THE THERAPEUTIC VALUE OF THE AMBULANT EXTRACORPOREAL SHOCK-WAVE LITHOTRIPSY OF SALIVARY STONES - RESULTS OF A PROSPECTIVE-STUDY

In a prospective study, results of the extracorporeal shock wave lithotripsy of salivary stones were evaluated. The study was performed with the currently available technical possibilities of electromagnetic systems to get indication criteria for this procedure. Using the Modulith SL 20-lithotripter of Storz Medical AG, 33 concrements in 25 patients were treated in 89 lithotripsy sections. The stone sizes, localized by ultrasound, ranged from 3 to 13 mm diameter (empty set 6,9 mm). After application of local anaesthesia, per session on an average 1300 shock waves with raising energy levels were applied, the succession of shocks fixed to 1 MHz. With the help of ultrasound localisation, a therapeutic success with complete emission of the concrement or an adequate disintegration of these stones could be achieved in 82 % of the parotid gland stones (n = 11) and in 14 % of the submandibular gland stones (n = 22). Since the unhampered functioning of these salivary glands is an inevitable pre-condition for the spontaneous emission of the disintegrated fragments, the status of function of salivary glands should be established by a scintigraphy before performing the ESWL. Even though complete emission of the stone could be achieved in only 4 patients, all patients were clinically free of symptoms after the treatment. In 3 of 25 patients, discrete bleeding of a passing nature occurred coming from the salivary duct. In 2 patients, formation of haematoma of varying dimensions could be visualized by ultrasound. 3 patients showed petechial skin bleeding. The tinnitus aurium which affected one patient eased after 3 days. In our patients collective a facial nerve damage did not occur. Considering the risks of parotid surgery, we see an absolute indication for lithotripsy in stones distally located from the masseter banding of the parotid duct. Because of the low success rate of ESWL and the comparatively low risk connected with surgical therapy, the indication for ESWL in case of concrement formations in the outlet path system of the submandibular gland must be viewed more critically. However, at present, the lack of clinical symptoms which was observed after lithotripsy in all cases does not yet permit a statement about the longterm prognosis after this procedure.