The Gait Deviation Index as an indicator of gait abnormality among degenerative spinal pathologies

The Gait Deviation Index (GDI) is a composite measure of gait abnormality derived from lower-limb joint range-of-motion which is increasingly being reported for clinical gait analysis among neurologic and orthopedic patients. A GDI score of 100 is representative of healthy individuals and decreasing scores represent a greater abnormality. Preliminary data is needed to help assess the utility of GDI as a measure of compromised gait among spine patients and to provide reference values for commonly treated pathologies.

GDI scores were obtained from healthy adults and four symptomatic degeneration groups: cervical spondylotic myelopathy (CSM), adult degenerative scoliosis (ADS), and single-level lumbar degeneration (LD). Clinical gait analysis was done using a three-dimensional motion tracking system. Evaluations were done 1 week prior to surgical intervention for degeneration groups. Two-sample t-tests were used to compare degenerative cohorts to healthy controls and for inter-cohort comparisons. Pearson correlations were used to test for significant relationships between GDI and walking speed.

Degenerative cohorts all showed significantly lower (worse) GDI scores compared to healthy (all p < 0.001). CSM patients showed the best GDI scores with an average of 90, and LD patients showed the worst GDI scores with an average of 86. Worsening GDI significantly correlated with decreased walking speed among ADS patients.

Composite metrics like GDI provide a tempting means to summarize nuanced and complex gait characteristics into a single, comparable value among cohorts. The results of this study provide preliminary GDI scores for common degenerative spine pathologies. These slides can be retrieved under Electronic Supplementary Material.