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Adolescent Idiopathic Scoliosis A New Classification to Determine Extent of Spinal Arthrodesis
Lawrence G. Lenke, MD; Randal R. Betz, MD; Jürgen Harms, MD; Keith H. Bridwell, MD; David H. Clements, MD; Thomas G. Lowe, MD; Kathy Blanke, RN
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Investigation performed at Barnes-Jewish Hospital, Washington University, St. Louis, Missouri
Lawrence G. Lenke, MD
Keith H. Bridwell, MD
Kathy Blanke, RN
Department of Orthopaedic Surgery, Washington University School of Medicine, One Barnes-Jewish Hospital Plaza, Suite 11300, West Pavilion, St. Louis, MO 63100. E-mail address for L.G. Lenke: lenkel@msnotes.wustl.edu

Randal R. Betz, MD
Shriners Hospital for Children, Philadelphia Unit, 3551 North Broad Street, Philadelphia, PA 19140-4131

Jürgen Harms, MD
SRH Klinikum Karlsbad-Langensteinbach, D-76307 Karlsbad, Germany

David H. Clements, MD
Temple University Hospital, 3401 North Broad Street, Philadelphia, PA 19140

Thomas G. Lowe, MD
Woodridge Orthopaedic Clinic, 3550 Lutheran Parkway, #201, Wheat Ridge, CO 80033-6017

In support of their research or preparation of this manuscript, one or more of the authors received grants or outside funding from Biedermann-Motech, Incorporated. None of the authors received payments or other benefits or a commitment or agreement to provide such benefits from a commercial entity. No commercial entity paid or directed, or agreed to pay or direct, any benefits to any research fund, foundation, educational institution, or other charitable or nonprofit organization with which the authors are affiliated or associated.

This paper was read at the Annual Meeting of the Scoliosis Research Society, St. Louis, Missouri, September 25, 26, and 27, 1997; was read at the International Meeting of Advanced Spine Techniques (IMAST), Sorrento, Italy, April 30 through May 2, 1998; and was presented as a scientific exhibit at the Annual Meeting of the American Academy of Orthopaedic Surgeons, Anaheim, California, February 4 through 8, 1999.

J Bone Joint Surg Am, 2001 Aug 01;83(8):1169-1181
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Background: The lack of a reliable, universally acceptable system for classification of adolescent idiopathic scoliosis has made comparisons between various types of operative treatment an impossible task. Furthermore, long-term outcomes cannot be determined because of the great variations in the description of study groups.

Methods: We developed a new classification system with three components: curve type (1 through 6), a lumbar spine modifier (A, B, or C), and a sagittal thoracic modifier (-, N, or +). The six curve types have specific characteristics, on coronal and sagittal radiographs, that differentiate structural and nonstructural curves in the proximal thoracic, main thoracic, and thoracolumbar/lumbar regions. The lumbar spine modifier is based on the relationship of the center sacral vertical line to the apex of the lumbar curve, and the sagittal thoracic modifier is based on the sagittal curve measurement from the fifth to the twelfth thoracic level. A minus sign represents a curve of less than +10°, N represents a curve of 10° to 40°, and a plus sign represents a curve of more than +40°.

Five surgeons, members of the Scoliosis Research Society who had developed the new system and who had previously tested the reliability of the King classification on radiographs of twenty-seven patients, measured the same radiographs (standing coronal and lateral as well as supine side-bending views) to test the reliability of the new classification. A randomly chosen independent group of seven surgeons, also members of the Scoliosis Research Society, tested the reliability and validity of the classification as well.

Results: The interobserver and intraobserver kappa values for the curve type were, respectively, 0.92 and 0.83 for the five developers of the system and 0.740 and 0.893 for the independent group of seven scoliosis surgeons. In the independent group, the mean interobserver and intraobserver kappa values were 0.800 and 0.840 for the lumbar modifier and 0.938 and 0.970 for the sagittal thoracic modifier. These kappa values were all in the good-to-excellent range (>0.75), except for the interobserver reliability of the independent group for the curve type (kappa = 0.74), which fell just below this level.

Conclusions: This new two-dimensional classification of adolescent idiopathic scoliosis, as tested by two groups of surgeons, was shown to be much more reliable than the King system. Additional studies are necessary to determine the versatility, reliability, and accuracy of the classification for defining the vertebrae to be included in an arthrodesis.

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    Posted on May 30, 2005
    Adolescent Idiopathic Scoliosis

    To the Editor:

    I would like to direct the attention of the authors of this excellent paper to a mistake that may result in confusion to its readers.

    On page 1172, the authors defined the curves type 3 and 6 as follows: Type 3—double major: The main thoracic and thoracolumbar/ lumbar curves are structural, while the proximal thoracic curve is nonstructural. The main thoracic curve is the major curve and is greater than, equal to, or no more than 5°less than the Cobb measurement of the thoracolumbar/lumbar curve.

    Type 6—thoracolumbar/lumbar-main thoracic: The thoracolumbar/lumbar curve is the major curve and measures at least 5° more than the main thoracic curve, which is structural. The proximal thoracic curve is nonstructural.

    Then, on pages 1172 and 1173 they wrote: "If the difference between the lumbar and thoracic curves is <_5 the="the" scoliosis="scoliosis" can="can" be="be" categorized="categorized" as="as" type="type" _3="_3" _4="_4" or="or" _5="_5" on="on" basis="basis" of="of" structural="structural" characteristics="characteristics" main="main" thoracic="thoracic" and="and" thoracolumbar="thoracolumbar" lumbar="lumbar" regions.="regions." for="for" sake="sake" clarity="clarity" major="major" curve="curve" with="with" largest="largest" cobb="cobb" measurement="measurement" always="always" distinguishes="distinguishes" between="between" is="is" _6="_6" major.="major." if="if" measurements="measurements" curves="curves" are="are" equal="equal" then="then" considered="considered" curve.="curve." thus="thus" in="in" figures="figures" _4-a="_4-a" through="through" _4-fthe="_4-fthe" classification="classification" _6.="_6." p="p" /> But by looking at the mentioned figures, I found the lumbar curve (60°) measuring only 3° more than the main thoracic curve (57°), which is according to the authors' definition, excludes type 6 and makes the curve type 3,4 or 5. As long as the proximal thoracic curve is non-structural, the curve is not type 4. On the other hand, because the main thoracic curve is structural, the curve is type 3.

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