title: Predictable imaging signs of cauda equina entrapment in thoracolumbar and lumbar burst fractures with greenstick lamina fractures.
abstract: METHODS
  A retrospective study.
  
  
  OBJECTIVE
  The aim of present study was to investigate imaging findings suggestive of cauda equina entrapment in thoracolumbar and lumbar burst fractures.
  
  
  BACKGROUND
  Burst fractures with cauda equina entrapment can cause neurologic deterioration during surgery. However, dural tears and cauda equina entrapment are very difficult to diagnose clinically or radiographically before surgery.
  
  
  METHODS
  Twenty-three patients who underwent spinal surgery for thoracolumbar or lumbar burst fractures were enrolled in this study. In magnetic resonance imaging T2-weighted images of the transverse plane, we defined cauda equina notch sign (CENS) as a v-shaped image that entrapped cauda equina gathers between lamina fractures. We evaluated the fractured spine by using CENS and lamina fractures and the rate of available space for the spinal canal at the narrowest portion of the burst fracture level. We classified patients into entrapment group or non-entrapment group, based on whether cauda equina entrapment existed.
  
  
  RESULTS
  Lamina fractures were detected in 18 (78.3%) and CENS were detected in 6 (26.1%) of 23 burst-fracture patients. Cauda equina entrapment existed in all the patients with CENS. In addition, the rate of available space for the spinal canal increased according to logistic regression. The size of the retropulsed fragment in the spinal canal was the most reliable of all the factors, suggesting cauda equina entrapment.
  
  
  CONCLUSIONS
  CENS was the most predictable sign of cauda equina entrapment associated with burst fractures.
authors: Department of Orthopaedic Surgery, Faculty of Medicine, Oita University, Yufu, Japan.
authors: Toyomi
authors: T
authors: Yoshiiwa
authors: Department of Orthopaedic Surgery, Faculty of Medicine, Oita University, Yufu, Japan.
authors: Masashi
authors: M
authors: Miyazaki
authors: Department of Orthopaedic Surgery, Faculty of Medicine, Oita University, Yufu, Japan.
authors: Ryuzo
authors: R
authors: Kodera
authors: Department of Orthopaedic Surgery, Faculty of Medicine, Oita University, Yufu, Japan.
authors: Masanori
authors: M
authors: Kawano
authors: Department of Orthopaedic Surgery, Faculty of Medicine, Oita University, Yufu, Japan.
authors: Hiroshi
authors: H
authors: Tsumura
keywords: Burst fracture; Cauda equina entrapment; Dural tear; Lamina fracture; Magnetic resonance imaging