The prevalence of proximal junctional kyphosis (PJK) and proximal junctional failure (PJF) in patients undergoing circumferential minimally invasive surgical (cMIS) correction for adult spinal deformity: long-term 2- to 13-year follow-up

Spine Deform. 2021 Sep;9(5):1433-1441. doi: 10.1007/s43390-021-00319-1. Epub 2021 Mar 16.


Objectives: This aim of this study is to evaluate the prevalence of PJK and PJF in patients who underwent circumferential minimally invasive surgery (cMIS) for ASD.

Methods: A prospective database of patients who underwent cMIS correction of ASD from November 2006 to July 2018 was queried. PJK was defined as angle > 10° and at least 10° greater than the baseline when measuring UIV to UIV + 2. PJF was defined as any type of symptomatic PJK which required surgery. Pre-op, latest and delta SVA and PI-LL mismatch were compared between patients with PJK and without. Only patients instrumented at 4 or more levels with full length 36″ films and a minimum 2-year follow-up were included.

Results: A total of 184 patients met inclusion criteria for this study. Mean follow-up time was 85.2 months (24-158.9 months, SD 39.1). Mean age was 66 years (22-85 years). The mean number of operated levels was 6.9 levels (4-16 levels, SD 2.8). A total of 21 patients (10.8%) met PJK criteria. Only 10 (4.9%) were symptomatic (PJF) and underwent revision surgery. The other 11 patients remained asymptomatic. Comparing PJK to non-PJK patients, there was no statistically significant difference in the post-op SVA, delta SVA, post-op PI/LL and delta PI/LL between the two groups.

Conclusion: Our study would suggest that in the appropriately selected and well-optimized patient, CMIS deformity correction is associated with a low prevalence of PJK and PJF.

Keywords: Adult spinal deformity (ASD); Circumferential minimally invasive surgery (CMIS); Proximal junctional failure (PJF); Proximal junctional kyphosis (PJK).

MeSH terms

  • Adult
  • Aged
  • Follow-Up Studies
  • Humans
  • Kyphosis* / epidemiology
  • Kyphosis* / surgery
  • Minimally Invasive Surgical Procedures
  • Postoperative Complications / epidemiology
  • Postoperative Complications / etiology
  • Prevalence
  • Spinal Fusion* / adverse effects