Radiation exposure during retrograde intrarenal surgery (RIRS): a prospective multicenter evaluation

Lower Pole Stones Are Associated with Low Stone-Free Rates in Retrograde Intrarenal Surgery: A Myth or Fact? - A Matched Case-Control Study from the RIRSearch Group

INTRODUCTION

There are conflicting results in the literature regarding the efficacy of retrograde intrarenal surgery (RIRS) in lower pole stones. This study aimed to evaluate RIRS outcomes in lower pole stones by forming matched case-control groups.

METHODS

The data of 491 patients who were diagnosed with kidney stones and underwent RIRS were retrospectively included in the study. A total of 209 patients with lower pole stones (Group 1) and 282 patients with pelvic stones (Group 2) were matched at a 1:1 ratio in terms of stone burden, stone density, preoperative double-J stenting status, and a previous history of shock wave lithotripsy, yielding 159 patients in each group. A computed tomography scan was performed to evaluate the stone-free status. The primary outcome was stone-free status 1 month after RIRS.

RESULTS

After case-control matching, the median age was 49 years (interquartile range [IQR]: 40-58) in Group 1 and 50 years (IQR: 35-60) in Group 2 (p = 0.388). The median stone burden values of Group 1 and Group 2 were 415.3 mm3 (IQR: 176.1-858.2) and 503.3 mm3 (IQR: 282.5-864), respectively (p = 0.100). After RIRS, stone-free status was achieved by 126 of the 159 (79.2%) in Group 1 and 133 of the 159 (83.6%) patients in Group 2 (p = 0.387). The groups were similar in terms of perioperative complications (4.4% in Group 1 and 3.8% in Group 2, p = 0.777), postoperative complications (13.8% in Group 1 and 10.3% in Group 2, p = 0.393), and median operation time (60 min in both, p = 0.230). A longer median fluoroscopy time was noted in Group 1 compared to Group 2 (26 s and 3 s, respectively, p = 0.013).

CONCLUSIONS

Stone-free rates and complications were comparable between the patients with lower pole and pelvic stones after RIRS. However, lower pole stones are associated with longer fluoroscopy time. RIRS can be performed effectively for the treatment of lower pole stones.

Recent advances in the treatment of renal stones using flexible ureteroscopys

Upper urinary tract stones are a common urological disease that can be treated by flexible ureteroscopy (FURS) through the natural urinary tract, in addition to extracorporeal shock wave lithotripsy and percutaneous nephrolithotomy. The advantages of FURS are less trauma, faster recovery, and fewer complications, while its disadvantages include poor results of lithotripsy and stone extraction when dealing with larger stones, and prolonged operation time. Over the last two decades, the emergence of new technologies such as FURS combined with negative pressure suction, robot-assisted FURS, and artificially intelligent FURS, coupled with improvements in laser technology (the use of thulium fiber lasers and the invention of single-use flexible ureteroscopes (su-fURS) suitable for primary level application, have significantly increased the global adoption of FURS. This surge in usage holds a promising future in clinical application, benefiting a growing number of patients with renal calculi. Accompanied by changes in technical concepts and therapeutic modalities, the scope of indications for FURS is broadening, positioning it as a potential primary choice for urolithiasis treatment in the future. This review outlines the progress in employing FURS for the treatment of renal calculi in order to generate insights for further research.

Optimizing outcome reporting after robotic flexible ureteroscopy for management of renal calculi: Introducing the concept of tetrafecta

Robotic flexible ureteroscopy (RFURS) has shown encouraging results in terms of stone free rate (SFR) and better ergonomics compared to conventional FURS. However, few studies have reported its outcomes. The goal of this study was to report our initial results of RFURS, furthermore we proposed a novel metrics for composite outcome reporting named tetrafecta. A retrospective analysis of electronic records of 100 patients treated with RFURS for renal stones between 2019 till 2023 was performed. Tetrafecta criteria included, complete stone removal after a single treatment session, without auxiliary procedures, absence of high-grade complications (GIII-V) and same-day hospital discharge. Mean patient age and stone size were 40.7 ± 9.2 and 11.7 ± 5.8 mm, respectively. Median stone volume was 916 (421-12,235) mm3. Twenty-eight patients had multiple renal stones. Staghorn stones were seen in 12 patients. Preoperative DJ stent was fixed in 58 patients. Median operative time and stone treatment time were 116 min (97-148) and 37 (22-69) min. The median stone treatment efficiency (STE) was 21.6 (8.9-41.6). A strong positive correlation between stone volume and STE (R = 0.8, p < 0.0001). Overall, 73 patients were stone free after the initial treatment session while tetrafecta was achieved in 70 patients. Univariate analysis showed that the stone size (p = 0.008), acute infundibulopelvic angle (p = 0.023) and preoperative stenting (p = 0.017) had significant influence on achieving tetrafecta. Multivariate analysis identified preoperative stenting (OR 0.3, 95% CI 0.1-0.8, p = 0.019) as the only independent predictor of tetrafecta achievement. A comprehensive reporting methodology for reporting outcomes of RFURS is indicated for patient counseling and comparing different techniques. Tetrafecta was achieved in 70% of cases. Presence of significant residual stones ≥ 3mm was the leading cause of missing tetrafecta. Absence of preoperative stent was the only predictor of missing tetrafecta.

2022 Recommendations of the AFU Lithiasis Committee: Radiation protection in the operating theater

It has been shown that the relative risk of cancer is higher in patients with urinary stone disease, probably due to the repeated radiological exams and procedures under fluoroscopic guidance. Reducing the radiation doses delivered to the patient also decreases the doses delivered to the operators and their assistants. The doses delivered during endoscopic procedures decrease with the urologist's experience. Training in radiation protection and the use of protocols can decrease the use of ionizing radiation in the operating room. METHODOLOGY: These recommendations were developed using two methods: the Clinical Practice Recommendation (CPR) method and the ADAPTE method, depending on whether the question was considered in the European Association of Urology (EAU) recommendations (https://uroweb.org/guidelines/urolithiasis) [EAU Guidelines on urolithiasis. 2022] and whether they were adaptable to the French context.

A robotic system for solo surgery in flexible ureteroscopy: development and evaluation with clinical users

PURPOSE

The robotic system CoFlex for kidney stone removal via flexible ureteroscopy (fURS) by a single surgeon (solo surgery, abbreviated SSU) is introduced. It combines a versatile robotic arm and a commercially available ureteroscope to enable gravity compensation and safety functions like virtual walls. The haptic feedback from the operation site is comparable to manual fURS, as the surgeon actuates all ureteroscope DoF manually.

METHODS

The system hardware and software as well as the design of an exploratory user study on the simulator model with non-medical participants and urology surgeons are described. For each user study task both objective measurements (e.g., completion time) and subjective user ratings of workload (using the NASA-TLX) and usability (using the System Usability Scale SUS) were obtained.

RESULTS

CoFlex enabled SSU in fURS. The implemented setup procedure resulted in an average added setup time of 341.7 ± 71.6 s, a NASA-TLX value of 25.2 ± 13.3 and a SUS value of 82.9 ± 14.4. The ratio of inspected kidney calyces remained similar for robotic (93.68 %) and manual endoscope guidance (94.74 %), but the NASA-TLX values were higher (58.1 ± 16.0 vs. 48.9 ± 20.1) and the SUS values lower (51.5 ± 19.9 vs. 63.6 ± 15.3) in the robotic scenario. SSU in the fURS procedure increased the overall operation time from 1173.5 ± 355.7 s to 2131.0 ± 338.0 s, but reduced the number of required surgeons from two to one.

CONCLUSIONS

The evaluation of CoFlex in a user study covering a complete fURS intervention confirmed the technical feasibility of the concept and its potential to reduce surgeon working time. Future development steps will enhance the system ergonomics, minimize the users' physical load while interacting with the robot and exploit the logged data from the user study to optimize the current fURS workflow.

Flexible Ureteroscopy Without Radiation Exposure

Introduction:Renal stones are a common pathology in daily practice with a continuously increasing incidence. Using flexible ureteroscopy (fURS), urologists can treat difficult renal stones through the natural orifice and maintain a satisfactory stone-free rate. Even though advancing technologies offer the opportunity for minimally invasive surgery, the surgeon is still exposed to a considerable amount of ionizing radiation during several procedures. In this study, the aim is to determine the efficacy of flexible ureteroscopy without fluoroscopy in terms of stone-free rates and complications. Materials and methods:In the Urology Department of Saint John Clinical Emergency Hospital in Bucharest, Romania, a retrospective study was conducted on 98 patients diagnosed with renal calculi between September 2020 and December 2021. Using two different groups, the demographic characteristics of patients, characteristics of stones (size, number, location), the use of fluoroscopy, the operative time (in minutes) and postoperative complications, and the stone-free rate were compared. In one of the groups, fluoroscopy was used during fURS (Group I), while in the second group (Group II), no ionizing radiation was used during fURS. Results:Twenty-four males and 23 females were enrolled in Group I, whereas 31 males and 20 females were enrolled in Group II. The mean age of subjects was 63.2 years old in the fluoroscopy group and 61.6 years old in the group without fluoroscopy. While the stone characteristics revealed some variations in stone location between the compared groups, there were no statistical differences in mean stone diameter (1.489 mm - Group I vs. 1.588 mm - Group II). Stone-free rates and complications classified using Clavien-Dindo modified system for urological surgeries were used to analyze the main results. Group II had a slightly higher stone-free rate, but statistical studies found no significant differences; therefore, both methods are deemed equal in this field. Identified complications were classified as Clavien I and II and were successfully treated for both groups. Conclusion:This study reveals that by adhering to additional intraoperative measurements for guiding the access sheath, fURS without fluoroscopy can be performed safely and with a high success rate.

Radiation protection measures during endourological therapies

Objective

The objective of this narrative review was to search the existing literature for studies reporting measures to minimize radiation use during endoscopic management of stone disease and present ways of reducing the exposure of both patients and operating room staff.

Methods

A literature review in PubMed was performed to identify studies describing protocols or measures to reduce radiation received during endourological procedures from January 1970 to August 2022. Eligible studies were those that reported outcomes for ureteroscopy or percutaneous nephrolithotripsy regarding measures to minimize radiation doses used intraoperatively, performed either in real-life theatres or using phantoms. Both comparative and non-comparative studies were deemed eligible.

Results

Protection can be achieved initially at the level of diagnosis and follow-up of patients, which should be done following an algorithm and choice of more conservative imaging methods. Certain protocols, which follow principles for minimized fluoroscopy use should be implemented and urologists as well as operating room staff should be continuously trained regarding radiation damage and protection measures. Wearing protective lead equipment remains a cornerstone for personnel protection, while configuration of the operating room and adjusting X-ray machine settings can also significantly reduce radiation energy.

Conclusion

There are specific measures, which can be implemented to reduce radiation exposure. These include avoiding excessive use of computed tomography scans and X-rays during diagnosis and follow-up of urolithiasis patients. Intraoperative protocols with minimal fluoroscopy use can be employed. Staff training regarding dangers of radiation plays also a major role. Use and maintenance of protective equipment and setting up the operating room properly also serve towards this goal. Machine settings can be customized appropriately and finally continuously monitoring of exposure with dosimeters can be adopted.

ALARA in Urology: Steps to Minimise Radiation Exposure During All Parts of the Endourological Journey

Purpose of the Review

The global burden of kidney stone disease (KSD) and its management relies on ionising radiation. This includes the diagnosis, treatment and follow-up of KSD patients. The concept ‘As Low As Reasonably Achievable’ (ALARA) developed in response to the radiation risks and the key principles include optimisation, justification and limitation of radiation. This article provides an overview of the topic including background to the risks and steps that can be taken during all stages of endourological management.

Recent Findings

Our review suggests that ionising radiation is an invaluable tool in delineating the anatomy, localising disease, guiding manoeuvres and monitoring treatment in patients with KSD. It therefore plays an integral role in many stages of patient care; preoperatively, intraoperatively and postoperatively.

The reduction of radiation pre- and post-surgical intervention relies on the use of low-radiation CT scan and ultrasound scan. It can also be achieved through various intraoperative techniques or fluoroless techniques in selected patients/procedures, customised to the patients and procedural complexity.

Summary

There are many parts of the patient journey where exposure to radiation can take place. Urologists must be diligent to minimise and mitigate this wherever possible as they too face exposure risks. Implementation of strategies such as teaching programmes, fluoroscopy checklists and judicious use of CT imaging among other things is a step towards improving practice in this area.