Reliability assessment of a novel cervical spine deformity classification system

Christopher P. Ames, Justin S. Smith, Robert Eastlack, Donald J. Blaskiewicz, Christopher I. Shaffrey, Frank Schwab, Shay Bess, Han Jo Kim, Gregory M. Mundis, Eric Otto Klineberg, Munish Gupta, Michael O'Brien, Richard Hostin, Justin K. Scheer, Themistocles S. Protopsaltis, Kai Ming G Fu, Robert Hart, Todd J. Albert, K. Daniel Riew, Michael G. FehlingsVedat Deviren, Virginie Lafage

Research output: Contribution to journalArticle

71 Citations (Scopus)

Abstract

Object Despite the complexity of cervical spine deformity (CSD) and its significant impact on patient quality of life, there exists no comprehensive classification system. The objective of this study was to develop a novel classification system based on a modified Delphi approach and to characterize the intra-and interobserver reliability of this classification. Methods?Based on an extensive literature review and a modified Delphi approach with an expert panel, a CSD classification system was generated. The classification system included a deformity descriptor and 5 modifiers that incorporated sagittal, regional, and global spinopelvic alignment and neurological status. The descriptors included: C, CT, and T for primary cervical kyphotic deformities with an apex in the cervical spine, cervicothoracic junction, or thoracic spine, respectively; S for primary coronal deformity with a coronal Cobb angle ? 15; and CVJ for primary craniovertebral junction deformity. The modifiers included C2-7 sagittal vertical axis (SVA), horizontal gaze (chin-brow to vertical angle [CBVA]), T1 slope (TS) minus C2-7 lordosis (TS-CL), myelopathy (modified Japanese Orthopaedic Association [mJOA] scale score), and the Scoliosis Research Society (SRS)-Schwab classification for thoracolumbar deformity. Application of the classification system requires the following: 1) full-length standing posteroanterior (PA) and lateral spine radiographs that include the cervical spine and femoral heads; 2) standing PA and lateral cervical spine radiographs; 3) completed and scored mJOA questionnaire; and 4) a clinical photograph or radiograph that includes the skull for measurement of the CBVA. A series of 10 CSD cases, broadly representative of the classification system, were selected and sufficient radiographic and clinical history to enable classification were assembled. A panel of spinal deformity surgeons was queried to classify each case twice, with a minimum of 1 intervening week. Inter-and intrarater reliability measures were based on calculations of Fleiss k coefficient values. Results?Twenty spinal deformity surgeons participated in this study. Interrater reliability (Fleiss k coefficients) for the deformity descriptor rounds 1 and 2 were 0.489 and 0.280, respectively, and mean intrarater reliability was 0.584. For the modifiers, including the SRS-Schwab components, the interrater (round 1/round 2) and intrarater reliabilities (Fleiss k coefficients) were: C2-7 SVA (0.338/0.412, 0.584), horizontal gaze (0.779/0.430, 0.768), TS-CL (0.721/0.567, 0.720), myelopathy (0.602/0.477, 0.746), SRS-Schwab curve type (0.590/0.433, 0.564), pelvic incidence-lumbar lordosis (0.554/0.386, 0.826), pelvic tilt (0.714/0.627, 0.633), and C7-S1 SVA (0.071/0.064, 0.233), respectively. The parameter with the poorest reliability was the C7-S1 SVA, which may have resulted from differences in interpretation of positive and negative measurements. Conclusions?The proposed classification provides a mechanism to assess CSD within the framework of global spinopelvic malalignment and clinically relevant parameters. The intra-and interobserver reliabilities suggest moderate agreement and serve as the basis for subsequent improvement and study of the proposed classification.

Original languageEnglish (US)
Pages (from-to)673-683
Number of pages11
JournalJournal of Neurosurgery: Spine
Volume23
Issue number6
DOIs
StatePublished - Dec 1 2015

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Spine
Scoliosis
Lordosis
Chin
Spinal Cord Diseases
Research
Thigh
Skull
Orthopedics
Thorax
Quality of Life
Incidence

Keywords

  • Cervical spine deformity
  • Classification
  • Horizontal gaze
  • Kyphosis
  • Myelopathy
  • Sagittal alignment
  • Validation

ASJC Scopus subject areas

  • Medicine(all)

Cite this

Ames, C. P., Smith, J. S., Eastlack, R., Blaskiewicz, D. J., Shaffrey, C. I., Schwab, F., ... Lafage, V. (2015). Reliability assessment of a novel cervical spine deformity classification system. Journal of Neurosurgery: Spine, 23(6), 673-683. https://doi.org/10.3171/2014.12.SPINE14780

Reliability assessment of a novel cervical spine deformity classification system. / Ames, Christopher P.; Smith, Justin S.; Eastlack, Robert; Blaskiewicz, Donald J.; Shaffrey, Christopher I.; Schwab, Frank; Bess, Shay; Kim, Han Jo; Mundis, Gregory M.; Klineberg, Eric Otto; Gupta, Munish; O'Brien, Michael; Hostin, Richard; Scheer, Justin K.; Protopsaltis, Themistocles S.; Fu, Kai Ming G; Hart, Robert; Albert, Todd J.; Riew, K. Daniel; Fehlings, Michael G.; Deviren, Vedat; Lafage, Virginie.

In: Journal of Neurosurgery: Spine, Vol. 23, No. 6, 01.12.2015, p. 673-683.

Research output: Contribution to journalArticle

Ames, CP, Smith, JS, Eastlack, R, Blaskiewicz, DJ, Shaffrey, CI, Schwab, F, Bess, S, Kim, HJ, Mundis, GM, Klineberg, EO, Gupta, M, O'Brien, M, Hostin, R, Scheer, JK, Protopsaltis, TS, Fu, KMG, Hart, R, Albert, TJ, Riew, KD, Fehlings, MG, Deviren, V & Lafage, V 2015, 'Reliability assessment of a novel cervical spine deformity classification system', Journal of Neurosurgery: Spine, vol. 23, no. 6, pp. 673-683. https://doi.org/10.3171/2014.12.SPINE14780
Ames CP, Smith JS, Eastlack R, Blaskiewicz DJ, Shaffrey CI, Schwab F et al. Reliability assessment of a novel cervical spine deformity classification system. Journal of Neurosurgery: Spine. 2015 Dec 1;23(6):673-683. https://doi.org/10.3171/2014.12.SPINE14780
Ames, Christopher P. ; Smith, Justin S. ; Eastlack, Robert ; Blaskiewicz, Donald J. ; Shaffrey, Christopher I. ; Schwab, Frank ; Bess, Shay ; Kim, Han Jo ; Mundis, Gregory M. ; Klineberg, Eric Otto ; Gupta, Munish ; O'Brien, Michael ; Hostin, Richard ; Scheer, Justin K. ; Protopsaltis, Themistocles S. ; Fu, Kai Ming G ; Hart, Robert ; Albert, Todd J. ; Riew, K. Daniel ; Fehlings, Michael G. ; Deviren, Vedat ; Lafage, Virginie. / Reliability assessment of a novel cervical spine deformity classification system. In: Journal of Neurosurgery: Spine. 2015 ; Vol. 23, No. 6. pp. 673-683.
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abstract = "Object Despite the complexity of cervical spine deformity (CSD) and its significant impact on patient quality of life, there exists no comprehensive classification system. The objective of this study was to develop a novel classification system based on a modified Delphi approach and to characterize the intra-and interobserver reliability of this classification. Methods?Based on an extensive literature review and a modified Delphi approach with an expert panel, a CSD classification system was generated. The classification system included a deformity descriptor and 5 modifiers that incorporated sagittal, regional, and global spinopelvic alignment and neurological status. The descriptors included: C, CT, and T for primary cervical kyphotic deformities with an apex in the cervical spine, cervicothoracic junction, or thoracic spine, respectively; S for primary coronal deformity with a coronal Cobb angle ? 15; and CVJ for primary craniovertebral junction deformity. The modifiers included C2-7 sagittal vertical axis (SVA), horizontal gaze (chin-brow to vertical angle [CBVA]), T1 slope (TS) minus C2-7 lordosis (TS-CL), myelopathy (modified Japanese Orthopaedic Association [mJOA] scale score), and the Scoliosis Research Society (SRS)-Schwab classification for thoracolumbar deformity. Application of the classification system requires the following: 1) full-length standing posteroanterior (PA) and lateral spine radiographs that include the cervical spine and femoral heads; 2) standing PA and lateral cervical spine radiographs; 3) completed and scored mJOA questionnaire; and 4) a clinical photograph or radiograph that includes the skull for measurement of the CBVA. A series of 10 CSD cases, broadly representative of the classification system, were selected and sufficient radiographic and clinical history to enable classification were assembled. A panel of spinal deformity surgeons was queried to classify each case twice, with a minimum of 1 intervening week. Inter-and intrarater reliability measures were based on calculations of Fleiss k coefficient values. Results?Twenty spinal deformity surgeons participated in this study. Interrater reliability (Fleiss k coefficients) for the deformity descriptor rounds 1 and 2 were 0.489 and 0.280, respectively, and mean intrarater reliability was 0.584. For the modifiers, including the SRS-Schwab components, the interrater (round 1/round 2) and intrarater reliabilities (Fleiss k coefficients) were: C2-7 SVA (0.338/0.412, 0.584), horizontal gaze (0.779/0.430, 0.768), TS-CL (0.721/0.567, 0.720), myelopathy (0.602/0.477, 0.746), SRS-Schwab curve type (0.590/0.433, 0.564), pelvic incidence-lumbar lordosis (0.554/0.386, 0.826), pelvic tilt (0.714/0.627, 0.633), and C7-S1 SVA (0.071/0.064, 0.233), respectively. The parameter with the poorest reliability was the C7-S1 SVA, which may have resulted from differences in interpretation of positive and negative measurements. Conclusions?The proposed classification provides a mechanism to assess CSD within the framework of global spinopelvic malalignment and clinically relevant parameters. The intra-and interobserver reliabilities suggest moderate agreement and serve as the basis for subsequent improvement and study of the proposed classification.",
keywords = "Cervical spine deformity, Classification, Horizontal gaze, Kyphosis, Myelopathy, Sagittal alignment, Validation",
author = "Ames, {Christopher P.} and Smith, {Justin S.} and Robert Eastlack and Blaskiewicz, {Donald J.} and Shaffrey, {Christopher I.} and Frank Schwab and Shay Bess and Kim, {Han Jo} and Mundis, {Gregory M.} and Klineberg, {Eric Otto} and Munish Gupta and Michael O'Brien and Richard Hostin and Scheer, {Justin K.} and Protopsaltis, {Themistocles S.} and Fu, {Kai Ming G} and Robert Hart and Albert, {Todd J.} and Riew, {K. Daniel} and Fehlings, {Michael G.} and Vedat Deviren and Virginie Lafage",
year = "2015",
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doi = "10.3171/2014.12.SPINE14780",
language = "English (US)",
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T1 - Reliability assessment of a novel cervical spine deformity classification system

AU - Ames, Christopher P.

AU - Smith, Justin S.

AU - Eastlack, Robert

AU - Blaskiewicz, Donald J.

AU - Shaffrey, Christopher I.

AU - Schwab, Frank

AU - Bess, Shay

AU - Kim, Han Jo

AU - Mundis, Gregory M.

AU - Klineberg, Eric Otto

AU - Gupta, Munish

AU - O'Brien, Michael

AU - Hostin, Richard

AU - Scheer, Justin K.

AU - Protopsaltis, Themistocles S.

AU - Fu, Kai Ming G

AU - Hart, Robert

AU - Albert, Todd J.

AU - Riew, K. Daniel

AU - Fehlings, Michael G.

AU - Deviren, Vedat

AU - Lafage, Virginie

PY - 2015/12/1

Y1 - 2015/12/1

N2 - Object Despite the complexity of cervical spine deformity (CSD) and its significant impact on patient quality of life, there exists no comprehensive classification system. The objective of this study was to develop a novel classification system based on a modified Delphi approach and to characterize the intra-and interobserver reliability of this classification. Methods?Based on an extensive literature review and a modified Delphi approach with an expert panel, a CSD classification system was generated. The classification system included a deformity descriptor and 5 modifiers that incorporated sagittal, regional, and global spinopelvic alignment and neurological status. The descriptors included: C, CT, and T for primary cervical kyphotic deformities with an apex in the cervical spine, cervicothoracic junction, or thoracic spine, respectively; S for primary coronal deformity with a coronal Cobb angle ? 15; and CVJ for primary craniovertebral junction deformity. The modifiers included C2-7 sagittal vertical axis (SVA), horizontal gaze (chin-brow to vertical angle [CBVA]), T1 slope (TS) minus C2-7 lordosis (TS-CL), myelopathy (modified Japanese Orthopaedic Association [mJOA] scale score), and the Scoliosis Research Society (SRS)-Schwab classification for thoracolumbar deformity. Application of the classification system requires the following: 1) full-length standing posteroanterior (PA) and lateral spine radiographs that include the cervical spine and femoral heads; 2) standing PA and lateral cervical spine radiographs; 3) completed and scored mJOA questionnaire; and 4) a clinical photograph or radiograph that includes the skull for measurement of the CBVA. A series of 10 CSD cases, broadly representative of the classification system, were selected and sufficient radiographic and clinical history to enable classification were assembled. A panel of spinal deformity surgeons was queried to classify each case twice, with a minimum of 1 intervening week. Inter-and intrarater reliability measures were based on calculations of Fleiss k coefficient values. Results?Twenty spinal deformity surgeons participated in this study. Interrater reliability (Fleiss k coefficients) for the deformity descriptor rounds 1 and 2 were 0.489 and 0.280, respectively, and mean intrarater reliability was 0.584. For the modifiers, including the SRS-Schwab components, the interrater (round 1/round 2) and intrarater reliabilities (Fleiss k coefficients) were: C2-7 SVA (0.338/0.412, 0.584), horizontal gaze (0.779/0.430, 0.768), TS-CL (0.721/0.567, 0.720), myelopathy (0.602/0.477, 0.746), SRS-Schwab curve type (0.590/0.433, 0.564), pelvic incidence-lumbar lordosis (0.554/0.386, 0.826), pelvic tilt (0.714/0.627, 0.633), and C7-S1 SVA (0.071/0.064, 0.233), respectively. The parameter with the poorest reliability was the C7-S1 SVA, which may have resulted from differences in interpretation of positive and negative measurements. Conclusions?The proposed classification provides a mechanism to assess CSD within the framework of global spinopelvic malalignment and clinically relevant parameters. The intra-and interobserver reliabilities suggest moderate agreement and serve as the basis for subsequent improvement and study of the proposed classification.

AB - Object Despite the complexity of cervical spine deformity (CSD) and its significant impact on patient quality of life, there exists no comprehensive classification system. The objective of this study was to develop a novel classification system based on a modified Delphi approach and to characterize the intra-and interobserver reliability of this classification. Methods?Based on an extensive literature review and a modified Delphi approach with an expert panel, a CSD classification system was generated. The classification system included a deformity descriptor and 5 modifiers that incorporated sagittal, regional, and global spinopelvic alignment and neurological status. The descriptors included: C, CT, and T for primary cervical kyphotic deformities with an apex in the cervical spine, cervicothoracic junction, or thoracic spine, respectively; S for primary coronal deformity with a coronal Cobb angle ? 15; and CVJ for primary craniovertebral junction deformity. The modifiers included C2-7 sagittal vertical axis (SVA), horizontal gaze (chin-brow to vertical angle [CBVA]), T1 slope (TS) minus C2-7 lordosis (TS-CL), myelopathy (modified Japanese Orthopaedic Association [mJOA] scale score), and the Scoliosis Research Society (SRS)-Schwab classification for thoracolumbar deformity. Application of the classification system requires the following: 1) full-length standing posteroanterior (PA) and lateral spine radiographs that include the cervical spine and femoral heads; 2) standing PA and lateral cervical spine radiographs; 3) completed and scored mJOA questionnaire; and 4) a clinical photograph or radiograph that includes the skull for measurement of the CBVA. A series of 10 CSD cases, broadly representative of the classification system, were selected and sufficient radiographic and clinical history to enable classification were assembled. A panel of spinal deformity surgeons was queried to classify each case twice, with a minimum of 1 intervening week. Inter-and intrarater reliability measures were based on calculations of Fleiss k coefficient values. Results?Twenty spinal deformity surgeons participated in this study. Interrater reliability (Fleiss k coefficients) for the deformity descriptor rounds 1 and 2 were 0.489 and 0.280, respectively, and mean intrarater reliability was 0.584. For the modifiers, including the SRS-Schwab components, the interrater (round 1/round 2) and intrarater reliabilities (Fleiss k coefficients) were: C2-7 SVA (0.338/0.412, 0.584), horizontal gaze (0.779/0.430, 0.768), TS-CL (0.721/0.567, 0.720), myelopathy (0.602/0.477, 0.746), SRS-Schwab curve type (0.590/0.433, 0.564), pelvic incidence-lumbar lordosis (0.554/0.386, 0.826), pelvic tilt (0.714/0.627, 0.633), and C7-S1 SVA (0.071/0.064, 0.233), respectively. The parameter with the poorest reliability was the C7-S1 SVA, which may have resulted from differences in interpretation of positive and negative measurements. Conclusions?The proposed classification provides a mechanism to assess CSD within the framework of global spinopelvic malalignment and clinically relevant parameters. The intra-and interobserver reliabilities suggest moderate agreement and serve as the basis for subsequent improvement and study of the proposed classification.

KW - Cervical spine deformity

KW - Classification

KW - Horizontal gaze

KW - Kyphosis

KW - Myelopathy

KW - Sagittal alignment

KW - Validation

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