Development of a clinical spasticity scale for evaluation of dogs with chronic thoracolumbar spinal cord injury.

OBJECTIVE To develop a spasticity scale for dogs with chronic deficits following severe spinal cord injury (SCI) for use in clinical assessment and outcome measurement in clinical trials. ANIMALS 20 chronically paralyzed dogs with a persistent lack of hind limb pain perception caused by an acute SCI at least 3 months previously. PROCEDURES Spasticity was assessed in both hind limbs via tests of muscle tone, clonus, and flexor and extensor spasms adapted from human scales. Measurement of patellar clonus duration and flexor spasm duration and degree was feasible. These components were used to create a canine spasticity scale (CSS; overall score range, 0 to 18). Temporal variation for individual dogs and interrater reliability were evaluated. Gait was quantified with published gait scales, and CSS scores were compared with gait scores and clinical variables. Owners were questioned regarding spasticity observed at home. RESULTS 20 dogs were enrolled: 18 with no apparent hind limb pain perception and 2 with blunted responses; 5 were ambulatory. Testing was well tolerated, and scores were repeatable between raters. Median overall CSS score was 7 (range, 3 to 11), and flexor spasms were the most prominent finding. Overall CSS score was not associated with age, SCI duration, lesion location, or owner-reported spasticity. Overall CSS score and flexor spasm duration were associated with gait scores. CONCLUSIONS AND CLINICAL RELEVANCE The CSS could be used to quantify hind limb spasticity in dogs with chronic thoracolumbar SCI and might be a useful outcome measure. Flexor spasms may represent an integral part of stepping in dogs with severe SCI.