Effect of age-Adjusted alignment goals and distal inclination angle on the fate of distal junctional kyphosis in cervical deformity surgery

Peter Passias, Samantha Horn, Virginie Lafage, Renaud Lafage, Justin Smith, Breton Line, Themistocles Protopsaltis, Alex Soroceanu, Cole Bortz, Frank Segreto, Waleed Ahmad, Sara Naessig, Katherine Pierce, Avery Brown, Haddy Alas, Han Kim, Alan Daniels, Eric Klineberg, Douglas Burton, Robert HartFrank Schwab, Shay Bess, Christopher Shaffrey, Christopher Ames

Research output: Contribution to journalArticlepeer-review

Abstract

Background: Age-Adjusted alignment targets in the context of distal junctional kyphosis (DJK) development have yet to be investigated. Our aim was to assess age-Adjusted alignment targets, reciprocal changes, and role of lowest instrumented level orientation in DJK development in cervical deformity (CD) patients. Methods: CD patients were evaluated based on lowest fused level: cervical (C7 or above), upper thoracic (UT: T1-T6), and lower thoracic (LT: T7-T12). Age-Adjusted alignment targets were calculated using published formulas for sagittal vertical axis (SVA), pelvic incidence-lumbar lordosis (PI-LL), pelvic tilt (PT), T1 pelvic angle (TPA), and LL-Thoracic kyphosis (TK). Outcome measures were cervical and global alignment parameters: Cervical SVA (cSVA), cervical lordosis, C2 slope, C2-T3 angle, C2-T3 SVA, TS-CL, PI-LL, PT, and SVA. Subanalysis matched baseline PI to assess age-Adjusted alignment between DJK and non-DJK. Results: Seventy-six CD patients included. By 1Y, 20 patients developed DJK. Non-DJK patients had 27% cervical lowest instrumented vertebra (LIV), 68% UT, and 5% LT. DJK patients had 25% cervical, 50% UT, and 25% LT. There were no baseline or 1Y differences for PI, PI-LL, SVA, TPA, or PT for actual and age-Adjusted targets. DJK patients had worse baseline cSVA and more severe 1Y cSVA, C2-T3 SVA, and C2 slope (P < 0.05). The distribution of over/under corrected patients and the offset between actual and ideal alignment for SVA, PT, TPA, PI-LL, and LL-TK were similar between DJK and non-DJK patients. DJK patients requiring reoperation had worse postoperative changes in all cervical parameters and trended toward larger offsets for global parameters. Conclusion: CD patients with severe baseline malalignment went on to develop postoperative DJK. Age-Adjusted alignment targets did not capture differences in these populations, suggesting the need for cervical-specific goals.

Original languageEnglish (US)
Pages (from-to)65-71
Number of pages7
JournalJournal of Craniovertebral Junction and Spine
Volume12
Issue number1
DOIs
StatePublished - Jan 1 2021

Keywords

  • Age-Adjusted
  • alignment targets
  • cervical deformity
  • distal junctional kyphosis
  • inclination angle

ASJC Scopus subject areas

  • Surgery
  • Clinical Neurology

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