Ultrasound-guided botulinum toxin treatment in neurology: established indications and techniques

Botulinum toxin (BT) therapy is used in neurology to treat muscle hyperactivity disorders including dystonia, spasticity and cerebral palsy, nerve entrapment syndromes caused by muscles, as well as exocrine gland hyperactivity disorders. Ultrasonography ( US) can visualise and guide the entire procedure of BT application into muscles and glands. The results of several studies suggest that US-guidance can improve efficacy and reduce adverse effects of BT therapy when compared to conventional placement. US is meanwhile established for guiding the BT injection into the parotid and submandibular glands in neurological disorders with sialorrhea. Moreover, US-guidance of BT-injection is recommendable for use in patients with complicated forms of cervical dystonia and dystonic head tremor, especially for exactly targeting the scaleni, obliquus capitis inferior, and longissimus capitis muscles. US-guidance can be regarded as being state-of-the-art in the treatment of single forearm muscles (e.g., single finger flexors) if their functionality matters, especially in task-related dystonia, and mild spasticity. US is recommended for guidance of BT injection in selected leg muscles. Here the technique and indications of US-guidance for BT injection in neurological disorders are reviewed.