Bracing to Keep Scoliosis Out of Surgery
A brace worn during growth can keep an adolescent scoliosis curve from reaching the size that needs spinal fusion.
Key terminology
- Adolescent idiopathic scoliosis (AIS)
- This sideways curve of the spine with rotation of the vertebrae appears between ages 10 and 18. It has no underlying cause and is the most common form of scoliosis.
- Cobb angle
- This angle is drawn on a standing radiograph between the most tilted vertebrae at each end of the curve. It is the standard measure of curve size.
- Risser sign
- This grade from 0 to 5 tracks how far the growth plate along the iliac crest has ossified. A low Risser grade means more spinal growth remains.
- Thoracolumbosacral orthosis (TLSO)
- This rigid plastic brace wraps the trunk from under the arms to the pelvis. The Boston brace is the most common type.
- Preference cohort
- These patients chose their own treatment instead of being randomized. Families who choose a brace may differ from those who decline, so the results can be biased.
- Intention-to-treat (ITT)
- This analysis counts each patient in the group they were assigned to, whether or not they followed it. It keeps the protection of randomization.
Takeaways
- A brace aims to keep a growing curve below the surgical range. Adolescent idiopathic scoliosis (AIS) is a lateral curve with a Cobb angle of at least 10° in a child aged 10 to 18. Curves larger than 50° usually need surgery, so brace trials count a curve that reaches 50° before skeletal maturity as treatment failure. (Weinstein et al, N Engl J Med 2013;369:1512-1521, PMID 24047455; Grossman et al, JAMA 2018;319:165-172, PMID 29318284).
- Curves progress while the child is still growing, so remaining growth decides who needs a brace. In 727 untreated patients with curves of 5° to 29°, 23.2% progressed before growth ended. Progression was linked to curve pattern and size, younger age, a low Risser sign and premenarchal status, and not to sex. (Lonstein & Carlson, J Bone Joint Surg Am 1984;66:1061-1071, PMID 6480635).
- The classic brace candidate is a skeletally immature child with a moderate curve. SRS criteria are age ≥10, Risser 0 to 2, a primary curve of 25° to 40°, no prior treatment, and in girls premenarchal or less than 1 year after menarche. BrAIST used a similar window (age 10 to 15, Risser 0 to 2, curves 20° to 40°). (Richards et al, Spine 2005;30:2068-2075, PMID 16166897; Weinstein et al, N Engl J Med 2013;369:1512-1521, PMID 24047455).
- A rigid brace keeps more high-risk curves out of the surgical range than observation. BrAIST prescribed a rigid thoracolumbosacral orthosis (TLSO) for at least 18 hours a day and was stopped early for efficacy. Across randomized and preference cohorts (242 patients), success was 72% with bracing vs 48% with observation. In the randomized cohort by intention-to-treat (ITT), success was 75% vs 42%. (Weinstein et al, N Engl J Med 2013;369:1512-1521, PMID 24047455).
- Brace benefit rises with the hours the brace is worn. BrAIST measured wear with temperature sensors, and patients averaged about 12 hours a day against an 18-hour prescription. The lowest quartile (0 to 6 hours a day) had 41% success, and an average of at least 12.9 hours a day had 90% to 93% success. This dose-response comes from patients who chose how long to wear the brace. (Weinstein et al, N Engl J Med 2013;369:1512-1521, PMID 24047455).
- Older studies could not show that bracing lowers the rate of surgery. A pooled review of 18 Level III and IV series found surgery in 23% after bracing vs 22% after observation, and graded the evidence D. A Dublin center that stopped bracing in 1991 reported surgery in 28.1% of 153 children, not different from a bracing center. (Dolan & Weinstein, Spine 2007;32:S91-S100, PMID 17728687; Goldberg et al, Spine 2001;26:42-47, PMID 11148644).
- Every controlled brace study favors bracing, and the evidence is still rated low quality. Cochrane found all 7 included studies (662 participants) showed bracing prevented curve progression. It rated the evidence low to very low, partly because parents refused randomization. An earlier SRS study of girls with 25° to 35° curves found 74% brace success vs 34% with observation. (Negrini et al, Cochrane Database Syst Rev 2015;(6):CD006850, PMID 26086959; Nachemson & Peterson, J Bone Joint Surg Am 1995;77:815-822, PMID 7782353).
- Bracing slows curve progression, and whether that improves adult health is unproven. The USPSTF found adequate evidence that bracing may slow progression of curves under 40° to 50° and inadequate evidence that this changes adult outcomes. It gave screening an I statement. In a 50-year study of untreated late-onset idiopathic scoliosis, 61% reported chronic back pain vs 35% of controls, with little other physical impairment. (Grossman et al, JAMA 2018;319:165-172, PMID 29318284; Weinstein et al, JAMA 2003;289:559-567, PMID 12578488).