Pre‐clinical evaluation of a laser system with emission control based on stone vs soft tissue recognition

OBJECTIVE: To evaluate the feasibility and performance of the StoneSense™ module (SSM; IPG Medical, Marlborough, MA, USA), a prototype real-time target recognition unit integrated into a IPG Thulium Fiber Laser (TFL). MATERIALS AND METHODS: The SSM analyses the spectral signature of back reflected light-emitting diode (LED) light from the target, stopping laser energy emission when incoming signal is originating from tissue or when the fibre-to-target distance is larger than pre-defined threshold (typically, ≥2-4 mm). The ex vivo tests were conducted on artificial BegoStone phantoms ((Bego GmbH & Co. KG, Bremen, Germany) embedded in porcine kidney tissue using energy settings of 0.1-2 J and 5-100 Hz at two fibre-scanning speeds (1 and 3 mm/s) through a translation stage movement. Human urinary stones were subsequently tested at 2 and 5 mm/s with setting of 0.5 J × 20 Hz. The in vivo trial was conducted by lithotripsy of pre-implanted human stones in porcine urinary tract. Primary outcome measures included ablation efficiency as well as specificity and sensitivity of stone recognition. RESULTS: Soft tissue ablation was completely prevented in all the ex vivo trials while maintaining high lithotripsy efficiency. Mean stone ablation reduction was 2.75% and 3% at fibre scanning speeds of 1 and 3 mm/s, respectively. The system achieved 100% sensitivity and up to 98% specificity in inhibiting laser emission to soft tissue. In vivo, complete dusting with fragments <500 μm was achieved for all studied stone types without observable mucosal injury. Specificity ranged from 85% to 100%, while sensitivity ranged from 90% to 100%. CONCLUSIONS: Integration of back reflected-light-spectra-based laser emission control into a TFL-based lithotripsy system is feasible and effective. The SSM enables precise real-time stone recognition, minimises unnecessary lasing, and preserves dusting efficiency.