In a study of 276 adolescents with the most common form of scoliosis, the overweight were more than twice as likely as those of normal weight to develop worsening curvatures, despite the brace. Almost half of these overweight teens eventually needed corrective surgery. The study's findings will be presented September 11at the annual meeting of the Scoliosis Research Society. Scoliosis affects approximately one in every 1,000 teens, mostly females, and overall, 75 percent are generally corrected with the brace.
"When you combine the rising number of overweight children in this country and the relatively frequent occurrence of scoliosis among teens, you're talking about a large percentage of children who might not benefit from wearing a back brace," said the study's senior author Paul D. Sponseller, M.D., a pediatric orthopedic surgeon at the Children's Center.
The Hopkins team recommends that all physicians take weight into consideration when making treatment decisions for scoliosis, Sponseller added. "Further study is needed," he said, "to determine if there is a particular body type and weight that should rule out bracing altogether."
Adolescent idiopathic scoliosis (AIS), the most common form of scoliosis, curves the spine from side-to-side. Onset is typically after the age of 10. Braces designed to stop curve progression by holding the spine in a straighter position are generally prescribed for children and teens who are still growing and who have moderate side-to-side curvatures of between 30 and 45 degrees. Patients with a more than 45-degree curvature, or worsening conditions, usually require surgery.
Braces exert their effects on the spine through biomechanical forces, which need to be of sufficient magnitude to create and sustain curve correction. However, because overweight patients have more and thicker soft tissue and surface area, researchers believe the effects may be compromised.
"It's possible that extra body fat, particularly around the abdomen, ribs, hips and lower back, hinder the brace's ability to transmit corrective forces to the spine, resulting in less curve correction," said Sponseller.
The current study included adolescents ranging in age from 10 to 17 years, who were seen at the Johns Hopkins Children's Center and the Texas Scottish Rite Hospital for Children from 1991 to 2001. Thirty-four children, or 12 percent of the study population, had a body mass index (the ratio of height to weight) greater than the 85th percentile and were considered to be clinically overweight.
All patients were prescribed the thoracolumbosacral orthosis brace, which fits under the arm and around the rib cage, lower back and hips. On average, the teens wore a back brace for about 14 hours per day until beginning a weaning protocol, which generally occurred after two years of treatment.
Almost half of all teens had a successful outcome following brace treatment, which researchers defined as no more than a five degree increase in the primary curve from brace initiation to discontinuation. However, among overweight patients, only 29 percent were treated successfully and 44 percent required surgery.
Co-authors of the study were Patrick J. O'Neill, Michael K. Shindle, Karlynn BrintzenhofeSzoc, and Kevin W. Farmer of the Department of Orthopaedic Surgery at Johns Hopkins; and Lori A. Karol, Emily Elerson, and Donald E. Katz of Texas Scottish Rite Hospital for Children, Dallas.
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