Presented by: Fabrice Henry MD
Cleveland Clinic Glickman Urological Institute

Introduction

A novel recessed tip (RT) laser fiber (Excalibur™) has been developed for use with ureteroscopy and laser lithotripsy, theorized to increase fragmentation efficacy and reduce fiber burn-back.  Using a bench-top model with TFL, we compared the dusting efficiency and fiber durability of the novel RT vs standard bare tip (BT) fibers, using two combinations of energy and frequency settings. 

Materials

Canine stones of similar weight and composition (100% CaOx monohydrate) were placed in a ureteroscopy model, using a saline-filled clear tube set at a 40 degree angle, with a mesh plug (1 mm aperture) at the end of the tube (Fig 1 c&d). The Quanta FiberDust SuperPulsed TFL was used with BT fibers (n = 6) and RT fibers (n = 6), inserted through an Olympus P6 ureteroscope. A single urologist dusted each stone until it was completely disintegrated, or up to a 5 minute cut-off time. Dusting was performed at 0.3 J and 100 Hz (3 trials each, with BT and RT fibers), and pop-dusting at 0.6 J and 30 Hz, again for 3 trials with each fiber type.  Any remaining fragments after five minutes were removed and weighed.  Dusting time and efficacy, visible “sparking”, and fiber burn-back were assessed after stone treatment.

Results

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Complete stone treatment within 5 minutes was accomplished with all six BT fibers with an average time of 3.77 min.  One of the RT fibers was excluded from analysis due to a manufacturing defect. Only 2 of 5 trials with RT fibers succeeded in completely dusting the stone in a 5 minute period, with an average residual stone volume of 30.8% (15.5% dusting, 52.1% pop dusting). The BT fibers had significantly increased burn-back (average 0.56 mm) compared to the RT fibers (0.08 mm) (p=0.05).

Conclusion

RT fibers result in less burn-back compared to BT fibers but trended towards less efficient dusting and pop-dusting.   The theoretical benefit of a recessed tip fiber was not evidenced in this study, indicating further research is required to elucidate the potential utility of RT fibers.

Funding

None

Co-Authors

Juan Sebastian Rodriguez Alvarez, MD
Cleveland Clinic Glickman Urological Institute

Sri Sivalingam, MD
Cleveland Clinic Glickman Urological Institute