a morphologic study].

Since 1934 when surgery for lumbar disc herniation was first performed various forms of disc herniation have been described. It is generally accepted that disc herniations can be classified as follows: disc protrusion, disc prolapse, and free sequestration. Histological evaluations of protruded and prolapsed disc have been presented in literature, revealing degenerative changes. No special attention was given to free sequestered disc elements. The aim of this paper was to analyse the frequency of freely sequestered intervertebral disc fragments and to investigate the morphologic nature of sequestered discs. The free sequesters were observed in 15.5% of all operated cases (N = 187). In 16 (55.2%) of these cases the sequester was composed of nucleus pulposus material, in 12 (41.4%) cases end-plate elements were noted and in one case (3.4%) anulus fibrosus elements were found.