To explore proximal junctional kyphosis
) as a function of age-adjusted surgical correction goals.
Summary of Background Data.
Recent adult spinal deformity
(ASD) studies show that alignment targets
are age-specific. Despite recognizing age and malalignment as PJK risk factors
, no study has assessed the age-specific effects of alignment on PJK
ASD patients with fusions to the pelvis were included and stratified into three groups: young adults (YA <40 years old), middle aged (MA: 40–65 years old), and the elderly (ED >65 years old). Analysis of variance compared the groups with respect to 1-year postoperative alignments and 1-year offsets from age-specific alignment targets
A total of 679 patients were enrolled (mean age = 61 years old, 77% female, body mass index = 28.1). At 1 year postoperatively, there was a significant decrease in pelvic tilt (PT; 29–23°), spinopelvic mismatch (pelvic incidence [PI]–lumbar lordosis [LL]) (28–5°), and sagittal vertical axis (SVA; 110–37 mm); overall incidence of PJK
was 45.1%. Stratification by age (YA, n = 28; MA, n = 389; ED, n = 262) revealed an increase in PJK
incidence with age: YA = 17.9%, MA = 43.8%, and ED = 50.2% (P
< 0.001). PJK
patients had smaller postoperative PI–LL mismatches (ED 0.8° vs.
9.8°, MA 3.1° vs.
7.3°) than non-PJK
patients, without any significant differences in PT or SVA. Analysis of the postoperative offsets from age-specific norms revealed that PJK
patients in the two older subgroups and in the study cohort as a whole were overcorrected as compared to non-PJK
patients (PI–LL offset—all: −5.2° vs.
2.8°, MA: −1° vs.
+4°, ED: −11° vs.
−2°; SVA offset—all: −10 mm vs.
7 mm, MA: −3 mm vs.
10 mm, ED: −18 mm vs.
−6 mm). The correlation coefficients between PJK
angles and the offsets from age-adjusted objective were small (0.320 for PI–LL, 0.114 for PT, and 0.136 for SVA).
Overall, this study suggests that PJK
patients were overcorrected when compared to age-adjusted alignment goals
. Certainly, elderly patients are subject to independent risk factors for PJK
, making the prevention of PJK
complex. However, individualized optimization of surgical alignment can improve outcomes. This emphasizes the need for surgeons to incorporate age-specific alignment targets
into the standard preoperative planning
Level of Evidence: 3