Intrathecal baclofen in subjects with spastic hemiplegia: assessment of the antispastic effect during gait.

OBJECTIVE

To determine whether leg muscle stiffness is measurably reduced after intrathecal baclofen (ITB) in subjects with spastic hemiplegia.

DESIGN

Nonrandomized trial.

SETTING

Inpatient multidisciplinary rehabilitation unit in France.

PARTICIPANTS

Seven consecutive subjects with spastic hemiplegia having Ashworth Scale scores for their quadriceps and triceps greater than 2.

INTERVENTION: Subjects were given ITB by lumbar puncture after a dose-selecting test period.

MAIN OUTCOME MEASURES: Triceps and quadriceps Ashworth scores, gait analysis at preferred and maximal speed measured by a motion analysis system with 2 forceplates, and electromyographic recording of leg muscles before and 4 hours after ITB. The slopes of the moment-angle curves were measured on the hemiplegic side at the onset of ankle and knee flexion to assess muscle stiffness during walking. Pre- and post-ITB spatiotemporal, kinetic, and kinematic data were compared by using a nonparametric test (Wilcoxon signed-rank test).

RESULTS

Ashworth scores of the quadriceps and triceps of all subjects decreased significantly after ITB. Maximal walking speed increased significantly, with a significant increase in stride length, but the preferred walking speed was unchanged. Minimal knee extension and maximal ankle flexion were the only kinematic data significantly different (increased) after ITB. The slope of the ankle moment-angle curve decreased significantly after ITB at preferred gait speed; it also decreased at maximal gait speed in all but 1 subject. Of the 4 available moment-angle curves, 3 showed decreased knee extensor muscle stiffness. The duration of the bursts of spastic muscles decreased after ITB.

CONCLUSION

Acute ITB improved walking and reduced muscle stiffness at both the ankles and knees on the spastic hemiplegic side of our subjects. Electromyographic findings suggest that some of the post-ITB reduction in muscle stiffness might be attributed to decreased spasticity.