Ultrasound-guided botulinum toxin injections in neurology: technique, indications and future perspectives

Abstract

Botulinum toxin (BT) therapy is used in neurology to treat muscle hyperactivity disorders including dystonia, spasticity, cerebral palsy, hemifacial spasms and re-innervation synkinesias as well as exocrine gland hyperactivity disorders. To increase its therapeutic effect and to decrease adverse effects in adjacent tissues, exact BT placement is important. Ultrasonography (US) allows non-invasive, real-time imaging of muscular and glandular tissues and their surrounding structures. It can visualize, guide, and standardize the entire procedure of BT application. Small randomized studies suggest that US-guidance can improve therapeutic efficacy and reduce adverse effects of BT therapy when compared to conventional placement. US-guidance should be used in forearm muscles when functionality is important, and in selected leg muscles. It may be used for targeting distinct neck muscles in cervical dystonia. It is helpful for targeting the salivary glands. Here we review the technique, indications and future developments of US-guidance for BT injection in neurological disorders.

Keywords::

• botulinum toxin
• cerebral palsy
• dystonia
• hypersalivation
• needle navigation
• placement
• spasticity
• task-related dystonia
• ultrasonography
• ultrasound-guidance

Financial & competing interests disclosure

U Walter has received speakers honoraria from Ipsen and Merz Pharma, and travel support from Allergan. D Dressler has received consultancy fees from Allergan, Ipsen, Merz, Eisai, Addex and Syntaxin Pharma. The authors have no other relevant affiliations or financial involvement with any organization or entity with a financial interest in or financial conflict with the subject matter or materials discussed in the manuscript. This includes employment, consultancies, honoraria, stock ownership or options, expert testimony, grants or patents received or pending or royalties.

No writing assistance was utilized in the production of this manuscript.

Key issues

• Ultrasonography (US) allows real-time imaging and guidance of the entire procedure of botulinum toxin (BT) application into target muscles and glands.

• US guidance should be used in forearm muscles when functionality is important, especially in writer’s or musician’s cramp and mild forearm spasticity.

• US guidance should be used especially in children for targeting selected leg muscles including psoas, lateral gastrocnemius and posterior tibial.

• US guidance is the only way for treating omohyoid muscle syndrome.

• US guidance may be used in patients with cervical dystonia when the anterior or middle scalene, longissimus capitis and the obliquus capitis inferior are target muscles.

• US guidance may also be used for targeting the submandibular and, optionally, the parotid gland.

• Small randomized studies suggest that US guidance can improve therapeutic efficacy and reduce adverse effects of BT therapy when compared to conventional placement.

• Large-scale studies comparing US with other techniques for guidance of BT application are warranted.

• In near future, electromagnetic needle position-tracking devices will become commercially available that allow the freehand needle navigation based on real-time image fusion of US with previously acquired MRI or computed tomography volume data sets.

• Upcoming advanced US technologies may enable even the detection of most hyperactive muscles on US for planning the optimum targets of BT application.

Notes