This is a a prospective single-arm pilot study to investigate the safety and feasibility of flexible ureteroscopy under local anaesthesia. All consecutive patients who have undergone kidney-sparing surgery for managing upper tract urothelial carcinoma will be screened for study eligibility. The primary outcome is the procedural technical success rate. Secondary outcomes include the 30-day complication rate following flexible ureteroscopy, readmission rates, cost analysis, and patient-reported outcomes. Ureterorenoscopy will be conducted in the recruited patients under local anaesthesia in the ambulatory urology centre. Procedural details, technical success rates, adverse events and patient reported outcomes will be documented. The anticipated risks of this intervention are not expected to exceed those associated with the standard of care, that is ureterorenoscopy under anaesthesia. This pilot study aims to recruit a total of 10 subjects to assess the safety and feasibility of flexible ureterorenoscopy in an ambulatory care setting.

The study is designed to examine the safety and feasibility to conduct surveillance flexible ureteroscopy of the upper urinary tract under local anaesthesia in an ambulatory care setting.

The study is intended to identify patients who have undergone kidney-sparing surgery for upper tract urothelial carcinoma with need of surveillance of the upper urinary tract.

Prior to procedure, mid-stream or catheterised urine samples will be collected two weeks beforehand. To ensure a sterile urinary tract, asymptomatic bacteriuria will be treated with antibiotics tailored to the urine culture results, or with broad spectrum antibiotics. Anti-platelet or anticoagulation medications will be discontinued in accordance with local guidelines prior to the operation.

Procedures will be conducted by experienced urology specialists.The procedure will commence with the patient in a supine position, followed by the administration of transurethral lidocaine jelly five minutes prior to the procedure - either in room temperature or chilled preparation. Additional intravenous sedative medication prior to the endoscopic examination will be optional.

Initially, a flexible cystoscope will be introduced to examine the bladder and ureteric orifices, and a lower tract surveillance will be performed. In cases without a pre- existing ureteric double J stent, the ureteric orifice may be cannulated with a guidewire, followed by the introduction of a flexible ureteroscope, either alongside or railroading the guidewire.

The decision to use a guidewire in cases with tight ureteric orifices will be made by the operating urologist. If a ureteric double J stent is in situ, it will be retrieved using foreign body forceps with a flexible cystoscope, and a guidewire will be used for the stent exchange, then the flexible ureteroscope will be introduced alongside or railroading the guidewire.

The choice of ureteroscope will be left to the operating urologist's discretion. The procedure will either be performed with a reusable or a disposable fURS. The fURS will be inserted to the renal pelvis by direct vision. A complete renoscopy for the tip of the fURS deflecting to the different calyces will be performed. After renoscopy, the fURS will be carefully and slowly withdrawn. Saline irrigation through the instrumental channel will continually take place to ensure visibility of the lumen. During withdrawal, the ureter will be inspected, until the fURS is retrieved through the ureteric orifice. During renoscopic and ureteroscopic examination, findings will be documents in a pre-specified electornic form. Any suspicious mucosal lesion may be biopsied, subject to the operating urologist's judgment. A circulating nurse will monitor the patient's blood pressure, pulse, and pulse oximetry throughout the procedure. Should the patient experience intolerable discomfort or significant derangement in vital signs, the procedure will be immediately ceased.

Post-procedure, patients will be observed in the observation are of the ambulatory centre. Vital signs including blood pressure, pulse, oxygen saturation, and temperature will be monitored. Patients who do not require an indwelling urinary catheter will be encouraged to void, and their post-void residual urine volume will be recorded. Discharge from the ambulatory unit will be authorized only if the patient's vital signs remain stable and they demonstrate adequate voiding.

Upon discharge, all baseline characteristics and peri-procedural complications will be meticulously recorded in a designated electronic form. Complications will be graded using the Clavien-Dindo classification, and electronic records will be reviewed for up to 30 days post-procedure to document any instances of hospital attendance and the reasons thereof. i.e., ureterorenoscopy under anesthesia in an operating theatre. However, should any suspected ureteric injury or avulsion occur-a risk also inherent in standard procedures-the ureterorenoscopy will be halted, a double J stent will be placed via the guidewire, and the patient will be admitted to an inpatient ward for further monitoring and management.

The participants will be continually monitored if they suffer from any adverse event, till resolution of the event. All patients who experience an adverse event (AE) will be evaluated at appropriate time intervals until the event resolves or stabilizes. At the conclusion of the study, the investigator will assess unresolved AE and determine if additional follow-up is warranted based on clinical assessment.

Collection of Serious adverse event (SAE) information will begin at the time the patient signs the informed consent and continue through screen failure, end of study follow-up, or safety follow-up if the condition is not resolved or stabilized All SAE must be followed with appropriate medical management until resolved or until progression has been stabilized.

Inclusion Criteria:

1. Aged 18 years or older
2. Capable of giving informed consent
3. Having undergone an kidney-sparing surgery (endoscopic operation or segmental ureterectomy)

Exclusion Criteria:

1. Allergy to transurethral lidocaine jelly
2. On anticoagulation or anti-platelet medication with contraindications for cessation prior to the procedure
3. Structural abnormalities in the upper urinary tract on the intended side of examination

IPD could be shared upon contacting the principal investigator