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 for some data items. For example, there were eighty cases (29%) for whom either the neurological level or extent of injury at discharge was missing. It was apparent that the cases with missing clinical information at discharge tended to be, more often than other cases, classified as complete tetraplegics at admission. An examination of the dates of injury of these cases and expected length of stay suggested that many would not have been discharged at the time that this report was being prepared. Exclusion of these cases from the analysis would have biased the results. Given that the neurological level (major grouping) and extent of injury rarely change between admission and discharge, especially for complete tetraplegics, the clinical information at admission was used where missing at discharge for all tabulations except those concerning the comparison of 'ASIA impairment category' ⁶ between admission and discharge (Table 3) and length of stay (Table 4).

In future years this issue of the Bulletin will be re-focussed on the features of SCI at admission so that reporting can be finalised shortly after the completion of each financial year without the need for the troublesome adjustment and case selection required to deal with missing clinical discharge data. Reports dealing with other issues, such as features at discharge and change in clinical status between admission and discharge, length of stay and trends in SCI will be published as the availability of complete information permits.

Neurological level of injury

Figure 6: Incidence of persisting SCI from traumatic causes by neurological level of injury at discharge, Australia 1997/98 (per centages)

• Where neurological level was reported (n=261) the most commonly injured spinal cord segments were: the cervical segments, particularly C5 (18%, n=47), C4 (17%, n=44), and C6 (12%, n=32); the lumbar segments L1 (7%, n=19) and L3 (7%, n=17); and the lower thoracic segments, particularly T12 (6%, n=15).
• Injury to the cervical segments resulting in tetraplegia was more common in 1997/98 (55%) than 1995/96 (51%) and 1996/97 (45%). The increase was particularly notable for the cervical segments C4 and C5 which accounted for thirty five per cent of reported cases of SCI in 1997/98 compared with twenty-three per cent in 1996/97 and twenty-nine per cent in 1995/96.

Neurologic category

• Fifty-five per cent 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-one per cent (n=115) 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 (36% of total, n=101), followed by incomplete paraplegia (21% of total, n=58), complete paraplegia (21% of total, n=57), and complete tetraplegia (17% of total, n=46).
• 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, with incomplete damage to the cord being most common at this level (57%, n=35).
• Unprotected road users most often suffered thoracic level injuries, which generally involved complete damage to the cord (79%, n=15).

• Water-related SCIs almost exclusively involved the cervical segments of the spine.
• Low falls and water-related accidents primarily resulted in cervical level injury, whereas high falls more often resulted in damage to the thoracic and lumbar spine. It is interesting to speculate on the reasons for this pattern of results. It is probable that different mechanisms of injury are involved in high falls versus low falls and diving-related accidents, with the latter probably having a higher frequency of impact to the head with consequent loading onto the cervical spine. More detailed information than is available on the register would be required to test this hypothesis.

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: Incidence of persisting SCI from traumatic causes by ASIA impairment category at admission and discharge, Australia 1997/98 (counts and per centages)

	ASIA category at admission
ASIA category at discharge	A		B		C		D		Total
	Count	%	Count	%	Count	%	Count	%	Count	%
A	54	34	1	1	0	0	1	1	56	35
B	5	3	5	3	2	1	0	0	12	7
C	7	4	5	3	9	6	0	0	21	13
D	5	3	9	6	28	17	30	19	72	45
Total	71	44	20	12	39	24	31	19	161	100

Note: ASIA impairment category at both admission and discharge was not reported for 117 cases

• For the majority of cases (61%, n=98), 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-six per cent of cases (n=42), 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 previous reports^{1, 2}, there was a small number of cases that had an apparent increase in the extent of impairment between admission and discharge.

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 for all cases discharged in 1997/98 irrespective of whether the injury date was in 1997/98 or a previous year. This table is not strictly comparable with those presented in the earlier reports which were based only on cases where the injury date and discharge date were in the same year.

• The ALOS for all persisting cases discharged in 1997/98 was eighteen weeks, ranging from more than thirty one weeks for cases of complete tetraplegia to about four 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.

Table 4: Incidence of persisting SCI from traumatic causes by neurological level (major grouping) and extent of injury at discharge, Australia 1997/98 (counts and average length of stay)

Extent of injury	Tetraplegia		Paraplegia
	Cervical		Thoracic		Lumbar		Sacral		All Paraplegia		Not reported		Total
	Count	ALOS (days)	Count	ALOS (days)	Count	ALOS (days)	Count	ALOS (days)	Count	ALOS (days)	Count	ALOS (days)	Count	ALOS (days)
Complete	34	223	33	146	9	130	0	0	42	143	2	175	78	179
Incomplete	87	104	15	142	33	74	2	29	50	91	8	69	145	98
Total	121	138	48	145	42	86	2	29	92	115	10	90	223	126

Note: Discharge date was not reported for 117 cases