Age changes in lumbar intervertebral discs

Measurements of disc thickness, shape and degeneration, using the criteria described by Rolander (1966), were recorded from 204 post-mortem lumbar spines. The "true average disc height" increased with age as the discs "sink" into the vertebrae. These results add information to previous studies which indicate that the loss of transverse trabeculae of lumbar vertebrae is primarily responsible for the change in shape of both vertebrae and discs in the elderly. While the incidence of disc degeneration does increase in old age, the majority of the discs examined did not show evidence of any such change.     

Age changes in lumbar intervertebral discs

Measurements of disc thickness, shape and degeneration, using the criteria described by Rolander (1966), were recorded from 204 post-mortem lumbar spines. The “true average disc height” increased with age as the discs “sink” into the vertebrae. These results add information to previous studies which indicate that the loss of transverse trabeculae of lumbar vertebrae is primarily responsible for the change in shape of both vertebrae and discs in the elderly. While the incidence of disc degeneration does increase in old age, the majority of the discs examined did not show evidence of any such change.     

Age changes in lumbar intervertebral discs

Measurements of disc thickness, shape and degeneration, using the criteria described by Rolander (1966), were recorded from 204 post-mortem lumbar spines. The “true average disc height” increased with age as the discs “sink” into the vertebrae. These results add information to previous studies which indicate that the loss of transverse trabeculae of lumbar vertebrae is primarily responsible for the change in shape of both vertebrae and discs in the elderly. While the incidence of disc degeneration does increase in old age, the majority of the discs examined did not show evidence of any such change.     

Protrusion of thoracic intervertebral discs

Summary A critical analysis of 23 cases of thoracal disc prolapse observed by the authors as well as of 168 cases gathered from the literature is made.The different etiological factors are considered and the signification of the different kind of traumas is stressed.It is shown that in cases with a long clinical evolution local pain may be absent and the absence of radicular pain in some cases may be due to the relative great distance between a median disc prolapse and the posterior root.In search for a more adequate technique for the removal of the prolapsed disc an analysis of the different surgical approaches is made.The results obtained in 19 cases aut of the total number of cases are presented because in 2 cases a coexistent vertebral tumour has been found and in 2 cases the time follow-up was too short. There was one post-operative death, 1 late death, 3 patients were not benefited by the operation, in 6 the result was fair, good in 4 cases and excellent in 4 cases.

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Zusammenfassung Die Autoren geben eine kritische Analyse von 23 eigenen und 168 Fällen des Schrifttums mit thorakalem Bandscheibenvorfall. Die einzelnen ätiologischen Faktoren werden dargelegt und die verschiedenen Arten von Traumen hervorgehoben. Es wurde gezeigt, daß bei Fällen mit langer klinischer Entwicklung örtliche Schmerzen fehlen können und daß das Fehlen von radikulären Schmerzen bei manchen Fällen auf dem relativ großen Abstand zwischen einem medialen Diskusprolaps und der hinteren Wurzel beruht. Auf der Suche nach einer zweckmäßigeren Technik für die Entfernung des Bandscheibenvorfalles werden die verschiedenen operativen Zugänge analysiert.Aus dem eigenen Krankengut werden die Behandlungsergebnisse nur von 19 Fällen wiedergegeben, weil bei 2 Fällen gleichzeitig Wirbeltumoren bestanden und bei 2 anderen Fällen die Beobachtungszeit noch zu kurz war. In der Serie findet sich ein postoperativer Todesfall und ein späterer Todesfall; 3 Fälle wurden durch die Operation nicht gebessert; bei 6 Fällen war das Ergebnis befriedigend, bei 4 gut und bei 4 ausgezeichnet.

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Resumen Se hace un análisis crítico de 23 casos de hernias y protusiones de los discos torácicos observados por los autores, así como de 168 casos recogidos de la literatura.Se consideran los diferentes factores etiolicos y la significación de las distintas clases de traumas.Puede ocurrir que en casos con una larga evolución clínica no exista dolor local y la ausencia de dolor radicular en algunos casos puede ser debida a la distancia relativamente grande entre el disco mediano prolapsado y la raiz posterior.En busca de una técnica más adecuada para la extirpación de los discos torácicos prolapsados se analizan las diferentes vias quirúrgicas de acceso.Se presentan los resultados obtenidos en 19 casos del total, ya que en 2 casos se encontró un tumor vertebral coexistente y en los otros 2 el tiernpo de observación era muy corto. Hubo una muerte postoperatoria, otra tardía, 3 enfermos que no se beneficiaron con la operación, otros 6 en los cuales los resultados fueron medianos, buenos en 4 y excelentes en los otros 4 casos.

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Résumé Analyse de 23 cas de hernies discales thoraciques vus par les auteurs, et de 168 cas rassemblés dans la littérature.Etude des différents facteurs étiologiques, et valeur des différentes sortes de traumatismes. On montre que dans les cas ayant une longue évolution clinique, la douleur locale peut manquer, et l'absence de douleur radiculaire dans quelques cas peut être dûe à la distance relativement grande, qui sépare une hernie discale médiale et la racine postérieure.Cherchant la technique d'exérèse du disque la meilleure, on fait une analyse des différentes voies d'abord chirurgicales.Les résultats obtenus dans 19 cas sont présentés (dans 2 cas, coexistait une tumeur vertébrale, et dans 2 autres cas, le recul était insuffisant). Il y a eu un décès post-opératoire, un décès tardif, 3 malades ne furent pas améliorés par l'opération, chez 6 le résultat fut moyen, bon dans 4 cas, excellent dans 4 cas.

     

Age changes in lumbar vertebrae and intervertebral discs

Reduction of stature in old age has been attributed to loss of disc height. A measurement study of 204 cadaveric lumbar spines from subjects ranging in age from one day to 97 years confirmed data on loss of "spinal stature" but could not confirm a loss of disc height. With aging, there is a progressive increase in vertebral end-plate concavity, associated with decreased bone density. These changes are more evident and take place earlier in females than in males. In the cancellous bone of vertebral bodies, a decrease in the number of horizontal trabecular "cross braces" leads to fracture of the vertical weight-bearing "beams" supporting the vertebral endplate. The intervertebral discs expand centrally and become increasingly convex. Measurements of average disc height demonstrate that loss of disc height is unusual in a normal, aging population. Only a minority of lower lumbar discs from elderly subjects show "thinning" and degeneration (beyond Rolander's Grade 2). Thus, loss of stature in the elderly is attributable to loss in vertebral height rather than loss in disc height. Dessication and thinning of discs, or discs that "bulge like underinflated automobile tires" are not typical of elderly spines.     

Elastic fibers in human intervertebral discs.

Although previous studies failed to demonstrate elastic fibers in intervertebral discs, electron microscopy of twenty human intervertebral discs obtained at autopsy and operation revealed characteristic elastic fibers in both the annulus fibrosus and the nucleus pulposus. Their contribution to the mechanical properties of the intervertebral disc remains to be determined.     

(iii) Prolapsed intervertebral discs

The understanding of the aetiology of sciatic pain continues to develop. There is an increasing understanding of the role of cytokines and inflammatory mediators in the origin of this pain. Early clinical trials seem to suggest that there may eventually be a non-operative solution to the treatment of this condition. However, the gold standard for operative treatment for those patients who fail to resolve spontaneously remains microdiscectomy.The condition itself is one that with relatively little knowledge in terms of understanding the dermatomal distribution of nerves and the clinical history of patterns of pain can be easily diagnosed from a history and examination. The imaging techniques now available to us should be used to confirm the clinical impression given by the patient on consultation. They should never be used as a substitute for obtaining a good history and a thorough examination.     

腰椎间盘内神经侵润生长

椎间盘源性下腰痛的产生可能与神经向椎间盘深层侵入生长有关,本质上也是一种牵涉性痛.腰椎间盘内感觉纤维主要由背根神经节内的小型肽能神经元发出,由交感神经和窦椎神经双重性、多节段支配,且以交感神经为主.蛋白聚糖、髓核和周围靶细胞组成的生物性屏障可能是影响轴突生长的主要因素,椎间盘细胞减弱了聚集蛋白聚糖对轴突生长的抑制作用,髓核组织和软骨素酶ABC促进轴突再生,体外培养条件下IL-1β、TNF等炎性因子也可抑制轴突生长.     

Surface strain on human intervertebral discs

The biomechanical functions of the internal components of the intervertebral disc are not well understood. The surface deformation of 17 human cadaveric lumbar intervertebral discs was studied by photogrammetry by adhering small optical targets to the disc surface and thereby recording the length, bulge, and vertical height of lines on the disc surface representing annular fibers. Discs were studied in pure compression, flexion and extension, axial rotation, and shear. Two definitions of a fiber were investigated: first with the end-points of the fiber on the vertebra ("bone-to-bone" definition), second, where the end points of the fiber were just before the disc vertebra junction (the "disc-only" definition). Measurements were compared with a "constant-volume" physical model and with a mathematical model of the intervertebral disc. Fiber strains were 6% or less under physiological conditions. Comparison of results from the two definitions of fiber length showed greater strains for the disc-only definition in compressive loading. Fiber strains were less than in the constant-volume model of comparable dimensions in compressive loading by a factor of about two, thus suggesting fluid loss or end-plate deformations in the physiologic conditions. The mathematical model indicated that the surface strain for intervertebral discs is very sensitive to the disc-height: diameter ratio and to fluid loss from the disc but is less sensitive to the helix angle of the fibers.