SCIWORA and SCIWORET
Spinal Cord Injury Without Radiologic Abnormality
Spinal Cord Injury Without Radiologic Evidence of Trauma
SCIWORA is more common in children, presumably because of laxity of their spinal ligaments and weakness of their paraspinal muscles
SCIWORET is more common in adults, and is seen in the context of cervical stenosis, ankylosing spondylitis, spinal stenosis, disc herniation
These terms are probably not going to be seen very often now that MRI has become a critical part of the radiologic evaluation of patients with spinal cord injuries. Prior to CT, the incidence of SCIWORET in adults was about 14%. After CT, the incidence was about 5%. With the advent of MRI, very few spinal cord injuries will go undetected.
CERVICAL CORD NEUROPRAXIA
Defined by Torg J.S. et al., Journal of Neurosurgery, 87: 843-850, 1997
transient neurologic phenomenon following injury to the cervical spine.
symptoms may involve both arms, both legs, all four extremities, or an ipsilateral arm and leg.
sensory changes include burning pain, numbness, or tingling
motor changes include weakness or complete paralysis
episodes typically last fewer than 15 minutes, although in some cases gradual resolution can take up to 48 hours
by definition, results in a complete return of motor function and full, pain-free cervical range of motion.
Can occur by hyperflexion or hyperextension mechanisms
“Pincer” hyperextension mechanism described by Penning, Neurology, 12:513-519, 1962
measured the sagital diameter of the spinal canal in flexion and extension xrays, and noted compression in extension between the posteroinferior aspect of the vertebral body and the anterosuperior aspect of the spinolaminar line of the inferior vertebrae. The degree of compression is dependent on the sagittal diameter of the spinal canal and the degree of hyperextension.
SAGITAL DIAMETER OF THE CANAL – THE TORG/PAVLOV RATIO
standard C-spine film taken with the source 72 inches from the plate.
measurements are influenced by the technique
ratio between the spinal canal and the width of the vertebral body
spinal canal is measured from the vertical midpoint of the vertebral body to the nearest point on the spinolaminar line.
vertebral body is measured through the middle of the body
a ratio of 0.8 or less is significant for spinal stenosis
Torg J.S. et al. Neuropraxia of the Cervical Spinal Cord with Transient Quadriplegia, Journal of Bone and Joint Surgery, Vol 68-A, 9:1354-1374, 1986
devised the Torg/Pavlov ratio
retrospectively reviewed 24 patients with a history of a transient cervical cord injury (“neuropraxia”) and compared these to a group of 49 controls.
in all 24 patients, the ratio was less than 0.80, and for the controls the average was 0.98.
acute cervical disc herniation was noted in 2 patients, one with a myelogram and one with CT
Concluded that patients who suffered the neuropraxia had a significantly narrower canal than normals, as measured by the Torg ratio.
Kang, J.S., Figgie, M.P., Bohlman, H.H., Sagittal Measurements of the Cervical Spine in Subaxial Fractures and Dislocations, Journal of Bone and Joint Surgery, Vol 76-A, 11:1617-1628, 1994
examined 288 patients who presented with cervical spine fractures and dislocations either with complete spinal cord injuries, incomplete spinal cord injuries, root injuries, or no neurologic injuries.
measured Torg ratios at the level of the injury and at the uninjured levels
mean Torg ratio at the uninjured levels was 0.82 for those with complete injuries, 0.84 for those with incomplete injuries, 0.96 for those with isolated root injuries, and 0.96 for those with no neurologic injuries. A statistically significant difference in the ratio existed between the complete/incomplete versus the root/no injury groups.
Concluded that patients who sustained a permanent injury to the cord had a narrower sagittal diameter of the spinal canal before the injury.