Echoes of Doubt: Does Ultrasound Truly Enhance Botulinum Toxin Outcomes in Cervical Dystonia?

Abstract

Introduction: Botulinum neurotoxin (BoNT) injection is the gold standard treatment for cervical dystonia (CD). Treatment failures often result from anatomical variations, inadequate technique, incorrect muscle targeting, or suboptimal dosing. Ultrasound guidance has been proposed as a means to address these issues by increasing precision, although its clinical superiority remains debated due to limited robust evidence.

Objective: To assess the clinical impact and potential advantages of ultrasound-guided BoNT injections for CD compared to standard anatomical landmark-based methods.

Methodology: A narrative review was performed by searching PubMed for studies evaluating ultrasound-guided BoNT injections in patients with CD.

Results: Ultrasound guidance significantly enhances injection accuracy, especially for deep cervical muscles such as the obliquus capitis inferior, and semispinalis capitis, reducing variability both within and between operators. It enables better targeting of deep anatomical structures, consequently minimizing adverse effects like dysphagia and unintended muscle weakness. Clinical response rates with ultrasound guidance range from 82–97%, compared to 48–62% using traditional landmark methods. However, improvements in clinical outcomes are not always directly proportional to improved accuracy, suggesting the greatest benefit occurs in refractory cases or anatomically challenging patients.

Conclusions: Ultrasound-guided BoNT injections demonstrate significant advantages in precision, safety, and clinical outcomes. The favorable risk-benefit ratio supports broader adoption, especially for injections targeting deeper or thinner muscles, structures near critical anatomical landmarks, patients with obesity, or complex and refractory CD cases.