Ghorbani M et al, 2016: Review on Lithotripsy and Cavitation in Urinary Stone Therapy
Ghorbani M, Oral O, Ekici S, Gozuacik D, Kosar A.
Cavitation is the sudden formation of vapor bubbles or voids in liquid media and occurs after rapid changes in pressure as a consequence of mechanical forces. It is mostly an undesirable phenomenon. Although the elimination of cavitation is a major topic in the study of fluid dynamics, its destructive nature could be exploited for therapeutic applications. Ultrasonic and hydrodynamic sources are two main origins for generating cavitation. The purpose of this review is to give the reader a general idea about the formation of cavitation phenomenon and existing biomedical applications of ultrasonic and hydrodynamic cavitation. Because of the high number of the studies on ultrasound cavitation in the literature, the main focus of this review is placed on the lithotripsy techniques, which have been widely used for the treatment of urinary stones. Accordingly, cavitation phenomenon and its basic concepts are presented in Section II. The significance of the ultrasound cavitation in the urinary stone treatment is discussed in Section III in detail and hydrodynamic cavitation as an important alternative for the ultrasound cavitation is included in Section IV. Finally, side effects of using both ultrasound and hydrodynamic cavitation in biomedical applications are presented in Section V. Index Terms—Cavitation, hydrodynamic, ultrasound, shock wave, histotripsy.
This is a comprehensive review for all being interested in shock wave lithotripsy and the role of cavitation in urinary stone fragmentation. After an introduction in shock wave lithotripsy SWL and the nature of cavitation different techniques such as tandem shock waves are described and supported by according references. Since the mechanism of urinary stone fragmentation by SWL is still not fully understood further investigations are required. Cavitation is, beside others, an important but not the only mechanism of fragmentation and also a potential reason for tissue lesions and hematomas. This paper lists many detailed studies of cavitation effects but finally, the reader has to answer the question himself, whether he should favour cavitation to enhance fragmentation or to avoid cavitation to reduce risk of tissue lesions.