A Comparison of Diagnostic Stability of the ASIA Impairment Scale Versus Frankel Classification Systems for Traumatic Spinal Cord Injury

Abstract

ObjectiveTo determine whether the “sacral sparing” definition for completeness of traumatic spinal cord injury (SCI) is a more stable definition than the previously used Frankel Classification. DesignRetrospective analysis of individuals enrolled in the Spinal Cord Injury Model Systems (SCIMS) database between 2011 and 2018. SettingSCIMS centers. ParticipantsIndividuals (N=804) with traumatic SCI who were at least 16 years old at time of injury, were admitted to rehabilitation within 30 days, had American Spinal Injury Association Impairment Scale (AIS) grades A-D at admission, and had complete neurologic data at the time of admission and 1 year. InterventionNot applicable. Main Outcome MeasuresFrankel and AIS scores were computed for a cohort of 804 eligible cases. Stability was compared between the 2 classification systems by calculating the proportions of cases in which regression (conversion to a more severe impairment level) was observed. ResultsA larger proportion of individuals classified with “incomplete” injuries (grades B-D) at the time of admission using the Frankel system regressed to complete status at 1 year compared with the AIS criteria (9.4% vs 2.0%). Those with grade B injuries regressed to grade A more often using the Frankel system compared with the AIS system (19.7% to 5.4%). A larger proportion of people diagnosed as Frankel grade C or D regressed to Frankel grade A compared with individuals diagnosed as AIS grade C or D who regressed to AIS grade A (5.0% to 1.1%). ConclusionsMore individuals diagnosed with neurologically incomplete SCI regressed to complete status at 1 year when using the Frankel system compared with AIS classification, which is based on sacral sparing. This reinforces the finding that the “sacral sparing” definition is a more stable classification in traumatic SCI.