Saturday, September 29, 2018 9:00 am–10:00 am Impact of Adult Deformity Correction: 265. Comparison of the incidence and risk factors for proximal junctional failure (PJF) in surgically treated patients with adult spinal deformity (ASD) between patients from Japan and the United States: series of 509 patients with 2-year follow-up

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BACKGROUND CONTEXT Proximal junctional failure (PJF) is one of the most devastating complications in the surgical treatment of adult spinal deformity (ASD). There are cultural differences between Eastern and Western countries that may impact the incidence and risk factors for developing PJF. Therefore, international comparisons of the incidence and risk factors for PJF following ASD surgery can provide insight into the pathology of PJF. PURPOSE To assess whether cultural differences can impact the incidence and risk factors for developing PJF following surgery for ASD based on patients from Japan (JP) and the United States (US). STUDY DESIGN/SETTING Multicenter retrospective case series. PATIENT SAMPLE A total of 509 ASD patients surgically treated for ASD from JP and US. OUTCOME MEASURES Incidence of PJF and revision for PJF. METHODS A total of 136 JP and 373 US ASD patients with age>40 years with minimum 2-year follow-up following corrective surgery were analyzed. Radiographic and demographic data were compared. Outcome measures included ODI and SRS22. PJF was defined as either an increase from baseline of proximal junctional angle ≥20° with concomitant deterioration of at least one SRS-Schwab sagittal modifier grade from immediate postoperation or any type of PJK requiring revision. RESULTS A total of 509 patients were analyzed (JP vs. US women: 94% vs 80%; age: 64.3 years vs 62.7 years; BMI: 22.2 vs 27.8). Significantly worse baseline spinopelvic alignment was observed in JP (PI-LL: 36° ± 24° vs 19° ±21°). JP and US patients had similar incidence of PJF (17.6% vs 18.8%; p=.46), but revision surgery was more commonly performed in the US (5.1% vs 2.2%; p=.02). No differences were observed for ODI and SRS22 clinical outcomes between non-PJF patients and conservatively treated PJF patients in both JP and US (p>.05). Age and baseline thoracic kyphosis were both significantly greater in PJF patients compared with non PJF patients in both countries (p CONCLUSIONS The incidence of PJF following ASD surgery was similar in the US and JP, whereas revision surgery for PJF was more commonly performed in the US. Greater age and baseline thoracic kyphosis were risk factors for PJF in both US and JP, whereas baseline sagittal alignment and its compensatory mechanisms had different impact on developing PJF between JP and US patients. FDA DEVICE/DRUG STATUS This abstract does not discuss or include any applicable devices or drugs.