Safety and effectiveness of external shock wave lithotripsy in emergency: A narrative review

To perform a narrative review on safety and efficiency of external shockwave lithotripsy (ESWL) for managing acute renal colic due to ureteral stone.

Systematic search of Scopus, Web of Science, Embase and PubMed databases was performed in April 2024 to identify original research articles pertaining ESWL as an emergency management for acute renal colic (ARC). The search terms "extracorporeal shock wave lithotripsy", "emergency", "immediate", "urinary stones" were used and the filters 'English' and 'humans' were applied. Reference lists of selected manuscripts were checked manually for eligible additional articles. Due to high data heterogeneity, a comprehensive synthesis was performed.

Fourteen original studies were selected for final review including 3 single-center retrospective studies, 6 single-center prospective studies and 5 randomized controlled trials. Emergency ESWL (eESWL) was used in addition to the medical treatment for acute renal colic (ARC) management in all studies. eESWL was proposed for single radio-opaque ureteral stoneswith a maximum size ranging from 5 to 20mm, without context of ESWL contraindication or complicated ARC presentation. The procedures were carried out on alert patients but most often premedicated with an intravenous anti-inflammatory around 30minutes before the session and an analgesic (morphine) during the session. Mean stone size was around 7mm. Regarding eESWL outcomes, pain relief was achieved in 48 to 89%, higher for midureter and lower ureter locations (89 and 85% respectively). Lower Hounsfield units (HU, < 842HU) and mild pyelo-calyceal dilatation at presentation were independent predictive factors of pain relief. Stone clearance, using stone-free rate (SFR), respectively ranged from 60 to 94% and 82 and 86% at one and three months postoperatively, respectively. eESWL was associated with lower rates of ancillary procedures than delayed ESWL (dESWL) (from 8 to 16% versus from 32 to 44% respectively). eESWL and dESWL presented similar post-procedure complication rates.

eESWL is an effective and safe treatment of acute renal colic due to single radio-opaque ureteral stones from 5mm to 10mm, with high pain relief and SFR rates within one month compared to dESWL. Without higher complication rates than dESWL, eESWL represents a reliable and safe option within the first 48hours of the ARC. Prospective randomized prospective studies will help to confirm eESWL in the emergency pipeline to manage ARC.