Spine
Trunkal back shape asymmetry is used to select children at risk of developing progressive idiopathic scoliosis (IS). Traditionally, this asymmetry, as thoracic and/or lumbar humps, is the main indicator for referral to clinics during school screening for scoliosis (SSS). Such trunkal asymmetry is also the most important sign for assessing IS in scoliosis clinics.
The goal of SSS, traditionally, is to detect scoliosis at an early stage, when the deformity is likely to go unnoticed and there is an opportunity for a less invasive method of treatment or a decrease in the amount of surgery required than would otherwise be the case.
What the SSS program does in reality, using the scoliometer or any other surface measuring device, is to reveal trunkal back shape asymmetry/deformity in children. The scoliometer reads and documents trunkal asymmetry and not scoliosis per se. Scoliosis and trunkal asymmetry are not equivalent measurements, especially at a younger age, and it is now established that the surface asymmetry/deformity does not accurately predict the magnitude of scoliosis, especially in younger children.1,2 This is because, in younger children, trunkal surface and spinal asymmetry do not correlate statistically. The relationship of these two asymmetries becomes statistically significant in older children.1
As Bunnell characteristically states,3,4'it has become apparent from many reports that, although there is a significant correlation between clinical deformity and radiographic measurement, the standard deviation is so high that it is not possible to reliably predict the degree of curvature from surface topography in any given patient by any technique'.
The above described phenomenon (discordance of spinal and surface asymmetry/deformity in younger children) leads to over-referrals from SSS programs and it is the main cause of the ongoing controversy over its application.
As a fact, it must be widely accepted that, with SSS programs, which detect trunkal asymmetry, a chance is mainly given to rule out those who will be at risk for developing scoliosis within the school-aged population, rather than discover those who definitely have scoliosis. This is especially true if there is a significant surface deformity justifying the central axis (that is the spinal) deformity.
There is something else that must be highlighted and clearly understood. The SSS program aims at detection of surface asymmetry/deformity and/or the existing number of scoliosis cases; it does not aim at predicting which scoliotic curves will progress to a type that will require some type of conservative or surgical treatment.
The criteria used to predict progression of a small or moderate curve are unfortunately not related to SSS programs. All asymmetric children, therefore, who will be at risk of developing scoliosis will miss the opportunity to be picked up and will probably be discovered too late, when surgery will be the only treatment option. As expected, the outcome will be particularly worse in poor societies. It was reported that the discontinuation of school screening for scoliosis in Canada resulted in suboptimal / late referrals with regards to brace treatment indications.5
Moreover, in explaining the role of SSS, it must also be clearly understood that its cost is the direct cost of performance of the actual screening program and not the subsequent expenditures of follow-up, radiographs and other modalities described in the current literature.
It was in Kyoto, Japan, during the 45th Scoliosis Research Society (SRS) meeting in 2010, that after a very successful lunch time symposium on SSS, the discussion on the issue of the SSS, which had been fading in the previous decades, revived. The SRS presidential line (the president at that time was Dr L. Lenke) wisely suggested the establishment of an International SSS Task Force in order to evaluate the present status of a currently controversial but definitely useful medical issue. The international members of this Task Force met at the recent Denmark (IMAST) and Kentucky (SRS) meetings and have also been working using e-communications as well. Hopefully they will soon present the current wisdom on SSS, and they will make suggestions for the improvement of these programs for the benefit of all children.
Dr Theodoros Grivas, Orthopaedic and Spinal Surgeon, “Tzanio” General Hospital of Piraeus, Greece
References
1. Grivas TB, Vasiliadis ES, Mihas C, Savvidou O. The effect of growth on the correlation between the spinal and rib cage deformity: implications on idiopathic scoliosis pathogenesis. Scoliosis 2007;14;2:11.
2. Grivas TB, Vasiliadis E, Mouzakis V, Mihas C, Koufopoulos G. Association between adolescent idiopathic scoliosis prevalence and age at menarche in different geographic latitudes. Scoliosis 2006;23:9.
3. Grivas TB, Wade MH, Negrini S, et al. SOSORT consensus paper: school screening for scoliosis. Where are we today? Scoliosis 2007;26:17.
4. Bunnell WP. Selective screening for scoliosis. Clin Orthop Relat Res 2005;434:40-45.
5. Beausejour M, Roy-Beaudry M, Goulet L, Labelle H. Patient characteristics at the initial visit to a scoliosis clinic: a cross-sectional study in a community without school screening. Spine 2007;32:1349-1354.
