Incidence of Acute, Progressive, and Delayed Proximal Junctional Kyphosis Over an 8-Year Period in Adult Spinal Deformity Patients

Frank A. Segreto, Peter G. Passias, Renaud Lafage, Virginie Lafage, Justin S. Smith, Breton G. Line, Gregory M. Mundis, Cole A. Bortz, Nicholas D. Stekas, Samantha R. Horn, Bassel G. Diebo, Avery E. Brown, Yael Ihejirika, Pierce D. Nunley, Alan H. Daniels, Munish C. Gupta, Jeffrey L. Gum, D. Kojo Hamilton, Eric O. Klineberg, Douglas C. BurtonRobert A. Hart, Frank J. Schwab, Shay Bess, Christopher I. Shaffrey, Christopher P. Ames

Research output: Contribution to journalArticlepeer-review

10 Scopus citations


BACKGROUND: Proximal junctional kyphosis (PJK) is a common radiographic complication of adult spinal deformity (ASD) corrective surgery. Although previous literature has reported a 5 to 61% incidence of PJK, these studies are limited by small sample sizes and short-term follow-up. OBJECTIVE: To assess the incidence of PJK utilizing a high-powered ASD database. METHODS: Retrospective review of a prospective multicenter ASD database. Operative ASD patients > 18 yr old from 2009 to 2017 were included. PJK was defined as ≥ 10° for the sagittal Cobb angle between the inferior upper instrumented vertebra (UIV) endplate and the superior endplate of the UIV + 2. Chi-square analysis and post hoc testing assessed annual and overall incidence of acute (6-wk follow-up [f/u]), progressive (increase in degree of PJK from 6 wk to 1 yr), and delayed (1-yr, 2-yr, and 3-yr f/u) PJK development. RESULTS: A total of 1005 patients were included (age: 59.3; 73.5% F; body mass index: 27.99). Overall PJK incidence was 69.4%. Overall incidence of acute PJK was 48.0%. Annual incidence of acute PJK has decreased from 53.7% in 2012 to 31.6% in 2017 (P = .038). Overall incidence of progressive PJK was 35.0%, with stable rates observed from 2009 to 2016 (P = .297). Overall incidence of 1-yr-delayed PJK was 9.3%. Annual incidence of 1-yr-delayed PJK has decreased from 9.2% in 2009 to 3.2% in 2016 (P < .001). Overall incidence of 2-yr-delayed PJK development was 4.3%. Annual incidence of 2-yr-delayed PJK has decreased from 7.3% in 2009 to 0.9% in 2015 (P < .05). Overall incidence of 3-yr-delayed PJK was 1.8%, with stable rates observed from 2009 to 2014 (P = .594). CONCLUSION: Although progressive PJK has remained a challenge for physicians over time, significantly lower incidences of acute and delayed PJK in recent years may indicate improving operative decision-making and management strategies.

Original languageEnglish (US)
Pages (from-to)75-82
Number of pages8
JournalOperative neurosurgery (Hagerstown, Md.)
Issue number1
StatePublished - Jan 1 2020


  • Adult spinal deformity
  • Incidence
  • Proximal junctional kyphosis

ASJC Scopus subject areas

  • Surgery
  • Clinical Neurology


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