The morphology of the medial gastrocnemius in typically developing children and children with spastic hemiplegic cerebral palsy.

We collected 3D ultrasound images of the medial gastrocnemius muscle belly (MG) in 16 children with spastic hemiplegic cerebral palsy (SHCP) (mean age: 7.8 years; range: 4-12) and 15 typically-developing (TD) children (mean age: 9.5 years; range: 4-13). All children with SHCP had limited passive dorsiflexion range on the affected side with the knee extended (mean+/-1SD: -9.3 degrees +/-11.8). Scans were taken of both legs with the ankle joint at its resting angle (RA) and at maximum passive dorsiflexion (MD), with the knee extended. RA and MD were more plantar flexed (p<0.05) in children with SHCP than in TD children. We measured the volumes and lengths of the MG bellies. We also measured the length of muscle fascicles in the mid-portion of the muscle belly and the angle that the fascicles made with the deep aponeurosis of the muscle. Volumes were normalised to the subject's body mass; muscle lengths and fascicle lengths were normalised to the length of the fibula. Normalised MG belly lengths in the paretic limb were shorter than the non-paretic side at MD (p=0.0001) and RA (p=0.0236). Normalised muscle lengths of the paretic limb were shorter than those in TD children at both angles (p=0.0004; p=0.0003). However, normalised fascicle lengths in the non-paretic and paretic limbs were similar to those measured in TD children (p>0.05). When compared to the non-paretic limb, muscle volume was reduced in the paretic limb (p<0.0001), by an average of 28%, and normalised muscle volume in the paretic limb was smaller than in the TD group (p<0.0001). The MG is short and small in the paretic limb of children with SHCP. The altered morphology is not due to a decrease in fascicle length. We suggest that MG deformity in SHCP is caused by lack of cross-sectional growth.

Changes to medial gastrocnemius architecture after surgical intervention in spastic diplegia.

We assessed the architecture of the medial gastrocnemius in nine children (five males, four females; age range 6 to 15 years; mean 10 years 10 months, SD 3 years 6 months) with spastic diplegia by ultrasound imaging before and after a gastrocnemius recession. The children were ambulant (seven independent, one with a posterior walker, one using crutches) before and after surgical intervention. We compared values for fascicle lengths and deep fascicular-aponeurosis angles with those from a group of normally developing children (five males, five females; age range 6 to 11 years; mean 8 years 4 months, SD 1 year 4 months). Despite a variable interval between assessments (from 56 to 610 days), fascicles were shorter (p=0.00226) and the deep fascicular-aponeurosis angle increased (p=0.0152) after intervention. Fascicle lengths of patients were similar to those in the group of normally developing children before surgery. After surgery, fascicles in the group of children with spastic diplegia were shorter than in their normally developing peers (p=0.00109). The gastrocnemius recession procedure alters muscle architecture, though the degree of fascicular shortening varied, with four of the participants in our study losing less than 10% of their original fascicular length at maximum dorsiflexion. Increases in ankle-joint power in walking, observed after surgical intervention in children with spastic diplegia, may be due to a more normal ankle position rather than to improvements in the active mechanical performance of the gastrocnemius.

Short-term outcome of multilevel surgical intervention in spastic diplegic cerebral palsy compared with the natural history.

Outcome in 24 ambulant children with spastic diplegic cerebral palsy, in whom multilevel surgical intervention was recommended following gait analysis, is reviewed. Twelve children had surgical intervention (treatment group; eight males, four females; mean age 9 years 10 months, SD 3 years 4 months) while the other 12 did not (control group; five males, seven females; mean age 10 years 1 month, SD 2 years 11 months). All children had interval three-dimensional gait analyses (mean time between analyses: control group, 14.1 months; treatment group, 17.9 months). At follow-up the control group (mean age 11 years 9 months) showed a significant increase in minimum hip and knee flexion in stance which was not related to age, the interval between analyses, changes in the passive joint range of motion, nor changes in anthropometric measurements. The treatment group (mean age at follow-up 11 years 3 months) showed a significant improvement in minimum knee flexion and in ankle dorsiflexion in stance. Parents of nine children said their child's walking distance had increased following intervention. Of five children using posterior walkers preoperatively, two continued to use them postoperatively; two were using crutches or sticks and the remaining child walked independently. Two children who walked independently preoperatively used sticks postoperatively for community ambulation. The deterioration seen in the kinematics of the control group suggests that previous outcome studies comparing postoperative gait with preoperative gait have underestimated the immediate effects of surgery. It also raises concerns about the long-term effects of surgical intervention.