Proximal Junctional Kyphosis Following Adult Spinal Deformity Long Posterior Segmental Instrumentation and Fusion: Minimum 5 Years Follow-Up
Methods: Clinical and radiographic data of 90 (59 female and 31 male) adult deformity patients with a minimum 5 years follow-up (average 7.0 years, range 5-16 years) treated with long posterior spinal instrumentations and fusion were analyzed. Radiographic data included sagittal parameters. SRS outcome scores at the ultimate follow-up were evaluated. Abnormal PJK was defined by the proximal junction sagittal Cobb angle between the lower end plate of the uppermost instrumented vertebra and the upper end plate of 2 supradjacent vertebra ³ +10 degrees and at least 10 degrees greater than the preoperative measurement at the ultimate follow-up.
Results: The prevalence of the PJK at 7.0 years postoperative was 39% (35/90 patients). PJK group (n=35) demonstrated significant increase in proximal junctional angle at 2 years postoperation and at the ultimate follow-up (p <0 .0001 and p55 years vs. 55 or below) demonstrated significantly higher PJK prevalence (p="0.039" p="0.044" respectively). The SRS outcome scores did not demonstrate significant differences.
Conclusions: The prevalence of proximal junctional kyphosis at 7.0 years postoperation was 39% and progressed slightly after 2 years postoperation. All pedicle screw instrumentation and age at surgery (>55 years) were identified as risk factors for developing PJK. The SRS 24 outcome instrument was not affected by PJK.