Xiao K. et al., 2023: Which frequency is better for pediatric shock wave lithotripsy? Low intermediate or high: A systematic review and meta-analysis.
Department of Urology/Institute of Urology, West China School of Medicine, West China Hospital, Sichuan University, Chengdu, China.
Background: To explore the optimal frequency for pediatric extracorporeal shock wave lithotripsy (ESWL) in the treatment of upper urinary stones.
Methods: A systematic literature search was undertaken using PubMed, Embase, Web of Science and Cochrane Central Register of Controlled Trials databases to identify eligible studies published before January 2023. Primary outcomes were perioperative efficacy parameters, including ESWL time, anesthesia time for ESWL sessions, success rates after each session, additional interventions needed, and treatment sessions per patient. Secondary outcomes were postoperative complications and efficiency quotient.
Results: Four controlled studies involving 263 pediatric patients were enrolled in our meta-analysis. In the comparison between the low-frequency and intermediate-frequency groups, we observed no significant difference as regards anesthesia time for ESWL session (WMD = -4.98, 95% CI -21.55∼11.58, p = 0.56), success rates after ESWL sessions (first session: OR = 0.02 95%CI -0.12∼0.17, p = 0.74; second session: OR = 1.04 95%CI 0.56∼1.90, p = 0.91; third session: OR = 1.62 95%CI 0.73∼3.60, p = 0.24), treatment sessions needed (WMD = 0.08 95%CI -0.21∼0.36, p = 0.60), additional interventions after ESWL (OR=0.99 95%CI 0.40∼2.47, p = 0.99) and rates of Clavien grade 2 complications (OR = 0.92 95%CI 0.18∼4.69, p = 0.92). However, the intermediate-frequency group may exhibit potential benefits in Clavien grade 1 complications. In the comparison between intermediate-frequency and high-frequency, the eligible studies exhibited higher success rates in the intermediate-frequency group after the first session, the second session and the third session. More sessions may be required in the high-frequency group. With respect to other perioperative, postoperative parameters and major complications, the results were similar.
Conclusions: Intermediate-frequency and low-frequency had similar success rates and seemed to be the optimal frequency for pediatric ESWL. Nevertheless, future large-volume, well-designed RCTs are awaited to confirm and update the findings of this analysis.
Front Surg. 2023 Mar 15;10:1063159. doi: 10.3389/fsurg.2023.1063159. eCollection 2023.PMID: 37009606 Review.
Free article.
Comments 1
Which frequency that should be applied in SWL has been discussed and analyzed extensively over the years. Thereby it has been found that a low frequency is associated with better disintegration and less tissue injuries, at least in adults and in animals. The explanation provided is that a certain minimal time interval is necessary for elimination of cavitation bubbles that otherwise both hinder the transmission of shock waves and cause SW scattering in tissues such as kidneys and other nearby organs.
That this effect should be less important for SWL in children is unlikely, and it is surprising that the authors chose to carry out a literature review based on a small number of studies in which low and intermediate frequencies, 1 Hz and 1.5 Hz were compared with 2 Hz. The success rate was superior with low and intermediate frequencies, and in line with a huge literature experience in adults.
Conclusions on treatment and anesthesia times are difficult to draw because it very often is difficult to determine the success of disintegration and it is likely that the treatment will be prolonged with a good safety margin, given that the children are treated with general anesthesia.
The lesson learnt from this very small systemic review and meta-analysis is that treatment with frequencies of 1 Hz and 1.5 Hz (60 and 90/min) are superior to treatment with 2 Hz (120 /min). This is important but expected information. I completely disagree with the authors that there is a need of large volume RCTs to further respond to the question formulated in this report. That would be meaningless waste of time, manpower and money. The information presented in the current article is enough!
Hans-Göran Tiselius