CORRECTED IMAGE In the Image titled “Assessment of Lumbar Fusion: Importance of Dynamic Plain Standing X-rays” by Francis H Shen, MD, and Dino Samartzis, DSC, MSC, DIP EBHC, which appeared in the December 2008 issue of the Journal of the American College of Surgeons, volume 207, page 955–956, the content of figures B and C was not visible. We are reprinting the entire article below. Assessment of Lumbar Fusion: Importance of Dynamic Plain Standing X-rays Francis H Shen, MD, University of Virginia, Charlottesville, VA and Shriners Hospitals for Children, Chicago, IL, Dino Samartzis, DSC, MSC, DIP EBHC, Erasmus University, Rotterdam, The Netherlands and Shriners Hospitals for Children, Chicago, IL A 57-year-old woman sustained an unstable flexion- distraction fracture of the lumbar spine. She underwent surgical stabilization at another institution. This en- tailed a staged anterior and posterior approach with in- terbody fusion of L1-L2, L3-L5 and posterior fusion and instrumentation of L1-L5. There was initial improve- ment of her symptoms, but she later developed recurrent onset of back pain that was activity-related and im- proved with rest. She had no fever, chills, nausea, vom- iting, weight change, or bowel or bladder dysfunction. On examination, she was neurologically intact with full motor strength and normal sensation. Range of motion of the lumbar spine was reduced, which accentuated her back pain. The presence of severe persistent back pain along with fractured spinal implants at L2-L3 on plain x-rays re- sulted in the presumed diagnosis of a pseudarthrosis (A, anteroposterior, B, lateral). Nonunion of the fusion masses was not evident. Subsequent evaluation and ex- tensive multimodality workup at several institutions in- cluding oblique x-rays, CT scan (C, sagittal; D, axial), and MRI with gadolinium demonstrated bridging bone and an apparent solid arthrodesis on multiple views. CT-guided biopsy, bone scan, and laboratory blood work did not reveal any evidence of a tumor or infection. Because of a negative workup for evidence of infection, tumor, or stenosis, combined with evidence of a solid fusion, she was referred to us for evaluation. Simple standing flexion-extension x-rays (E, flexion; F, exten- sion) revealed obvious motion at L2-L3 and motion at the fractured implant, confirming the pseudarthrosis. Lumbar fusion is a commonly performed spine sur- gery, increasing in rate in the past decade, and often involving a multidisciplinary surgical team. 1 The deci- sion to undergo revision surgery for persistent back pain after spinal fusion is a challenge. The main goal is to establish a diagnosis to develop a treatment plan. The differential diagnosis includes pseudarthrosis, infection, tumor, stenosis, or unstable fracture. The evaluation should include a careful history specifically for “red flag” signs. If present, such signs may indicate the presence of non-mechanical causes for back pain, including infec- tion, tumor, or unstable fracture. Imaging studies should complement the history and examination. The careful history and examination of this patient appeared most consistent with a mechanical source, spe- cifically a nonunion, contributing to the patient’s pain. Various authors have contended the superiority of sur- gical exploration with direct examination of the fusion mass, 2 and advanced imaging to assess the presence of bone fusion. 3 But in this case, despite multiple advanced static imaging techniques and the presence of broken A B 318 © 2009 by the American College of Surgeons ISSN 1072-7515/09/$36.00 Published by Elsevier Inc. doi:10.1016/j.jamcollsurg.2008.12.004