Injection techniques for botulinum toxin using electromyography and electrical stimulation

Increasing data supports the use of botulinum toxin injection as a therapeutic intervention in the management of spasticity. The avid binding of botulinum toxin (BTX) to presynaptic neuron terminals and the diffusion characteristics of the medication allow relative ease of administration. For many clinical applications, efficacy may be improved, and adverse effects reduced, by more precise targeting of the muscles to be injected. Electromyographic guidance (EMG) is commonly used to confirm appropriate localization of the injection needle in specific muscles immediately before injection. Electrical stimulation (ES) may be more useful in patients who are unresponsive or sedated. Equipment options and technical aspects of EMG and ES are discussed, including some adjunctive imaging methods for injecting difficult-to-localize muscles.