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

Abstract

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. Methods – 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. Results – 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. Conclusion – 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 tortiforms and the more frequent injection of especially the obliquus capitis inferior, mainly in cases with no-no tremor.