Presented by: Jia-Lun Kwok MBBS, FRCS(Urol)(Glasg)
Department of Urology, University Hospital Zurich, University of Zurich, Zurich, Switzerland ; Department of Urology, Tan Tock Seng Hospital Singapore, Singapore

Introduction

Optical characteristics of flexible ureteroscopes have been extensively evaluated in air. To the best of our knowledge, the effects of an enclosed cavity in the kidney collecting system in saline on light properties of ureteroscopes is unknown. The aim of the study was to evaluate light properties in an in-vitro kidney model setting in saline, simulating the human kidney collecting system.

Materials

We evaluated a series of contemporary flexible ureteroscopes including the Storz Flex-Xc and Flex-X2s, Olympus V3 and P7, Pusen 7.5F and 9.2F, as well as OTU Wiscope using a 3D printed pink in-vitro kidney model consisting of a closed spherical cavity with 20mm diameter submerged in saline. A colour spectrometer incorporating the Vishay VEML 6040 color sensor was used for lux measurements at different openings located at the centre (direct light), 45°(direct and indirect light) and 90°(indirect light only) to the axis of the scope.

Results

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The maximum illuminance was at the centre opening for all scopes (range: 516 to 12058 lux at 50% brightness and 454 to 11871 lux at 100% brightness settings). For each scope, when comparing illuminance at centre vs 45° or 90°openings, the difference ranged from -43% to -92% at 50% brightness and -43% to -88% at 100% brightness settings (all p < 0.01). The two scopes with the highest peripheral drop were the P7 (centre vs 45°: -88%, -83%; centre vs 90°: -92%, -87% at 50% and 100% brightness respectively) and the Pusen 9.2F (centre vs 45°: -86%, -85%; centre vs 90°: -89%, -88% at 50% and 100% brightness respectively). The scope with the least peripheral drop was the Pusen 7.5F (centre vs 45°: -49%, -48%; centre vs 90°: -43%, -43% at 50% and 100% brightness respectively).

Conclusion

Illumination varies widely between ureteroscopes in an enclosed cavity in saline, with brightness differing as well within scopes at centre vs 45° and 90° positions. Scopes can have a peripheral illuminance drop as high as -92% compared to the centre, which is an undesirable property possibly impacting diagnostic purposes in ureteroscopy. Urologists should be aware of this as it may affect the choice of ureteroscopes and light brightness setting used in surgery.

Funding

None

Co-Authors

Vincent De Coninck, MD, FEBU
Department of Urology, AZ Klina, Brasschaat, Belgium ; Young Academic Urologists (YAU), Endourology & Urolithiasis Working Group, Arnhem, The Netherlands ; Progressive Endourological Association for Research and Leading Solutions (PEARLS)

Eugenio Ventimiglia, MD, FEBU
Division of Experimental Oncology/Unit of Urology, Urological Research Institute, IRCCS Ospedale San Raffaele, Milan, Italy ; Young Academic Urologists (YAU), Endourology & Urolithiasis Working Group, Arnhem, The Netherlands; Progressive Endourological Association for Research and Leading Solutions (PEARLS)

Yazeed Barghouthy, MD
Department of Urology, Centre Hospitalier de Valenciennes, Valenciennes, France ; Progressive Endourological Association for Research and Leading Solutions (PEARLS)

Alexandre Danilovic, MD
Department of Urology, Universidade de São Paulo Hospital das Clínicas - HCUSP, Department of Urology, Hospital Alemão Oswaldo Cruz, São Paulo, Brazil ; Progressive Endourological Association for Research and Leading Solutions (PEARLS)

Niamh Smyth, MD
University Hospital Monklands, Monkscourt Avenue, Airdrie, ML60JS, United Kingdom ; Progressive Endourological Association for Research and Leading Solutions (PEARLS)

Jan Brachlow, MD
Zentrum für Urologie Winterthur, Winterthur, Switzerland ; Progressive Endourological Association for Research and Leading Solutions (PEARLS)

Florian Schmid, MD, FEBU
Department of Urology, University Hospital Zurich, University of Zurich, Zurich, Switzerland

Manuela Hunziker, MD, FEBU
Department of Urology, University Hospital Zurich, University of Zurich, Zurich, Switzerland

Cédric Poyet, MD, FEBU
Department of Urology, University Hospital Zurich, University of Zurich, Zurich, Switzerland

Olivier Traxer, MD
Sorbonne Université, GRC n°20, Groupe de Recherche Clinique sur la Lithiase Urinaire, Hôpital Tenon, F-75020 Paris, France ; Progressive Endourological Association for Research and Leading Solutions (PEARLS)

Daniel Eberli, MD, FEBU
Department of Urology, University Hospital Zurich, University of Zurich, Zurich, Switzerland

Etienne Xavier Keller, MD, FEBU
Department of Urology, University Hospital Zurich, University of Zurich, Zurich, Switzerland ; Young Academic Urologists (YAU), Endourology & Urolithiasis Working Group, Arnhem, The Netherlands ; Progressive Endourological Association for Research and Leading Solutions (PEARLS)