gms | German Medical Science

56. Jahrestagung der Deutschen Gesellschaft für Neurochirurgie e. V. (DGNC)
3èmes journées françaises de Neurochirurgie (SFNC)

Deutsche Gesellschaft für Neurochirurgie e. V.
Société Française de Neurochirurgie

07. bis 11.05.2005, Strasbourg

The putative role of inflammatory infiltrates in the hypertrophied ligamentum flavum

Die Rolle inflammatorischer Infiltrate im hypertrophierten Ligamentum flavum

Meeting Abstract

  • corresponding author M. Löhr - Klinik für Neurochirurgie der Universität zu Köln
  • W. Stenzel - Institut für Neuropathologie der Universität zu Köln
  • J. Y. Lee - Klinik für Neurochirurgie der Universität zu Köln
  • T. Reithmeier - Klinik für Neurochirurgie der Universität zu Köln
  • N. Klug - Klinik für Neurochirurgie der Universität zu Köln

Deutsche Gesellschaft für Neurochirurgie. Société Française de Neurochirurgie. 56. Jahrestagung der Deutschen Gesellschaft für Neurochirurgie e.V. (DGNC), 3èmes journées françaises de Neurochirurgie (SFNC). Strasbourg, 07.-11.05.2005. Düsseldorf, Köln: German Medical Science; 2005. DocP097

The electronic version of this article is the complete one and can be found online at:

Published: May 4, 2005

© 2005 Löhr et al.
This is an Open Access article distributed under the terms of the Creative Commons Attribution License ( You are free: to Share – to copy, distribute and transmit the work, provided the original author and source are credited.




Hypertrophy of the ligamentum flavum (HLF) and its encroachment into the spinal canal play a major role in the pathogenesis of neurogenic claudication. The exact mechanisms underlying HLF are still unknown. Whereas the alterations in the architecture of the extracellular matrix components in HLF were well characterized in previous studies, there is no detailed information about the changes in the cellular composition.


Specimens of hypertrophied ligamenta flava were obtained at operation from 20 patients with lumbar osteoligamentous spinal canal stenosis. All samples were taken from the ligamentous insertion at the inferior articular process where it blends with the fibrous joint capsule and has contact with the nerve root. Paraffin sections were stained with hematoxylin and eosin and Elastica van Giesson. Immunohistochemistry was performed on 4μm paraffin sections using an ABC-method for demonstration of CD68, leucocyte common antigen, CD3 and CD20. For comparative reasons, sections of 5 normal ligamenta flava were examined in the same manner.


The hypertrophied ligamenta flava were characterized by a relative increase in collagen fibers that were obviously disordered, sometimes interspersed with calcium crystal deposition or ossification of the extracellular matrix. Apart from an increment of fibroblasts, all specimen showed regions of neovascularization and perivascular inflammatory infiltrates, composed mainly of macrophages and T-lymphocytes. The extent of vascular proliferation and cellular infiltrates was correlated to the degree of hypertrophy, being moderate and peripherally arranged in moderate HLF and distinctive and scattered throughout the whole specimen in the advanced stages.


Hypertrophy of the ligamantum flavum is accompanied by a chronic inflammatory reaction, that might promote the proliferative process and contribute to nerve root injury. Although the etiology of this phenomenon remains obscure, our findings offer the potential therapeutic strategy of decelerating the process of HLF by the local application of anti-inflammatory agents.