239. Risk factors for distal junctional failure in long construct instrumentation for adult spinal deformity

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<h3>BACKGROUND CONTEXT</h3> The surgical management of adult spinal deformity (ASD) presents a difficult challenge for spine surgeons and is associated with a high complication profile in the postoperative period. Particularly, junctional failure is a major postoperative complication that necessitates revision. Little is known about risk factors for distal junctional failure (DJF) compared to proximal junctional failure (PJF). <h3>PURPOSE</h3> The aim of this study is to identify risk factors associated with postoperative DJF in long constructs for ASD. <h3>STUDY DESIGN/SETTING</h3> A retrospective review was performed at a tertiary referral spine center. <h3>PATIENT SAMPLE</h3> Patients who underwent long construct fixation at our institution from 1st Jan 2007 to 31st December 2016. <h3>OUTCOME MEASURES</h3> Evaluate demographic, clinical, and radiological risk factors for postoperative occurrence of distal junctional failure in ASD patients. Additionally, assess the incidence rate and causative pathophysiology for DJF in these patients. <h3>METHODS</h3> Demographic, clinical and radiographic parameters were collated for patients with DJF in the postoperative period and compared to those without DJF. Survival analyses were performed using univariate logistic regression to identify variables with a p-value <0.05 for inclusion in multivariate analysis. Spearman's correlations were performed where applicable. <h3>RESULTS</h3> A total of 102 patients were identified. Forty-one (40.2%) suffered DJF in the postoperative period, with rod fracture being the most common sign of DJF (13/65; 20.0%). Mean time to failure was 32.4 months. On univariate analysis, pedicle subtraction osteotomy (p=0.03), transforaminal lumbar interbody fusion (p<0.001), preop LL (p<0.01), preop SVA (p<0.01), preop SS (p=0.02), postop LL (p=0.03), postop SVA (p=0.01), postop PI/LL (p<0.001), LL correction (p<0.001), SVA correction (p<0.001), PT correction (p=0.03), PI/LL correction (p<0.001), SS correction (p=0.03) all proved significant. On multivariate analysis, pedicle subtraction osteotomy (OR: 27.3; p=0.03), postop SVA (OR: 1.66; p<0.01) and LL correction (OR: 1.12; p=0.02) remained statistically significant as independent risk factors for DJF. <h3>CONCLUSIONS</h3> Recently, DJF has received recognition as its own entity due to a notable postoperative incidence. Few studies to date have evaluated risk factors for DJF. The results of our study highlight that pedicle subtraction osteotomy and poor correction of lumbar lordosis and sagittal vertical axis are significantly associated with postoperative occurrence of DJF. <h3>FDA DEVICE/DRUG STATUS</h3> This abstract does not discuss or include any applicable devices or drugs.