Background: The use of magnetic resonance imaging has led to the
diagnosis of abnormalities of the central nervous system associated with
apparent idiopathic scoliosis. The indications for magnetic resonance imaging
for presumed adolescent idiopathic scoliosis have not been established.
Methods: One thousand, two hundred and eighty children with presumed
adolescent idiopathic scoliosis were evaluated over a ten-year period.
Magnetic resonance imaging of the central nervous system (brainstem and spinal
cord) was performed for specific patients, on the basis of the presence of
selected indicators determined from the clinical history, physical
examination, and plain radiographic examination of the spine. The medical
records were reviewed to determine the specific indicators, the results of the
imaging studies, and the subsequent treatment.
Results: Magnetic resonance imaging was ordered for 274 (21%) of the
1280 children who were evaluated. Abnormal findings were seen in twenty-seven
(10%) of the 274 patients who underwent imaging, or 2% of the entire cohort.
The most valuable single indicator of an abnormal finding on magnetic
resonance imaging was absence of thoracic apical segment lordosis: eight of
thirty-nine patients with that indicator had an abnormal finding on magnetic
resonance imaging. The optimal diagnostic yield for a single category of
indicators occurred when an atypical curve pattern was the only indicator: six
of fifty-eight patients in whom this was the case had an abnormal finding on
magnetic resonance imaging. None of the twenty children in whom pain was the
only indicator category had an abnormal imaging study. The optimal diagnostic
yield occurred when both an atypical curve pattern and neurological indicators
were present: thirteen (25%) of fifty-three patients in whom this was the case
had an abnormal finding on magnetic resonance imaging. Thirteen of the
twenty-seven patients received surgical treatment for the abnormality of the
central nervous system revealed by the imaging.
Conclusions: The correct use of diagnostic tests is an important
component of effective medical practice. An abnormality of the central nervous
system is present in approximately 10% of patients with presumed adolescent
idiopathic scoliosis in whom only subtle abnormalities are identified on the
basis of the clinical history, physical examination, or radiographic
examination. Knowledge of the diagnostic value of the specific clinical
indicators, considered individually and in combination, can help the clinician
to determine more effectively when advanced imaging of the central nervous
system should be performed.
Level of Evidence: Diagnostic study, Level III-1 (study
of nonconsecutive patients [no consistently applied reference
"gold" standard]). See Instructions to Authors for a complete
description of levels of evidence.