Research Report Abstracts - Gesundheit

eS104
Results: Mean muscle length (SD) averaged across the three
ankle joint angles was 237 ± 25 mm in the TD group and
207 ± 42 mm in the CP group. The US-tape method overestimated
MG muscle length by 0.2 mm (8 years).
Participants: Fifteen SCP children (45 ± 4 months) and
twenty TD children (48 ± 3 months) were recruited for
morphological measurements of the medial gastrocnemius
muscle.
Methods: Freehand 2D and 3D ultrasound was used to assess
muscle belly volume and length, muscle fascicle length and
pennation angle of the relaxed MG muscle at three ankle
joint angles, maximum dorsiflexion, neutral and maximum
plantarflexion.
Analysis: A general linear model with relevant covariates
was used to assess the effect of between and within group
factors and their interactions on the dependent measures. Pairwise
comparisons were used to assess group differences in
each measure at the three ankle joint angles.
Results: MG muscle volume was significantly lower in the
SCP group compared to the TD group, 25 ± 2mL versus
33 ± 2 mL when corrected for body weight. MDF angle was
also significantly reduced in the SCP group 8 ± 2 ◦ , TD group
26 ± 1 ◦ . Pairwise comparisons showed significantly longer
fascicle length (36 ± 1mm vs 28 ± 1 mm) and smaller pennation
angle (13 ± 1 ◦ vs 18 ± 1 ◦ ) at MPF ankle angle in the
SCP compared to the TD group.
Conclusions: The primary difference in muscle morphology
and structure identified in the present study was the 22%
lower muscle volume in SCP compared to TD. These differences
in muscle volume are likely to contribute to the
clinically observed weakness in SCP and suggest the need for
early intervention to minimise muscle volume loss in SCP.
The findings that the SCP group had smaller changes in fascicle
length and pennation angle from MPF to MDF suggest
that the passive mechanical properties of the muscle-tendon
unit of the MG were different compared to the TD group.
Implications: The practical significance of these findings
is that lack of volumetric muscle growth in young children
with SCP and the associated muscle weakness are likely to
contribute to functional limitations observed in young children
with SCP. Given that muscle weakness tends to progress
over time, and can be a barrier to mobility and independent
living in later stages of development, an important goal
of treatment and management of SCP in young children
may be to facilitate muscle growth through use of suitable
exercise interventions. These findings also suggest that treatments
with the potential to compromise muscle growth (e.g.
Botulinum toxin) may need to be carefully considered when
used for young children with SCP.
Keywords: Muscle morphology; Ultrasound; Cerebral palsy
Funding acknowledgements: This work was supported by
funding from the National Health and Medical Research
Council, Australia (Biomedical Postgraduate Scholarship
Grant ID: 481953).
Ethics approval: Griffith University HREC (GU Ref No:
PES/29/07/HREC), The Royal Children’s Hospital, Melbourne
HREC (HREC RCH:27062, HREC: 07083C).