Accuracy of Ultrasound-Guided and Non-ultrasound-Guided Botulinum Toxin Injection Into Cadaver Salivary Glands

OBJECTIVE: To compare the accuracy of ultrasound (US)-guided and non-US-guided botulinum toxin (BTX) injection into the salivary glands (parotid and submandibular glands) of cadavers. METHODS: Two rehabilitation physician injected dye into three sites in the salivary glands (two sites in the parotid gland and one site in the submandibular gland) on one side of each cadaver (one was injected on the right side, while the other was injected on the left side), using either a non-US-guided injection procedure based on superficial landmarks or a US-guided procedure. Orange dye was used for the US-guided procedure, and green dye was used for the blind procedure. Two physicians uninvolved with the injection procedures and who were blinded to the method of injection dissected the cadavers to identify whether the dye was accurately injected into each target site. RESULTS: The accuracies of the blind and US-guided injections into the parotid gland were 79.17% and 95.83%, respectively. In the submandibular gland, the accuracies of the blind and US-guided injections were 50.00% and 91.67%, respectively. The difference in accuracy between the two procedures was statistically significant only in the submandibular gland (p=0.025). There were no significant differences in the accuracy of US-guided and non-US-guided injections between the two physicians for the two sites in the parotid gland (p=0.278 and p=0.146, respectively). CONCLUSION: US-guided BTX injection into the submandibular gland offers significantly greater accuracy over blind injection. For the treatment of drooling by injecting BTX into the submandibular gland, clinicians should consider using US guidance for improved accuracy.