Analysis of factors affecting radiation exposure during percutaneous nephrolithotomy procedures

Trends in the use of radiation protection and radiation exposure of European endourologists: a prospective trial from the EULIS-YAU Endourology Group

INTRODUCTION

Due to the radiation exposure for the urology staff during endourology, our aim was to evaluate the trends of radiation protection in the operation room by endourologists from European centers and to estimate their annual radiation.

METHODS

We conducted a multicenter study involving experienced endourologists from different European centers to evaluate whether the protection and threshold doses recommended by the International Commission on Radiation Protection (ICRP) were being followed. A 36-question survey was completed on the use of fluoroscopy and radiation protection. Annual prospective data from chest, extremities, and eye dosimeters were collected during a 4-year period (2017-2020).

RESULTS

Ten endourologists participated. Most surgeons use lead aprons and thyroid shield (9/10 and 10/10), while leaded gloves and caps are rarely used (2/10 both). Six out of ten surgeons wear leaded glasses. There is widespread use of personal chest dosimeters under the apron (9/10), and only 5/10 use a wrist or ring dosimeter and 4 use an eye dosimeter. Two endourologists use the ALARA protocol. The use of ultrasound and fluoroscopy during PCNL puncture was reported by 8 surgeons. The mean number of PCNL and URS per year was 30.9 (SD 19.9) and 147 (SD 151.9). The mean chest radiation was 1.35 mSv per year and 0.007 mSv per procedure. Mean radiation exposure per year in the eyes and extremities was 1.63 and 11.5 mSv.

CONCLUSIONS

Endourologists did not exceed the threshold doses for radiation exposure to the chest, extremities and lens. Furthermore, the ALARA protocol manages to reduce radiation exposure.

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.

Personalized Prediction of Patient Radiation Exposure for Therapy of Urolithiasis: An Application and Comparison of Six Machine Learning Algorithms

The prediction of radiation exposure is an important tool for the choice of therapy modality and becomes, as a component of patient-informed consent, increasingly important for both surgeon and patient. The final goal is the implementation of a trained and tested machine learning model in a real-time computer system allowing the surgeon and patient to better assess patient's personal radiation risk. In summary, 995 patients with ureterorenoscopy over a period from May 2016 to December 2019 were included. According to the suggestions based on actual literature evidence, dose area product (DAP) was categorized into 'low doses' ≤ 2.8 Gy·cm² and 'high doses' > 2.8 Gy·cm² for ureterorenoscopy (URS). To forecast the level of radiation exposure during treatment, six different machine learning models were trained, and 10-fold crossvalidated and their model performances evaluated in training and independent test samples. The negative predictive value for low DAP during ureterorenoscopy was 94% (95% CI: 92-96%). Factors influencing the radiation exposure were: age (p = 0.0002), gender (p = 0.011), weight (p < 0.0001), stone size (p < 0.000001), surgeon experience (p = 0.039), number of stones (p = 0.0007), stone density (p = 0.023), use of flexible endoscope (p < 0.0001) and preoperative stone position (p < 0.00001). The machine learning algorithm identified a subgroup of patients of 81% of the total sample, for which highly accurate predictions (94%) were possible allowing the surgeon to assess patient's personal radiation risk. Patients without prediction (19%), the medical expert can make decisions as usual. Next step will be the implementation of the trained model in real-time computer systems for clinical decision processes in daily practice.

Fluoroscopy screening time and radiation dose during complete supine percutaneous nephrolithotomy

PURPOSE

Fluoroscopy-guided percutaneous nephrolithotomy (PCNL) is procedure of choice for treatment of large urinary tract calculi. This study aimed to investigate the affecting factors on fluoroscopy screening time (FST) and radiation dose (RD) of patients undergoing complete supine percutaneous nephrolithotomy (csPCNL).

METHODS

Analytic cross-sectional study was performed on 355 patients who underwent csPCNL. The correlation between the FST and RD and patients' demographics, stone characteristics, preoperative, intraoperative and postoperative parameters were assessed. Multivariate regression analysis was used to explore various parameters which affect FST and RD.

RESULTS

Of all 355 patients, 191 (54.65%) were male and 161 were (45.35%) female with mean age of 48.29 ± 12.38 (16-82) years. BMI was 27.61 ± 4.53 (16.61-39.00) kg/m². The mean operative time was 45.87 ± 18.29 min with mean FST of 101.72 ± 62.00 s. BMI, operative time, success rate, complications, stone number, and tract number had a significant relationship with FST and RD (P < 0.05). On multivariate analysis, BMI, tract number and success rate were found to be independent predictors for FST and RD. Age, gender, operation side, GFR, target calyx, lithotripsy history, stone opacity, size and site, stone configuration and distribution, and hydronephrosis did not have any correlation with FST and RD (P > 0.05).

CONCLUSION

BMI, success rate and tract number can be significant predictor for FST and RD during csPCNL. Identifying the affecting factors on FST and RD can help the surgeon to minimize the danger of radiation exposure by predicting and preoperative planning.

Safety During Ureteroscopy: Radiation, Eyes, and Ergonomics

It is known that urologic surgeons are at risk of work-place injury due to the physical requirements of operating and exposure to hazards. These hazards include radiation, exposure to body fluids, use of laser energy, and orthopedic injury due to the physical nature of operating. The risks that these hazards present can be mitigated by implementing several evidence-based safety measures. The methods to protect against radiation exposure include keeping radiation usage in the operating room as low as reasonably achievable, donning lead aprons, and wearing protective glasses. Additionally, protective glasses decrease the risk of eye injury from laser injury and exposure to body fluids. Finally, practicing sound surgical ergonomics is essential to minimize the risk of orthopedic injury and promote career longevity. The interventions discussed herein are simple and easy to implement in one's daily practice of urology.

Recent advances in percutaneous lithotripsy techniques

PURPOSE OF REVIEW

To describe and critically discuss the most recent evidence regarding the percutaneous nephrolithotomy (PCNL) techniques.

RECENT FINDINGS

Three-dimensional printing and virtual reality are promising tools to improve surgeon experience and operative performance. Totally ultrasound-guided PCNL is feasible and can reduce the radiological risk. Growing evidence highlights the safety and advantages of the use of miniaturized instrumentations, although some related limitations place the mini PCNL (mPCNL) in direct challenge with the retrograde intrarenal surgery. LithoClast Trilogy and ClearPetra system can improve the stone clearance. Thulium laser is a new source of energy with growing expectations and promising in-vitro results.

SUMMARY

Significant advances have recently been recorded in PCNL techniques. Thulium fiber laser, LithoClast Trilogy, new suction devices, and the development of novel technologies for teaching and planning procedures may overcome mPCNL drawbacks. Further studies are needed to confirm the promising preliminary results available on the topic.

FACTORS AFFECTING PATIENT RADIATION EXPOSURE DURING PRONE AND SUPINE PERCUTANEOUS NEPHROLITHOTOMY

Purpose Radiation exposure from fluoroscopy poses risks to patients and surgeons. Percutaneous Nephrolithotomy (PCNL) has traditionally required fluoroscopy, however the use of ultrasound (US) has decreased radiation exposure. US-guidance in supine PCNL may further reduce radiation exposure. In this study we investigate patient and operative factors affecting fluoroscopy time (s), total radiation dose (mGy) and effective radiation dose (ERD) (mSv) in patients undergoing US-guided supine or prone PCNL. Methods: We performed a retrospective study of patients undergoing US-guided PCNL in prone position and supine position. Patients with multiple access tracts, pre-existing renal access or fluoroscopic renal access were excluded. Patient demographic, radiologic and operative data were collected, and compared between the two groups. Results: 99 patients were included: 45 prone (P-PCNL) and 54 supine (S-PCNL). There were no significant demographic differences between the two groups. Operative time, access location, tract length and total radiation dose (mGy) also did not differ. S-PCNL was associated with lower ERD (2.92mSv ± 0.32 vs 5.3mSv ± 0.7, p=0.0014) despite increased fluoroscopy time (86.32s ± 7.7 vs. 51.00s ± 5.1, p=0.004), and was more likely a mini-PCNL (35.2‰ vs 15.9‰, p=0.032). In multivariate analysis, supine PCNL remained associated with reduced ERD compared to prone (p=0.002), whereas BMI (p<0.001) and staghorn calculi (p<0.001) were independently associated with increased ERD.

Minimizing radiation dose in management of stone disease: how to achieve 'ALARA'

PURPOSE OF REVIEW

Exposure to radiation is known to have adverse effects such as secondary malignancies. Patients with nephrolithiasis are exposed to radiation in the workup and treatment of their condition. Furthermore, exposure to radiation is often repeated due to the high recurrence rate of nephrolithiasis.

RECENT FINDINGS

We discuss practices inside and outside of the operating room to strive to keep radiation exposure as low as reasonably achievable (ALARA) for patients being treated for nephrolithiasis. These efforts include reduced dose computed tomography scans, fluoroless surgical techniques and new alternative technologies.

SUMMARY

Maintaining radiation exposure ALARA for our patients is increasingly practical. The urologist must make every effort to adhere to ALARA principles to protect patients from the stochastic effects of radiation.