Al-Dessoukey AA. et al., 2019: Ultraslow full-power shock wave lithotripsy versus slow power-ramping shock wave lithotripsy in stones with high attenuation value: A randomized comparative study
Al-Dessoukey AA, Abdallah M, Moussa AS, Sayed O, Abdelbary AM, Abdallah R, Massoud AM, Abdelhamid MH, Elmarakbi AA, Ragheb AM, ElSheemy MS, Ghoneima W.
Department of Urology, Faculty of Medicine, Beni-Suef University, Beni Suef, Egypt.
Urology Department, Faculty of Medicine, Cairo University, Cairo, Egypt.
OBJECTIVES: To compare the efficacy and safety of ultraslow full-power versus slow rate, power-ramping shock wave lithotripsy in the management of stones with a high attenuation value. METHODS: This was a randomized comparative study enrolling patients with single high attenuation value (≥1000 Hounsfield unit) stones (≤3 cm) between September 2015 and May 2018. Patients with skin-to-stone distance >11 cm or body mass index >30 kg/m2 were excluded. Electrohydraulic shock wave lithotripsy was carried out at rate of 30 shock waves/min for group A versus 60 shock waves/min for group B. In group A, power ramping was from 6 to 18 kV for 100 shock waves, then a safety pause for 2 min, followed by ramping 18-22 kV for 100 shock waves, then a safety pause for 2 min. This full power (22 kV) was maintained until the end of the session. In group B, power ramping was carried out with an increase of 4 kV each 500 shock waves, then maintained on 22 kV in the last 1000-1500 shock waves. Follow up was carried out up to 3 months after the last session. Perioperative data were compared, including the stone free rate (as a primary outcome) and complications (secondary outcome). Predicting factors for success were analyzed using logistic regression. RESULTS: A total of 100 patients in group A and 96 patients in group B were included. The stone-free rate was significantly higher in group A (76% vs 38.5%; P < 0.001). Both groups were comparable in complication rates (20% vs 19.8%; P = 0.971). The stone-free rate remained significantly higher in group A in logistic regression analysis (odds ratio 24.011, 95% confidence interval 8.29-69.54; P < 0.001). CONCLUSIONS: Ultraslow full-power shock wave lithotripsy for high attenuation value stones is associated with an improved stone-free rate without affecting safety. Further validation studies are required using other shock wave lithotripsy machines.
Int J Urol. 2019 Dec 2. doi: 10.1111/iju.14158. [Epub ahead of print]
A number of factors has been identified for designing the optimal treatment strategy for SWL. Slow rate administration has been suggested as a factor associated with improved stone disintegration and stone free rates. There are both experimental and clinical support for the value of reducing the frequency of SWL. There are, however, two arguments why sw-administration better treatment results with ultraslow (0.5Hz) full power SWL compared with slow (1Hz) power-ramping SWL. It is of note that for their patients with hard and large stones the TOTAL treatment times were not significantly different between the strategies.
I am not aware of how many of the lithotripters currently in use that can be run with 0.5Hz shockwave administration, but it seems as a very useful function.
It needs to be observed, however, that in the authors’ experimental program, not only the frequency differed but also the ramping strategy and presence or absence of pauses.