Comparison of Limited Fluoroscopy and Conventional URSL

Background and Rationale

Ureteric stone is a common urological condition. Ureteroscopic lithotripsy (URSL), with its minimal invasive nature and high stone clearance rate, has been the standard for treatment of ureteric stone. In conventional URSL, fluoroscopy is used routinely. Advantages of routine fluoroscopy include road mapping for difficult retrograde access in case of impacted stone or ureteric stricture, confirmation of position of guidewire or ureteric stent, and looking for complications such as extravasation of contrast or ureteric perforation. However, routine fluoroscopy also has its disadvantages. Patients suffering from ureteric colics already had exposure to various degrees of radiation during investigative procedures such as X-ray and computed tomography; routine fluoroscopy may further expose them to unnecessary radiation. Routine fluoroscopy also poses radiation hazards to surgeons and staff in the operating theatre. In addition, there are reports on occupational safety issues such as back pain attributed to lead apron. Furthermore, insertion of guidewire and ureteric stent can be accomplished by direct visualization through ureteroscope or cystoscope and tactile feedback instead of routine fluoroscopy.

In view of the potential advantage of URSL with limited fluoroscopy, different studies have looked into the feasibility of performing URSL with limited or even no fluoroscopy. Mandhani reported complete clearance of distal ureteric stones in 99 out of 110 patients by URSL with no fluoroscopy. Tepeler, Hsi and Olgin reported that URSLs can be performed safely and effectively with limited or no fluoroscopy. Unfortunately, all these studies are retrospective reviews or prospective series without randomization. More importantly, the stone clearance rate between limited fluoroscopy URSL and conventional URSL was never compared. Without a randomized controlled trial studying the two approaches of URSL for ureteric stone, it would be difficult to determine the superiority of one approach over the other.

Aim of Study

To evaluate feasibility and radiation exposure in limited-fluoroscopy ureteroscopic lithotripsy (URSL) and to compare its complication and outcome with conventional URSL.

Trial Design and Setting

This is a prospective randomized controlled trial conducted across two centers. Patients who undergo URSL for ureteric stone and consent to the study will be randomized to 2 groups: limited fluoroscopy URSL and conventional URSL with routine fluoroscopy.

In the limited fluoroscopy URSL group, guidewire insertion, endoscopic advancement, stone fragmentation and ureteric stent placement will be completed under direct endoscopic view and tactile feedback. Stand-by fluoroscopy will be available and the operating surgeon can always obtain fluoroscopic image during the procedure in the same way as conventional URSL at his discretion. Upon completion of the operation, limited retrograde pyelogram will be performed to rule out complication and to confirm the position of ureteral stent.

In the conventional URSL group, fluoroscopy will be used upon guidewire insertion, endoscopic advancement, stone fragmentation and ureteral stent placement. Completion retrograde pyelogram will be performed to look for extravasation.

Study Population

Inclusion criteria include all patients 18 years of age or older who decided for URSL as the treatment for ureteric stone. Exclusion criteria include patients who are unable to consent, no stone upon ureteroscopy, known ureteric stricture or complicated ureteral anatomy, stone in solitary kidney and bilateral ureteric stones. Patients are free to withdraw from the study at any time and will continue to be managed as per usual. Their data will be used and analyzed according to the intention-to-treat principle.

Data Collection

Data collected from patients will include demographic data, laterality, location, size and number of stone, laser energy used, need of stent placement during operation, operative time and outcome, radiation exposure, intra-operative and post-operative complication, stone free rate and need of auxiliary procedure upon follow up.

Statistical Analysis

The sample size calculation rationale is based on the following: the mean radiation exposure of conventional URSL was 46.4 mGy and a mean radiation dose of 1.1 mGy in limited fluoroscopy URSL was reported. To prove the difference in radiation dose with estimated 90% power and a prediction of 20% dropout, the calculated sample size required for the primary endpoint is 60 patients, with 30 patients in each group.

Patient demographic data including age and sex, laterality, location, size and number of stone, laser energy used, need of stent placement during operation, operative time and outcome, radiation exposure, intra-operative and post-operative complication, stone free rate and need of auxiliary procedure upon follow up will be analyzed statistically. The chi-square statistic is used for categorical variables and the t-test is used for continuous variables to compare difference between the two groups with statistical significance considered at p<0.05. The intention-to-treat principle is adopted. All participants are analyzed in their assigned groups. SPSS will be used for all statistical analyses.

Primary End-point

Radiation exposure of limited-fluoroscopy URSL

Secondary End-points

Success rate of limited-fluoroscopy URSL

Operative time

Complication

Stone free rate

Need of auxiliary procedure

Data Access, Handling and Ethics

To protect patient privacy, all research data will be handled in line with Hospital Authority's or Hospital's policy in handling/storage/destruction of patients' medical records. They would be locked in cabinets where the department/ward keep patients' medical records. Electronic data would be saved in secured computer of the hospital with restricted access. USB Device would not be used for patient information for personal data. Personal data (name, HKID, address and any other personal identifiable information) should not be recorded on the projects' data sheets or electronic files. A study code will be used. Any documents or electronic files containing personal identifiable information would be considered as part of the medical record and will be dealt with the same stringent regulations of security according to the hospital policies. The principal investigator/co-investigator will be responsible for the execution of data protection. This study complies with the requirements of ICH-GCP.

There is no conflict of interest in this study. Previous retrospective studies and prospective series demonstrated feasibility and safety of limited/no fluoroscopy URSL. In our current trial, fluoroscopy will be provided at the surgeon's discretion in the limited fluoroscopy arm to ensure smooth and safe URSL. No additional financing or insurance requirements are necessary.