• Stephen J Lewis, Harith Abbas, Sooyong Chua, Sarah Bacon, Yigal Bronstein, Sergey Goldstein, Sofia Magana, Kelly Sullivan, Andrew P Dold, and Andrew Bodrogi.
• Division of Orthopaedic Surgery, Toronto Western Hospital, University of Toronto, Toronto, Ontario, Canada. Stephen.Lewis@uhn.on.ca
• Spine. 2012 Jul 15;37(16):1407-14.

Study DesignA retrospective comparative study.ObjectiveTo investigate the risk factors associated with upper instrumented vertebral (UIV) fractures in adult lumbar deformity.Summary Of Background DataLong segment lumbar fusions may lead to junctional failures. The purpose of this study was to determine factors associated with junctional failures.MethodsTwenty-seven consecutive patients from 2001 to 2008 with minimum 4 levels fused, lower instrumented vertebra (LIV) of L5 or S1, upper instrumented vertebra of T10 or distal, and no previous surgery proximal to the instrumentation were retrospectively reviewed. We describe the UIV angle, the sagittal angle of the upper instrumented vertebra with the horizontal. Patients were divided into 3 groups: group 1, 7 patients with UIV fractures; group 2, 6 patients with other proximal failures; and group 3, 14 patients with no proximal complications.ResultsThe mean number of levels fused was 5.7 (4-7), 5.2 (4-8), and 6.2 (4-8); mean age was 64.1, 61.8, and 64.1, and mean body mass index was 33.5, 30.0, and 31.6 for groups 1, 2, and 3, respectively (P > 0.05). Osteotomies were performed in 5 of 7 in group 1, 1 of 6 in group 2, and 5 of 14 in group 3. Mean follow-up was 26.3 months. The average intraoperative UIV angle (UIV0) and immediate postoperative UIV angle (UIV1) were 18.6°/15.4° for group 1, 5.7°/5.3° for group 2, and 10.3°/7.1° for group 3 (P < 0.05). Surgical revision rates were higher in group 1 (71%) compared with groups 2 (50%) and 3 (43%). Eight of 11 (73%) patients with upper instrumented vertebra of L1 or L2 had either UIV fracture or other proximal failure compared with 5 of 16 (31%) in patients with upper instrumented vertebra of T10, T11, or T12.ConclusionOur series of long lumbar fusions had a high long-term complication and revision rate. A high UIV angle on intraoperative lateral radiograph was strongly associated with UIV fractures. UIVs of L1 or L2 had a higher rate of adjacent segment or UIV failure.

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