Traumatic thoracic ASIA A examinations and potential for clinical trials

Abstract

Study design: Retrospective review of prospective database.

Objective: To define the variability of neurologic examination and recovery after nonpenetrating complete thoracic spinal cord injuries (American Spinal Injury Association [ASIA] A).

Summary of background data: Neurologic examinations after spinal cord injury (SCI) can be difficult and inconsistent. Unlike cervical SCI patients, alterations in thoracic (below T1) complete SCI (ASIA A-based on the ASIA Impairment Scale [AIS]) patients' examinations are based only on sensory testing, thus changes in the neurologic level (NL) are determined only by sensory changes.

Methods: A retrospective review of the placebo control patients in a multicenter prospective database used for the pharmacologic trial of Sygen. Patients were included if they had a complete thoracic SCI on initial evaluation, with completed ASIA examinations at follow-up weeks 4, 8, 16, 26, and 52. Specifically, pin prick (PP) and light touch (LT) were assessed and the absolute change was calculated as the number of spinal levels at a given observation time.

Results: Three thousand one hundred sixty-five patients were initially screened for the Sygen clinical trial, of which 51 were the control placebo patients used in this analysis. Alterations from the baseline examination (PP and LT) were fairly consistent and the median change/recovery in neurologic examination was 1 spinal level. Across all observations postbaseline, the average change for PP was 1.48 +/- 0.13 (mean +/- SE), and for LT, 1.40 +/- 0.13. There were equal proportions of directional changes (none, improved, lost).

Conclusion: Changes in a thoracic complete (ASIA A) SCI patients ASIA examination as measured through sensory methods (PP/LT) are fairly uncommon. The overall examination had only 1- to 2-level variability across patients, indicating minimal change in the sensory examination over the follow-up period. Stability in the ASIA examination as measured through sensory methods has thus been demonstrated over time, making it an excellent tool to monitor changes in neurologic function.