Clinical information

• Neurological level of injury
• Neurologic category

Information on the neurological level of SCI and extent of injury to the cord is routinely reported by SUs.

Neurological level of injury

The neurological level of SCI at admission is presented in Figure 10. The most commonly injured spinal cord segments were: the cervical segments, particularly C4 (18%, n=47), C5 (17%, n=45), and C6 (9%, n=25); the lumbar segment L1 (11%, n=30); and the lower thoracic segment T12 (6%, n=17).

Figure 10: Incidence of SCI from traumatic causes by neurological level of injury at admission, Australia 1998/99 (percentages)

Neurologic category

The overall severity of SCI is usually measured by a combination of the neurological level and extent of injury into five neurologic categories (complete tetraplegia, incomplete tetraplegia, complete paraplegia, incomplete paraplegia, and complete recovery). Table 1 presents the counts and column percentages for the four neurological categories of SCI, as well as a finer breakdown of the paraplegia category.

• Fifty-eight percent of the cases (n=153) had an injury to the cord at the cervical level, resulting in impairment or loss of motor and/or sensory function in the arms as well as in the trunk, legs, and pelvic organs. This degree of impairment is referred to as tetraplegia.
• Forty-two percent (n=112) had an injury at the thoracic, lumbar, or sacral (but not cervical) levels, with an impairment or loss of motor and/or sensory function in these segments of the spinal cord. This degree of impairment is referred to as paraplegia. With paraplegia, upper limb function is spared, but depending on the level of injury, the trunk, pelvic organs, and lower limbs may be functionally impaired.
• The most common neurologic category was incomplete tetraplegia (38% of total, n=101), followed by incomplete paraplegia (24% of total, n=64), complete paraplegia (18% of total, n=48), and complete tetraplegia (19% of total, n=51).
• Complete injury was most common in the thoracic spinal segments, a finding which is explainable by the smallness of the spinal canal in this region in relation to the size of the cord (Bauer & Errico, 1991; Bohlman, 1985; Bohlman et al, 1985; White & Panjabi, 1990).

The external cause of injury for cases of SCI from traumatic causes is presented by neurological level in Table 2.

• Motor vehicle occupants most often suffered from injury to the cervical segments of the spine, resulting in tetraplegia, with incomplete damage to the cord being most common at this level (63%, n=33).
• Unprotected road users most often suffered thoracic level injuries, which generally involved complete damage to the cord (60%, n=12).
• Low falls primarily resulted in cervical level injury and most of these involved incomplete damage to the cord (84%, n=16).
• Fifty-seven percent (n=16) of the high falls tetraplegia cases suffered complete damage to the cord whereas sixty-four percent (n=21) of the high falls paraplegia cases suffered incomplete cord damage. There was a higher frequency of complete cord damage in high falls compared to low falls, which is probably explained by the higher energy of the high fall impacts.

Motor vehicle occupants and high falls cases make up the largest proportion of the most severely injured ie. those with complete tetraplegia (35% and 31% respectively; n=18 & 16 respectively). Arguably, the prevention of these injuries is of highest priority.