TY - JOUR
T1 - Global spinal deformity from the upper cervical perspective. What is 'Abnormal' in the upper cervical spine?
AU - Passias, Peter G.
AU - Alas, Haddy
AU - Lafage, Renaud
AU - Diebo, Bassel G.
AU - Chern, Irene
AU - Ames, Christopher P.
AU - Park, Paul
AU - Than, Khoi D.
AU - Daniels, Alan H.
AU - Hamilton, D. Kojo
AU - Burton, Douglas C.
AU - Hart, Robert A.
AU - Bess, Shay
AU - Line, Breton G.
AU - Klineberg, Eric O.
AU - Shaffrey, Christopher I.
AU - Smith, Justin S.
AU - Schwab, Frank J.
AU - Lafage, Virginie
N1 - Publisher Copyright:
© 2019 Medknow Publications. All rights reserved.
PY - 2019/7/1
Y1 - 2019/7/1
N2 - Hypothesis: Reciprocal changes in the upper cervical spine correlate with adult TL deformity modifiers. Design: This was a retrospective review. Introduction: The upper cervical spine has remarkable adaptability to wide ranges of thoracolumbar (TL) deformity. Methods: Patients >18 years with adult spinal deformity (ASD) and complete radiographic data at baseline (BL) and 1 year were identified. Patients were grouped into component types of the Roussouly classification system (Type 1: Pelvic incidence [PI] <45° and lumbar lordosis [LL] apex below L4; Type 2: PI <45° and LL apex above L4; Type 3:45°<PI <65°; and Type 4: PI >65°). Patients were categorized by increasing severity of Schwab modifiers at BL (0, +, and ++) and further grouped by regional malalignment moving cranially (P: pelvic only; LP: lumbopelvic; TL: thoracic and LP; C: subaxial and TL). Analysis of variance and Pearson's r assessed changes in BL upper cervical parameters (C0-2, C0 slope, McGregor's Slope [MGS], and CBVA) across groups. Results: A total of 343 ASD patients were analyzed. When grouped by BL Schwab and Roussouly, Group P had the lowest BL disability compared to other Groups, while Roussouley Type 1 correlated with higher BL disability compared to Type 2. Moving cranially up the spine, Group P, Group LP, and Group TL did not differ in C0-2 angle, C0 slope, MGS, or CBVA. Group C had a significantly smaller C0-C2, and more negative MGS, C0 slope, and CBVA than noncervical groups. Type 1 trended slightly higher CBVA and MGS than types 2-4, but no differences in cervical lordosis, C0-C2, or C0S were found. MGS (r = -0.131, P = 0.015), CBVA (r = -0.473, P < 0.001), and C0S (r = -0.099, P = 0.042) correlated most strongly with sagittal vertical axis (SVA) compared to other Schwab modifiers. We found SVA > 34 mm predicted a 1 unit (°°) decrease in MGS (odds ratio [OR]: 0.970 [0.948-0.993], P = 0.010), while cervical SVA >51 mm predicted a 1 unit increase in MGS (OR: 1.25 [1.12-1.38], P < 0.001). Conclusions: Our study suggests that upper cervical alignment remains relatively stable through most broad variations of adult TL deformity. Changes in SVA correlated most with upper cervical changes.
AB - Hypothesis: Reciprocal changes in the upper cervical spine correlate with adult TL deformity modifiers. Design: This was a retrospective review. Introduction: The upper cervical spine has remarkable adaptability to wide ranges of thoracolumbar (TL) deformity. Methods: Patients >18 years with adult spinal deformity (ASD) and complete radiographic data at baseline (BL) and 1 year were identified. Patients were grouped into component types of the Roussouly classification system (Type 1: Pelvic incidence [PI] <45° and lumbar lordosis [LL] apex below L4; Type 2: PI <45° and LL apex above L4; Type 3:45°<PI <65°; and Type 4: PI >65°). Patients were categorized by increasing severity of Schwab modifiers at BL (0, +, and ++) and further grouped by regional malalignment moving cranially (P: pelvic only; LP: lumbopelvic; TL: thoracic and LP; C: subaxial and TL). Analysis of variance and Pearson's r assessed changes in BL upper cervical parameters (C0-2, C0 slope, McGregor's Slope [MGS], and CBVA) across groups. Results: A total of 343 ASD patients were analyzed. When grouped by BL Schwab and Roussouly, Group P had the lowest BL disability compared to other Groups, while Roussouley Type 1 correlated with higher BL disability compared to Type 2. Moving cranially up the spine, Group P, Group LP, and Group TL did not differ in C0-2 angle, C0 slope, MGS, or CBVA. Group C had a significantly smaller C0-C2, and more negative MGS, C0 slope, and CBVA than noncervical groups. Type 1 trended slightly higher CBVA and MGS than types 2-4, but no differences in cervical lordosis, C0-C2, or C0S were found. MGS (r = -0.131, P = 0.015), CBVA (r = -0.473, P < 0.001), and C0S (r = -0.099, P = 0.042) correlated most strongly with sagittal vertical axis (SVA) compared to other Schwab modifiers. We found SVA > 34 mm predicted a 1 unit (°°) decrease in MGS (odds ratio [OR]: 0.970 [0.948-0.993], P = 0.010), while cervical SVA >51 mm predicted a 1 unit increase in MGS (OR: 1.25 [1.12-1.38], P < 0.001). Conclusions: Our study suggests that upper cervical alignment remains relatively stable through most broad variations of adult TL deformity. Changes in SVA correlated most with upper cervical changes.
KW - Cervical spine
KW - Roussouly classification
KW - Schwab classification
KW - global spinal deformity
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U2 - 10.4103/jcvjs.JCVJS_71_19
DO - 10.4103/jcvjs.JCVJS_71_19
M3 - Article
AN - SCOPUS:85074934646
SN - 0974-8237
VL - 10
SP - 152
EP - 159
JO - Journal of Craniovertebral Junction and Spine
JF - Journal of Craniovertebral Junction and Spine
IS - 3
ER -