The Muscle in Children With Cerebral Palsy - Longitudinal Exploration of Microscopic Muscle Structure.

Cerebral palsy (CP) is a motor impairment due to a brain malformation or a brain lesion before the age of two. Spasticity, hypertonus in flexor muscles, dyscoordination and an impaired sensorimotor control are cardinal symptoms. The brain lesion is non-progressive, but the flexor muscles of the limbs will during adolescence become relatively shorter and shorter (contracted), forcing the joints into a progressively flexed position. This will worsen the positions of already paretic and malfunctioning arms and legs. Due to bending forces across the joints, bony malformations will occur, worsening the function even further. Since about 25 years a combination treatment with intramuscular botulinum toxin injections, braces and training has had a tremendous and increasing popularity, although lasting long-term clinical advantage is not yet proven. Muscle morphology of the biceps brachii and the gastrocnemius muscles: * The hypothesis is that care as usual, i.e. training and splinting sessions with botulinum toxin as adjuvant treatment, will reduce (normalize) the expression of the fast fatigable myosin heavy chain MyHC IIx and increase the expression of developmental myosin, as a possible sign of growth. As the biceps in the arm is used irregularly and voluntarily, and the gastrocnemius is activated during automated gait, the adaptations of those muscles will be different. Methods: Baseline muscle biopsies: Percutaneous biopsies are taken just before the first intramuscular botulinum toxin injection is given. The doses and the intervals for the botulinum toxin treatment will follow clinical routines. Biopsies 4-6 months, 12 months and 24 months after the first botulinum toxin injection: The exact same procedure as above will be performed, but the biopsies will be taken 2 cm distant, medial or lateral, from previous biopsy sites * Significance:. More knowledge is warranted regarding the actual molecular process in the muscle leading to a contracture, and its relation to t