Flexibility of thoracic kyphosis affects postoperative sagittal alignment in adult patients with spinal deformity

  • Sebastian DeckerEmail author
  • Michael Mayer
  • Axel Hempfing
  • Lukas Ernstbrunner
  • Wolfgang Hitzl
  • Christian Krettek
  • Heiko Koller
Original Article



Proximal junctional kyphosis (PJK) in adult spinal deformity (ASD) surgery patients is a severe complication with potential need for revision surgery. While thoracic kyphosis (TK) is known to influence PJK, the role of TK flexibility is still unknown. We analyzed the influence of TK flexibility to predict postoperative sagittal alignment.


Patients with ASD, ≥ 2-year follow-up, and upper-most instrumented vertebra (UIV) including and below T10 were included in this retrospective study. TK flexibility, defined as > 10° difference of the TK in standing and supine imaging, was analyzed. Patient characteristics like age, sex, weight, total hip arthroplasty, and sagittal alignment parameters were studied.


Sixty-five patients aged 66 ± 8 years were included in the study. Lowest instrumented vertebra was S1 or the ilium in 85% of them; the number of levels being fused averaged 7. Flexible TK was present in 31% (n = 20). These patients had a larger preoperative TK (p < 0.01), but no PJK was found (p = 0.04). In contrast, patients who underwent revision surgery had a decreased TK flexibility (p = 0.04) and increased PJK angle at follow-up (p = 0.01). In the non-flexible patients, the PJK was found in 14% of patients.


Based on our retrospective data, TK flexibility influences the outcome of ASD surgery. In patients demonstrating no TK flexibility, a more cephalad UIV-level should be considered because spontaneous curve correction in the sagittal plane might be low in these patients. This new parameter should be included in future prediction models.

Graphic abstract

These slides can be retrieved under Electronic Supplementary Material.


Adult spinal surgery Proximal junctional kyphosis Thoracic kyphosis Sagittal alignment Thoracic flexibility 


Compliance with ethical standards

Conflict of interest

Authors declare that they do not have any conflict of interest.

Supplementary material

586_2019_6245_MOESM1_ESM.pptx (164 kb)
Supplementary file1 (PPTX 164 kb)


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Copyright information

© Springer-Verlag GmbH Germany, part of Springer Nature 2019

Authors and Affiliations

  1. 1.Trauma DepartmentHannover Medical SchoolHannoverGermany
  2. 2.German Scoliosis CenterWerner-Wicker ClinicBad WildungenGermany
  3. 3.Paracelsus Medical UniversitySalzburgAustria
  4. 4.Department of Traumatology and Sporty InjuriesParacelsus Medical UniversitySalzburgAustria

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