Purpose: To investigate the spontaneous clearance rates of remnant particles following miniaturized percutaneous nephrolithotomy (mini-PCNL) and retrograde intrarenal surgery (RIRS).
Methods: Among 624 patients who underwent mini-PCNL or RIRS at our institution from 2011 to 2015, we collected data of 247 patients with 2 years of follow-up. Of these, we included 148 patients with unilateral renal stones between 10 and 30 mm, as well as remnant particles after surgery. The size criteria of dusts and residual fragments (RFs) were, respectively, <1 and <3 mm.
Results: After excluding 22 patients, 126 patients (RFs = 21, dusts = 98, and both RFs and dusts = 7) were analyzed. Mean age was 56.5 (±14.4) years, and mean stone size was 19.5 (±12.5) mm. The mean follow-up period was 18.5 (± 12.9) months. In patients whose remnant particles were naturally eliminated following lithotripsy, the mean stone passage time was 9.0 (±9.3) months in the dusts and 13.9 (±11.1) months in the RFs groups (P = 0.135). Remnant particles disappeared in 42 out of 105 patients (40.0 %) in dusts and 7 out of 28 patients (25.0 %) in RFs groups (P = 0.187). The size of dusts and RFs increased, respectively, in 18.1 % (19/105) and 28.6 % (8/28) of patients with remnant particles during the follow-up period.
Conclusions: The presence of dusts and RFs was poor prognostic factors in patients underwent renal stone surgery using a holmium laser. Complete residual stone removal by using a basket or dusts eradication by irrigation for an adequate time during surgery can be a good surgical strategy.
Keywords: Laser; Lithotripsy; Predictive factors; Remnant particles; Urolithiasis.