In view of the positive results of the numerous studies conducted on forced diuresis after extra-corporeal lithotripsy, the investigators chose to evaluate forced diuresis by injection of Furosemide associated with intravenous hydration, which has never before been the subject of a specific analysis.

Flexible ureteroscopy is the most common technique to treat kidney stones and is the treatment of choice in France.

Kidney stones destruction requires its laser pulverization into small fragments in order to remove them through the ureter or improve their spontaneous expulsion along the urinary tract. However, most of the time, all the micro-fragments and dust created during stone destruction cannot be extracted using our surgical tools, and may stay intra-renally at the end of the procedure. Although these micro-fragments are expected to disappear spontaneously by the natural flushing and peristalsis of the upper urinary tract, they remain at risk of stagnation that could be the nest of new aggregation and stone formation.

Adjuvant treatments (such as forced diuresis, inversion or mechanical pressure) were previously described to improve the expulsion of stone fragments after extra-corporeal shock wave lithotripsy.

Nevertheless, the impact of adjuvant treatment after flexible ureteroscopy remains unclear and mainly theoretical.

In view of the positive results of the numerous studies conducted on forced diuresis after extra-corporeal lithotripsy, the investigators chose to evaluate forced diuresis by injection of Furosemide associated with intravenous hydration, which has never before been the subject of a specific analysis.

Loop diuretics (including Furosemide) significantly increase diuresis, which results in a greater flow of urine into the renal cavities, improving the chances of evacuating the residual fragments of the stone destroyed during flexible ureteroscopy, before they can sediment in the fundus of the renal calices or in the pyelon. Therefore, the investigators hypothesize that a forced diuresis with an injection of Furosemide at the end of ureteroscopy could improve the micro-fragments and stones dust clearance.

Inclusion Criteria:

• Patients ≥ 18 years old and < 80 years old
• With the need to perform a flexible ureteroscopy with destruction of the kidney stones with laser
• Participants covered by or entitled to social security
• Written informed consent obtained from the participant
• Ability for participant to comply with the requirements of the study

Exclusion Criteria:

• Persons covered by articles L1121-5 to L1121-8 of the CSP (corresponding to all protected persons: pregnant women, parturients, nursing mothers, persons deprived of their liberty by judicial or administrative decision, minors, and persons subject to a legal protection measure: guardianship or trusteeship)

• Contra-indication to Furosemide:

  • Hyper-sensitivity to the active substance or one of the excipients
  • Hyper-sensitivity to Sulfonamide
  • Renal failure with oligo-anuria refractory to Furosemide
  • Hypokalemia < 3,5 mmol/L
  • Severe hyponatremia
  • Hypovolemia with or without hypotension or dehydration
  • Ongoing hepatitis, hepatic insufficiency severe and hepatic encephalopathy

• Patient having Furosemide as usual treatment

• Patient requiring an injection of Aminoside or Vancomycin before or during the procedure

• Participation in other interventional research with an investigational drug or medical device

The study will not be blinded except for the outcome assessment: radiologists in charge of interpreting CT-Scans will be blinded.