Traumatic cervical cord injury at C3-4 without radiographic abnormalities: correlation of magnetic resonance findings with clinical features and outcome.

PURPOSE Clinical features and outcomes of 43 patients at the Department of Orthopaedic Surgery, Okayama Rosai Hospital, Okayama, were studied prospectively. These patients were not found to have radiographic abnormalities but magnetic resonance images showed acute cervical spinal cord trauma at the C3-4 disc level. METHODS Magnetic resonance images were analysed at presentation (immediately after the injury) and subsequent follow-up visits (at subacute and chronic stages, respectively) in an attempt to correlate imaging findings to clinical features and outcomes, respectively. RESULTS The injury mechanism was usually a hyperextension of the cervical spine. The level of neurological involvement was assessed in 9 patients with complete tetraplegia: the motor level was C5 in 6 patients and C4 in 3, whereas the sensory level was C5 in 7 patients, C4 in one, and C3 in one. Respiratory dysfunction in patients with severe paralysis, or numb and clumsy hands in patients with incomplete paralysis were the characteristic clinical features of cervical spinal cord injury at these lesions. Three patterns of signal change on magnetic resonance images were observed in patients with spinal cord injury at C3-4. A low-intensity area on T2-weighted images in the acute stage indicated a poor prognosis, while a high-intensity area at 2 to 3 weeks after injury indicated some degree of permanent paralysis. CONCLUSION The serial signal changes of magnetic resonance images and the clinical severity or outcome seemed to be well correlated.