Purpose: Due to lack of cervical clearance consensus in literature and the devastating consequences of missed cervical injuries, Magnetic resonance imaging (MRI) of the neurologically intact symptomatic patient with negative CT scan is frequently done to rule out disco-ligamentous injuries. This study retrospectively evaluates occult disco-ligamentous injuries detected by MRI in patients with no abnormalities detected by modern multi-detector CT scanning and postulates a new theory of ligamentous stability of cervical spine.
Methods: Cervical spine injury patients treated at a spinal trauma referral centre from 2010 to 2013 were retrospectively identified. Available clinical records and radiographic imaging were reviewed to find neurologically intact symptomatic patients with no identifiable acute cervical spine injury on CT scan but MRI evidence of isolated subaxial disco-ligamentous injuries. Patient demographics, injury profile, and treatment details were extracted. Subaxial Cervical Spine Injury Classification (SLIC) and Denis three-column spinal stability theory were adopted to assess stability of injuries.
Result: 316/566 cervical spinal admissions had CT and MRI scans. 11 (3.5%) CT negative patients were found to have occult discoligamentous injuries on MRI. The average age (51.1 years) was not significantly different to all cervical trauma admissions (p = 0.09). Eight had flexion type and three had extension type injuries. The most common mechanisms were sports and fall on flat surface. The average SLIC score was 3.1. Four patients were classified as having unstable or potentially unstable injuries (two patients each) and three of these patients were surgically managed. Subtle CT changes to indicate discoligamentous injury could be retrospectively identified in all four of these patients.
Conclusion: CT scans alone may be inadequate for clearing occult disco-ligamentous injuries of the subaxial cervical spine in trauma. Denis three-column stability theory may be beneficial in determining stability and guiding treatment along with the SLIC system for occult discoligamentous injuries of the subaxial cervical spine.
Keywords: Cervical spinal cord injury; Cervical spine trauma; Occult ligamentous injury.