Characteristics of Dysphagia Secondary to Ultrasound-guided Botulinum Injections for Cervical Dystonia

Treatment with Botulinum Toxin (BT) is safe and effective. Nonetheless, dysphagia is perhaps the most common side effect of BT injections for Cervical Dystonia (CD). We aimed to characterize the population at risk of suffering from dysphagia following BT injections of cervical muscles.

This is a retrospective observational study. We retrieved demographic and clinical data from the files of all patients diagnosed with CD who attended the Movement Disorders Unit at Shaare Zedek Medical Center during the years 2019 to 2025, and who were regularly treated with BT. The Sternocleidomastoids (SCMs) were injected either under Ultrasound Guidance (USg) or unguided, according to Anatomic Landmarks (AL). Thirty patients (18 females, 243 treatments) were included.

Dysphagia was reported in 12.6% of treatments, with a higher incidence in females compared to males (16.9% vs. 5.3%, p = 0.02). All reports of dysphagia (n = 25) were mild. Unguided SCM injections caused significantly less dysphagia than USg SCM injections (7.6% and 18.1%, respectively, p = 0.02). Among elderly patients (≥ 60 years), the incidence of dysphagia was also lower with unguided injections compared to US-guided injections (6.5% vs. 31.3%, p = 0.03).

Unguided BT injections into the Sternocleidomastoid (SCM) muscle resulted in a lower incidence of dysphagia compared to Ultrasound-guided (USg) injections. Additionally, elderly patients and women are at a heightened risk of experiencing dysphagia.

Dysphagia appears to be a common side effect of US-guided BT injections, and it is possibly related to SCM injections. Caution should be particularly made in older females. We recommend treating the SCM muscles without guidance, particularly in older female patients.