Effect of intrathecal baclofen bolus injection on lower extremity joint range of motion during gait in patients with acquired brain injury

Abstract

Horn TS, Yablon SA, Chow JW, Lee JE, Stokic DS. Effect of intrathecal baclofen bolus injection on lower extremity joint range of motion during gait in patients with acquired brain injury.

Objectives: To evaluate lower extremity joint range of motion (ROM) during gait before and after intrathecal baclofen (ITB) bolus administration, and to explore the relation between changes in ROM and concurrent changes in gait speed and muscle hypertonia.

Design: Case series.

Setting: Tertiary care rehabilitation center.

Participants: Adults (N=28) with muscle hypertonia due to stroke, trauma, or anoxia.

Interventions: 50-microg ITB bolus injection via lumbar puncture (75 and 100microg in 2 cases).

Main outcome measures: Ashworth score, self-selected gait speed, and sagittal plane ROMs in hip, knee, and ankle joints before and 2, 4, and 6 hours after ITB bolus.

Results: A significant decrease in the mean Ashworth score on the more involved side (2.0 to 1.3) and an increase in gait speed (41 to 47cm/s) were noted at different intervals after ITB bolus injection. Ankle ROM significantly increased on the more involved (13 degrees to 15 degrees , P<.01) and less involved (22 degrees to 24 degrees , P<.05) sides. ROM significantly improved, significantly worsened, or showed no significant change in 42%, 34%, and 24% of individual joints, respectively. The peak change in ROM did not coincide with the peak decrease in Ashworth score. Peak changes in ROM and speed coincided more often (P<.001) in participants who increased gait speed after ITB bolus compared with those who decreased speed. The absolute change in ROM after ITB bolus injection correlated better with the concurrent changes in speed (r=.41, P<.001) than with the baseline speed (r=.18, P<.05).

Conclusions: ITB bolus injection produces variable changes in joint ROM during gait, with significant improvements in the ankles only. Timing and magnitude of peak changes in ROM are associated with concurrent changes in speed but not muscle hypertonia.