Sheathless and fluoroscopy-free retrograde intrarenal surgery: An attractive way of renal stone management in high-volume stone centers

Design and Validation of a Novel 3D-Printed Retrograde Intrarenal Surgery Trainer

OBJECTIVE

To report on the design of a novel 3D-printed retrograde intrarenal surgery (RIRS) benchtop trainer and detail its validation against real-life experiences.

METHODS

Digital Imaging and Communications in Medicine (DICOM) files of 2 patients with normal computed tomography of the kidney and bladder were converted into stereolithography files to create 3D triangular mesh models. These images were further refined using Autodesk Meshmixer. These 3D models were fabricated through additive manufacturing, a process commonly known as 3D printing, and assembled in a polypropylene case. After development, the model was validated by 40 experienced urologists and urology residents in their final year of training. They were asked to rate the components of the simulation using a 9-point questionnaire.

RESULTS

The model's value in understanding the principles of RIRS and simulating contextual anatomy had mean scores of 9.43 (standard deviation [SD] = 0.74) and 9.21 (SD = 1.03), respectively. Mean scores for specific steps in RIRS were 8.07 (SD 1.47) for cannulating the ureteric orifice, 8.61 (SD 1.24) for inserting the ureteric access sheath, 9.29 (SD 0.97) for performing a renoscopy and evaluating all the calyces, 9.46 (SD 0.87) for laser lithotripsy, and 9.17 (SD 0.94) for manual stone retrieval. Participants scored the model with a mean score of 9.04 (SD 0.87) regarding realism and a mean score of 9.18 (SD 0.89) when evaluating its ability to enhance a trainee's confidence in RIRS.

CONCLUSION

The model performed well for all components of RIRS. This model allows high fidelity of the simulation and is cost-effective, portable, durable, reusable, and compatible with standard ureteroscopes.

Miniaturization of flexible ureteroscopes: a comparative trend analysis of 59 flexible ureteroscopes

The purpose of this review is to analyze the trend in miniaturization of flexible ureteroscopes over the past decades, identify the advantages and disadvantages, and determine the correlation of individual parameters with release period. Flexible ureteroscopes mentioned in the literature or those commercially available were searched. To minimize the search bias, the instruments were grouped by release date time periods of < 2000 year, 2000-2009, 2010-2019, and 2020 onwards. The final review included only those instrument models for which data on tip size, overall shaft, working length and channel size had been determined. The correlation among features investigated as well as with release period was also determined. 59 models of flexible ureteroscopes (26 fiber optic and 33 digital scopes) were included. Among the different features investigated among fiber optic endoscopes, only the sizes of the distal tip and overall shaft positively correlated with each other. In contrast to their fiber optic counterparts, a strong positive correlation was observed between tip and channel sizes, whereas negative correlation was found between channel size and overall shaft size and working length of digital scopes. Only distal tip of fiber optic flexible ureteroscopes and overall shaft of digital endoscopes were significantly reduced over their evolution. With the development of technology, there has been an improvement of flexible ureteroscopes and one of the indicators of this trend is a decrease in their size. With a definite trend towards miniaturization over the past decades, a significant correlation was observed in tip size and overall shaft for fiber optic and digital endoscopes, respectively.

The Role of Radiological Imaging in the Diagnosis and Treatment of Urolithiasis: A Narrative Review

The incidence and prevalence of urolithiasis have been increasing worldwide for the last several decades. This increase could be attributed to many factors, including missed cases of small stones, a sedentary lifestyle, a high BMI, a lack of physical activity, and poor dietary intake. In addition, the increased incidence of co-morbidities such as diabetes, dyslipidemia, infections, and multiple urinary tract surgeries could contribute significantly to the formation of urolithiasis. Radiology has a major role in diagnosing a variety of these stone types and can be used in planning management approaches, either as guidance or as a direct therapeutic method for stones. Because of the availability, safety, cost, and effectiveness of radiological imaging nowadays, urolithiasis is rarely missed; furthermore, the availability of radiological treatment options decreases the need for surgical intervention for urolithiasis, which minimizes hospital stay and surgical-related complications. This review aims to scope and analyze the role of radiological imaging modalities in reaching a diagnosis and planning treatment options for urolithiasis in different circumstances. Information was gathered from relevant peer-reviewed publications in PubMed and thereafter refined and summarized to provide a comprehensive review. The selected indexing terms included "radiological imaging modality," "treatment of urolithiasis," and "diagnosis of urolithiasis," among others.

Learning retrograde intrarenal surgery as a sheathless and radiation-free technique

The aim of this study was to evaluate the learning curve of inexperienced surgeon who can perform the operation on their own for access sheatless and radiation-free retrograde intrarenal surgery (RIRS) technique. Results of 70 consecutive patients who have renal stones and underwent RIRS which performed by a single surgeon were evaluated retrospectively. Cumulative stone free rates and fragmentation efficacy were taken as the primary outcomes for the learning curve analyses. Stone free rate was 74% (52/70). The learning curve constructed with moving average of cumulative stone free rates showed that learning curve of sheathless RIRS consisted of three phases; rapid ascent (0-15: phase 1), slight decline (16-35: phase 2) and plateau (36-70: phase 3). The number of case needed to obtain a final plateau in stone free rates was about 35. Fragmentation efficacy reached a plateau after 50 cases. The learning curve of access sheatless and radiation-free RIRS reached plateau phase after 35-50 cases. This steep learning curve points out that surgeons do not need to experience the classical RIRS technique before starting to perform access sheatless and radiation-free technique.

Systematic Review and Meta-Analysis Comparing Fluoroless Ureteroscopy and Conventional Ureteroscopy in the Management of Ureteral and Renal Stones

Context: Stone recurrence is frequent in stone formers, and repeated diagnostic and therapeutic procedures in recurrent stone formers place patients and urologists at a significant risk of radiation-related effects. Objective: To assess the efficacy and safety of fluoroless ureteroscopy (fURS) compared with conventional ureteroscopy (cURS) in the management of ureteral and renal stones. Evidence Acquisition: A systematic review was performed in accordance with the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) statement. Studies providing data on the stone-free rate (SFR), secondary procedures, operative time (OT), and complication rate for fURS and cURS were included. An overall analysis and a subgroup analysis based on the stone target (ureteral stones, renal stones, or a combination thereof) were performed. Evidence Synthesis: A total of 23 studies were included, recruiting 4029 patients. Pooled data showed that in comparison with cURS, fURS exhibited a similar SFR (odds ratio [OR]: 0.99; 95% confidence interval [CI]: 0.92 to 1.06; p = 0.709), without significant differences in overall intraoperative complication rate (OR: 0.73; 95% CI: 0.33 to 1.63; p = 0.446), overall postoperative complication rate (OR: 0.98; 95% CI: 0.59 to 1.63; p = 0.949), major postoperative complication rate (Clavien ≥3; OR: 0.46; 95% CI: 0.14 to 1.53; p = 0.205), OT (standardized mean difference [SMD]: 0.07; 95% CI: -0.15 to 0.29; p = 0.537), hospital stay (SMD: -0.12; 95% CI: -0.26 to 0.02; p = 0.084), or secondary procedures (OR: 1.20; 95% CI: 0.58 to 2.49; p = 0.616). The subgroup analysis revealed no differences in outcomes according to the stone target. We also identified a rate of conversion to the conventional technique of 5% (95% CI: 3% to 7%). Conclusions: The available data suggest that for the treatment of ureteral and renal stones, fURS offers a similar SFR to that provided by the cURS without any increase in complication rate, OT, hospital stay, or secondary procedures. Critical review of the dogmatic routine use of fluoroscopy during ureteroscopy may be warranted.