As many of our readers know, the Scoliosis Research Society, the
American Academy of Orthopaedic Surgeons, and over 23 states suggest
or require school screening for abnormal spinal curvatures. In September
of 1992, Dr. William P. Bunnell, Professor and Chairperson, Loma
Linda University Medical Center, presented his paper, "Outcome of
Spinal Screening" to members of the Scoliosis Research Society;
his findings will also be published in an upcoming issue of Spine.
Dr. Bunnell is a developer of the Scoliometer, a hand-held device
used in assisting spinal screening programs across the country.
What follows are excerpts from an interview that the NSF conducted
with Dr. Bunnell about his study:
Q: Dr. Bunnell, would you start by giving us some background
information about spinal screening as it pertains to your study?
A: The major criticism of spinal screening, as it is being practiced
today, is that schools are referring too many students who do not
require treatment. The primary cause of over-referral is lack of
objective screening criterion; in the state of California, for example,
any amount of asymmetry of the thoracic ribs or the lumbar area
is an indication for referral. As a result of over-referral, many
screening programs are cost ineffective. Youngsters who are referred--whether
they need treatment or not--will be sent to a doctor for a medical
consultation; they may have several x-rays taken; and then they'll
be asked to return to the doctor six months or a year later for
another consultation. All of this adds up to skyrocketing costs.
Q: What were some of the goals you wanted to achieve by undertaking
A: One of my many goals was to determine the prevalence of scoliosis--i.e.,
how many in the general population presently have it. Another was
to use the data on prevalence in combination with previous studies
to determine what is a reasonable level orcriterion for recommending
Q: What were some of your findings?
A: In our study of 1,000 physically mature high school students--in
which we used the Scoliometer as the screening device--we found
that only 16 out of 1,000 students (1.6%) had a clinically straight
spine. Eighty percent had three or more degrees of rotation at one
or more levels of the spine. We also learned that within this population,
if "any degree of deformity" (i.e. one degree) is used
as the criterion, then 98.4 % of students will be referred.
Q: Would you explain the criterion--the degree of deformity--that
screeners currently look for, and tell us why you feel this criterion
should be changed?
A: When I first started out in practice, everybody thought we should
treat 20 degree curves with low profile braces. There is a direct
correlation between 20 degree curve and a 5 degree Angle of Trunk
Rotation (ATR), so screeners referred anybody with 5 degrees of
ATR or greater, and they're sill using 5 ATR as the criterion. Today,
we know that at least 4 out of 5 kids with 20-degree idiopathic
(causes unknown) curves will never get any worse. In fact, most
doctors wait until a youngster with this type of curvature reaches
30 degrees before starting treatment. So it's clear that we should
be screening for these children in the 30 degree and above category.
Q: Based on the data from your study, what are some of your
A: We know that spinal screening programs must have defined referral
criteria and "treatment-eligible" degrees of scoliosis
in order to judge their effectiveness. The ideal criteria will minimize
both the number of referrals and the number of false-negative examinations.
In view of the new prevalence data from my study and the current
recommendations to wait until scoliosis approaches 30 degrees (Cobb
angle) before starting brace treatment, I am recommending changing
the screening referral criterion to seven degrees ATR at any level
of the spine and changing the definition of false-negative (treatment-eligible
curves that are missed) to 30 degrees Cobb angle for the purposes
of spinal screening.
Q: If it is implemented in screening programs across the country,
what will your new recommendation accomplish?
A: It will accomplish a referral rate of 3% and detect 95% of all
"treatment eligible" curvatures, thus preserving an acceptably
low false-negative rate and helping maintain cost effectiveness
of spinal screening programs.
Q: What about youngsters whose curves are below that "treatment
eligible" line--let's say, between 20 and 25?
A: Those youngsters should be rescreened within six months or a
year. Rescreening would take place at school, which would keep it
a public health issue.
Q: In light of your findings, how do you now view the importance
of screening for spinal deformity?
A: Screening is vitally important, but we do not want to screen
out a whole bunch of people who don't need medical attention because
it's very costly. We're not looking for the cheapest way to screen--we're
looking for a better quality outcome for our patients.
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