Botulinum neurotoxin in cervical dystonia revisited - recent advances and unanswered questions.

Cervical dystonia (CD) usually presents a complex pattern of head/neck movements accompanied by tremor, myoclonic jerks and a wide spectrum of non-motor disturbances such as pain, depression, anxiety, and sleep problems. This is the most challenging indication for botulinum neurotoxin (BoNT) treatment. It can offer significant improvement, but it can be difficult after the first injection. Thorough examination and identification of the proper CD pattern, the identification of the muscles responsible, and adjusting doses given precisely under ultrasound and/or electromyographic guidance seem to be the key success modifiers. Nevertheless, this is a lifelong treatment and should be planned and conducted carefully to avoid failures and drop outs. The aim of this paper was to examine the current concepts in terms of anatomy, physiology and CD patterns (Col-Cap concept) as well as the proper dosages and any possible obstacles impeding successful treatment.