Changes in the Volume and Length of the Medial Gastrocnemius After Surgical Recession in Children With Spastic Diplegic Cerebral Palsy

Abstract

Morphology is an important determinant of muscle force and power generation. Children with spastic diplegic cerebral palsy (SDCP) have reduced muscular strength, which in part is caused by inadequate muscle growth. There is a widespread concern that surgery to correct soft tissue deformities may exacerbate the underlying muscle weakness and further retard muscle growth. In this study, we compared measurements of medial gastrocnemius (MG) muscle morphology in typically developing (TD) children to those in children with SDCP with calf muscle deformities before and after corrective surgery. We measured the length and volume of the MG muscle belly using 3-dimensional ultrasound immediately before and at 7 weeks and 1 year after vulpius procedure (VP) surgery in children with SDCP. We made similar measurements in a group of TD children. The SDCP group consisted of 7 children (6 boys, 1 girls; total of 8 limbs; age range, 6-10 years; mean 8 years 1 month, SD +/- 1 year 11 months) and the TD group consisted of 10 children (4 boys, 6 girls; age range, 6-12 years; mean, 9 years 5 months; SD +/- 2 years 6 months). The children with SDCP presented with MG muscle bellies both smaller and shorter than the TD children even when normalized to body mass and limb length, respectively. Muscle belly length was reduced by surgery and remained unaltered 1 year later, despite skeletal growth. Muscle volume was not significantly changed 7 weeks after surgery, but increased significantly between 7 weeks and 1 year after surgery. Children with SDCP presented with short and small MG when compared with TD children. Our results indicate that gastrocnemius muscle volume recovers within a year of VP surgery. This study is the first to investigate the effects of surgery on muscle belly volume and length in the human subject. The study indicates that VP surgery is not an agent of long-term muscle atrophy in individuals with SDCP with plantarflexion deformities.