Low Bone-Mineral Density Is a Significant Risk for Proximal Junctional Failure after Surgical Correction of Adult Spinal Deformity

Mitsuru Yagi, Nobuyuki Fujita, Osahiko Tsuji, Narihito Nagoshi, Takashi Asazuma, Ken Ishii, Masaya Nakamura, Morio Matsumoto, Kota Watanabe

Research output: Contribution to journalArticlepeer-review

74 Citations (Scopus)


Study Design. A propensity-matched comparison of risk factors for proximal junctional failure (PJF), which is a symptomatic proximal junctional kyphosis developing after corrective surgery for adult spinal deformity (ASD). Objective. To elucidate the role of bone strength for developing PJF. Summary of Background Data. PJF, a devastating complication of corrective surgery for ASD, often recurs even after revision surgery. Most studies of risk factors for PJF are retrospective and have a selection bias in surgical strategy, making it difficult to identify modifiable PJF risk factors. Methods. We conducted propensity-matched comparisons of 113 surgically treated ASD patients who were followed for at least 2 years, to elucidate whether low bone-mineral density (BMD) was a true risk factor for PJF in a uniform population from a multicenter database. Patients were grouped as having mildly low to normal BMD (M group; T-score≧-1.5) or significantly low BMD (S group; T-score<-1.5), and were propensity-matched for age, upper and lower instrumented vertebrae, history of spine surgery, and Schwab-Scoliosis Research Society (SRS) ASD classification. PJF was defined as a ≥20° increase from the baseline proximal junction angle with a concomitant deterioration of at least one SRS-Schwab sagittal modifier grade, or any type of proximal junctional kyphosis requiring revision. Results. PJF developed in 22 of 113 patients (19%). There were 48 propensity-matched patients in the M and S groups (24 in each) with similar parameters for age, body mass index, number of vertebrae involved, C7SVA, pelvic incidence -LL, and SRS-Schwab type. In this propensity-matched population, the incidence of PJF was significantly higher in the S group (33% vs. 8%, P<0.01, odds ratio 6.4, 95% CI: 1.2-32.3). Conclusion. Low BMD was a significant risk factor for PJF in this propensity-matched cohort (odds ratio 6.4). Surgeons should consider prophylactic treatments when correcting ASD in patients with low BMD. Level of Evidence: 3

Original languageEnglish
Pages (from-to)485-491
Number of pages7
Issue number7
Publication statusPublished - 2018 Apr 1


  • BMD
  • PJF
  • PJK
  • adult spinal deformity
  • risk factor

ASJC Scopus subject areas

  • Orthopedics and Sports Medicine
  • Clinical Neurology


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