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WCET 2022: Does Pressure Matter?

(UroToday.com) Dr. Helene Jung took the stage to discuss the role of pressure in the intrarenal environment in relation to infection/sepsis, pain, and renal damage. She first reviewed the historical timeline of intra-renal pressure research: as early as the 1920’s there were investigations into pressure and bacterial endotoxins entering the blood stream, and this continued through the birth of endoscopic surgery, with more focus on infection, sepsis, and other complications following ureteroscopy (URS) and percutaneous nephrolithotomy (PCNL). Dr. Jung commented on the use of high-powered lasers today generates dust that demands increased irrigation for visibility, resulting in higher intra-renal pressure and backflow, making the consideration of pressure a very timely and relevant topic.

PCNL-0.jpg

With regards to infection and sepsis, Dr. Jung shared data that fever, UTI, and sepsis are the most common post-operative complications for URS1 and that in a larger meta-analysis with 16 studies and 5597 patients, the sepsis risk after URS was 5%, with risk factors being larger stone size, positive urine culture, pre-stenting, and longer operative time;2-4 in addition, there are a multitude of studies that conclude renal backflow increases the risk for post-operative infections and those authors recommend utilizing lower pressure when feasible but Dr. Jung points out that the mechanism linking increased pressure to sepsis has not been described.

PCNL-1.jpg

Ureteral access sheaths have been used as a strategy during URS to keep intra-renal pressure low. Dr. Jung cited a large, multicenter study that included 2239 URSs revealed having an access sheath reduced complications of fever, UTI, and sepsis.5 For PCNL, she refenced a meta-analysis that showed the risk of post-operative sepsis was lower when intrarenal pressure was lowered with a suctioning sheath.6

PCNL-2.jpg

Dr. Jung touched on the idea that increased renal pressure might be related to pain and described a retrospective study of 234 patients that underwent URS showed pain (along with SIRS, fever, infection, and sepsis) was reduced when using a continuous-flow, fixed-pressure bag set at 150 mmHg rather than a hand-operated irrigation pump.7 With regards to PCNL, intra-real pressures less than 40 mmHg8 or using a suction device,9 reduced pain. 

PCNL-3.jpg

Finally, Dr. Jung introduced the idea that intra-renal pressure may induce renal damage in porcine models, with URS pressures ranging from 30 - 210 mmHg.10,11 She acknowledging that there was not much data in humans but chronic kidney disease, diabetes mellites, and hypertension could be risk factors of declining renal function following repeat procedures.11

Dr. Jung left the audience with a final thought that intra-renal pressure should be a factor to consider in endoscopic surgery and she advised surgeons reduce pressure when feasible, generate more evidence to provide safety recommendations, personalize each endoscopic approach, and involve patients in shared decision making with the current data.

Presented by: Helene Jung, MD, PhD, Senior Consultant, Urologist, Department of Urology, Hospital Lillebaelt, Denmark, Associate Professor at University of Southern Denmark, Institute of Regional Health Science

Written by: Zachary E Tano, MD Endourology Fellow, Department of Urology, University of California, Irvine during the 39th World Congress of Endo urology and Uro-Technology (WCET), Oct 1 - 4, 2022, San Diego, California. 

References:

  1. Somani, B.K., et al., Complications associated with ureterorenoscopy (URS) related to treatment of urolithiasis: the Clinical Research Office of Endourological Society URS Global study. World Journal of Urology, 2017. 35(4): p. 675-681.
  2. Bhojani, N., et al., Risk Factors for Urosepsis After Ureteroscopy for Stone Disease: A Systematic Review with Meta-Analysis. J Endourol, 2021. 35(7): p. 991-1000.
  3. Skolarikos, A., et al., Outcomes of Flexible Ureterorenoscopy for Solitary Renal Stones in the CROES URS Global Study. J Urol, 2015. 194(1): p. 137-43.
  4. Fan, S., et al., Risk factors of infectious complications following flexible ureteroscope with a holmium laser: a retrospective study. Int J Clin Exp Med, 2015. 8(7): p. 11252-9.
  5. Traxer, O. and E.X. Keller, Thulium fiber laser: the new player for kidney stone treatment? A comparison with Holmium:YAG laser. World J Urol, 2020. 38(8): p. 1883-1894.
  6. Bapir, R., et al., Infectious complications of endourological treatment of kidney stones: A meta-analysis of randomized clinical trials. Arch Ital Urol Androl, 2022. 94(1): p. 97-106.
  7. Farag, M., et al., Pressurized-Bag Irrigation Versus Hand-Operated Irrigation Pumps During Ureteroscopic Laser Lithotripsy: Comparison of Infectious Complications. J Endourol, 2020. 34(9): p. 914-918.
  8. Alsyouf, M., et al., Elevated Renal Pelvic Pressures during Percutaneous Nephrolithotomy Risk Higher Postoperative Pain and Longer Hospital Stay. J Urol, 2018. 199(1): p. 193-199.
  9. Lai, D., et al., Use of a Novel Vacuum-Assisted Access Sheath in Minimally Invasive Percutaneous Nephrolithotomy: A Feasibility Study. J Endourol, 2020. 34(3): p. 339-344.
  10. Loftus, C., M. Byrne, and M. Monga, High pressure endoscopic irrigation: impact on renal histology. Int Braz J Urol, 2021. 47(2): p. 350-356.
  11. Mykoniatis, I., et al., Are endourological procedures for nephrolithiasis treatment associated with renal injury? A review of potential mechanisms and novel diagnostic indexes. Clin Kidney J, 2020. 13(4): p. 531-541.