Assessment of MRI as a Modality for Evaluation of Soft Tissue Injuries of the Spine as Compared to Intraoperative Assessment

Abstract

Introduction: Traumatic injuries of the spine and spinal cord are potentially devastating as they may lead to significant neurological damage as the clinical and prognostic spectrum of the effects of spinal injuries is vast. Timely imaging studies can help mitigate these possibly life threatening complications. There is a dearth of studies that directly compare MR imaging findings to surgical findings. Aim: Hence, this study was undertaken to assess the sensitivity of MRI in identifying injuries to the soft tissue structures of the spine. Materials and Methods: MRI scans were performed on 31 cases of acute spinal injuries that presented within 72 hours of the trauma and underwent surgical fixation by either an anterior or posterior approach. The non-osseous structures namely; Anterior Longitudinal Ligament (ALL), Posterior Longitudinal Ligament (PLL), Intervertebral Disc, Ligamentum Flavum, Interspinous Ligament (ISP) and the Spinal Cord were evaluated. They were classified as ‘True Positive’ if an injury was found to correlate with intraoperative findings and as ‘False Negative’ when diagnosed falsely as normal. The statistical sensitivity of MRI in diagnosing injuries to the non-osseous structures of the spine were thus calculated. Results: Of the 31 patients, in 51.6% of patients the site of injury was to the cervical spine (n=16), thoracic spine was the next highest in occurrence of 39% (n=12) and lumbar spine accounted for the least. In correlating the imaging findings to the intraoperative findings, MRI was highly sensitive in detecting injuries to the Posterior Longitudinal Ligament (94.4%) and the Spinal cord (93%) and fairly high in detecting injuries to the Intervertebral disc. However coming to the ligamentum flavum and interspinous ligaments, the sensitivity of the MRI dropped to 62.5% and 63.6% respectively. Conclusion: MRI was found to be highly sensitive in detecting injuries to the spinal cord and the posterior longitudinal ligament and moderately sensitive for detection of disc injuries. Though concerning the Anterior Longitudinal Ligament, Ligamentum Flavum and the Interspinous Ligaments MRI performed ineffectively with higher number of false negative interpretations.

Keywords

• spinal injuries
• ligamentous injury
• spinal cord injury