Aims: Cervical pain is one of the most common non-motor symptoms of cervical dystonia (CD) and affects from 54.6% to 88.9% of patients. To date, minority of studies investigated the relevance of pain in a long-term botulinum toxin (BoNT) therapy of CD. The aim of the study was to define an impact of cervical pain on the disease severity and disability, as well as to assess antinociceptive BoNT efficacy in a long-term treatment of CD.
Materials and methods: In this case-control study, CD patients who received stable doses of BoNT for at least 3 years were assessed with the use of validated scales. Participants were divided into two groups depending on the occurrence of CD-related pain.
Results: We examined 50 participants who received a mean of 24 injection cycles (6-51) of BoNT during a mean treatment period of 10.3 years (3.0-23.5). Participants with cervical pain (68.0%) were characterized by higher scores in all scales used in this study: TWSTRS severity (p = 0.030), disability (p < 0.001), total (p < 0.001) and TSUI score (p = 0.046). Pain reduction following BoNT injection lasted longer than muscle relaxation in 85.3% of patients. Pain improvement between first and last BoNT injection cycle was reported by 76.5% of patients with CD-related pain.
Conclusions: The presence of cervical pain in CD may increase the severity of muscular symptoms and disease-related disability. BoNT has a noticeable antinociceptive effect in the long-term treatment of CD.
Keywords: Cervical dystonia; botulinum toxin A; pain.