He Z. et al., 2019: Energy output modalities of shockwave lithotripsy in the treatment of urinary stones: escalating or fixed voltage? A systematic review and meta-analysis

Wednesday, 05 February 2020

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He Z, Deng T, Yin S, Xu Z, Duan H, Chen Y, Duan X, Zeng G.
Department of Urology, Minimally Invasive Surgery Center, The First Affiliated Hospital of Guangzhou Medical University, Kangda Road 1#, Haizhu District, Guangzhou, 510230, Guangdong, China.
Guangzhou Institute of Urology, Guangzhou, China.
Guangdong Key Laboratory of Urology, Guangzhou, China.
Department of Urology, Minimally Invasive Surgery Center, The First Affiliated Hospital of Guangzhou Medical University, Kangda Road 1#, Haizhu District, Guangzhou, 510230, Guangdong, China.
Guangzhou Institute of Urology, Guangzhou, China.
Guangdong Key Laboratory of Urology, Guangzhou, China.

PURPOSE: To compare the effectiveness and safety of escalating and fixed energy output modalities of shockwave lithotripsy (SWL) in the treatment of urinary stones.
METHODS: A systematic literature search using PubMed, Embase, Cochrane Library and Web of Science was performed to obtain relevant studies up to December 2018. Summarized mean differences (MDs) and risk differences (RDs) with 95% confidence intervals (CIs) were used for comparing continuous and dichotomous variables, respectively. RESULTS: Six RCTs including 775 patients were identified. In the overall pooled outcomes, no significant difference was detected between escalating and fixed voltage group regarding initial and final success rate (SR) and stone-free status (SFS), auxiliary procedure and complication (hematoma, febrile episode, and pain) rate. However, when shockwave frequency ≥ 90 shocks/min, total shocks per session ≤ 3000, or 1-3 SWL sessions were performed, escalating group was associated with significantly higher SR1 (defined as SFS + fragments ≤ 4 mm); in addition, escalating group brought significantly less hematoma when total shocks per session ≤ 3000. CONCLUSIONS: Escalating voltage SWL offered comparable safety and effectiveness to that of fixed voltage SWL. However, escalating voltage SWL could be recommended in following conditions: (1) shockwave frequency ≥ 90 shocks/min, total shocks per session ≤ 3000, or 1-3 SWL sessions, for better stone removal; (2) total shocks per session ≤ 3000, for less hematoma formation.
World J Urol. 2019 Dec 7. doi: 10.1007/s00345-019-03049-2. [Epub ahead of print]

Comments 1

Hans-Göran Tiselius on Wednesday, 05 February 2020 09:30

How should SWL be carried out to be maximally effective and maximally safe? Should shockwaves be delivered at fixed rate or is it advisable to use a ramping strategy by escalating the power?
The authors of this report have carried out a systematic review and meta-analysis in order to answer the questions posed above. With the different ways in which SWL had been carried out in the six RCTs, with different lithotripters, it is difficult to know which conclusions that really can be drawn. The stone burden varies and there is no information on stone composition. Moreover, one of the studies had its focus entirely on ureteral stones. One of the fundamental problems with modern SWL is to achieve satisfactory pain control in order to proceed with the treatment in a rational way, but there is, in this summary, no details on how this problem was solved.
It is of note that with a total number of sessions up to 3000 or with repeated treatment sessions it was concluded that the outcome was better with ramping. The problem, however, is that when SWL is started it is difficult to predict the total number of shockwaves or sessions that will be required. Therefore, the bottom-line of this report that there were no significant differences between the two treatment strategies seems little helpful in the clinical practice. There are, however, other obvious advantages of voltage escalation than final stone-free rates.
The patients will in most cases adapt to the treatment in a much better way when the energy is increased stepwise, at least when pain is counteracted by analgesics and sedatives. Moreover, stepwise increments in power will enable determination at which energy level that disintegration starts. And if this possibility is used during treatment rather than applying a stereotypic treatment regimen it is possible to avoid over-treatment, which certainly will add safety to SWL.
My personal opinion is that it is difficult to draw any valid conclusions from this review and I cannot but support the authors that larger and well conducted studies are necessary if definite conclusions should be drawn on treatment strategies.

How should SWL be carried out to be maximally effective and maximally safe? Should shockwaves be delivered at fixed rate or is it advisable to use a ramping strategy by escalating the power?
The authors of this report have carried out a systematic review and meta-analysis in order to answer the questions posed above. With the different ways in which SWL had been carried out in the six RCTs, with different lithotripters, it is difficult to know which conclusions that really can be drawn.  The stone burden varies and there is no information on stone composition. Moreover, one of the studies had its focus entirely on ureteral stones. One of the fundamental problems with modern SWL is to achieve satisfactory pain control in order to proceed with the treatment in a rational way, but there is, in this summary, no details on how this problem was solved.
It is of note that with a total number of sessions up to 3000 or with repeated treatment sessions it was concluded that the outcome was better with ramping. The problem, however, is that when SWL is started it is difficult to predict the total number of shockwaves or sessions that will be required. Therefore, the bottom-line of this report that there were no significant differences between the two treatment strategies seems little helpful in the clinical practice. There are, however, other obvious advantages of voltage escalation than final stone-free rates.
The patients will in most cases adapt to the treatment in a much better way when the energy is increased stepwise, at least when pain is counteracted by analgesics and sedatives. Moreover, stepwise increments in power will enable determination at which energy level that disintegration starts. And if this possibility is used during treatment rather than applying a stereotypic treatment regimen it is possible to avoid over-treatment, which certainly will add safety to SWL.
My personal opinion is that it is difficult to draw any valid conclusions from this review and I cannot but support the authors that larger and well conducted studies are necessary if definite conclusions should be drawn on treatment strategies.

How should SWL be carried out to be maximally effective and maximally safe? Should shockwaves be delivered at fixed rate or is it advisable to use a ramping strategy by escalating the power? The authors of this report have carried out a systematic review and meta-analysis in order to answer the questions posed above. With the different ways in which SWL had been carried out in the six RCTs, with different lithotripters, it is difficult to know which conclusions that really can be drawn. The stone burden varies and there is no information on stone composition. Moreover, one of the studies had its focus entirely on ureteral stones. One of the fundamental problems with modern SWL is to achieve satisfactory pain control in order to proceed with the treatment in a rational way, but there is, in this summary, no details on how this problem was solved. It is of note that with a total number of sessions up to 3000 or with repeated treatment sessions it was concluded that the outcome was better with ramping. The problem, however, is that when SWL is started it is difficult to predict the total number of shockwaves or sessions that will be required. Therefore, the bottom-line of this report that there were no significant differences between the two treatment strategies seems little helpful in the clinical practice. There are, however, other obvious advantages of voltage escalation than final stone-free rates. The patients will in most cases adapt to the treatment in a much better way when the energy is increased stepwise, at least when pain is counteracted by analgesics and sedatives. Moreover, stepwise increments in power will enable determination at which energy level that disintegration starts. And if this possibility is used during treatment rather than applying a stereotypic treatment regimen it is possible to avoid over-treatment, which certainly will add safety to SWL. My personal opinion is that it is difficult to draw any valid conclusions from this review and I cannot but support the authors that larger and well conducted studies are necessary if definite conclusions should be drawn on treatment strategies.

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