SECTION III: REGULAR AND SPECIAL FEATURES: Orthopaedic • Radiology • Pathology Conference: Letters to the Editor
The letter from Doctors Bunge and de Koning actually raises no challenge to the premise of my paper,1 ie, that screening for scoliosis would be more effective if made selective and objective. It does question two of my assumptions: (1) screening reduces the need for spinal fusion; and (2) there is an effective nonoperative treatment for scoliosis.
The report by Wiegersma et al presented to show that screening makes no difference in the need for surgery is a good example of faulty screening practice.4 They performed screening too late (subject ages 12-13 years) even though they reported the average age of menarche in the population is 13.1 years and that peak growth velocity occurs between the ages of 9.5-14.5 years. They must realize that progression typically occurs before menarche and during the time of peak growth velocity and that the opportunity for nonoperative treatment already has been missed. Subjects screened would not be expected to require fewer spinal fusions than subjects not screened. There are other shortcomings in this report. No screening criteria are described. No surgical criteria are described. One hundred twenty-eight of 317 surgical cases were excluded from the analysis, therefore making the conclusions suspect. There is no mention of brace treatment which is the only factor one would expect to reduce the need for spinal fusion. Even if brace treatment were used for subjects found during the screening process, it would not be expected to alter the natural history that late in its course.
Numerous factors make it difficult to prove a reduction in the number of spinal fusions in a given population with time. Chief among these are the changing indications for surgery resulting from improved surgical techniques, instrumentation, spinal cord monitoring, pain management, and the increased reluctance of teenagers to wear a brace. It is apparent that these factors have increased the number of patients having spinal fusions despite an apparently stable or somewhat reduced prevalence of scoliosis.
I did accept the premise that brace treatment is effective in preventing progression of scoliosis. I am supported by the meta-analysis of Rowe et al3 who showed an overall reduction in the percentage of patients who experienced progression of the deformity, from 51% of untreated patients to 7% if treated with bracing. Similarly, the prospective study by Nachemson and Peterson,2 using data from the Brace Study of the Scoliosis Research Society, showed a reduction in progressive scoliosis from 66% of untreated cases to 26% of treated cases. Natural history data (much of which was derived from school screening studies) predicted a risk of progression greater than 50% for each group.
There are many problems evaluating the outcome of brace programs. Small curves (< 25o) and more mature patients (Risser 2+) skew the results favorably, as both have a relatively low risk of progression. Curves greater than 40o and subjects with significant deformities skew results unfavorably because they already have exceeded brace capability. Both extremes are included inappropriately in some of the earlier reports. Also, the quality and effectiveness of braces varies and cannot be verified in any of the studies. Poorly constructed braces (of which there are many) skew the results unfavorably.
I too am troubled by the strict definition of “progression”, the over-referrals from screening, and the compliance problem of patients with braces. In the real world of statistics, screening and braces may seem to fail, but in the real world of clinical medicine, both offer realistic hope and demonstrable benefit and should not be abandoned.
William P. Bunnell, MD
Department of Orthopaedic Surgery, Loma Linda University, Loma Linda, CA
1. Bunnell WP. Selective screening for scoliosis. Clin Orthop Relat Res
2. Nachemson AL, Peterson LE. Effectiveness of treatment with a brace in girls who have adolescent idiopathic scoliosis: a prospective, controlled study based on data from the Brace Study of the Scoliosis Research Society. J Bone Joint Surg Am
3. Rowe DE, Bernstein SM, Riddick MF, Adler F, Emans JB, Gardner-Bonneau D. A meta-analysis of the efficacy of non-operative treatments for idiopathic scoliosis. J Bone Joint Surg Am
. 1997;79: 664-674.
4. Wiegersma PA, Hofman A, Zielhuis GA. The effect of school screening on surgery for adolescent idiopathic scoliosis. Eur J Public Health