Clinical features of cervical dystonia patients classified by the COL-CAP concept and treated with ultrasound-guided botulinum neurotoxin.

Background and purpose:

Cervical dys­tonia (CD) is the most common form of focal dystonias, where the identification of the involved muscles, the determination of optimal botulinum neurotoxin A (BoNT-A) dose per muscle injection, and precise tar­ge­ting may be challenging. The aim of the current study is to compare local centre data with international data, enabling the iden­tification of population and me­tho­do­­lo­gical factors behind the differences, there­by further improvement of the care of Hun­ga­rian patients with CD.

The data of all consecutive CD patients, who were injected with BoNT-A at the botulinum neurotoxin outpatient clinic at the Department of Neurology, University of Szeged between 11 August and 21 Sep­tember 2021, were retrospectively col­lected and analysed in a cross-sectional manner. The frequency of the involved muscles, determined by the application of the collum-caput (COL-CAP) concept, and the parameters for the BoNT-A formulations, injected via ultrasound (US)-guidance, were calculated and compared with available international data.

In the current study, 58 patients (19 males and 39 females) were involved with mean age of 58.4 (± SD 13.6, range 24-81) years. The most common subtype was torticaput (29.3%). Tremor affected 24.1% of patients. The most injected muscles were trapezius (56.9% of all cases), followed by the levator scapulae (51.7%), splenius capitis (48.3%), sternocleidomastoid (32.8%), and semispinalis capitis (22.4%). The injected mean doses per patient were 117 ± SD 38.5 (range: 50-180) units for onaBoNT-A, 118 ± SD 29.8 (range: 80-180) units for incoBoNT-A, and 405 ± SD 162 (range: 100-750 units) for aboBoNT-A.

Although there were several similarities between the results of the current and the multicentre studies, all were carried out using the COL-CAP concept and US-guided BoNT-A injections, authors should pay attention to better distinction of torti-forms and the more frequent injection of especially the obliquus capitis inferior, mainly in cases with no-no tremor.