Use of Point-of-care Neuro-sacral Electrophysiology Following Spinal Cord Injury

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BACKGROUND: Following spinal cord and cauda equina injuries, clinicians perform a neuro-sacral assessment to establish the injury severity, select proper treatment and rehabilitation needs (neuro-sacral dysfunction is an indication for surgery and requires rehabilitation in a specialized facility), and predict recovery. Current assessments rely on a qualitative digital rectal evaluation, which lacks sensitivity and depends heavily on the clinician's experience. Our previous findings suggest that assessing acute neuro-sacral function within the first days post-injury provides important insights on motor, sensory and bowel/bladder recovery. However, the lack of an accessible quantitative evaluation method adapted to the clinical setting is a major barrier limiting our knowledge on neuro-sacral function, hampering the improvement in care management. We have recently validated an quantitative electrophysiological method to assess neuro-sacral function at bedside that preserves the key assessments of the manual evaluation (anal contraction/sensation and sacral reflexes) and eliminates the need to insert the finger into the rectum while being more sensitive to detect changes in neuro-sacral function. GOALS: We believe that using a quantitative evaluation method is an essential step for optimizing the neurological assessment by clinicians, and for underpinning the impact of early neuro-sacral function on long-term recovery. We therefore hypothesize that acute neuro-sacral function is associated with motor, sensory and bowel/bladder recovery 6 months post-injury. The specific aims are: Assess longitudinal neuro-sacral function for 6 months post-injury. Assess the relationship between neuro-sacral function and neurofunctional recovery, in order to identify clinical phenotypes of neuro-sacral function and quantitative thresholds associated with improved recovery. METHODS: For this 4-year longitudinal study, neuro-sacral function and recovery will be assessed in 450 individuals 1, 2, 6 weeks and 6 months after an acute spinal cord and cauda equina injuries. Neuro-sacral assessments will be performed by the attending physiatrist to measure the 1) electromyographic signal amplitude of voluntary anal contraction, 2) electromyographic signal amplitude of anal contraction elicited through anal reflex testing, and 3) perianal electrical perceptual threshold. Study endpoints 6 months post-injury include the improvement in neurological status (primary endpoint: 10-point improvement in motor score) and bowel/bladder function. Longitudinal changes in neuro-sacral function will be characterized from ANOVA. Classification and regression tree analysis will be used to identify clinical phenotypes and objective quantitative thresholds. EXPECTED OUTCOMES: By implementing an accessible point-of-care quantitative method to assess neuro-sacral function in the clinical setting, we have a real potential to transform the care standards for spinal cord and cauda equina injuries, and improve the efficiency and accuracy for identifying of neuro-sacral dysfunction. We will improve our understanding of the early changes in neuro-sacral dysfunction, therefore bringing new knowledge on the predictors of recovery. We will identify clinical phenotypes of neuro-sacral function and propose objective threshold values to help clinicians identifying proper care trajectory and optimize resources use, using an accessible and validated method that is well tolerated by patients.