Cervical mismatch: the normative value of T1 slope minus cervical lordosis and its ability to predict ideal cervical lordosis

International Spine Study Group

Research output: Contribution to journalArticle

1 Citation (Scopus)

Abstract

OBJECTIVENumerous studies have attempted to delineate the normative value for T1S-CL (T1 slope minus cervical lordosis) as a marker for both cervical deformity and a goal for correction similar to how PI-LL (pelvic incidence-lumbar lordosis) mismatch informs decision making in thoracolumbar adult spinal deformity (ASD). The goal of this study was to define the relationship between T1 slope (T1S) and cervical lordosis (CL).METHODSThis is a retrospective review of a prospective database. Surgical ASD cases were initially analyzed. Analysis across the sagittal parameters was performed. Linear regression analysis based on T1S was used to provide a clinically applicable equation to predict CL. Findings were validated using the postoperative alignment of the ASD patients. Further validation was then performed using a second, normative database. The range of normal alignment associated with horizontal gaze was derived from a multilinear regression on data from asymptomatic patients.RESULTSA total of 103 patients (mean age 54.7 years) were included. Analysis revealed a strong correlation between T1S and C0-7 lordosis (r = 0.886), C2-7 lordosis (r = 0.815), and C0-2 lordosis (r = 0.732). There was no significant correlation between T1S and T1S-CL. Linear regression analysis revealed that T1S-CL assumed a constant value of 16.5° (R2 = 0.664, standard error 2°). These findings were validated on the postoperative imaging (mean absolute error [MAE] 5.9°). The equation was then applied to the normative database (MAE 6.7° controlling for McGregor slope [MGS] between -5° and 15°). A multilinear regression between C2-7, T1S, and MGS demonstrated a range of T1S-CL between 14.5° and 26.5° was necessary to maintain horizontal gaze.CONCLUSIONSNormative CL can be predicted via the formula CL = T1S - 16.5° ± 2°. This implies a threshold of deformity and aids in providing a goal for surgical correction. Just as pelvic incidence (PI) can be used to determine the ideal LL, T1S can be used to predict ideal CL. This formula also implies that a kyphotic cervical alignment is to be expected for individuals with a T1S < 16.5°.

Original languageEnglish (US)
Pages (from-to)31-37
Number of pages7
JournalJournal of neurosurgery. Spine
Volume30
Issue number1
DOIs
StatePublished - Oct 5 2018

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Lordosis
Aptitude
Databases
Linear Models
Regression Analysis
Incidence
Decision Making

Keywords

  • ASD = adult spinal deformity
  • C0 = occiput
  • CBVA = chin-brow vertical angle
  • cervical lordosis
  • cervical mismatch
  • CL = cervical lordosis (C2–7 lordosis)
  • cSVA = cervical SVA
  • deformity
  • HRQOL = health-related quality of life
  • LL = lumbar lordosis
  • MAE = mean absolute error
  • MGS = McGregor slope
  • PI = pelvic incidence
  • PT = pelvic tilt
  • RMSE = root mean square error
  • sagittal alignment
  • SVA = sagittal vertical axis
  • T1 slope
  • T1S = T1 slope
  • T1S−CL
  • T1S−CL = T1S minus CL
  • TIA = thoracic inlet angle
  • TK = thoracic kyphosis

ASJC Scopus subject areas

  • Surgery
  • Neurology
  • Clinical Neurology

Cite this

Cervical mismatch : the normative value of T1 slope minus cervical lordosis and its ability to predict ideal cervical lordosis. / International Spine Study Group.

In: Journal of neurosurgery. Spine, Vol. 30, No. 1, 05.10.2018, p. 31-37.

Research output: Contribution to journalArticle

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title = "Cervical mismatch: the normative value of T1 slope minus cervical lordosis and its ability to predict ideal cervical lordosis",
abstract = "OBJECTIVENumerous studies have attempted to delineate the normative value for T1S-CL (T1 slope minus cervical lordosis) as a marker for both cervical deformity and a goal for correction similar to how PI-LL (pelvic incidence-lumbar lordosis) mismatch informs decision making in thoracolumbar adult spinal deformity (ASD). The goal of this study was to define the relationship between T1 slope (T1S) and cervical lordosis (CL).METHODSThis is a retrospective review of a prospective database. Surgical ASD cases were initially analyzed. Analysis across the sagittal parameters was performed. Linear regression analysis based on T1S was used to provide a clinically applicable equation to predict CL. Findings were validated using the postoperative alignment of the ASD patients. Further validation was then performed using a second, normative database. The range of normal alignment associated with horizontal gaze was derived from a multilinear regression on data from asymptomatic patients.RESULTSA total of 103 patients (mean age 54.7 years) were included. Analysis revealed a strong correlation between T1S and C0-7 lordosis (r = 0.886), C2-7 lordosis (r = 0.815), and C0-2 lordosis (r = 0.732). There was no significant correlation between T1S and T1S-CL. Linear regression analysis revealed that T1S-CL assumed a constant value of 16.5° (R2 = 0.664, standard error 2°). These findings were validated on the postoperative imaging (mean absolute error [MAE] 5.9°). The equation was then applied to the normative database (MAE 6.7° controlling for McGregor slope [MGS] between -5° and 15°). A multilinear regression between C2-7, T1S, and MGS demonstrated a range of T1S-CL between 14.5° and 26.5° was necessary to maintain horizontal gaze.CONCLUSIONSNormative CL can be predicted via the formula CL = T1S - 16.5° ± 2°. This implies a threshold of deformity and aids in providing a goal for surgical correction. Just as pelvic incidence (PI) can be used to determine the ideal LL, T1S can be used to predict ideal CL. This formula also implies that a kyphotic cervical alignment is to be expected for individuals with a T1S < 16.5°.",
keywords = "ASD = adult spinal deformity, C0 = occiput, CBVA = chin-brow vertical angle, cervical lordosis, cervical mismatch, CL = cervical lordosis (C2–7 lordosis), cSVA = cervical SVA, deformity, HRQOL = health-related quality of life, LL = lumbar lordosis, MAE = mean absolute error, MGS = McGregor slope, PI = pelvic incidence, PT = pelvic tilt, RMSE = root mean square error, sagittal alignment, SVA = sagittal vertical axis, T1 slope, T1S = T1 slope, T1S−CL, T1S−CL = T1S minus CL, TIA = thoracic inlet angle, TK = thoracic kyphosis",
author = "{International Spine Study Group} and Staub, {Blake N.} and Renaud Lafage and Kim, {Han Jo} and Shaffrey, {Christopher I.} and Mundis, {Gregory M.} and Richard Hostin and Douglas Burton and Lawrence Lenke and Gupta, {Munish C.} and Christopher Ames and Klineberg, {Eric Otto} and Shay Bess and Frank Schwab and Virginie Lafage",
year = "2018",
month = "10",
day = "5",
doi = "10.3171/2018.5.SPINE171232",
language = "English (US)",
volume = "30",
pages = "31--37",
journal = "Journal of neurosurgery. Spine",
issn = "1547-5654",
publisher = "American Association of Neurological Surgeons",
number = "1",

}

TY - JOUR

T1 - Cervical mismatch

T2 - the normative value of T1 slope minus cervical lordosis and its ability to predict ideal cervical lordosis

AU - International Spine Study Group

AU - Staub, Blake N.

AU - Lafage, Renaud

AU - Kim, Han Jo

AU - Shaffrey, Christopher I.

AU - Mundis, Gregory M.

AU - Hostin, Richard

AU - Burton, Douglas

AU - Lenke, Lawrence

AU - Gupta, Munish C.

AU - Ames, Christopher

AU - Klineberg, Eric Otto

AU - Bess, Shay

AU - Schwab, Frank

AU - Lafage, Virginie

PY - 2018/10/5

Y1 - 2018/10/5

N2 - OBJECTIVENumerous studies have attempted to delineate the normative value for T1S-CL (T1 slope minus cervical lordosis) as a marker for both cervical deformity and a goal for correction similar to how PI-LL (pelvic incidence-lumbar lordosis) mismatch informs decision making in thoracolumbar adult spinal deformity (ASD). The goal of this study was to define the relationship between T1 slope (T1S) and cervical lordosis (CL).METHODSThis is a retrospective review of a prospective database. Surgical ASD cases were initially analyzed. Analysis across the sagittal parameters was performed. Linear regression analysis based on T1S was used to provide a clinically applicable equation to predict CL. Findings were validated using the postoperative alignment of the ASD patients. Further validation was then performed using a second, normative database. The range of normal alignment associated with horizontal gaze was derived from a multilinear regression on data from asymptomatic patients.RESULTSA total of 103 patients (mean age 54.7 years) were included. Analysis revealed a strong correlation between T1S and C0-7 lordosis (r = 0.886), C2-7 lordosis (r = 0.815), and C0-2 lordosis (r = 0.732). There was no significant correlation between T1S and T1S-CL. Linear regression analysis revealed that T1S-CL assumed a constant value of 16.5° (R2 = 0.664, standard error 2°). These findings were validated on the postoperative imaging (mean absolute error [MAE] 5.9°). The equation was then applied to the normative database (MAE 6.7° controlling for McGregor slope [MGS] between -5° and 15°). A multilinear regression between C2-7, T1S, and MGS demonstrated a range of T1S-CL between 14.5° and 26.5° was necessary to maintain horizontal gaze.CONCLUSIONSNormative CL can be predicted via the formula CL = T1S - 16.5° ± 2°. This implies a threshold of deformity and aids in providing a goal for surgical correction. Just as pelvic incidence (PI) can be used to determine the ideal LL, T1S can be used to predict ideal CL. This formula also implies that a kyphotic cervical alignment is to be expected for individuals with a T1S < 16.5°.

AB - OBJECTIVENumerous studies have attempted to delineate the normative value for T1S-CL (T1 slope minus cervical lordosis) as a marker for both cervical deformity and a goal for correction similar to how PI-LL (pelvic incidence-lumbar lordosis) mismatch informs decision making in thoracolumbar adult spinal deformity (ASD). The goal of this study was to define the relationship between T1 slope (T1S) and cervical lordosis (CL).METHODSThis is a retrospective review of a prospective database. Surgical ASD cases were initially analyzed. Analysis across the sagittal parameters was performed. Linear regression analysis based on T1S was used to provide a clinically applicable equation to predict CL. Findings were validated using the postoperative alignment of the ASD patients. Further validation was then performed using a second, normative database. The range of normal alignment associated with horizontal gaze was derived from a multilinear regression on data from asymptomatic patients.RESULTSA total of 103 patients (mean age 54.7 years) were included. Analysis revealed a strong correlation between T1S and C0-7 lordosis (r = 0.886), C2-7 lordosis (r = 0.815), and C0-2 lordosis (r = 0.732). There was no significant correlation between T1S and T1S-CL. Linear regression analysis revealed that T1S-CL assumed a constant value of 16.5° (R2 = 0.664, standard error 2°). These findings were validated on the postoperative imaging (mean absolute error [MAE] 5.9°). The equation was then applied to the normative database (MAE 6.7° controlling for McGregor slope [MGS] between -5° and 15°). A multilinear regression between C2-7, T1S, and MGS demonstrated a range of T1S-CL between 14.5° and 26.5° was necessary to maintain horizontal gaze.CONCLUSIONSNormative CL can be predicted via the formula CL = T1S - 16.5° ± 2°. This implies a threshold of deformity and aids in providing a goal for surgical correction. Just as pelvic incidence (PI) can be used to determine the ideal LL, T1S can be used to predict ideal CL. This formula also implies that a kyphotic cervical alignment is to be expected for individuals with a T1S < 16.5°.

KW - ASD = adult spinal deformity

KW - C0 = occiput

KW - CBVA = chin-brow vertical angle

KW - cervical lordosis

KW - cervical mismatch

KW - CL = cervical lordosis (C2–7 lordosis)

KW - cSVA = cervical SVA

KW - deformity

KW - HRQOL = health-related quality of life

KW - LL = lumbar lordosis

KW - MAE = mean absolute error

KW - MGS = McGregor slope

KW - PI = pelvic incidence

KW - PT = pelvic tilt

KW - RMSE = root mean square error

KW - sagittal alignment

KW - SVA = sagittal vertical axis

KW - T1 slope

KW - T1S = T1 slope

KW - T1S−CL

KW - T1S−CL = T1S minus CL

KW - TIA = thoracic inlet angle

KW - TK = thoracic kyphosis

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