Lee CC et al, 2018: Comparison of electrohydraulic and electromagnetic extracorporeal shock wave lithotriptors for upper urinary tract stones in a single center.
Lee CC, Lin WR, Hsu JM, Chow YC, Tsai WK, Chiang PK, Chen M, Chiu AW.
Department of Urology, MacKay Memorial Hospital, No. 92, Sec. 2, Zhongshan N. Rd, Zhongshan Dist, Taipei, 104, Taiwan.
School of Medicine, MacKay Medical College, New Taipei City, Taiwan.
Department of Cosmetic Applications and Management, MacKay Junior College of Medicine, Nursing and Management, Taipei, Taiwan.
School of Medicine, National Yang-Ming University, Taipei, Taiwan.
PURPOSE: To compare the efficacy and outcomes of shock wave lithotripsy (SWL) for upper urinary tract stones with an electrohydraulic (EH) and an electromagnetic (EM) lithotriptor in a single center. METHODS: The medical records of 272 patients with upper urinary tract stones ≤ 2 cm in size who underwent SWL with either the Medispec E3000 EH lithotriptor (179 cases) or the Medispec EM1000 EM lithotriptor (93 cases) were reviewed. The demographic data, stone parameters, stone-free rates, and retreatment rates were analyzed.
RESULTS: The EH group had a higher stone-free rate (53.6 vs. 30.1%, p < 0.001) and a lower retreatment rate (32.4 vs. 61.2%, p < 0.001) for renal and upper third ureteral stones than the EM group. The stone-free rates for renal stones < 1 cm (55.5 vs. 32.2%, p = 0.045), ureteral stones < 1 cm (64.5 vs. 42.1%, p = 0.028), and renal stones ≥ 1 cm (43.1 vs. 0%, p = 0.03) were higher in the EH group. Two patients in the EH group had a renal hematoma needing hospitalization after SWL. There were no complications in the EM group.
CONCLUSIONS: The Medispec E3000 EH lithotriptor had higher stone-free rates and lower retreatment rates than the Medispec EM1000 EM lithotriptor for renal stones < 2 cm and ureteral stones < 1 cm. Complications were rare.
World J Urol. 2018 Aug 28. doi: 10.1007/s00345-018-2464-7. [Epub ahead of print]
This report shows that the lithotripter and most certainly also how the SWL was carried out are fundamental for outcome of the treatment. Personally, I have not worked with any of the lithotripters included in this study. My own experience with electrohydraulic devices is based on the unmodified Dornier HM3 lithotripter operated with both general and regional anesthesia as well as with analgesics-sedatives, the MFL 5000 and the Lithocut with administration of analgesics-sedatives and subsequently with the two electromagnetic lithotripters Storz Modulith SLX classic and SLX-F2 also with analgesics and sedatives.
One fundamental misconception regarding SWL is that the modern lithotripters based on electromagnetic technology are constructed to allow treatment without anesthesia and without administration of analgesic agents. From my own experience of more than 10 000 treatments with electromagnetic devices I am fully convinced that effective SWL is never pain-free whether the treatment has been carried out with electrohydraulic or electromagnetic devices. Therefore, when anesthesia-analgesic free treatment strategies are applied the treatment is directly or indirectly influenced by this restriction.
Moreover, I have a feeling that when stereotypic strategies are formulated to enable treatment by technicians it is difficult to know how optimal such treatments really are. How the upper number of shockwaves applied in the authors’ treatment strategy was decided is not known, but there are a number of factors that need to be controlled such as for instance the interference of shielding structures and the tolerance by the patient.,
Overall the results obtained with the two lithotripters are inferior to what I had expected. Stone-free rates after SWL of stones in the kidney are often difficult to judge, but for ureteral stones that are perfectly suited for SWL, I had expected much higher stone-free rates after one session and lower re-treatment rates.
Nothing is mentioned about the geometry of the two lithotripters but it stands to reason that the strategy particularly for the electro-magnetic device needs to be re-considered.