A retrospective study.
To analyze time-dependent change of, prevalence of, and risk factors for proximal junctional kyphosis (PJK) in adult spinal deformity
after long (≥5 vertebrae) segmental posterior spinal instrumented fusion with a minimum 5-year postoperative follow-up.
Summary of Background Data.
No study has focused on time-dependent long-term proximal junctional change
in adult spinal deformity
after segmental posterior spinal instrumented fusion with minimum 5-year follow-up.
Clinical and radiographic data of 161 (140 women/21 men) adult spinal deformity
patients with minimum 5-year follow-up (average 7.8 years, range 5–19.8 years) treated with long posterior spinal instrumentation and fusion were analyzed. Radiographic measurements included sagittal Cobb angle at the proximal junction on preoperative, 8-weeks postoperation, 2-year postoperation, and ultimate follow-up (≥5 years). Postoperative SRS outcome scores were also evaluated.
The prevalence of PJK at 7.8 years postoperation was 39% (62/161 patients). The PJK group (n = 62) demonstrated a significant increase in proximal junctional angle at 8 weeks (59%), between 2 years postoperation and ultimate postoperation (35%), and in thoracic kyphosis (T5–T12) at ultimate follow-up (P
= 0.001). However, the sagittal vertical axis change at ultimate follow-up did not correlate with PJK (P
= 0.53). Older age at surgery >55 years (vs.
≤55 years) and combined anterior and posterior spinal fusion (vs.
posterior only) demonstrated significantly higher PJK prevalence (P
= 0.001, 0.041, respectively). The SRS outcome scores did not demonstrate significant differences with the exception of the self-image domain when PJK exceeded 20°.
The prevalence of PJK at 7.8 years postoperation was 39%. PJK progressed significantly within 8 weeks postoperation (59%) and between 2 years postoperation and ultimate follow-up (35%). Older age at surgery (>55 years) and combined anterior and posterior spinal fusion were identified as risk factors for developing PJK. The SRS outcome instrument was not adversely affected by PJK, except when PJK exceeded 20°.