Effective Botulinum Toxin Treatment in Patients With Different Patterns of Cervical Dystonia: A Retrospective SPECT...

The Col-Cap classification for cervical dystonia (CD) has been proposed to optimize treatment strategies with botulinum toxin type A (BTX-A). Although this concept has been used for 15 years, the efficacy of BTX-A in various CD patterns remains unclear. The present study compared the efficacy of BTX-A, aided by single-photon emission computed tomography (SPECT) and electromyography (EMG), in various CD patterns.

CD patients who underwent SPECT scans to detect dystonic muscles were included. Candidate muscles were first selected based on clinical evaluation and abnormal radioactivity on SPECT imaging. All patients were injected under the guidance of EMG, and only candidate muscles with positive EMGs were injected. The efficacy of BTX-A was assessed via the subjective clinical improvement rate and the reduction in the Tsui score at four weeks after injection.

The study enrolled 252 patients. The subjective improvement rates were 63.5%±20.6% for simple types and 59.9%± 22.2% for complex types, and this difference was not significant (p=0.247). The reduction rates of the Tsui score did not differ between the simple type (52.4%±24.2%) and the complex type (49.6%±23.6%, p=0.556). Moreover, clinical improvement rates did not significantly differ within each group of simple subtypes, complex subtypes, or patients with different types of tremors (p>0.05).

The efficacy of BTX-A treatment was comparable in different CD patterns because of the appropriate selection of dystonic muscles via SPECT and EMG. Therefore, employing multifaceted approaches to identify dystonic muscles can yield favorable outcomes, even in complex cases.