Ethanol ablation guided by sonographic appearance of the nodule is effective for treatment of primary hyperparathyroidism in dogs

Objective: To evaluate the efficacy and safety of a modified percutaneous ultrasound-guided ethanol ablation technique for the treatment of primary hyperparathyroidism in dogs. Methods: This prospective observational study was conducted at a single veterinary referral center. Dogs with persistent ionized hypercalcemia, normal/increased parathyroid hormone concentrations, normal/undetectable parathyroid hormone-related protein concentrations, and ultrasonographic identification of ≥ 1 presumed hyperfunctioning parathyroid nodule (≥ 2.5 mm) underwent percutaneous ultrasonographically guided ethanol ablation, in which ethanol was administered until real-time diffuse intralesional hyperechogenicity was achieved. Dogs with alternative causes of hypercalcemia were excluded. Data collected from October 2018 through April 2023 included signalment, lesion characteristics, ethanol volume administered, complications, and biochemical outcomes. Resolution of hypercalcemia following ablation was the primary outcome measure. Results: 49 dogs were enrolled, and follow-up data were available for 47. Hypercalcemia resolved in 42 of 47 dogs (89.4%). Complications occurred in 12 of 47 dogs (25.5%) and were classified as minor in 10 and major in 2. Dogs with resolution of hypercalcemia received a greater median volume of ethanol than dogs without resolution (0.60 mL [IQR, 0.30 to 1.00 mL] vs 0.15 mL [IQR, 0.09 to 0.37 mL]; P = .012). Ethanol volume was not associated with ethanol leakage severity or complication rates. Conclusions: Sonographically guided ethanol ablation was an effective treatment for primary hyperparathyroidism in dogs, achieving resolution of hypercalcemia in nearly 90% of cases with a low rate of major complications. Clinical Relevance: Ultrasound-guided ethanol ablation based on real-time nodule hyperechogenicity may be a practical alternative to volume-based protocols while maintaining efficacy and safety.