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Optimizing the Definition of Proximal Junctional Kyphosis: A Sensitivity Analysis.

Publication ,  Journal Article
Lovecchio, F; Lafage, R; Line, B; Bess, S; Shaffrey, C; Kim, HJ; Ames, C; Burton, D; Gupta, M; Smith, JS; Eastlack, R; Klineberg, E ...
Published in: Spine (Phila Pa 1976)
March 15, 2023

STUDY DESIGN: Diagnostic binary threshold analysis. OBJECTIVE: (1) Perform a sensitivity analysis demonstrating the test performance metrics for any combination of proximal junctional angle (PJA) magnitude and change; (2) Propose a new proximal junctional kyphosis (PJK) criteria. SUMMARY OF BACKGROUND DATA: Previous definitions of PJK have been arbitrarily selected and then tested through retrospective case series, often showing little correlation with clinical outcomes. MATERIALS AND METHODS: Surgically treated adult spinal deformity patients (≥4 levels fused) enrolled into a prospective, multicenter database were evaluated at a minimum 2-year follow-up for proximal junctional failure (PJF). Using PJF as the outcome of interest, test performance metrics including sensitivity, positive predictive value, and F1 metrics (harmonic mean of precision and recall) were calculated for all combinations of PJA magnitude and change using different combinations of perijunctional vertebrae. The combination with the highest F1 score was selected as the new PJK criteria. Performance metrics of previous PJK definitions and the new PJK definition were compared. RESULTS: Of the total, 669 patients were reviewed. PJF rate was 10%. Overall, the highest F1 scores were achieved when the upper instrumented vertebrae -1 (UIV-1)/UIV+2 angle was measured. For lower thoracic cases, out of all the PJA and magnitude/change combinations tested, a UIV-1/UIV+2 magnitude of -28° and a change of -20° was associated with the highest F1 score. For upper thoracic cases, a UIV-1/UIV+2 magnitude of -30° and a change of -24° were associated with the highest F1 score. Using PJF as the outcome, patients meeting this new criterion (11.5%) at 6 weeks had the lowest survival rate (74.7%) at 2 years postoperative, compared with Glattes (84.4%) and Bridwell (77.4%). CONCLUSIONS: Out of all possible PJA magnitude and change combinations, without stratifying by upper thoracic versus lower thoracic fusions, a magnitude of ≤-28° and a change of ≤-22° provide the best test performance metrics for predicting PJF.

Duke Scholars

Published In

Spine (Phila Pa 1976)

DOI

EISSN

1528-1159

Publication Date

March 15, 2023

Volume

48

Issue

6

Start / End Page

414 / 420

Location

United States

Related Subject Headings

  • Thoracic Vertebrae
  • Spinal Fusion
  • Retrospective Studies
  • Prospective Studies
  • Postoperative Complications
  • Orthopedics
  • Musculoskeletal Abnormalities
  • Kyphosis
  • Humans
  • Follow-Up Studies
 

Citation

APA
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ICMJE
MLA
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Lovecchio, F., Lafage, R., Line, B., Bess, S., Shaffrey, C., Kim, H. J., … International Spine Study Group ISSG. (2023). Optimizing the Definition of Proximal Junctional Kyphosis: A Sensitivity Analysis. Spine (Phila Pa 1976), 48(6), 414–420. https://doi.org/10.1097/BRS.0000000000004564
Lovecchio, Francis, Renaud Lafage, Breton Line, Shay Bess, Christopher Shaffrey, Han Jo Kim, Christopher Ames, et al. “Optimizing the Definition of Proximal Junctional Kyphosis: A Sensitivity Analysis.Spine (Phila Pa 1976) 48, no. 6 (March 15, 2023): 414–20. https://doi.org/10.1097/BRS.0000000000004564.
Lovecchio F, Lafage R, Line B, Bess S, Shaffrey C, Kim HJ, et al. Optimizing the Definition of Proximal Junctional Kyphosis: A Sensitivity Analysis. Spine (Phila Pa 1976). 2023 Mar 15;48(6):414–20.
Lovecchio, Francis, et al. “Optimizing the Definition of Proximal Junctional Kyphosis: A Sensitivity Analysis.Spine (Phila Pa 1976), vol. 48, no. 6, Mar. 2023, pp. 414–20. Pubmed, doi:10.1097/BRS.0000000000004564.
Lovecchio F, Lafage R, Line B, Bess S, Shaffrey C, Kim HJ, Ames C, Burton D, Gupta M, Smith JS, Eastlack R, Klineberg E, Mundis G, Schwab F, Lafage V, International Spine Study Group ISSG. Optimizing the Definition of Proximal Junctional Kyphosis: A Sensitivity Analysis. Spine (Phila Pa 1976). 2023 Mar 15;48(6):414–420.

Published In

Spine (Phila Pa 1976)

DOI

EISSN

1528-1159

Publication Date

March 15, 2023

Volume

48

Issue

6

Start / End Page

414 / 420

Location

United States

Related Subject Headings

  • Thoracic Vertebrae
  • Spinal Fusion
  • Retrospective Studies
  • Prospective Studies
  • Postoperative Complications
  • Orthopedics
  • Musculoskeletal Abnormalities
  • Kyphosis
  • Humans
  • Follow-Up Studies