Aspects of the complexity of cervical dystonia

Most cases of cervical dystonia (CD) can easily be treated by injections of botulinum toxin A (BTX-A) into a few cervical muscles among which the splenius capitis, the semispinalis capitis the levator scapulae and the scalenii muscles are the most important ones whereras the trapezius and the sternocleidomastoideus muscles are of less importance. However, in some cases of CD the treatment of these easily injectable muscles does not lead to a satisfactory clinical outcome. Damage of and compensatory increase of connective tissue in muscles, additional activation of non-injected muscles by special motor tasks as lying, sitting, standing, walking and speaking and involvement of deep muscles remaining usually untreated may add to the complexity of treatment of cervical dystonia.