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Scoliosis and Spinal Disorders

Open Access

Evaluation of the effect of vertebral and disc mechanical torsion on the correction achieved by posterior instrumentation in adolescent idiopathic scoliosis

Scoliosis20072(Suppl 1):S28

Published: 12 October 2007


Magnetic Resonance ImagingVertebral BodyAdolescent Idiopathic ScoliosisIdiopathic ScoliosisCobb Angle


To evaluate the effect of rotational deformation ('mechanical torsion') on the short-term and long-term effectiveness of modern posterior spinal instrumentation in treating the three-dimensional deformity of adolescent idiopathic scoliosis.


Ten patients with idiopathic scoliosis were imaged with three-dimensional magnetic resonance imaging pre-operatively and at six weeks and twelve months post-operatively following Isola posterior instrumentation [1]. Changes in the three-dimensional deformity were measured, and the effect of mechanical torsion within the vertebral bodies and discs on the overall changes analysed.


Posterior instrumentation causes partial and temporary improvement in disc mechanical torsion but insignificant improvement in vertebral mechanical torsion. Changes in disc torsional deformity correlate with changes in apical rotation, Cobb angle and thoracic hypokyphosis.


Mechanical torsion within the vertebral bodies and discs of patients with idiopathic scoliosis presents a fundamental obstacle to effective derotational surgery, and is closely related to subsequent changes in the overall three-dimensional deformity following instrumentation.

Authors’ Affiliations

Consultant and Head of Division, Northern Neurosciences Centre, Newcastle, UK


  1. Benli IT, Akalin S, Aydin E, Baz A, Citak M, Kis M, Duman E: Isola spinal instrumentation system for IS. Arch Orthop and Trauma Surgery. 2001, 121: 17-25. 10.1007/s004020000170.View ArticleGoogle Scholar


© Birchall et al; licensee BioMed Central Ltd. 2007

This article is published under license to BioMed Central Ltd.