Abstract
The disc nucleus is commonly thought of as a largely unstructured gel. However, exactly how the nucleus integrates structurally with the endplates remains somewhat ambiguous. The purpose of this study was to investigate whether a substantial level of structural/mechanical cohesion does, in fact, exist across the nucleus-endplate junction. Vertebra–nucleus–vertebra samples were obtained from mature ovine lumbar motion segments and subjected to a novel technique involving circumferential transverse severing (i.e. ring-severing) of the annulus fibrosus designed to eliminate its strain-limiting influence. These samples were loaded in tension and then chemically fixed in order to preserve the stretched nucleus material. Structural continuity across the nucleus-endplate junctions was sufficient for the samples to support, on average, 20 N before tensile failure occurred. Microscopic examination revealed nucleus fibres inserting into the endplates and the significant level of load carried by the nucleus material indicates that there is some form of structural continuity from vertebra to vertebra in the central nucleus region.
Similar content being viewed by others
References
Humzah MD, Soames RW (1988) Human intervertebral disc: structure and function. Anat Rec 220:337–356
Adams MA (2004) Biomechanics of back pain. Acupunct Med 22:178–188
Coventry MB, Ghormley, Ralph K, Kernohan, James W (1945) The intervertebral disc: its microscopic anatomy and pathology part I. Anatomy, Development and Physiology. The J Bone Joint Surg XXVII
Cassidy JJ, Hiltner A, Baer E (1989) Hierarchical structure of the intervertebral disc. Connect Tissue Res 23:75–88
Hukins DWL, Meakin JR (2000) Relationship between structure and mechanical function of the tissues of the intervertebral joint. Am Zool 40:42–52
Adams MA, McMillan DW, Green TP, Dolan P (1996) Sustained loading generates stress concentrations in lumbar intervertebral discs. Spine 21:434–438
Nachemson A (1975) Towards a better understanding of low back pain: a review of the mechanics of the lumbar disc. Rheumatol Rehabil 14:129–143
Urban JPG, Roberts S, Ralphs JR (2000) The nucleus of the intervertebral disc from development to degeneration. Am Zool 40:53–61
Adams MA, Green TP (1993) Tensile properties of the annulus fibrosus. I. The contribution of fibre-matrix interactions to tensile stiffness and strength. Eur Spine J 2:203–208
Green TP, Adams MA, Dolan P (1993) Tensile properties of the annulus fibrosus. II. Ultimate tensile strength and fatigue life. Eur Spine J 2:209–214
Galante JO (1967) Tensile properties of the human lumbar annulus fibrosus. Acta Orthop Scand
Holzapfel GA, Schulze-Bauer CAJ, Feigl G, Regitnig P (2005) Single lamellar mechanics of the human lumbar anulus fibrosus. Biomech Model Mechanobiol 3:125–140
Pezowicz CA, Robertson PA, Broom ND (2006) The structural basis of interlamellar cohesion in the intervertebral disc wall. J Anat 208:317–330
Pezowicz CA, Robertson PA, Broom ND (2005) Intralamellar relationships within the collagenous architecture of the annulus fibrosus imaged in its fully hydrated state. J Anat 207:299–312
Schollum ML, Robertson PA, Broom ND (2009) A microstructural investigation of intervertebral disc lamellar connectivity: Detailed analysis of the translamellar bridges. J Anat 214:805–816
Schollum ML, Robertson PA, Broom ND (2008) ISSLS prize winner: microstructure and mechanical disruption of the lumbar disc annulus: part I: a microscopic investigation of the translamellar bridging network. Spine 33:2702–2710
Yu J, Peter C, Roberts S, Urban JPG (2002) Elastic fibre organization in the intervertebral discs of the bovine tail. J Anat 201:465–475
Yu J, Tirlapur U, Fairbank J, Handford P, Roberts S, Winlove CP, Cui Z, Urban J (2007) Microfibrils, elastin fibres and collagen fibres in the human intervertebral disc and bovine tail disc. J Anat 210:460–471
Buckwalter JA, Cooper RR, Maynard JA (1976) Elastic fibers in human intervertebral discs. J Bone Joint Surg Ser A 58:73–76
Inoue H (1981) Three-dimensional architecture of lumbar intervertebral discs. Spine 6:139–146
Inoue H, Takeda T (1975) Three dimensional observation of collagen framework of lumbar intervertebral discs. Acta Orthopaed Scand 46:949–956
Takeda T (1975) Three dimensional observation of collagen framework of human lumbar discs. J Jap Orthop Ass 49:45–57
Roberts S, Menage J, Urban JPG (1989) Biochemical and structural properties of the cartilage end-plate and its relation to the intervertebral disc. Spine 14:166–174
Melrose J, Smith SM, Little CB, Moore RJ, Vernon-Roberts B, Fraser RD (2008) Recent advances in annular pathobiology provide insights into rim-lesion mediated intervertebral disc degeneration and potential new approaches to annular repair strategies. Eur Spine J 17:1131–1148
Vernon-Roberts B, Moore RJ, Fraser RD (2007) The natural history of age-related disc degeneration: the pathology and sequelae of tears. Spine 32:2797–2804
Raj PP (2008) Intervertebral disc: anatomy–physiology–pathophysiology-treatment. Pain Pract 8:18–44
Heinegard D (2009) Proteoglycans and more—from molecules to biology. Int J Exp Pathol 90:575–586
Acknowledgments
The authors are grateful for the award of funding in support of this research from both the Wishbone Trust (New Zealand Orthopaedic Association) and the University of Auckland.
Author information
Authors and Affiliations
Corresponding author
Rights and permissions
About this article
Cite this article
Wade, K.R., Robertson, P.A. & Broom, N.D. A fresh look at the nucleus-endplate region: new evidence for significant structural integration. Eur Spine J 20, 1225–1232 (2011). https://doi.org/10.1007/s00586-011-1704-y
Received:
Revised:
Accepted:
Published:
Issue Date:
DOI: https://doi.org/10.1007/s00586-011-1704-y