The majority of patients assessed AIS A at admission remain so at discharge, whereas a much greater proportion of individuals assessed AIS B recovered significant motor function during rehabilitation so as to be assessed AIS C or D. The conversion rate is even greater for those assessed initially as AIS C but much less so for those assessed as AIS D.
These conversion rates appear similar across these studies and therefore provide a base for comparison with other findings. For example, Moslavac et al. (Moslavac et al. 2008) reported data for a centre-based study in Croatia at which all national cases of SCI resulting from road traffic accidents received rehabilitative care. In this case, although 49% of people were AIS A at admission and 93% of these remained AIS A at discharge, there was a tendency for greater proportions of persons making conversions to AIS D or E of those assessed with an incomplete injury at admission. Importantly, Wilde et al. (2020) found that interhospital transfer does not reduce functional recovery.
Similarly, many individuals also make significant functional gains during comprehensive inpatient rehabilitation. Most often, functional status has been assessed at admission and discharge from rehabilitation using the FIM (De Vivo et al. 1991; Muslumanoglu et al. 1997; Tooth et al. 2003; Chan & Chan 2005) or MBI (Yarkony et al. 1987). Typically, functional gains are greater with rehabilitation for those with incomplete injuries as compared to complete injuries and for those with paraplegia as compared to those with tetraplegia (Chan & Chan 2005; De Vivo et al. 1991; Muslumanoglu et al. 1997; Tooth et al. 2003). In particular, DeVivo et al. (1991) reported similar average FIM gains for those with incomplete and complete paraplegia and incomplete tetraplegia (i.e., 37, 36 and 34 respectively) but much reduced gains for those with complete tetraplegia (i.e., 15). For the most part increases seen in the FIM have been attributed to motor FIM changes with little change in cognitive FIM scores at least partly due to an apparent ceiling effect (Chan & Chan 2005).
There is level 4 evidence that a significant proportion of people (~50%) initially assessed as AIS B and C will improve by at least one AIS grade in the first few months post-injury concomitant with inpatient rehabilitation. Fewer individuals (~10%) initially assessed as AIS A and D will improve by one AIS grade.
There is level 4 evidence that individuals make significant functional gains during inpatient rehabilitation, more so for those with complete and incomplete paraplegia and incomplete tetraplegia.