Durability of current generation flexible ureteroscopes: the experience from a high-volume centre.

Introduction: The aim of this article was to evaluate the durability of current generation fibreoptic flexible ureteroscopes (FURS), analyse factors that influence durability, identify reasons for premature damage of FURS and offer suggestions to expand its life span. Material and methods: A total of 952 retrograde intrarenal surgeries (RIRS) done for upper tract calculi using 8 fibreoptic FURS, namely three Storz Flex X2, one Flex X2S, two Olympus URF- P6, two Olympus URF- P7, between March 2013 and December 2018, were reviewed retrospectively. All procedures were done by two consultants, in a single referral centre. Data relating to stone characteristics and flexible ureteroscopy procedure were retrieved from hospital database. The primary end point was damage of FURS requiring first repair. Results: The average stone burden was 14.59 ±3.37 mm (range 3-22 mm). Ureteral access sheath was used in 95.4% of cases, 36.7% of the cases were pre-stented. Mean ureteroscope durability was 119 procedures and mean ureteroscopy time was 71.99 hours of use before first repair. Prolonged laser usage time and increased usage of accessories had significant negative impact on longevity of FURS (p = 0.002, p = 0.036 respectively). Inadvertent laser fibre misfire and extreme torque caused premature FURS damage, at the end of 35 and 12 procedures respectively. Conclusions: Current generation fibreoptic flexible ureteroscopes have a mean durability of 119 procedures. Anticipation of torque, knowledge of the common reasons for damage and meticulous handling is essential to maximise the durability of FURS.