Clinical Study Two-year fusion and clinical outcomes in 224 patients treated with a single-level instrumented posterolateral fusion with iliac crest bone graft John R. Dimar II, MD a , Steven D. Glassman, MD a , J. Kenneth Burkus, MD b , Philip W. Pryor, MD c , James W. Hardacker, MD c , Leah Y. Carreon, MD, MSc a, * a Kenton D. Leatherman Spine Center, 210 East Gray Street, Suite 900, Louisville, KY 40202, USA b The Hughston Clinic, P.C. , 6262 Veterans Parkway, Columbus, GA 31909, USA c The Spine Institute, 13431 Old Meridian Street, Suite 200, Carmel, IN 46032, USA Received 20 August 2008; received 18 March 2009; accepted 31 March 2009 Abstract BACKGROUND CONTEXT: Reported fusion rates for spine fusions using iliac crest bone graft (ICBG) vary between 40% and 100% because of different fusion techniques, patient comorbidity, diagnosis and assessment criteria. PURPOSE: We report two-year results of single-level instrumented posterolateral fusions evalu- ated with radiographs, fine-cut computed tomography (CT) scans with reconstructions and outcome measures. STUDY DESIGN/ SETTING: Retrospective analysis of data from a prospective multicenter ran- domized clinical controlled trial. PATIENT SAMPLE: Patients with various degenerative diagnoses enrolled in the control arm of a Food and Drug Administration (FDA)-regulated, multicenter trial of single-level decompression and posterolateral fusion for degenerative lumbar disease. OUTCOME MEASURES: Short Form-36 (SF-36), Oswestry Disability Index (ODI), Numeric Rating Scales (0–20) for back, leg, and graft site pain, CT scans, anteroposterior and lateral flex- ion/extension radiographs. METHODS: Patients enrolled in an FDA-regulated, multicenter trial at 29 sites with degenerative lumbar disease treated with single-level instrumented posterolateral fusion with ICBG were in- cluded in the analysis. Demographic and surgical data were collected. Clinical outcomes were fol- lowed using standard metrics. Fusion was assessed by independent radiologists at 6, 12, and 24 months postoperatively. Two fusion criteria were compared: anteroposterior and flexion/extension radiographs to assess motion and bridging bone, with CT scans as needed to confirm bridging bone; and CT scan assessment for bridging bone only. RESULTS: One hundred ninety-four of 224 subjects (86.6%) completed the study. The mean op- erative time was 2.9 hours with a blood loss of 448.6 mL. The average graft volume was 36.3 mL. There were 21 (9.4%) wound infections, 18 (8.0%) incidental durotomies, 3 (1.3%) implant dis- placements, 2 (0.9%) malpositioned implants, and 17 (7.6%) graft-related complications. Twenty-seven patients (13.9%) required reoperation, the majority for nonunions. Fusion rates based on radiographs with selective CTs at 6, 12, and 24 months were 65.3%, 82.5%, and 89.3%, respec- tively. Fusion rates based on bridging bone on CT scans were 56.1%, 71.5%, 83.9%, respectively. Two-year improvement for all outcome measures was significant (p !.001)dODI 25.3, SF-36 Phys- ical Component Score (PCS) 12.2, back pain 7.9, and leg pain 7.1. Two years postoperatively, 60% of patients complained of graft site pain (mean pain score58.5). FDA device/drug status: not applicable. Author disclosures: JRD, SDG (research support, royalties, consultant, Medtronic Sofamor Danek); JKB, PWP, JWH (research support, consultant, Medtronic Sofamor Danek); PWP (speaker, Medtronic Sofamor Danek); JKB (travel support, Medtronic Sofamor Danek). * Corresponding author. Kenton D. Leatherman Spine Center, 210 East Gray Street, Suite 900, Louisville, KY 40202, USA. Tel.: (502) 584-7525; fax: (502) 584-6851. E-mail address: lcarreon@spinemds.com (L.Y. Carreon) 1529-9430/09/$ – see front matter Ó 2009 Elsevier Inc. All rights reserved. doi:10.1016/j.spinee.2009.03.013 The Spine Journal 9 (2009) 880–885