Percutaneous Salivary Gland Ablation using Ethanol in a Rat Model

Objectives Sialorrhea is a common health and psychosocial problem for children with neuromuscular dysfunction secondary to a variety of disorders such as cerebral palsy. Current accepted treatments include the injection of botulinum toxin into the submandibular glands for temporary symptom relief. The purpose of this study is to demonstrate the feasibility of percutaneous ethanol injection for longer lasting salivary gland ablation in an animal model. Material and Methods Twenty rats were used in this study. In each rat, 98% ethanol was injected into the right submandibular gland under ultrasound guidance. No intervention was performed on the left gland, which served as the control. Ten rats were sacrificed and glands evaluated at three weeks, with the remaining 10 rats sacrificed and evaluated at three months. Unpaired, 1-tailed T-tests were used to analyse the data. Results Ethanol injections induced a significant and sustained reduction in salivary gland size. Treated glands were 41% smaller by mass than untreated controls in the 10 rats sacrificed at three weeks (P < 0.001). Treated glands were 43% smaller by mass than untreated controls in the 10 rats sacrificed at three months (P < 0.001). Qualitative histologic analysis demonstrated extensive parenchymal damage, inflammation, and fibrosis at both three week and three month time points. Conclusions Using a rat model, we demonstrated dramatic and sustained submandibular gland damage after percutaneous injection of ethanol.