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European Spine Journal

, Volume 4, Issue 5, pp 291–295 | Cite as

Accuracy and applicability of measurement of the scoliotic angle at the frontal plane by Cobb's method, by Ferguson's method and by a new method

  • K. M. Diab
  • J. A. Sevastik
  • R. Hedlund
  • I. A. Suliman
Original Articles

Summary

A new method for the measurement of scoliotic curves in antero-posterior (AP) radiographs is presented, in which the centre of the surface image of the vertebral bodies of the apical and two end vertebrae of the curvature are defined on the basis of geometric principles. Measurements using the Cobb, the Ferguson, and the new method were performed on ten AP radiographs from each of three groups of young patients with right convex thoracic idiopathic scoliosis with Cobb angles of between 7 and 15°, 16 and 45° and 46 and 80°, respectively. Measurements using the Cobb method yielded significantly higher values than measurements using either the Ferguson method or the new method. In curves with Cobb angles of between 7 and 15°, the values using Ferguson's method were significantly lower than those using the new method; the difference increased significantly in curves with a Cobb angle of 16° or more. The level of significance of the intra- and interobserver differences between the new, the Cobb and the Ferguson methods was significantly higher in curves with a Cobb angle of 16° or more. It is argued that measures of the scoliotic angle obtained by the new method are of greater clinical relevance than those obtained by the two other methods. Unlike the Cobb method, the new method takes into consideration the translation of the apical vertebra in relation to the end vertebrae and not only the tilt of the end vertebrae of the curve. As compared to the Ferguson method, the new method is based on standardised geometric principles, and is not influenced by changes in the shape of the vertebral body. Moreover, the repeatability of the new method is greater than that of both the Cobb method and the Ferguson method. Therefore, it is believed that the new method provides a more accurate measure of the scoliotic curve than do the two other methods, and it is to be preferred over the other two methods in longitudinal evaluation of the development of the curve.

Key words

Scoliosis angle Measurements New method Cobb method Ferguson method 

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References

  1. 1.
    Bass RK, Duncan RL, Fisher L, McGuire R (1994) Cobb angle measurement error before and after posterior segmental spinal instrumentation (abstract). Proceedings of the 29th Annual meeting of the Scoliosis Research Society, Portland, Oregon, pp 134–135Google Scholar
  2. 2.
    Beekman CE, Hall V (1979) Variability of scoliosis measurement from spinal roentgenograms. Phys Ther 59:764–765Google Scholar
  3. 3.
    Carman DL, Browne RH, Birch JG (1990) Measurement of scoliosis and kyphosis radiographs. J Bone Joint Surg [Am] 72:328–333Google Scholar
  4. 4.
    Capasso G (1981) A new method for the radiographic evaluation of deformity in scoliosis. Ital J Orthop Traumatol 7:127–136Google Scholar
  5. 5.
    Cobb JR (1948) Outline for the study of scoliosis. Am Acad Surg Leet 5:261–275Google Scholar
  6. 6.
    Dawson EG, Smith RK, McNiece GM (1978) Radiographic evaluation of scoliosis. A reassessment and introduction of the scoliosis chariot. Clin Orthop 131:151–155Google Scholar
  7. 7.
    DeSmet AA, Goin JE, Asher MA, Scheuch HG (1982) A clinical study of the differences between the scoliotic angles measured on posteroanterior and anteroposterior radiographs. J Bone Joint Surg [Am] 64:489–493Google Scholar
  8. 8.
    Ferguson AB (1949) Roentgen diagnosis of the extremities and spine. Hoeber, New York, pp 414–415Google Scholar
  9. 9.
    George K, Rippstein J (1961) A comparative study of the two popular methods of measuring scoliotic deformity of the spine. J Bone Joint Surg [Am] 43:809–818Google Scholar
  10. 10.
    Kittleson AC, Lim LW (1970) Measurement of scoliosis. Am J Roentgenol Radium Ther Nucl Med 108:775–777Google Scholar
  11. 11.
    Lusskin R (1962) Curves and angles, a comparison of scoliosis measurement. Clin Orthop 23:232–235Google Scholar
  12. 12.
    McAlister WH, Shackelford MGD (1975) Measurement of spinal curvatures. Radiol Clin North Am 13:113–121Google Scholar
  13. 13.
    Morrissy RT, Goldsmith GS, Hall EC, Kehl D, Cowie HC (1990) Measurement of the Cobb angle on radiographs of patients who have scoliosis. Evaluation of intrinsic error. J Bone Joint Surg [Am] 72:320–327Google Scholar
  14. 14.
    Oda M, Rauh S, Gregory PB, Silverman F, Bleck EE (1982) The significance of roentgenographic measurement in scoliosis. J Pediatr Orthop 2:378–382Google Scholar
  15. 15.
    Sevastik JA, Bergquist E (1969) Evaluation of the reliability of radiological methods for registration of scoliosis. Acta Orthop Scand 40:608–613Google Scholar
  16. 16.
    Stokes IAF, Aronson DD, Ronchetti PJ, Labelle H, Dansereau J (1993) Reexamination of the Cobb and Ferguson angles: bigger is not always better. J Spinal Disord 6:333–338Google Scholar
  17. 17.
    Torell G, Nachemson A, Haderspeck-Grib K, Schultz A (1985) Standing and supine Cobb measures in girls with idiopathic scoliosis. Spine 10:425–427Google Scholar
  18. 18.
    Zetterberg C, Hansson T, Lidström J, Irstam L, Andersson G (1983) Daytime postural changes of the scoliotic spine. Orthop Trans 7:7–8Google Scholar

Copyright information

© Springer-Verlag 1995

Authors and Affiliations

  • K. M. Diab
    • 1
  • J. A. Sevastik
    • 1
  • R. Hedlund
    • 1
  • I. A. Suliman
    • 1
  1. 1.Department of Orthopaedic SurgeryHuddinge University Hospital, Karolinska InstituteStockholmSweden

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