Comment on: Intrarenal pressure with hand-pump or pressurized-bag irrigation: randomized clinical trial at retrograde intrarenal surgery

BJS, https://doi.org/10.1093/bjs/znae137, published 15 June 2024

We have read the article by Croghan et al. 1 published recently in BJS. This study provides valuable insights into the impact of irrigation techniques on intrarenal pressure during retrograde intrarenal surgery. While meaningful, there are several points that deserve further discussion.

First, although the article attempts to control certain variables, such as the type of ureteral access sheath and standardized holmium laser settings, other potential confounding factors may not have been fully accounted for. These include anaesthesia method and depth, preoperative health status, irrigation fluid temperature, and individual differences like anatomical structure, renal compliance, stone location, and size. These factors could affect intrarenal pressure measurements, and adjusting for these interactions could further strengthen the robustness of the findings.

Second, intrarenal pressure is a variable that changes over time. Relying solely on mean and peak values may overlook the dynamic characteristics of pressure changes. Additionally, besides the mean and peak values, the variability and variance of intrarenal pressure are also important outcome indicators. Greater pressure fluctuations may be more harmful than stable high pressure, and these indicators should be further investigated for their impact on postoperative outcomes. Using time series analysis or mixed-effects models could further reveal patterns of pressure changes and their potential effects.

Finally, conducting long-term, detailed, and comprehensive follow-up is essential to evaluate the efficacy and health outcomes of the two irrigation methods. This study can provide more valuable information, including postoperative renal function, stone recurrence rates, and quality of life, in addition to postoperative complications. Establishing multiple follow-up points after surgery is recommended, and assessments should include renal function tests, imaging evaluations (e.g. ultrasound and CT), and quality of life, pain scores, and satisfaction questionnaires.