In teenagers, being overweight appears to threaten the
success of wearing a back brace, the most commonly
prescribed and only proven nonsurgical treatment for
curvature of the spine, say researchers from the
Johns Hopkins
Children's Center.
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 were presented Sept.11 at the annual
meeting of the Scoliosis Research Society. Scoliosis
affects approximately one in every 1,000 teens, mostly
females, and overall, 75 percent of cases 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, a pediatric orthopedic surgeon at the
Children's Center.
The Johns 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, 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," Sponseller said.
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 a 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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