Medial gastrocnemius muscle volume and fascicle length in children aged 2 to 5 years with cerebral palsy

Abstract

MDF Maximum dorsiflexion MPF Maximum plantarflexion PCSA Physiological cross-sectional area AIM The aim of this article was to compare medial gastrocnemius muscle volume, physiological cross-sectional area (PCSA), muscle length, fascicle length, and pennation angle in children aged 2 to 5 years with spastic cerebral palsy (CP) and in typically developing children.METHOD Fifteen children with spastic CP (11 males, four females; mean age 45mo [SD 15mo]; five with hemiplega; 10 with diplega; 10 classified at Gross Motor Function Classification System (GMFCS) level I, five at GMFCS level II) and 20 typically developing children (11 males, nine females; mean age 48mo [SD 14mo]) participated in the study. Individuals with spastic CP were included if they had a minimum range of motion of 0°ankle dorsiflexion with the knee extended and were excluded if they had had previous botulinum toxin treatment to the calf muscles or previous calf surgery. Typically developing children were included if they were able to walk independently and were excluded if there was a history of previous lower leg injury or other developmental disorder affecting the lower limb. Freehand two-dimensional and threedimensional ultrasound was used to assess muscle properties of the relaxed medial gastrocnemius muscle at three ankle joint angles: maximum dorsiflexion, neutral and maximum plantarflexion. PCSA was calculated as a function of muscle volume and muscle fascicle length and pennation angle was recorded at the neutral ankle joint angle.RESULTS Medial gastrocnemius muscle volume was 22% lower in the group with spastic CP than in the typically developing group, which in the absence of significant group differences in neutral fascicle length gave rise to an equivalent reduction in PCSA for the group with spastic CP. Significant positive correlations were found between muscle volume and age (r=0.63-0.65) and between muscle length and age (r=0.72-0.81) in both groups. Maximum ankle dorsiflexion angle was also reduced in the group with spastic CP (8°) compared with the typically developing group (26°). INTERPRETATIONThe observed reduction in muscle PCSA in the group with spastic CP would be expected to contribute to the clinically observed muscle weakness in spastic CP and suggests the need for early intervention in order to minimize loss of muscle PCSA in spastic CP.Spastic cerebral palsy (CP) is a group of non-progressive motor impairment syndromes that occur secondary to lesions of the brain in the early stages of development.1 Spasticity is the key feature of spastic CP and is neural in origin. However, it is clear that spastic muscle also undergoes significant morphological and structural alterations during development. Involved muscles often shorten to create muscle contractures, which contribute to increased joint stiffness and reduced joint range of motion and may contribute to reduced voluntary strength. These impairments progress over time, and limb movement and general functional ability often decline.2-4 As the secondary effects of spas...

Muscle-specific changes in length-force characteristics of the calf muscles in the spastic Han-Wistar rat

“…Consistent with previous findings in human patients (1, 2, 13), we found reduced maximal active forces of GA and PL in spastic rats. Loss of muscle volume has been reported in humans with spasticity (4,31,34,35) and, therefore, atrophy is believed to be the main cause of muscle weakness. In the present study, maximal active force of GA was decreased by 31%, whereas GA muscle mass was decreased by only 14%, albeit not significantly.…”

Muscle volume alterations in spastic muscles immediately following botulinum toxin type‐A treatment in children with cerebral palsy

“…23 Over the last decade, weakness has been increasingly recognised as a significant motor impairment, [22][23][24] purportedly affecting functional ability in children with CP. 25,26 A recent review of the literature on spastic CP found consistent evidence for small muscle size as indicated by reduced muscle volume, crosssectional area, thickness, and belly length in comparisons of paretic muscles with non-paretic and typically developing muscles. 24 Barber et al 25 described volumetric deficits of 22% in the medial gastrocnemii of young children (2-5y) with spastic CP compared with typically developing children.…”

Challenges of instrumented spasticity assessment

“…In their study, WillerslevOlsen et al demonstrate the important contribution of nonreflex mediated torque to muscle stiffness in the soleus muscle in CP, at a very young age. In line with this conclusion, Barber et al 3 have recently highlighted the altered gross morphology of the distal lower limb muscles in very young (2-5y) children with CP. These authors thereby challenge a prevalent view that the development of altered muscle structure is predominantly caused secondary to altered muscle behavior, such as hypertonia.…”