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

The objective of this study was to evaluate a new concept in flexible ureteroscopy: instrumental dead space (IDS). Various proximal working channel connector designs, as well as the impact of ancillary devices occupying the working channel were evaluated in currently available flexible ureteroscopes.

Materials

IDS was defined as the volume of saline irrigation needed to inject at the proximal connector for delivery at the distal working channel tip. Because IDS is related to working channel diameter and length, we also reviewed proximal connector design as well as occupation of working channel by ancillary devices.

Results

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IDS significantly varied between flexible ureteroscope models, ranging from 1.1 ml for the Pusen bare scopes, up to 2.3 ml for Olympus scopes with their 4-way connector (p<0.001). Proximal connector designs showed a high degree of variability in the number of available Luer locks, valves, seals, angles and rotative characteristics. The measured length of the working channel of bare scopes ranged between 739 to 854 mm and significantly correlated with measured IDS (R² = 0.82, p<0.001). The coupling of scopes with an alternative ancillary proximal connector and the insertion of ancillary devices into the working channel significantly reduced IDS (mean IDS reduction of 0.1 to 0.5 ml; p<0.001).

Conclusion

IDS appears as a new parameter that should be considered for future applications of flexible ureteroscopes. A low IDS seems desirable for clinical applications. Main factors impacting IDS are working channel and proximal connector design, as well as ancillary devices inserted into the working channel. Future studies should clarify how reducing IDS may affect irrigation flow, intrarenal pressure and direct in-scope suction, as well as evaluate the most desirable proximal connector design properties.

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)

Amelia Pietropaolo, MD, FEBU
Department of Urology, University Hospital Southampton, Southampton, UK ; Young Academic Urologists (YAU), Endourology & Urolithiasis Working Group, Arnhem, The Netherlands

Patrick Juliebø-Jones, MD, FEBU
Department of Urology, Haukeland University Hospital, Bergen, Norway ; Young Academic Urologists (YAU), Endourology & Urolithiasis Working Group, Arnhem, The Netherlands

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)

Thomas Tailly, MD, FEBU
Department of Urology, University Hospital Ghent, Belgium ; Young Academic Urologists (YAU), Endourology & Urolithiasis Working Group, Arnhem, The Netherlands

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)