H. Iro et al., ELECTROHYDRAULIC INTRACOPOREAL LITHOTRIPS Y FOR THE TREATMENT OF SALIVARY DUCT STONES - IN-VITRO AND ANIMAL-EXPERIMENTS, HNO. Hals-, Nasen-, Ohrenarzte, 41(8), 1993, pp. 389-395
Background: Extracorporeal lithotripsy is now used routinely for the t
reatment of salivary duct stones. The question arose whether electrohy
draulic intracorporeal lithotripsy, which is applied in urology and ga
stroenterology, might also be useful in the treatment of this disease.
Before its possible clinical application the influence of electrohydr
aulic intracorporeal shock waves on salivary stones in vitro and any i
nfluence on the tissue in the head and neck region (in vivo) had to be
investigated. Materials and methods: In vitro experiments. Fifty-eigh
t salivary stones and 11 extirpated human submandibular glands were tr
eated by three different electrohydraulic devices. Animal experiments.
Electrohydraulic shock waves were applied to the dilated Stensen's du
ct and other tissues (muscle, parotid gland, facial nerve) of six rabb
its. Results: Of 58 salivary stones, 53 (91%) were fragmented, 39 (67%
) with a remaining size of less than 1.5 mm and 14 (24%) more than 1.5
mm. In 5 cases (9%) no effects were seen at all. Fragmentation occurr
ed independent of the mineralogical components of the stone and indepe
ndent of the different lithotriptors used. The smaller the probe diame
ter and the larger the stone, the more shock waves were needed to achi
eve fragmentation. With the smaller probes the stones could not be fra
gmented completely. In human submandibular glands, extensive tissue le
sions could be evidenced macroscopically and histologically after appl
ication of electrohydraulic shock waves in vitro. Application of elect
rohydraulic shock waves to the dilated parotid gland duct of rabbits l
ed to perforations of the duct after 1-5 single pulses. Lesions of ner
ves and blood vessels could also be observed within the duct environme
nt. This occurred with all of the different electrohydraulic devices,
probe diameters and intensities used. In our opinion the damage produc
ed is probably the result of both the direct effect of the plasma as w
ell as the resultant stress wave. Conclusion: In view of the severe da
mage caused to different tissues, use of the described method for the
treatment of stones in the narrow human salivary ducts should be great
ly restricted.