Wednesday, September 26, 2018 7:35 AM–9:00 AM ePosters: P92. Does UIV affect rate of pjk in adult deformity surgery fused to the pelvis?

Abstract

BACKGROUND CONTEXT The rate of proximal junctional kyphosis (PJK) is high in surgery for adult spinal deformity (ASD), especially when the fusions extend to the sacrum and pelvis. Determining the appropriate upper instrumented vertebra (UIV) can sometimes be difficult. Establishing whether rates of PJK are higher in patients with high thoracic vs lower thoracic UIV, may influence the choice of UIV in ASD. PURPOSE To assess the prevalence of PJK in ASD comparing high thoracic and low thoracic UIV in patients fused distally to the pelvis. A secondary question was to determine if rates of neurologic injury secondary to PJK vary according to high versus low thoracic spine UIV. STUDY DESIGN/SETTING Retrospective Cohort. PATIENT SAMPLE A total of 106 cases underwent surgical correction for adult spinal deformity. OUTCOME MEASURES (1) Rate of PJK (2) Rate of neurologic injury. METHODS A total of 143 consecutive patients who underwent surgical correction for ASD between 2007 and 2016 with thoracic to pelvis fusions were assessed. Twenty-eight patients were excluded as their imaging was unavailable due to institutional reasons. A further 8 were excluded due to the EMR containing only partial data. A total of 106 cases were examined (average age 61.0, 80% female). Patients were grouped into high thoracic (HT) UIV (T1–T6) or low thoracic (LT) UIV (T9–T12). PJK was defined as UIV or UIV+1 fracture, kyphosis >10°, or presence of a junctional disc herniation requiring surgery. Presence of PJK was determined by examining 3-foot radiographs at 1 year post-operatively. RESULTS There were 61(57.5%) patients in the HT group and 45(42.4%) in the LT group. PJK occurred in 38 patients (62.5%) in the HT group compared to 12 patients (26.7%) in the LT group (P=0.0004). Proximal junctional kyphosis associated with acute neurologic injury of ASIA A, B or C occurred in two patients in the HT group and 1 patient in the LT group. CONCLUSIONS One-year postoperative PJK prevalence in adult spinal deformity following thoracic to pelvis fusions was higher when the UIV was in the high thoracic spine compared to the lower thoracic region. PJK with associated major neurological deficits was similar in both groups.