title: Posterior instrumentation and simultaneous intertransverse approach using transforaminal cage fusion for thoracic pseudoarthrosis in ankylosing spondylitis: a case report.
abstract: BACKGROUND
  Unrecognized or untreated injury in patients with ankylosing spondylitis (AS) may develop anterior column spinal pseudoarthrosis with an open wedge bone defect. The methods of surgical treatment are controversial. Combined anterior and posterior stabilizations or posterior instrumentation with osteoclasis are beneficial as shown in an existing literature review.
  
  
  METHODS
  A 36-year-old Asian man with AS sustained a motor vehicle accident 2 years before presentation. At that time, his immediate magnetic resonance imaging scan demonstrated T10-T11 bone edema and granulation tissue formation with fluid accumulation in T10-T11 disc space. He opted for conservative treatment. His back pain was then exacerbated 2 years after the accident, and he underwent three-dimensional (3D) computed tomography (CT) scan revealing a severe pseudoarthrosis with sclerotic margins across the T10 caudal end vertebra to the T11 upper end plate, with a maximal fracture gap of 15 mm. Spinal cord compression was not present. After selecting for an appropriate cage size with the aid of the preoperative 3D CT images, we used a single posterior approach to apply pedicle screws, removed pseudoarthrotic granulation tissue through an intertransverse posterior lateral approach without entering the spinal canal, and inserted a transforaminal lumbar interbody fusion (TLIF) cage with bone graft. There was radiographic evidence of spinal fusion at the 9-month follow-up, and the patient had resumed all normal daily activities.
  
  
  CONCLUSIONS
  The authors found that a less invasive single posterior surgical approach using a TLIF cage and pedicle screws could be applied to AS patients with combined thoracic pseudoarthrosis and an anterior column defect. Using a TLIF cage may provide circumferential stability immediately, bone graft fusion, and sagittal plane correction simultaneously. An appropriate cage size and placement selected with preoperative 3D CT images are the keys to success.
authors.affiliation: Department of Orthopaedic Surgery, Chung-Shan Medical University Hospital, Institute of Medicine, Chung-Shan Medical University, Taichung, Taiwan.
authors.forename: Hung-Kai
authors.initials: HK
authors.lastname: Lo
authors.affiliation: Department of Orthopaedic Surgery, Chung-Shan Medical University Hospital, Institute of Medicine, Chung-Shan Medical University, Taichung, Taiwan.
authors.forename: Tsay-I
authors.initials: TI
authors.lastname: Chiang
authors.affiliation: Medical School, Tulane University School of Medicine, New Orleans, United States.
authors.forename: Olivia Hui-Chiun
authors.initials: OH
authors.lastname: Chang
authors.affiliation: Department of Orthopaedic Surgery, Chung-Shan Medical University Hospital, Institute of Medicine, Chung-Shan Medical University, Taichung, Taiwan.
authors.forename: I-Chang
authors.initials: IC
authors.lastname: Chang
mesh_terms: D000063:Accidents, Traffic; D000328:Adult; D001863:Bone Screws; D016025:Bone Transplantation; D005593:Fracture Fixation, Internal / Q000379:methods*; D006801:Humans; D016268:Internal Fixators; D008279:Magnetic Resonance Imaging; D008297:Male; D011542:Pseudarthrosis / Q000209:etiology / Q000601:surgery*; D013123:Spinal Fusion / Q000379:methods*; D013167:Spondylitis, Ankylosing / Q000150:complications*; D013904:Thoracic Vertebrae; D016896:Treatment Outcome