Classification system for cervical spine deformity morphology: a validation study

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  • 1 Department of Orthopaedic Surgery, Hospital for Special Surgery, New York, New York;
  • | 2 Department of Neurosurgery, Center for Neurosciences and Spine, Virginia Mason Franciscan Health, Seattle, Washington;
  • | 3 Department of Orthopaedic Surgery, Indiana Spine Group, University of Indiana, Carmel, Indiana;
  • | 4 Department of Orthopaedic Surgery, Northwell Health, New Hyde Park, New York;
  • | 5 Spine Institute, MountainStar Healthcare, Murray, Utah;
  • | 6 Department of Orthopedics, Adventist Health, Willits, California;
  • | 7 Department of Orthopedics, Taipei Veterans General Hospital, Taipei, Taiwan; and
  • | 8 Department of Orthopedics and Traumatology, University of Chile, Santiago, Chile
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OBJECTIVE

The objective of this study was to initially validate a recent morphological classification of cervical spine deformity pathology.

METHODS

The records of 10 patients for each of the 3 classification subgroups (flat neck, focal deformity, and cervicothoracic), as well as for 8 patients with coronal deformity only, were extracted from a prospective multicenter database of patients with cervical deformity (CD). A panel of 15 physicians of various training and professional levels (i.e., residents, fellows, and surgeons) categorized each patient into one of the 4 groups. The Fleiss kappa coefficient was utilized to evaluate intra- and interrater reliability. Accuracy, defined as properly selecting the main driver of deformity, was reported overall, by morphotype, and by reviewer experience.

RESULTS

The overall classification demonstrated a moderate to substantial agreement (round 1: interrater Fleiss kappa = 0.563, 95% CI 0.559–0.568; round 2: interrater Fleiss kappa = 0.612, 95% CI 0.606–0.619). Stratification by level of training demonstrated similar mean interrater coefficients (residents 0.547, fellows 0.600, surgeons 0.524). The mean intrarater score was 0.686 (range 0.531–0.823). A substantial agreement between rounds 1 and 2 was demonstrated in 81.8% of the raters, with a kappa score > 0.61. Stratification by level of training demonstrated similar mean intrarater coefficients (residents 0.715, fellows 0.640, surgeons 0.682). Of 570 possible questions, reviewers provided 419 correct answers (73.5%). When considering the true answer as being selected by at least one of the two main drivers of deformity, the overall accuracy increased to 86.0%.

CONCLUSIONS

This initial validation of a CD morphological classification system reiterates the importance of dynamic plain radiographs for the evaluation of patients with CD. The overall reliability of this CD morphological classification has been demonstrated. The overall accuracy of the classification system was not impacted by rater experience, demonstrating its simplicity.

ABBREVIATIONS

AP = anteroposterior; C2S = C2 slope; CBVA = chin-brow vertical angle; CD = cervical deformity; CL = cervical lordosis; cSVA = cervical SVA; HRQOL = health-related quality of life; LL = lumbar lordosis; PI = pelvic incidence; PT = pelvic tilt; SVA = sagittal vertical axis; T1-PA = T1 pelvic angle; T1S = T1 slope.

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  • 1

    Smith JS, Lafage V, Schwab FJ, et al. Prevalence and type of cervical deformity among 470 adults with thoracolumbar deformity. Spine (Phila Pa 1976).2014;39(17):E1001E1009.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • 2

    Ames CP, Blondel B, Scheer JK, et al. Cervical radiographical alignment: comprehensive assessment techniques and potential importance in cervical myelopathy. Spine (Phila Pa 1976). 2013;38:S149S160.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • 3

    Smith JS, Line B, Bess S, et al. The health impact of adult cervical deformity in patients presenting for surgical treatment: comparison to United States population norms and chronic disease states based on the EuroQuol-5 Dimensions questionnaire. Neurosurgery. 2017;80(5):716725.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • 4

    Scheer JK, Tang JA, Smith JS, et al. Cervical spine alignment, sagittal deformity, and clinical implications: a review. J Neurosurg Spine. 2013;19(2):141159.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • 5

    Liu S, Lafage R, Smith JS, et al. Impact of dynamic alignment, motion, and center of rotation on myelopathy grade and regional disability in cervical spondylotic myelopathy. J Neurosurg Spine. 2015;23(6):690700.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • 6

    Smith JS, Lafage V, Ryan DJ, et al. Association of myelopathy scores with cervical sagittal balance and normalized spinal cord volume: analysis of 56 preoperative cases from the AOSpine North America Myelopathy study. Spine (Phila Pa 1976).2013;38(22)(suppl 1):S161S170.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • 7

    Lafage R, Challier V, Liabaud B, et al. Natural head posture in the setting of sagittal spinal deformity: validation of chin-brow vertical angle, slope of line of sight, and McGregor’s slope with health-related quality of life. Neurosurgery. 2016;79(1):108115.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • 8

    Labelle H, Mac-Thiong JM, Roussouly P. Spino-pelvic sagittal balance of spondylolisthesis: a review and classification. Eur Spine J. 2011;20(suppl 5):641-646.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • 9

    Lenke LG, Betz RR, Harms J, et al. Adolescent idiopathic scoliosis: a new classification to determine extent of spinal arthrodesis. J Bone Joint Surg Am. 2001;83(8):11691181.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • 10

    Schwab F, Ungar B, Blondel B, et al. Scoliosis Research Society-Schwab adult spinal deformity classification: a validation study. Spine (Phila Pa 1976).2012;37(12):10771082.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • 11

    Terran J, Schwab F, Shaffrey CI, et al. The SRS-Schwab adult spinal deformity classification: assessment and clinical correlations based on a prospective operative and nonoperative cohort. Neurosurgery. 2013;73(4):559568.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • 12

    Fisher CG, DiPaola CP, Ryken TC, et al. A novel classification system for spinal instability in neoplastic disease: an evidence-based approach and expert consensus from the Spine Oncology Study Group. Spine (Phila Pa 1976).2010;35(22):E1221E1229.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • 13

    Vaccaro AR, Oner C, Kepler CK, et al. AOSpine thoracolumbar spine injury classification system: fracture description, neurological status, and key modifiers. Spine (Phila Pa 1976).2013;38(23):20282037.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • 14

    Vaccaro AR, Koerner JD, Radcliff KE, et al. AOSpine subaxial cervical spine injury classification system. Eur Spine J. 2016;25(7):21732184.

  • 15

    Ames CP, Smith JS, Eastlack R, et al. Reliability assessment of a novel cervical spine deformity classification system. J Neurosurg Spine. 2015;23(6):673683.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • 16

    Kim HJ, Virk S, Elysee J, et al. The morphology of cervical deformities: a two-step cluster analysis to identify cervical deformity patterns. J Neurosurg Spine. 2020;32(3):353359.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • 17

    Rillardon L, Levassor N, Guigui P, et al. Validation of a tool to measure pelvic and spinal parameters of sagittal balance. Article in French. Rev Chir Orthop Repar Appar Mot. 2003;89(3):218227.

    • Search Google Scholar
    • Export Citation
  • 18

    Landis JR, Koch GG. The measurement of observer agreement for categorical data. Biometrics. 1977;33(1):159174.

  • 19

    Protopsaltis TS, Scheer JK, Terran JS, et al. How the neck affects the back: changes in regional cervical sagittal alignment correlate to HRQOL improvement in adult thoracolumbar deformity patients at 2-year follow-up. J Neurosurg Spine. 2015;23(2):153158.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • 20

    Roguski M, Benzel EC, Curran JN, et al. Postoperative cervical sagittal imbalance negatively affects outcomes after surgery for cervical spondylotic myelopathy. Spine (Phila Pa 1976).2014;39(25):20702077.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • 21

    Kato S, Nouri A, Wu D, Nori S, Tetreault L, Fehlings MG. Impact of cervical spine deformity on preoperative disease severity and postoperative outcomes following fusion surgery for degenerative cervical myelopathy: sub-analysis of AOSpine North America and International studies. Spine (Phila Pa 1976).2018;43(4):248254.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • 22

    Bakouny Z, Khalil N, Otayek J, et al. Are the sagittal cervical radiographic modifiers of the Ames-ISSG classification specific to adult cervical deformity?. J Neurosurg Spine. 2018;29(5):483490.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • 23

    Lenke LG, Edwards CC II, Bridwell KH. The Lenke classification of adolescent idiopathic scoliosis: how it organizes curve patterns as a template to perform selective fusions of the spine. Spine (Phila Pa 1976).2003;28(20):S199S207.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • 24

    Ames CP, Smith JS, Scheer JK, et al. A standardized nomenclature for cervical spine soft-tissue release and osteotomy for deformity correction: clinical article. J Neurosurg Spine. 2013;19(3):269278.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • 25

    Steinmetz MP, Stewart TJ, Kager CD, Benzel EC, Vaccaro AR. Cervical deformity correction. Neurosurgery. 2007;60(1 supp1 1):S90-S97.

  • 26

    Hann S, Chalouhi N, Madineni R, et al. An algorithmic strategy for selecting a surgical approach in cervical deformity correction. Neurosurg Focus. 2014;36(5):E5.

    • Crossref
    • Search Google Scholar
    • Export Citation

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