Adolescent idiopathic scoliosis as developmental instability

Abstract

Adolescent idiopathic scoliosis is the most common spinal deformity affecting children, with a prevalence from mass screening programmes of 1-3%. Despite centuries of study, it remains a problem with no generally accepted theory of aetiology, and disagreement on its natural history and management. Because the deformity consists ultimately of gross left-right asymmetry, a study was undertaken to test the hypothesis that it might be a manifestation of developmental instability. Palmar dermatoglyphics in 112 normal subjects, 62 with non-scoliosis trunk asymmetry and 85 with defined adolescent idiopathic scoliosis were examined and both the absolute right-left difference and the ratio of this to the total were considered. There was increased fluctuating asymmetry of atd difference in those with any asymmetry, scoliotic or not, and increased directional asymmetry of ab and cd ridge counts only in those with pure scoliosis. This suggests that, at adolescence, developmental instability may result in a loss of symmetry in growth, and that in the presence of an increased developmental left-right gradient, this may be of sufficient severity to be classified as deformity and come to the attention of orthopaedic surgeons. This interpretation changes the focus of many previous observations on scoliosis and raises the prospect that developmental stability in humans has relevance to problems hitherto restricted to clinical practice.

Maturity Assessment and Curve Progression in Girls with Idiopathic Scoliosis

“…Another question is why the stage of skeletal maturity correlates so highly with the curve acceleration phase, particularly at CAP 0 to +6. Does this occur because skeletal maturation is a better reflector of longitudinal growth with the spine becoming unstable from rapid growth leading to curve progression, as suggested by Goldberg et al 22,23 ? Is it because the vertebral apophysis and growth plate is more susceptible to Heuter-Volkmann compressive growth inhibition at this stage, or is some other mechanism at work?…”

Scoliosis: a review

“…The hypothesis being tested was that scoliosis was a manifestation of developmental instability, rather than a specific disease process, a non-specific response to physiological stress, occurring under a variety of environmentally stressful conditions [45,46]. Preliminary work here and elsewhere had shown that patients with AIS showed more and greater asymmetry over a large variety of paired anatomical features than did normal controls [47][48][49][50]. The question asked was: does the back surface itself and hence the torso, follow the same pattern of asymmetry?…”

The effectiveness of the Pilates method: Reducing the degree of non-structural scoliosis, and improving flexibility and pain in female college students

“…Furthermore, the degree of scoliosis was re-evaluated by measurement of the Cobb angle (Goldberg et al, 1995) by tracing a line parallel to the upper boundary of the top vertebra and another line on the bottom edge of the adjacent lower vertebra and measuring the angle with a goniometer (CARCI, Brazil). The intersection of these two lines determined the angle of deviation of the spine.…”