When Does Scoliosis Need a Brace? Treatment by Cobb Angle

Whether adolescent idiopathic scoliosis needs a brace, observation or surgery is set by the size of the curve and the child's remaining growth. Curves under 10 degrees are not scoliosis. Curves of 10 to 25 degrees are observed with periodic X-rays. Between 25 and 40 degrees bracing has a role in children who are still growing, and curves beyond 40 to 45 degrees with a visible deformity are corrected surgically.

Those thresholds come from Dr. Manoj Miglani, Principal Director Orthopaedics, Fortis Flt. Lt. Rajan Dhall Hospital, Vasant Kunj, New Delhi, India, and they frame a deliberately conservative approach. Most children with adolescent idiopathic scoliosis need nothing more than careful follow-up, and Dr. Miglani is candid that the main non-surgical tool, the brace, delivers less than many families expect. The way these thresholds are measured, using the Cobb angle (the X-ray measure of curve size) and the Risser sign (an X-ray grade of skeletal maturity), is covered in the article on scoliosis diagnosis, and the wider picture in the complete guide to adolescent idiopathic scoliosis.

The goal of treatment

Treatment has two aims: to prevent progression and, where the deformity warrants it, to correct it. Curves of up to 30 to 40 degrees rarely need correction. Such curves are usually visible only on very close inspection, and in a child already close to skeletal maturity they are unlikely to progress significantly. A child who is still growing is a different matter and must be kept under observation.

Before anything else, Dr. Miglani insists on a neurological evaluation. Adolescent idiopathic scoliosis does not cause limb weakness, so any deficit means a different diagnosis is in play and an MRI is required. Only once the neurology is normal does the curve-based framework apply.

When does scoliosis need a brace? The decision by Cobb angle

Three inputs set the plan: skeletal maturity (the Risser stage and, in girls, whether menarche has occurred), curve magnitude (the Cobb angle) and the curve's behaviour over time. The options are observation, orthosis (a brace) or surgery.

The behaviour of the curve over time can override the snapshot. A child who suddenly decompensates and develops a rapid deformity needs intervention. If a curve has not progressed over the previous six months or a year, the frequency of imaging can be reduced, keeping an eye on it without undue worry.

Observation: what it involves

Observation is the right treatment for the large majority of curves. Dr. Miglani observes all curves under 20 degrees regardless of the child's age, and observation remains the default for curves up to 25 degrees. It is active management, not neglect: it involves educating the parents, scheduling follow-up, examining the child clinically and repeating X-rays.

How often to repeat scoliosis X-rays

The follow-up interval depends on age and Risser stage, because those predict how fast the curve could move. Dr. Miglani's examples:

• A 10-year-old with a 20-degree curve is highly likely to progress. X-rays every three months, or at most every six months, confirm that the curve is not worsening rapidly.
• A 13 or 14-year-old with a 20-degree curve needs an X-ray every six months to a year.
• A 14-year-old with a 20-degree curve at Risser 4 or 5 can be checked after a year, or even two. Curves of 20 to 25 degrees at Risser 5 are unlikely to progress much, even later in life, and are treated conservatively.

Scoliosis exercises during observation

Asked whether children with curves of 10 to 20 degrees should do rehabilitation exercises, Dr. Miglani's answer was simple. The only thing needed is exercise that keeps the back muscles healthy, together with avoiding extremes of posture. No other intervention is required at 10 to 20 degrees.

Post-traumatic curves

The same restraint applies outside idiopathic scoliosis. Asked by an attendee about a post-traumatic curve of about 22 degrees, Dr. Miglani advised that no brace is needed if the area is not painful. A painless post-traumatic curve of that size has already stabilised in its position and is unlikely to progress, and nothing further needs to be done for 22 degrees of deformity.

Bracing: what a brace can and cannot do

For curves between 25 and 40 degrees, a brace is the standard non-surgical option. Dr. Miglani is, in his own words, "not a big fan of bracing." His reservations rest on three points.

Does a scoliosis brace correct the curve?

A brace cannot reverse a curve or correct the deformity. Its only role is to prevent rapid progression. Dr. Miglani's view is that even when a brace is worn religiously, 22 to 23 hours a day, continuously for months, it may stop the curve progressing too rapidly but it will not correct it. In practice he sees much of its value as reassurance for parents that something is being done. A child whose curve at presentation is going to need correction will most likely still need it after bracing; the brace mainly maintains the curve.

How many hours a day a brace must be worn

In Dr. Miglani's view, a brace must be worn for 20 to 23 hours a day to control progression, and few children, or adults, manage that. Most of the time, he said, bracing is not useful because patients cannot wear it for long enough each day. A brace that is not worn has no effect, and a child who cannot cope with the regime gains nothing from it.

Braces can affect posture in unwanted ways

Dr. Miglani also cautioned that bracing tends to create lordosis in the thoracic spine. The chest needs space for the heart and lungs, and a flattened or lordotic thoracic spine pushes the vertebrae forward and can restrict cardiac and pulmonary function.

What the trial evidence shows

Dr. Miglani's scepticism is a clinical judgement shaped by compliance. The best trial evidence is more favourable to bracing in compliant patients: the Bracing in Adolescent Idiopathic Scoliosis Trial (BrAIST, 2013) found that bracing significantly reduced the progression of high-risk curves to the surgical threshold in skeletally immature children, and that the benefit rose with the number of hours the brace was worn, with the highest success rates in children averaging about 13 hours a day or more. Both positions point to the same practical conclusion: a brace helps only a child who will wear it for many hours a day.

When a brace should not be used

Dr. Miglani set out clear contraindications:

1. Skeletal maturity. A brace only maintains a curve during growth. In a child who is already 15 or 16 years old and skeletally mature, it makes no difference.
2. A curve already over 40 degrees. Even in a 12 or 13-year-old, a brace is unlikely to stop such a curve. If the deformity is clinically obvious, bracing only allows it to increase gradually and wastes the patient's time; if the child is fit for surgery, the curve should be corrected.
3. Poor compliance. If the child cannot cope with wearing the brace, there is no point prescribing it.

Types of scoliosis brace

Several designs exist, and they differ in how they work, how visible they are and which curves they suit.

• Milwaukee brace. This brace extends up to the neck, with occipital and chin pads. It stretches the spine, straightening both the lumbar lordosis and the thoracic kyphosis to resist sagging and rotation. It is cumbersome and cosmetically poor, so children are unlikely to wear it, and it is used less often today.
• Boston brace. A snug-fitting underarm thoracolumbosacral orthosis (TLSO), a brace that encloses the trunk from below the arms to the pelvis. It is hidden under clothing and cosmetically acceptable, but it suits only curves whose apex is at the eighth thoracic vertebra (T8) or lower.
• Charleston bending brace. Worn only at rest, while sleeping, it holds the spine acutely bent in the direction opposite to the curve. It aims to maintain the curve and prevent progression rather than correct it.
• Flexible strap braces. These use elastic straps rather than a rigid shell to hold the spine and resist progression.

When observation and bracing give way to surgery

Surgery is considered for children with curves of more than 40 to 45 degrees and a clinically obvious deformity who are skeletally immature, because these curves are likely to progress to severe deformity. It is also considered for mature adolescents whose curve already exceeds 45 degrees, causes a clinical problem and who want it corrected. Untreated, curves of this size continue to progress into adult life. The operation, its history and its risks are covered in the article on scoliosis surgery.

For families comparing approaches across specialists, Dr. Puneet Girdhar's guide to scoliosis and kyphosis in children covers congenital and neuromuscular curves, where the treatment logic differs. The follow-up and exercise questions summarised above are answered in full in the Live Discussion from this masterclass.