Extracorporeal lithotripsy for salivary calculi: a long-term clinical experience

OBJECTIVES/HYPOTHESIS: The objective was to assess in a large series of patients with a long-term clinical follow-up the validity of extracorporeal electromagnetic shock wave lithotripsy as a minimally invasive therapy for sialolithiasis. STUDY DESIGN: Consecutive patient series. METHODS: Three hundred twenty-two consecutive symptomatic outpatients with single or multiple calculi in the submandibular (234 patients) or parotid (88 patients) gland underwent a complete extracorporeal electromagnetic shock wave lithotripsy treatment. Treatment results were classified into three groups: successful result with complete ultrasonographic elimination of the stone after lithotripsy, successful result with residual ultrasonographic fragments that were less than 2 mm in diameter, and unsuccessful result with residual ultrasonographic fragments that were greater than 2 mm in diameter. Univariate and multivariate statistical analyses were performed. RESULTS: Complete elimination of the stone was achieved in 45% of patients. On ultrasonography, residual fragments (<2 mm in diameter) were detected in 27.3% of patients, and persisting fragments greater than 2 mm in diameter were assessed in 27.7% of patients. In 3.1% of patients, all with submandibular gland stones, sialoadenectomy was performed. Recurrence of calculi in the treated gland was observed during a median follow-up period of 57 months in four patients with complete ultrasonographic clearance of the stone occurring 10 to 58 months after lithotripsy. Univariate analysis showed that a favorable treatment result was significantly associated with the younger age of the patients (< or = 46 y), parotid and intraductal localization of the stone, diameter of the stone (< or = 7 mm), and number of therapeutic sessions (< or = 6). On multivariate analysis, the age of the patient, parotid site of the stone, stone diameter, number of therapeutic sessions, and number of shock waves were associated with favorable outcome. CONCLUSION: Extracorporeal electromagnetic shock wave lithotripsy is to be considered an efficient, minimally invasive treatment modality for salivary calculi.