PAPER 049: EARLY EFFECT OF BOTULINUM TOXIN TYPE A ON ANKLE RANGE OF MOTION IN CHILDREN DIAGNOSED WITH SEVERE IDIOPATHIC TOE WALKING

Abstract

Purpose: The purpose of this study is to report on the outcomes of children with ITW who received Botulinum A Toxin (BTX-A) as an adjunct treatment to manipulations/casting and maintenance protocol.

Method: ITW severity was classified using gait analysis and defined by the absence of 1^st ankle rocker, early 3^rd rocker and an early and increased first ankle moment¹. Subjects who met the three severity criteria received a single BTX-A injection into both gastrocsoleus and placed immediately in below-knee casts. Casts were changed two weeks later for a total casting period of four weeks. Subjects then entered a maintenance protocol involving use of night splints or articulated ankle-foot-orthotics. Outcome measures collected at all follow-up visits were ankle dorsiflexion with knee in 90° flexion (DFF) and extension (DFE).

Results: Thirteen subjects with severe bilateral ITW participated. Subjects were followed for an average of 48 weeks (range 7 – 168 weeks) post BTX-A injection. Given the variability in subject outcomes, analyses and reporting were stratified according to subjects’ right and left feet. At day of BTX-A, right foot DFF/DFE were 1.7° ± 14.4 and −1.5° ± 13.0 and mean left DFF/DFE were −1.5° ± 12.8 and −6.5° ± 12.1. Immediate improvement following BTX-A (2 weeks) were seen as right foot DFF/DFE were 14.1° ± 10.0 and 6.3° ± 7.7 and left DFF/DFE were 9.6° ± 14.1 and 3.9° ± 10.6. At 4 weeks, right DFF/DFE were 16.6° ± 9.5 and 11.7° ± 9.1 and left DFF/DFE were 13.1° ± 8.6 and 7.3° ± 8.3. At the half-life of BTX-A (12 weeks), right DFF/DFE were 15.2° ± 12.2 and 10.8° ± 10.5 and left DFF/DFE were 15.8° ± 12.4 and 13.0° ± 11.6. At follow-up visits, correction was maintained as right DFF/DFE were 15.6° ± 9.1 and 10.4° ± 10.3 and left DFF/DFE were 16.9° ± 11.2 and 9.8° ± 10.7.

Conclusion: This is the first study to show early outcomes (improved DFF/DFE) following BTX-A injections in ITW and provides evidence for obtaining and maintaining the correction from a single BTX-A injection over a short-term follow-up period.