Salivary gland stones: US evaluation in shock wave lithotripsy

PURPOSE: To assess the usefulness of ultrasonography (US) in the selection and monitoring of patients with sialolithiasis to be treated with extracorporeal electromagnetic shock wave lithotripsy. MATERIALS AND METHODS: US was performed in 80 symptomatic outpatients who were to undergo shock wave lithotripsy because they were not candidates for endoral extraction of calculi. The location and diameter of stones and the condition of the affected gland and duct were determined. RESULTS: Swollen and sclerotic glands and dilated ducts were the most frequently observed characteristics. After lithotripsy, stone clearance or a residual fragment of less than 2 mm in diameter was seen at US in 37 of 56 patients with submandibular gland calculi and in all 24 patients with parotid gland calculi. Favorable outcome after lithotripsy was associated with smaller (less than 7 mm) stone diameter (P < .001) and, in the case of submandibular gland stones, with intraductal location (P < .05). A return to a normal parenchymal echotexture was seen in all patients in whom the stone was completely eliminated; a limited reduction in swelling was observed in patients with residual fragments. CONCLUSION: US is useful in the selection of candidates for extracorporeal electromagnetic shock wave lithotripsy and in monitoring the progress of treatment.