MRI determination of subaxial cervical anterior longitudinal ligament and posterior longitudinal ligament injury

English Keywords:Subaxial cervical vertebrae  Anterior longitudinal ligament  Posterior longitudinal ligament  Injury  MRI

English Abstract:

  【Abstracts】　Objectives:　To investigate the diagnostic value and criteria of magnetic resonance imaging(MRI) in detecting subaxial cervical anterior longitudinal ligament(ALL) and posterior longitudinal ligament(PLL) injury and responsive management.　Methods: From August 2010 to July 2011, 87 patients with subaxial cervical spinal injury and without vertebral fracture or dislocation underwent anterior surgical stabilization.　X-ray, computed tomography(CT) and MRI were performed in all patients pre-operatively. MRI features of discontinuity on sagittal T1-weighted image(T1D),　longitudinal high signal intensity on sagittal T2-weighted image(T2L),transversal high or intermediate signal intensity on sagittal T2-weighted image(T2T) were used to assess the status of ALL and PLL by two physicians. During the operation, ALL and PLL were carefully examined.　The MRI results were compared with surgical findings.　Inter-observer agreement for each assessment was determined using the Kappa statistic. The sensitivity, specificity, accuracy, positive and negative predictive values of different MRI features in detection of ALL and PLL injury were calculated, and the operative finding was used as the gold standard.　Results:　Inter-observer agreement of T1D for the assessment of ALL and PLL injury was poor or fair(Kappa value =0.152, 0.238), and the sensitivity(57.4%-67.2%, 64.7%-64.7%), specificity(43.3%-60.8%, 56.5%-59.7%), accuracy(48.7%-63.3%, 58.2%-60.8%), positive predictive value(38.9%-51.9%, 29.0%-30.6%) and negative predictive value(61.8%-74.7%, 81.4%-86.1%) of T1D by comparing with the operative finding were low. For T2L, the inter-observer agreement was good(Kappa value =0.657, 0.607), and high specificity by comparing with the operative finding(78.4%-80.4%, 88.7%-90.4%) was noted, however, the sensitivity was only 54.1%-65.8% and 29.4%-50%, and the accuracy(70.3%-73.4%, 75.9%-84.8%), positive predictive value(63.5%-65.8%, 41.7%-70.8%) and negative predictive value(73.6%-78.4%, 82.1%-87.3%) were low. By contrast, the inter-observer agreement of T2T for the assessment of ALL and PLL injury was very good(Kappa value =0.837, 0.799), and high sensitivity(83.6%-86.9%, 82.4%-88.2%), specificity(91.8%-95.9%, 90.3%-91.9%), accuracy(89.9%-91.1%, 89.9%-89.9%), positive predictive value(86.9%-92.7%, 71.4%-73.7%) and negative predictive value(90.3%-91.8%, 95.0%-96.6%) were noted. Conclusions: T2T of MRI is a reliable indicator for ALL and PLL injury and useful in evaluating the stability of cervical spine.