The extracorporeal shock wave treatment of parotid stones is a rather new therapy. Its usefulness was determined in a prospective study. Seventy-six patients (36 female, 40 male, 2 to 80 years of age) with symptomatic, sonographically detectable solitary sialoliths of the parotid gland were treated with an extracorporeal piezoelectric shock wave therapy after unsuccessful conservative therapy (sialagogues, gland massage, bougienage of the secretory duct). At most, 3 treatments per patient were performed. Altogether, 38 of the 76 patients (50%) were free of stones and no longer suffered from complaints after completion of shock wave treatment and a mean follow-up period of 48 months (range 6 to 71 months). During the follow-up period, in no case could renewed stone formation be observed. Residual stone fragments were detectable in 20 patients (26%), but did not cause further symptoms. Thirteen patients (17%) with residual stone fragments stated a significant improvement of their complaints after therapy. Five patients (7%) did not observe any changes of their pretherapeutic complaints and underwent parotidectomy. The therapeutic success was not influenced by stone size or by stone localization within the gland. During the follow-up period, no side effects of the therapy were identified. With stones of the parotid gland, extracorporeal shock wave lithotripsy is -- after one has used conservative therapies (sialagogues, gland massage) -- the treatment of choice, avoiding in the majority of cases a parotidectomy with its operative risks (paresis of the facial nerve, Frey's syndrome).

Sialolithiasis is the most common disease of the great salivary glands with an incidence of 1.2%. New minimal-invasive methods like extracorporeal shockwave application or intracorporeal laser lithotripsy have changed the established ways of treatment of human sialolithiasis during the last years. Twenty per cent of our patients (n = 402) suffered from parotid duct stones and 80% from submandibular duct calculi. The typical symptoms were post-prandial pain and swelling of the glands. Until now there has been no proof of a metabolic disorder which could be responsible for coincidental stone development (6%) in the urinary tract or the bile duct system. Concrements are diagnosed by B-scan ultrasonography in nearly 100% of all cases. After our basic in vitro and in vivo investigations two systems of shockwave treatment are useful for clinical application: extracorporeal shockwave lithotripsy (piezoelectric) and intracorporeal laser lithotripsy (Rhodamine-6G-dye-laser), both supported by auxiliary measures (slitting and widening of the duct, dormia-basket extraction, sialagogues and gland massage). Due to our experiences with these minimally-invasive methods a new management of sialolithiasis is recommended depending on the localization of the calculi and their maximal diameters. Submandibular stones should be treated by extracorporeal lithotripsy, if the stone is located in intraglandular parts or in the hilum. Stones of the hilum also can be treated by laser lithotripsy. In the distal parts and near the orifice papillotomy and stone extraction should be tried independent of the stone size. If the maximum diameter is more than 12 mm and the concrement is detected in the intraglandular parts of the duct system or deep in the hilum, submandibulectomy is necessary. Calculi of the parotid gland should only be treated by extracorporeal lithotripsy, regardless of their size and location. Because of severe duct stenosis papillotomy is not indicated. Parotidectomy should be carried out only in cases reluctant to minimally-invasive measures.

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Color-coded duplex sonography is being increasingly used in the head and neck as another method for diagnosis of such disorders as stenosis of arteries or veins or hemangiomas. A possible additional advantage of testing is the ability to differentiate benign from malignant tumors. Since the underlying cause of a suspicious lesion is most important for treatment strategies, we investigated histologically-proven benign and malignant cervical lymph nodes for determining the value of color-coded duplex sonography. In the present study, 135 patients (45 women and 90 men; ages 30-63 years) with palpable cervical lymph nodes were examined with both ultrasound and color-coded duplex sonography. Afterwards, lymph nodes were removed by open biopsies or neck dissections. The histological results were then compared to perfusion velocities and pulsation indices from the color-coded duplex sonography. However, no significant differences were found between the benign and malignant nodes. When comparing perfusion and color, each group was seen to be non-homogeneous and no typical distribution of vascularization was demonstrable. Findings showed that color-coded duplex sonography is currently not an accurate indicator of lymph node pathology.

Before clinical application of an extracorporeal piezoelectric lithotripter to treat sialolithiasis, tissue reaction during shockwave application was examined in vitro and in experiments with animals. Application of shockwaves to human tissue in vitro showed neither macroscopic nor microscopic effects. In animal experiments, the acute experiment (16 rabbits, Chinchilla-Bastard) revealed minor bleeding in the parenchyma of the parotid gland, while the chronic experiment (14 rabbits, Chinichilla-Bastard) revealed no morphologic tissue damage to the parotid region of the rabbit, as a result of piezoelectric shockwaves. However, when the eye was placed in the shockwave focal area and the shockwaves were transmitted via the fissura orbitalis to the endocranium, brain damage could be detected morphologically. In conclusion, the authors feel that the clinical application of extracorporeal piezoelectric fragmentation of salivary stones is justified, provided that a reliable positioning of the patient and exact sonographic location of the concrement are possible.