PNEUMATIC INTRACORPOREAL LITHOTRIPSY OF S ALIVARY STONES - AN IN-VITRO AND IN-VIVO ANIMAL INVESTIGATION

Background: The effort to use minimally invasive strategies in the tre atment of human sialolithiasis in principle seems to allow the clinica l application of pneumatic lithotripsy because of the small diameters of the probes involved. While this kind of therapy is already used suc cessfully in urology, we investigated the method during in vitro and a nimal experiments. Materials and methods: The treatment of stones and tissue utilized the pneumatic lithotripter ''Litho-clast''. This syste m works with ballistic energy and is similar to a biologic ''pneumatic hammer''. Thirty salivary calculi were treated with pneumatic lithotr ipsy. Four submandibular salivary glands and their ducts were removed intraoperatively and were exposed to the pneumatic probes. Moreover, i n two cases a salivary concretion was also implanted prior to pneumati c lithotripsy. In two rabbits the ducts of the parotid glands were lig ated for 2 weeks. On the basis of the in vitro experiments, concretion s were placed in two of the four salivary ducts. Following this, the p neumatic probes were inserted along the ducts and lithotripsy was comp leted. Results: All of the 30 salivary calculi were reduced to sizes s maller than 1.5 mm in diameter. No macroscopic or microscopic damage w as detectable while the probe was in a duct. However, in both cases wi th implanted calculi retropulsion of fragments occurred consequent per foration of the ducts. After application of ballistic pulses along the duct, small periductal hematoma without any perforation were detected macroscopically. Microscopically, only small bleeding was observed al ong the submucosa and partial loss of epithelium was found. In contras t, the pulse application to the implanted concretions lead to destruct ion of the calculi with perforation of the ducts as well as hemorrhage in the surrounding tissue. Conclusions: The method of pneumatic litho tripsy used in the present study resulted in sufficient destruction of salivary calculi. In vitro and in vivo lithotripsy of duct implanted calculi led to perforation of the salivary duct in all cases. Because of these results, the clinical use of this technique to treat human si alolithiasis appears to be not justified.