Functional outcomes of upper extremity cerebral palsy

Intramuscular botulinum toxin A injections (BTI) are commonly used to treat spasticity in patients with cerebral palsy. They are used to reduce excessive muscle activation caused by spasticity or involuntary contractions. Anecdotal clinical evidence suggests that continuous use of BTI can contribute to muscle and tendon weakness. This can detrimentally affect the potential candidacy of tendons for use in future surgical intervention, such as tendon transfers. At present, it is not known for certain how BTI affects the material properties of tendons and no evaluation is performed to assess tendon material properties prior to surgery.
The aim of this study is firstly, to validate the use of a state-of-the-art ultrasound-based imaging technique (shear-wave elastography) as a measurement tool for the mechanical properties of tendons in the upper extremity. In vitro measurements will be assessed against results from direct measurement in a materials testing machine. Secondly, this non-invasive imaging technique will be used to quantify the mechanical changes in the tendons at various time points after BTI in children with spastic upper extremity cerebral palsy. The last aim is to use the results and computational models to identify limits of suitability for a tendon to aid in surgery treatment. This project has the potential to have direct clinical impact through combining mechanical and in-vivo testing with computational modelling.