The goal of this clinical investigation is to evaluate whether the Hydrustent® medical device is safe and if maintain the urinary flow inside the ureter in adults.

The main questions it aim to answer are:

• Does Hydrustent® maintain urinary patency post-surgery in adults?
• What medical issues do participants experience while using Hydrustent®?

Researchers will compare the Hydrustent® medical device to a comparator (a standard medical device used in clinical practice) to determine whether Hydrustent® is at least non-inferior in terms of safety and efficacy.

Other questions that the study will answer are:

• Does Hydrustent® exhibit a durability of at least 24 hours?
• Does Hydrustent® prevents the need of the surgical procedure to remove the ureteral stent?
• Does Hydrustent® reduce urinary symptoms associated with a ureteral stent?

Participants will:

• Have either the Hydrustent® or a comparator device inserted following the removal of ureteral or renal stones via endourological techniques.
• Be monitored for 3 months post-surgery through regular follow-up visits.
• Complete questionnaires and undergo imaging exams, as well as blood and urine analyses to assess recovery.

Multicentric, randomized, controlled clinical study comprising both phases of the pre-market device clinical development stage: pilot and pivotal. The first exploratory phase of the study (16 participants) will assess the safety of Hydrustent® for the first time in humans, while providing preliminary results on its efficacy. Following this, the second phase is confirmatory (118 participants), allowing the collection of the information necessary to evaluate the clinical performance and safety of Hydrustent®.

Pilot phase:

Inclusion:

• Subjects with the ability to understand the requirements of the study, who have provided written ICF before any assessment is performed, and are willing to undergo all FU assessments according to the specified schedule;
• Adult patients, males or females, aged between 18 and 70 years old;
• Subjects with ureteral and/or renal stones who have undergone a successful, uncomplicated, unilateral URS and RIRS, with clinical indication to place a post-operative US, as judged by the medical investigator;
• Subjects with a height and body sizeable to accommodate a 22, 24, 26, 27 and 28 cm long US and diameter of 7 Fr, as judged by the medical investigator;
• Female participants of childbearing potential and male participants whose partner is of childbearing potential must be willing to ensure that they or their partner use protocol's recommended effective contraception methods during all the trial duration;
• Male participants must agree to refrain from donation of semen from the start of the study treatment up to the end of the study.

Exclusion:

• Subjects with urinary anatomic malformations or previous relevant surgical modifications.
• Subjects with known/suspicion of urothelial or renal tumour;
• Subjects with known/suspicion of extrinsic compression of the ureter and/or stricture;
• Subjects with known/suspicion of ureteral perforation and/or fistula;
• Subjects under active treatment for bladder outlet obstruction (e.g., benign prostatic obstruction), neurogenic bladder, overactive bladder, and/or urge urinary incontinence;
• Subjects with a solitary kidney;
• Subjects with calculated GFR below 60 mL/min/1.73m2;
• Subjects with known renal insufficiency or chronic impairment;
• Subjects with post-operative suspicion/known incomplete stone fragmentation with the presence of relevant residual urinary lithiasis, requiring an additional procedure;
• Subjects with active history of bleeding diathesis or currently taking anticoagulants (except antiplatelet agents);
• Subjects with pre-operative evidence of staghorn calculi;
• Subjects with suspicious/diagnosed UTI at the time of US placement, or pre-operative positive urine culture or active UTI taking antibiotic medication;
• Subjects with contrast allergy; Pregnant, lactating, or women of childbearing potential who do not employ a highly effective contraceptive method as judged by the medical investigator, and/or who are not willing to use a highly effective contraception for the duration of study participation;
• Subject with a known severe psychiatric disorder, substance abuse, or other reason for being unable to follow study FU instructions or unable to reliably complete patient questionnaires;
• Subjects with signs of local or systemic acute/active or chronic infections;
• Subjects with sensibility or known hypersensitivity to the implantable materials;
• Subjects with ureteral blockage or stricture;
• Subjects with failed guidewire placement or failed ureteroscopy access;
• Subjects with suspect ureteral avulsion;
• Subjects with untreated infected urinary obstruction of the kidneys (pyonephrosis);
• Subjects with vascular abnormalities of the renal pelvis outlet;
• Subjects with unexplained haematuria;
• Subjects with significant urethral obstruction;
• Subjects with concomitant or untreated bladder lithiasis;
• Any other condition that would deem a subject ineligible for treatment with the investigational device in the opinion of the medical investigator;
• Subject is known to be currently enrolled in another investigational study.

Pivotal phase:

Inclusion:

• Subjects with the ability to understand the requirements of the study, who have provided written or oral informed consent form before any assessment is performed, and are willing to undergo all FU assessments according to the specified schedule;
• Adult patients, males or females, aged > 18 years old;
• Subjects with ureteral and/or renal stones who have undergone a successful, unilateral ureteroscopy and retrograde intra-renal surgery, with clinical indication to place a post-operative US, as judged by the medical investigator;
• Subjects with a height and body sizeable to accommodate a 22, 24, 26, 27 and 28 cm long US and diameter of 7 Fr, as judged by the medical investigator;
• Female participants of childbearing potential and male participants whose partner is of childbearing potential must be willing to ensure that they or their partner use protocol's recommended effective contraception methods during all the trial duration;
• Male participants must agree to refrain from donation of semen from the start of the study treatment up to the end of the study.

Exclusion:

• Urinary anatomic malformations or previous relevant surgical modifications;
• Subjects with known/suspicion of urothelial or renal tumour;
• Subjects with known/suspicion of extrinsic compression of the ureter and/or stricture;
• Subjects with known/suspicion of ureteral perforation and/or fistula;
• Subjects under active treatment for bladder outlet obstruction (e.g., benign prostatic obstruction), neurogenic bladder, overactive bladder, and/or urge urinary incontinence;
• Subjects with a solitary kidney;
• Subjects with calculated Glomerular Filtration Rate below 60 mL/min/1.73m2;
• Subjects with post-operative suspicion/known incomplete stone fragmentation with the presence of relevant residual urinary lithiasis, requiring an additional procedure;
• Subjects with active history of bleeding diathesis or currently taking anticoagulants (except antiplatelet agents);
• Subjects with pre-operative evidence of staghorn calculi;
• Subjects with suspicious/diagnosed urinary tract infection at the time of ureteral stent insertion, or pre-operative positive urine culture or active urinary tract infection taking antibiotic medication;
• Subjects with contrast allergy;
• Pregnant, lactating, or women of childbearing potential who do not employ a highly effective contraceptive method and/or who are not willing to use a highly effective contraception for the duration of study participation;
• Subject with a known severe psychiatric disorder, substance abuse, or other reason for being unable to follow study FU instructions or unable to reliably complete patient questionnaires;
• Subjects with signs of local or systemic acute/active or chronic infections;
• Subjects with sensibility or known hypersensitivity to the implantable materials;
• Subjects with ureteral blockage or stricture;
• Subjects with failed guidewire placement or failed ureteroscopy access;
• Subjects with suspect ureteral avulsion;
• Subjects with untreated infected urinary obstruction of the kidneys (pyonephrosis);
• Subjects with vascular abnormalities of the renal pelvis outlet;
• Subjects with unexplained haematuria;
• Subjects with significant urethral obstruction;
• Subjects with concomitant or untreated bladder lithiasis;
• Any other condition that would deem a subject ineligible for treatment with the investigational device in the opinion of the medical investigator;
• Subject is known to be currently enrolled in another investigational study.

Investigators that will place the stent will not be the same that will perform the follow-up visits.