Sebastian Decker, Michael Mayer, Axel Hempfing, Lukas Ernstbrunner, Wolfgang Hitzl, Christian Krettek, Heiko Koller

April 2020, Volume 29, Issue 4, pp 813 - 820 Original Article Read Full Article 10.1007/s00586-019-06245-1

First Online: 03 December 2019


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 


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

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