Clinical information

• Neurological level of injury
• Neurologic category
• ASIA impairment category
• Length of stay

The clinical picture of persisting cases of SCI was affected by incomplete reporting. There were 67 cases for whom the neurological category of injury at discharge was not reported. Analysis of the characteristics of these cases, compared with the other 162 cases for whom neurological category was reported, revealed no significant nor substantial differences on the basis of the neurological level of injury at admission, the extent of injury at admission, ASIA impairment category at admission, age group, and length of stay in hospital. Given that there was no evidence of unrepresentativeness, the following discussion of the clinical features of SCI was based on the 162 cases for whom neurological category was reported.

Neurological level of injury

Figure 6: Incidence of persisting SCI from traumatic causes by neurological level of injury at discharge, Australia 1996/97 (percentages)

• Forty-five per cent of the cases (n=73) 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.
• Fifty-five per cent (n=89) 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.
• Injury to the cervical segments resulting in tetraplegia was more common in 1995/96 (51%, n=92) than in 1996/97 (45%, n=73). This change was not statistically significant.
• The most commonly injured spinal cord segments were the cervical segments, particularly C4 (10%, n=16), C5 (14%, n=22), C6 (14%, n=22), the lumbar segment L1 (12%, n=20), and the lower thoracic segments.
• The frequency of injury to the L1 (n=20) spinal segment in 1996/97 almost doubled the frequency reported in 1995/96 (n=12). This change was not statistically significant. The increase was most apparent in the high falls group (increased to 11 in 1996/97 from 4 in 1995/96). Half of the cases suffered complete impairment at this level.

Neurologic category

Table 1: Incidence of persisting SCI from traumatic causes by neurological level (major grouping) and extent of injury at discharge, Australia 1996/97 (counts and column percentages)

Extent of injury	Tetraplegia		Paraplegia
	Cervical		Thoracic		Lumbar		Sacral		All Paraplegia		Total
	Count	%	Count	%	Count	%	Count	%	Count	%	Count	%
Complete	29	40	30	63	12	32	0	0	42	47	71	44
Incomplete	44	60	18	38	26	68	3	100	47	53	91	56
Total	73	100	48	100	38	100	3	100	89	100	162	100

Note: Neurologic category was not reported for 67 cases out of the 229 persisting cases of SCI

• The most common neurologic category was incomplete paraplegia (29% of total, n=47), followed by incomplete tetraplegia (27% of total, n=44), complete paraplegia (26% of total, n=42), and complete tetraplegia (18% of total, n=29).
• Complete injury was most common in the thoracic spinal segments.

The external cause of injury for persisting 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, and the damage to the cord was most often incomplete for both cervical level injuries (61%, n=14) and for injuries at other levels of the cord (67%, n=12).
• Unprotected road users most often suffered thoracic level injuries, most of which resulted in complete damage to the cord (89%, n=8).

Note: Neurological level and extent of injury was not reported for 67 cases out of the 229 persisting cases of SCI

• Low falls and diving primarily resulted in cervical level injury, whereas high falls more often resulted in damage to the thoracic and lumbar spine. Whilst incomplete injury was most common amongst the low falls cases (88%, n=14), complete injury was most common amongst the diving (53%, n=9) and high falls cases (51%, n=20).
• Amongst the diving cases that suffered cervical level SCI, sixty-nine percent (n=9) suffered complete damage to the cord. The number of cases of complete tetraplegia from diving was the same as the number for motor vehicle occupants which demonstrates the relative importance of diving as a cause of severe SCI.

ASIA impairment category

A = Complete.

No sensory or motor function is preserved in the sacral segments S4-S5.

B = Incomplete.

Sensory but not motor function is preserved below the neurological level and extends through the sacral segments S4-S5.

C = Incomplete.

Motor function is preserved below the neurological level, and the majority of key muscles below the neurological level have a muscle grade less than 3.

D = Incomplete.

Motor function is preserved below the neurological level, and the majority of key muscles below the neurological level have a muscle grade greater than or equal to 3.

Table 3 presents ASIA impairment categories at admission and discharge.

• For the majority of cases (70%, n=114), there was no change in the degree of impairment between admission and discharge.
• ASIA impairment categories `A' and `D' at admission were least likely to change between admission and discharge.
• For twenty-seven per cent of cases (n=44), there was a reduction in the degree of impairment between admission and discharge, particularly from category `C' to `D' which signified a clinically important improvement in muscle strength below the neurological level of injury. A number of cases had a particularly significant reduction in impairment from categories `A' and `B' to `D'.
• As noted in the 1995/96 report, there was a small number of cases that had an apparent increase in the extent of impairment between admission and discharge. This warrants further attention.

Note: ASIA impairment category at admission was not reported for 67 cases, and at discharge for 69 cases.

Length of stay

Information on the average length of stay (ALOS) in hospital from the date of injury to the date of discharge from the SU, by neurologic category, is presented in Table 4.

• The ALOS for all persisting cases was about four months, ranging from nearly six and a half months for cases of complete tetraplegia to about three weeks for cases of incomplete paraplegia involving sacral level injury.
• Amongst the cases with paraplegia, the longest length of stay was for cases with thoracic level injury whether complete or incomplete.

Note: Neurologic category was not reported for 67 cases out of the 229 persisting cases of SCI.

• For complete injury, the ALOS decreased with a decrease in the neurological level of injury, from the cervical to the sacral segments of the spinal cord.