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Interobserver and intraobserver reliability of determining the deformity angular ratio in severe pediatric deformity curves

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Abstract

Study design

Cross-sectional reliability study.

Objective

The deformity angular ratio (DAR) is a means of quantifying magnitude of the coronal (C-DAR) and sagittal (S-DAR) plane of deformity curves to produce a total DAR (T-DAR). It has been shown to predict the risk of spinal cord monitoring alerts and actual neurologic deficits. We sought to assess the reliability of determining the C-DAR and S-DAR among pediatric spinal deformity surgeons.

Methods

Twelve preoperative anterior–posterior (AP) and lateral X-rays from the Fox multi-center pediatric deformity study were de-identified and sent to7 pediatric spinal deformity surgeons. Each surgeon measured: coronal/sagittal Cobb angles, upper/lower endplate vertebrae (UEV/LEV), apices, and number of vertebrae included in the main curve. The C-DAR and S-DAR were then calculated by dividing the Cobb angles by the number of vertebrae included in the curve. Intra- and interobserver reliability was calculated using interclass correlation (ICC).

Results

The mean C-DAR was 14.9 (range 1.3–51.5) with a mean Cobb angle of 88.8° (range 15.0–163.0) over a mean of 7.5 (range 2.0–14.0) levels. The mean S-DAR was 8.6 (range 1.0–19.6), with a mean Cobb angle of 68.0° (range 10.0–137.0) over a mean of 7.5 (range 3–11) levels. The intraobserver reliability of the C-DAR was ICC = 0.908 (range 0.846–0.960) and the S-DAR 0.914 (range 0.815–0.961). The interobserver reliability of the C-DAR was ICC = 0.868 (range 0.846–0.938), and the S-DAR was ICC = 0.848 (range 0.815–0.961). Despite poor reliability among UEV, LEV, and apex selection (aggregated range 0.340–0.724), the C-DAR and S-DAR were demonstrated to be reliable in our study

Conclusions

Reliability was good to excellent for C-DAR and S-DAR, despite poor to moderate reliability among UEV, LEV, and apex selection. These data support the use of the C-DAR, S-DAR, and combined T-DAR as a means of quantifying deformity magnitude.

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Abbreviations

DAR:

Deformity angular ratio

LEV:

Lower endplate vertebrae

UEV:

Upper endplate vertebrae

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Acknowledgements

Fox pediatric spinal deformity study group

Funding

Fox Study Group.

Author information

Authors and Affiliations

  1. Department of Orthopaedics, Columbia University Medical Center, The Spine Hospital at New York-Presbyterian, 5141 Broadway, New York, NY, 10034, USA

    Scott L. Zuckerman, Lawrence G. Lenke & Meghan Cerpa

  2. Department of Orthopaedics, Washington University, St. Louis, MO, USA

    Michael P. Kelly, Brenda Sides & Munish Gupta

  3. Rady Children’s Hospital, San Diego, USA

    Burt Yaszay

  4. Johns Hopkins University, Baltimore, USA

    Paul Sponseller

  5. Children’s Hospital Colorado Aurora, Aurora, USA

    Mark Erickson & Sumeet Garg

  6. Shriners Hospitals for Children, Philadelphia, USA

    Joshua Pahys

  7. Children’s Hospital of Philadelphia, Philadelphia, USA

    Patrick Cahill

Authors
  1. Scott L. Zuckerman
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  2. Lawrence G. Lenke
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  3. Meghan Cerpa
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  4. Michael P. Kelly
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  5. Burt Yaszay
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  6. Paul Sponseller
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  7. Mark Erickson
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  8. Sumeet Garg
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  9. Joshua Pahys
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  10. Patrick Cahill
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  11. Brenda Sides
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  12. Munish Gupta
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Consortia

Fox Pediatric Spinal Deformity Study Group

Contributions

SLZ, LGL, MC, MK, BY, PS, ME, SG, JP, PC, BS, MG: substantial contributions to the conception and design of the work; the acquisition, analysis, and interpretation of data for the work. SLZ: drafting the work and revising it critically for important intellectual content. LGL, MC, MK, BY, PS, ME, SG, JP, PC, BS, MG: revising the work critically for important intellectual content. SLZ, LGL, MC, MK, BY, PS, ME, SG, JP, PC, BS, MG: final approval of the version to be published. SLZ, LGL, MC, MK, BY, PS, ME, SG, JP, PC, BS, MG: contributed effort to the study.

Corresponding author

Correspondence to Meghan Cerpa.

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Conflict of interest

The authors report no conflict of interest concerning the materials or methods used in this study or the findings specified in this paper.

Informed consent

Columbia University Institutional Review Board Approved Protocol #AAAI2200for informed consent.

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Disclosure This abstract was presented the 2015 Scoliosis Research Society Annual Meeting.

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Zuckerman, S.L., Lenke, L.G., Cerpa, M. et al. Interobserver and intraobserver reliability of determining the deformity angular ratio in severe pediatric deformity curves. Spine Deform 9, 435–440 (2021). https://doi.org/10.1007/s43390-020-00239-6

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  • DOI: https://doi.org/10.1007/s43390-020-00239-6

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