Abstract
Introduction: Spine and trunk deformity are different; trunk deformity is probably more important to the patient, and trunk deformity has received much less attention. This study was designed to determine the extent and stability of trunk deformity correction and is part of an ongoing effort to study trunk deformity.
Material and methods: This is a prospective case series the inclusion criteria being pre-, post- and follow-up surface topography evaluation of idiopathic scoliosis patients undergoing posterior instrumentation and arthrodesis. Twenty-eight patients (25 female, 3 male) met these inclusion criteria. The average age at surgery was 15 years 3 months (11 years 3 months – 38 years 2 months). Spine deformity measurement and classification were done from standing 36” PA and lateral scoliosis radiographs. Trunk asymmetry was determined from standing posterior rastersterography. Coronal plane asymmetry was calculated utilising the Posterior Trunk Symmetry Index (POTSI), threshold for change being ±8. Transverse plane asymmetry was determined by the Suzuki Hump Sum (SHS), threshold for change being ±3.5. Curve classification and number in each category were King Moe I – three; IIA – two; IIB – three; III – ten; IV – four;V – five and Triple – one. Initial follow-up averaged 2.3 months (±7) and latest follow-up 15.8 months (±8.1).
Results: Pre-operative; post-operative; and 1atest follow-up spine deformity measurements with percent correction (for spine and trunk deformity) were as follows: Major scoliosis-63°, 19° (69%) and 21° (66%); POTSI 52, 26 (50%), and 24 (54%); and SHS 18, 11 (38%), and 12 (37%). Thus, spine deformity (Cobb) and trunk deformity (POTSI and SHS) correction appeared to be stable over the follow-up period. Spine deformity correction was better than coronal trunk plane asymmetry correction which was better than transverse plane asymmetry correction. At latest follow-up, spine deformity correction for single curves was similar to multiple curve, 69% versus 64% as was transverse plane trunk asymmetry correction 34% versus 37%. However, coronal plane trunk asymmetry correction was better for single curves than double curves 63% versus 42%. At follow-up POTSI was better in all patients with single curves whereas in double curves it was better in nine, same in three, and worse in two. Transverse plane trunk asymmetry for single curves was better in ten, same in three, and worse in one, whereas for double curves it was better in eight, same in four and worse in two.
Discussion and conclusion: The obvious weaknesses in this study are the small numbers and relative short follow-up. However, the trend seems clear. Trunk deformity correction is not as good as spine deformity correction. This is especially true for the transverse plane for all curves and the coronal plane for double curves in comparison to single curves.
Abstracts prepared by Mr J. Dorgan. Correspondence should be addressed to him at the Royal Liverpool Children’s Hospital, Alder Hey, Eaton Road, Liverpool L12 2AP, UK
President’s Lecture: Natural history and management of Congenital Kyphosis and Kyphoscoliosis M.J. McMaster, Edinburgh, Scotland, UK
Greg Houghton Lecture: Idiopathic Scoliosis – Alternatives to traditional surgery R.R. Betz, Philadelphia, USA
Instructional Lecture:New thoughts on the treatment of paralytic scoliosis R.R. Betz, Philadelphia, USA
Keynote Lectures: Idiopathic Scoliosis – How to manage the patient R.A. Dickson, Leeds, UK
Concave or convex approach for Kyphoscoliosis J. Dubousset, Paris, France Surgery or bracing for moderate AIS. How long term follow-up studies change your perspective A. Nachemson, Göteborg, Sweden
