Injection technique in paediatric spasticity

Objectives: The intramuscular application of botulinum toxin type A (BoNT/A) is an established treatment option to reduce muscular hyperactivity in children with spasticity. Accurate injection is a prerequisite for efficient and safe treatment with BoNT/A. So far, treatment procedures have not been standardized.

This is a review and video demonstration of injection techniques and their suitability in children with spasticity.

Methods: Different injection techniques, i.e. manual needle placement as well as guidance by electromyography, electrical stimulation, and ultrasound, are weighted in terms of the clinical impact for children with spasticity. Advantages and disadvantages of the different injection techniques are discussed with a focus on needle positioning within the targeted muscle and injection close to the neuromuscular junction. The review is based on evidence of actual literature and own experience of the years 2000–2006.

Results: Manual needle placement proved to be inaccurate – especially in general anaesthesia, whereas electrical stimulation and ultrasound guidance are reliable localization techniques. The usefulness of EMG in particular in children with CP is limited. EMG and electrical stimulation require a high degree of expertise by the user. They are time consuming and often need repositioning of the needle prior to injection.

Conclusion: Using ultrasound, typical patterns of the targeted muscle can be recognized easily with in a short period of time without the need of painful needle repositioning. Especially in areas with small muscles (e.g. forearm, head and neck) ultrasound has the potential to evolve into a procedure that may equal the current gold-standard of EMG and electrical stimulation in adult neurology. For children it may develop to be the gold-standard.

Characteristics of different approaches to guide BoNT/A injections (+: advantageous, 0: acceptable, –: unfavourable
	EMG	Muscle stimulation	Ultrasound
Accuracy of needle placement	0	+	+
Time required for muscle identification	–	0	+
Availability of technical equipment (children's hospital)	0	0	+
pain and distress caused by procedure	–	–	+
Dependency on epert knowledge	–	–	0
Necessary number of stabs	–	–	+
Control of injection depth	0	0	+
Differentiation of neighboring (co-contracting) muscles	0	0	+
Differentiation from surrounding structures (vessels, nerve, bone)	–	–	+
Independency on patient cooperation	–	+	+
Possibility to ascertain correct placement after injection	–	–	+
Possibility to document the injection	–	–	+
Control of proximity to neuromuscular junctions	+	+	–
Control of muscular hyperactivity	+	0	–
Control of muscle dimension	0	0	+
Conrtol of muscle fibrosis	0	0	+
Potential for further development and research	0	–	+