Instability and Manipulation

Summary

Spinal instability is ‘the loss of the ability of the spine under physiolgoic loads to maintain relationships between vertebrae in such a way that there is neither initial damage nor subsequent irritation to the spinal cort or nerve roots, and, in addition, there is no development of incapacitating deformity or pain due to structural changes’ (White and Panjabi, 1982).

Spinal instability has been perceived and defined in different ways by several authors:

1	A clinical syndrome in which it is seen as the cause of recurrent acute back pain and of chronic back pain.
2	An abnormality defined by imaging techniques, which reinforces the idea of laxity within the functional spinal unit and which then provides an indication for surgical stabilisation.
3	A feature of disc degeneration which leads to abnormal biomechanics.

These three definitions relate to an abnormality of the motion segment. The question then arises about manipulation: how does this abnormality influence decisions on the appropriate use of manipulation, where the paraphysiological zone (or functional barrier) of segmental mobility is affected?

Résumé

L’idée d’une instabilité segmentate répond à des constats biomécanique, clinique, et d’imagerie. Sa sémiologie est évocatrice quoique non spécifique, mais la bioméchanique se présente comme la meilleure approche pour argumenter la place des traitements manipulatifs. Les lésions correspondent à des modifications au sein de l’Unité Vertébrale Fonctionnelle, intéressant l’amplitude de mouvement, globalement ou sectoriellement. Il en résulte une distribution anormale des efforts au sein de l’articulation, sur fond d’hypermobilité aussi bien que d’enraidissement. Compte tenu d’une revue dans la littérature des propositions physiopathologiques, les auteurs discutent les arguments qui justifient le recours au traitement manipulatif sur un tel état.