Objective: The aim of the study was to present the background, procedure, and technique of bilateral ultrasound-guided, single-dose injections of botulinum toxin type A (BTX) into the salivary glands in patients with severe drooling.
Study design: Clinical trial.
Methods: Initially, an in vitro study was performed to determine the volume of the dilution of BTX required for optimal spreading and to gain insight in the spreading pattern of the fluid in the submandibular gland. Subsequently, patients with severe drooling were included in a clinical study. Salivary flow was measured under standardized conditions, and BTX was injected into the submandibular glands with the patient under general anesthesia and with ultrasound guidance as an outpatient procedure or during a short stay at the daytime care unit.
Results: BTX for each gland should be diluted in a volume of 1 to 1.5 mL saline to achieve adequate spreading within the gland and to diminish the risk of diffusion into surrounding structures. With ultrasound guidance, separate structures surrounding the glands and structures within the glandular parenchyma are well recognized and injection errors can be avoided.
Conclusions: With the procedure described, it is possible to accurately inject BTX directly into the glandular parenchyma and to visualize spreading of the fluid in the glandular parenchyma. It is found to be a safe method that guarantees an optimal clinical effect and avoids potentially harmful side effects. We recommend ultrasound guidance if injections of BTX into the salivary glands are considered.