Endoscopically Determined Stone Clearance Predicts Disease Recurrence Within 5 Years After Retrograde Intrarenal Surgery

J Endourol. 2016 Jun;30(6):644-9. doi: 10.1089/end.2016.0101. Epub 2016 Apr 22.


Objective: To assess stone-related events (SREs) requiring retreatment in a series of 100 consecutive patients treated by retrograde intrarenal surgery (RIRS) for renal stones and to evaluate potential risk factors thereof.

Patients and methods: The primary outcome was incidence of SRE (medical or surgical treatment). Secondary outcomes included side of SRE, time to SRE, and late complications. Analysis of potential risk factors included high-risk stone formers (HRSFs), obesity, high stone burden, and lower pole stones. In addition, we evaluated endoscopically determined small residual fragments (SRF) of <1 mm (i.e., fragments too small for retrieval) as an independent risk factor.

Results: Eighty-five of the 99 patients were followed up for a mean of 59 months (31-69), among whom 26 (30.1%) had SRE. Thirty-four of the 85 (40%) patients were HRSFs, 22 of whom experienced SRE (both sides) during follow-up (64.7%, p < 0.001). Eight of the 17 patients (47.1%) with SRF experienced ipsilateral side SRE compared with 13 (19.1%) of the 68 without SRF (p = 0.022, hazard ratio 2.823, 95% confidence interval [95% CI] 1.16, 6.85). Risk for ipsilateral SRE was unaffected by the presence of SRF among HRSFs (p = 0.561). Of low-risk patients with SRF, 33.3% experienced ipsilateral SRE, while those without SRF experienced no ipsilateral SRE (p < 0.001).

Conclusion: Endoscopically determined stone clearance predicts disease recurrence within 5 years after RIRS. Even SRF are an important risk factor for future stone-related (ipsilateral) events; therefore, patients with residual fragments of any size should not be labeled "stone free" and endoscopic stone treatment should aim at complete stone clearance.

MeSH terms

  • Adolescent
  • Adult
  • Aged
  • Aged, 80 and over
  • Endoscopy / methods*
  • Female
  • Follow-Up Studies
  • Humans
  • Kidney / surgery
  • Kidney Calculi / diagnosis*
  • Kidney Calculi / surgery*
  • Male
  • Middle Aged
  • Obesity / complications
  • Proportional Hazards Models
  • Recurrence
  • Retreatment
  • Risk Factors
  • Young Adult