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Latero-posterior directed migration of trunk to the concave side of the curve: a biomechanical principle in treating the three dimensional deformity of idiopathic scoliosis with a custom molded high profile TLSO

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Scoliosis20138 (Suppl 1) :P13

  • Published:


  • Idiopathic Scoliosis
  • Individual Interview
  • Lumbar Lordosis
  • High Profile
  • Abdominal Pressure


The biomechanical principles that guide orthotic treatment for Idiopathic Scoliosis (IS) are not fully defined, except for the ‘three point correction’ principle.


This study aims to discover the underlying biomechanical principles, used by experienced orthotists, in treating the three dimensional deformity of IS, with a custom molded TLSO.


Semi-structured individual interview, and focus group methodology , were the primary methods of data collection. Detailed descriptions of orthotic treatment, for a specified case example, were obtained from seven experienced spinal orthotists; participants held an average of 16.7 years experience in IS treatment. Sessions were audiotaped, transcribed and data was analyzed using a systematic approach to identify themes. Triangulation of data was completed.


Achieving a “balanced and aligned spine and trunk in all 3 planes” emerged as the primary biomechanical goal for all 7 participants (100%). The orthotists identified specific techniques of the treatment process such as:

• drawing an iliac-clavicle box on the PA x-ray

• determining the location and the degree of forces and finding flexibility of the curve with a hand technique

• reducing lumbar lordosis during casting de-rotating the trunk

• centering the upper torso at the axillas over the pelvis

• creating space on the lateral posterior area of the concave side of curve and the mid-posterior area of the spine

• carving the model to achieve desired forces

• applying abdominal pressure

• building a sternal extension and a trochanteric extension.


To achieve the biomechanical goal, and re-align the 3-dimentional deformity of IS, orthotists apply de-rotational, anterior, and lateral translational forces on the lateral side of the convex curve, and create space on the side opposite the applied force. These factors result in a biomechanical principle called latero-posterior directed migration of the trunk to the concave side of the curve.

Authors’ Affiliations

Assistive Technology Department, Gillette Children's Specialty Healthcare, St. Paul, MN, USA


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© Jang and Hutson; licensee BioMed Central Ltd. 2013

This article is published under license to BioMed Central Ltd. This is an Open Access article distributed under the terms of the Creative Commons Attribution License (, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.