title: Clearance rates of residual stone fragments and dusts after endoscopic lithotripsy procedures using a holmium laser: 2-year follow-up results.
abstract: OBJECTIVE
  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.
authors.affiliation: Department of Urology, Seoul National University Hospital, 101 Daehak-ro, Jongno-gu, Seoul, 110-744, Republic of Korea.
authors.forename: Minyong
authors.initials: M
authors.lastname: Kang
authors.affiliation: Department of Urology, Seoul National University Boramae Medical Center, Sindaebang 2-dong, 395, Dongjak-gu, Seoul, 156-707, Republic of Korea.
authors.forename: Hwancheol
authors.initials: H
authors.lastname: Son
authors.affiliation: Department of Urology, Seoul National University Boramae Medical Center, Sindaebang 2-dong, 395, Dongjak-gu, Seoul, 156-707, Republic of Korea.
authors.forename: Hyeon
authors.initials: H
authors.lastname: Jeong
authors.affiliation: Department of Urology, Seoul National University Boramae Medical Center, Sindaebang 2-dong, 395, Dongjak-gu, Seoul, 156-707, Republic of Korea.
authors.forename: Min Chul
authors.initials: MC
authors.lastname: Cho
authors.affiliation: Department of Urology, Seoul National University Boramae Medical Center, Sindaebang 2-dong, 395, Dongjak-gu, Seoul, 156-707, Republic of Korea. kmoretry@daum.net.
authors.forename: Sung Yong
authors.identifier: http://orcid.org/0000-0001-9271-6951
authors.initials: SY
authors.lastname: Cho
mesh_terms: D018450:Disease Progression; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D007669:Kidney Calculi / Q000628:therapy*; D053844:Lasers, Solid-State / Q000627:therapeutic use*; D017602:Lithotripsy, Laser / Q000379:methods*; D008297:Male; D008875:Middle Aged; D012189:Retrospective Studies; D013997:Time Factors; D016896:Treatment Outcome; D018666:Ureteroscopy / Q000379:methods*
keywords: Laser; Lithotripsy; Predictive factors; Remnant particles; Urolithiasis