Preoperative botulinum toxin test injections before muscle lengthening in cerebral palsy

Muscle weakening is a well-known side effect of muscle-tendon lengthening. Botulinum toxin A (BTX-A) weakens the muscle temporarily by blocking the neuromuscular junction. Hence application of the drug is a logical step to test whether weakness deteriorates function prior to an operation. In the present study, BTX-A application is used to test preoperatively whether the gait pattern depends on the strength of the tested muscle. Since 1999, instrumented gait analysis, including kinematic, kinetic, and dynamic electromyographic data, is routinely used to define the individual surgical program.