Stone free rates following ureteroscopy at Mater Dei Hospital

Abstract

INTRODUCTION: Renal calculi pose a huge burden on health care systems and their rising prevalance has led to an increased reliance on surgery, particulary for upper urinary tract stones. Techincal advancements has made ureterscopy (URS) a mainstay treatment for both renal and ureteric stones. Despite its increase use, reported stone free rates following URS vary considerably owing to the different imaging modalites used and the different defintions of stone free. The aim of this audit is to assess the stone free rates of patients who underwent a URS at Mater Dei Hospital, Malta.

METHODS: All patients who underwent a URS for stones between January 2019 and December 2020 were included. Data was collected retrospectively by reviewing records on two main online hospital systems: Isoft Clincal Manager (ICM) and Picture Archiving and Communication System (PACS).

RESULTS: A total of 588 patients were selected for data analysis after applying inclusion/exclusion criteria. CT KUB was most common imaging modality for both diagnosis (83%, n=496) and follow-up (64%). At first follow-up, 418 patients (71%) were stone free when using the 5mm cut off, while 298 patients (50%) were stone free when using the 2mm criteria. At first follow-up, 209 (66%) of pre-stented patients were stone free when using the 5mm cut off, while 148 (47%) patients were stone free when using the stricter 2mm criterion. Patients with ureteric stones had better stone free rates at first follow-up at both 2mm (0.01) and 5mm cuts offs (p=0.013). Stone free rates were worse for patients who had stones higher up in the calyces of the kidney (p=0.01). The distribution of HU was the same across all categories of stone free at first follow-up when considering 2mm cut off (p=0.544). A total of 22 patients sufferred post-operative complications. 13 of these were re-admitted within 30 days of surgery and one patient died.

CONCLUSION: Different stone parameters as well as different imaging techniques influence stone free rates. Ureteroscopy is now the most commonly performed stone removing procedure. Efforts should be made to render patients stone free, as this will reduce the requirements for future secondary interventions.