Assessments
HYDRONEPHROSIS, COMPLICATIONS, COMPLICATION
Prior to inclusion in the study, all the patients underwent contrast-enhanced computed tomography (CT) to assess stone size and medium density (HU) [All the data were recorded by a single researcher. Stone size, stone volume, density, laser-on time (LOT, total time of laser ablation, automatically measured and recorded by the laser machine), total energy for stone ablation (automatically measured and recorded by the laser machine), operation time (from instrument insertion until removal), fluoroscopy time, radiation exposure, catheterization time, and hemoglobin level prior to and after surgery were measured. Where the patient had several stones (2 or 3), the total volume was calculated using the sum of the volumes of each stone. The following parameters were also calculated: stone ablation speed (stone volume/LOT, mmThe postoperative stone-free rate as well as the subsequent complication rates (e.g., hydronephrosis) were assessed using low-dose CT three months after surgery. Patients without residual fragments, or with fragments smaller than 2 mm on CT at 3 months, were considered to be stone-free. Post-operative complications were scored according to the Clavien–Dindo classification [