Journal of Craniovertebral Junction and Spine (Jan 2019)

Global spinal deformity from the upper cervical perspective. What is “Abnormal” in the upper cervical spine?

  • Peter G Passias,
  • Haddy Alas,
  • Renaud Lafage,
  • Bassel G Diebo,
  • Irene Chern,
  • Christopher P Ames,
  • Paul Park,
  • Khoi D Than,
  • Alan H Daniels,
  • D Kojo Hamilton,
  • Douglas C Burton,
  • Robert A Hart,
  • Shay Bess,
  • Breton G Line,
  • Eric O Klineberg,
  • Christopher I Shaffrey,
  • Justin S Smith,
  • Frank J Schwab,
  • Virginie Lafage

DOI
https://doi.org/10.4103/jcvjs.JCVJS_71_19
Journal volume & issue
Vol. 10, no. 3
pp. 152 – 159

Abstract

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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] 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 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.

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