Illumination matters part IV: blackout and whiteout in flexible ureteroscopy - first report on a phenomenon observed by PEARLS.

PURPOSE: To date, no study has evaluated effects of varying brightness settings on image quality from flexible ureteroscopes submerged in saline. The aim was to evaluate blackout and whiteout occurrences in an in-vitro kidney calyx model. MATERIAL AND METHODS: We evaluated a series of contemporary flexible ureteroscopes including the Storz Flex-Xc and Flex-X2s, Olympus V3 and P7, Pusen 7.5F and 9.2F, as well as OTU WiScope using a 3D-printed enclosed pink in-vitro kidney calyx model submerged in saline. Endoscopic images were captured with ureteroscope tip placed at 5 mm,10 mm and 20 mm distances. The complete range of brightness settings and video capture modes were evaluated for each scope. Distribution of brightness on a grayscale histogram of images was analyzed (scale range 0 to 255). Blackout and whiteout were defined as median histogram ranges from 0 to 35 and 220 to 255, respectively (monitor image too dark or too bright for the human eye, respectively). RESULTS: Blackout occurred with the P7, Pusen 7.5F, 9.2F and WiScope at all distances, and V3 at 20 mm - with lowest brightness settings. Whiteout occurred with Flex-X2s, V3 and P7 at 5 mm and 10 mm, as well as with V3 and P7 at 20 mm - mostly with highest brightness settings. The Flex-Xc had neither blackout nor whiteout at all settings and distances. CONCLUSION: Blackout or whiteout of images is an undesirable property that was found for several scopes, possibly impacting diagnostic and therapeutic purposes during ureteroscopy. These observations form a guide to impact a urologist's choice of instruments and settings.

Can the introduction of single-use flexible ureteroscopes increase the longevity of reusable flexible ureteroscopes at a high volume centre?

OBJECTIVES: To assess whether the introduction of single use flexibles ureteroscopes (su-fURS) at our high-volume centre had an advantageous impact on the turn-over and breakage rates of reusable fURS (re-fURS). METHODS: We analysed re-fURS number of usages and breakages at our centre between February 2015 and December 2018. We recorded the number of usages for analysed scope between the first usage until a breakage requiring reconditioning. Usage count was restarted following each reconditioning episode. Since su-fURS (Lithovue, Boston Scientific, USA) were introduced at our center in September 2016, we had the chance to compare different re-fURS life cycles according to both su-fURS availability and usage intensity (i.e., number of su-fURS used during each re-fURS life cycle). We then explored the relationship between su-fURS usage intensity and reusable scope survival (i.e., number of utilizations before any breakage requiring reconditioning) using locally weighted scatterplot smoothing (LOWESS) approach. RESULTS: Five different re-fURSs were employed at our centre, for a total of 1820 usages and 40 breakages requiring reconditioning. The overall mean (SD) number of usages before breaking was 40 (22). After su-fURS introduction, mean (SD) re-fURS number of usages increased from 35 (22) to 49 (20), (+ 40%, p = 0.02). The relationship between su-fURS usage intensity and reusable scopes survival showed a linear survival increase after 10 or more su-fURS scopes were used per life cycle. CONCLUSIONS: The life cycle of re-fURS increased by 40% after the introduction of su-fURS. Ten or more used su-fURS per life cycle were associated with increased re-fURS survival.

A systematic review of long-duration stents for ureteral stricture: which one to choose?

OBJECTIVE: To define which long-term stent would work best in malignant ureteral obstruction (MUO) and benign ureteral obstruction (BUO), focusing on their mechanisms of action, price and insertion approach. METHODS: A systematic review was developed using the MEDLINE and Scopus databases and in accordance with the PRISMA checklist. There were no language restrictions for the search. Studies describing the use of metallic ureteric stents for MUO and for BUO in humans were included. RESULTS: We analyzed five types of metallic stents (35 papers) and also the experience with the tumor and extra-anatomical stents. The Resonance, Memokath and Allium ureteral stents were found to be useful in BUO and MUO. The Uventa stent performed well in chronic ureteral obstruction. The Detour bypass stent was a recommended option in those patients who had complete obstruction of the ureter and were unfit for reconstructive surgery. There was no difference with regard to the insertion technique and both antegrade and retrograde approaches were equally successful. Although tumor stents showed a good performance, there were very few published studies on it. CONCLUSION: Metallic stents are a suitable option for MUO and BUO. When compared to standard double J stents, although they are relatively high priced, they show a financial benefit in the long-term. The Detour bypass stent seems to be an effective alternative for complete ureteral obstruction or patients unfit for surgery. Further prospective randomized studies should be done on the effectiveness of tumor stents versus metallic stents.

Comparison of intrapelvic pressures during flexible ureteroscopy, mini-percutaneous nephrolithotomy, standard percutaneous nephrolithotomy, and endoscopic combined intrarenal surgery in a kidney model.

PURPOSE: To compare intrapelvic pressure (IPP) levels achieved during f-URS, mini-PCNL, standard PCNL, and endoscopic combined intrarenal surgery in a kidney model. METHODS: A silicone model simulating the complete urinary tract was used for all the experiments. We compared: a 9.5Fr f-URS, a 12Fr mini-nephroscope and a 26Fr nephroscope. The irrigation pressure was set at 40 and 193 cmH2O. We compared: f-URS-S ± ureteral access sheath (UAS, 10/12Fr, 11/13Fr, 12/14Fr) ± 273 µm laser fiber, Mini-PCNL with different sizes of operating sheath (15/16Fr, 16.5/17.5Fr, 21/22Fr) ± 365 µm laser fiber, Standard PCNL with an operating sheath of 30Fr ± Lithotripter LithoClast Master 11.4Fr. RESULTS: f-URS: IPP values ranged between 1.4 and 46.2 cmH2O. Factors reducing IPP were an irrigation pressure at 40 cmH2O, an occupied working channel, and the use of a UAS except with the 10/12Fr at 193 cmH2O. Mini-PCNL: IPP values ranged between 2.4 and 39.7 cmH2O. Factors reducing IPP were irrigation pressure at 40 cmH2O, a large operating sheath (> 15/16Fr). The occupation of the working channel did not affect the IPP at 40 cmH2O, while it decreased at 193 cmH2O. Standard PCNL: IPP values ranged between 1.4 and 7.3 cmH2O. Occupancy of the working channel did not affect IPP at 40 cmH2O, while it increased at 193 cmH2O. CONCLUSION: We recorded for the first time IPP values according to different endourological techniques and configurations. IPP never exceed 50 cmH2O irrespectively of the assessed technique/setup. The factors reducing IPP were a low irrigation pressure (40 cmH2O), the use of a UAS or a working sheath appropriate to the diameter of the endoscope, as well as the occupation of the working channel in the case of f-URS.

Operator-assisted vs self-achieved basketing during ureteroscopy: results from an in vitro preference study.

OBJECTIVES: A recently introduced device (LithoVue Empower™ or LE, Boston Scientifics, USA) allows the surgeon to directly control the stone-retrieving basket without the need of an assistant during flexible ureteroscopy. We aimed to evaluate the stone-retrieval performance of this device. METHODS: We used a bench-training model for flexible ureteroscopy, the Key-box (K-Box®, Porgès-Coloplast, France), to compare the LE configured with a 1.9F stone-retrieval tipless basket (ZeroTip™, Boston Scientific, USA) and a traditional assistant-maneuvered 1.9F stone-retrieval tipless basket. Seven experienced endo-urologists and seven residents-in-training retrieved a fake stone from three different renal cavities of the K-Box with increasing access complexity first with the traditional basket and then with the LE device. We recorded retrieval time and all the operators filled in the NASA Task Load Index (TLI) for the self-evaluation of their performance. We then compared the use of LE in terms of retrieval time, failure rates, and NASA-TLI scores. RESULTS: Stone retrieval times and failure rates were similar according to the retrieval technique, although residents had non-statistically significant shorter times with the LE. NASA-TLI scores revealed lower frustration (p = 0.03) when LE was used by experienced urologists as compared to the traditional basketing. When stratifying the analyses according to surgical experience, fully trained urologists performed faster stone retrieval and showed lower effort scores than residents-in-training (p < 0.05). CONCLUSIONS: The individually controlled retrieval system is an effective device assisting stone retrieval and does not necessitate specific training among experienced endo-urologists. Young residents might benefit from LE during their learning curve.

Percutaneous nephrolithotomy in supine position with less than 24-hour hospital stay; a single-center experience.

Objectives: To report our initial experience of day care percutaneous nephrolithotomy (PCNL) with early hospital discharge within less than 24 hours of the procedure. Patients and Methods: The files of patients treated with PCNL between 1st January 2020 till 31st December 2022 were retrospectively reviewed. Day care PCNL was defined as the discharge of patients either on the same day or within 24 hours after surgery. Patient age, ASA score, body mass index, stone diameter, laterality, stone burden, Hounsfield unit, and Guy's score were analyzed. Operative time, size of the access tract, method of lithotripsy, estimated blood loss, and length of hospital stay were also recorded. Postoperative complications were stratified according to the Dindo-Clavien classification. The primary outcome was to evaluate the feasibility and safety of early discharge within 24 hours after PCNL compared to the in-patients who were kept in hospital for at least 2 days after surgery. Results: A total of 85 patients underwent PCNL at our center of whom 36 patients were discharged within 24 hours (day care PCNL) of the procedure and 49 patients were kept for at least 2 days (in-patient PCNL). In the day care group, median stone burden was 465 mm2 (360-980) and 18 patients (50%) had Guy's stone score ≥ III. The median tract size was 24 (13-30) and endoscopic combined intrarenal surgery (ECIRS) was performed in 7 cases in the day care group. Tubeless PCNL was carried out in 88.8% of the day care surgery group compared to 37.5% in the in-patient group (p < 0.0001). The postoperative complication rate was comparable between both groups (13.8% vs 22.4% for day care vs in-patient group, respectively, p = 0.08). Conclusions: Day care PCNL is feasible and safe for selected patients including those having large stone burden without increasing the risk of complications or readmission rate.

Ultrasound or Fluoroscopy for Percutaneous Nephrolithotomy Access, Is There Really a Difference? A Review of Literature.

Objective: To compare whether the outcomes of ultrasound-guided access percutaneous nephrolithotomy (USGA-PCNL) are similar to standard fluoroscopy-guided access percutaneous nephrolithotomy (FGA-PCNL). Methods: A review was developed by using the MEDLINE and Scopus databases and following the Preferred Reporting Items for Systematic Reviews and Meta-Analyses protocol. Studies comparing the USGA-PCNL and the FGA-PCNL were included. Case reports, editorials and letters, unpublished studies, posters, and comments abstracts were excluded. Results: We found 12 published articles that compared USGA-PCNL and FGA-PCNL. These included six randomized controlled trials, three case-control trials, and three meta-analyses. The overall results showed no difference in the success of percutaneous access, bleeding, blood transfusion, operative time, postoperative complications, or hospital stay. Conclusion: The reported data demonstrate that there are no significant differences between the fluoroscopic-guided access PCNL and the ultrasonographic access PCNL. The choice of puncture depends on the surgeon's expertise in a particular technique and the patient and stone characteristics. Both approaches are equally safe and effective in experienced hands. It is important to recall that the use of one technique does not exclude the use of the other, and they can sometimes be complementary to each other.

High- and Low-Power Laser Lithotripsy Achieves Similar Results: A Systematic Review and Meta-Analysis of Available Clinical Series.

Purpose: There is no clear evidence that high-power (HP) laser generators perform better than low-power (LP) ones in terms of lithotripsy outcomes. We aimed to perform a systematic review of literature to compare the efficacy outcomes of both HP and LP during ureteroscopic lithotripsy. Materials and Methods: A computerized bibliographic search of the Medline, Embase, and Cochrane databases was performed for all studies reporting perioperative outcomes of HP and LP lithotripsy. Using the methodology recommended by the preferred reporting items for systematic reviews and meta-analyses (PRISMA) guidelines, we identified 22 nonrandomized noncomparative retrospective studies published between 2015 and 2019 that were eligible for inclusion in this systematic review. Because of the lack of comparative studies, we decided to perform two separate meta-analytic syntheses for LP and HP studies, then we compared them using a Wald-type test. Results: Overall, the selected studies included 6403 patients. Study design, exposure assessment, selection criteria, and outcome of interest were heterogeneous. LP studies were more common (n = 17, 77%), whereas HP studies were more common in the latest inclusion period. Faster lithotripsy (32.9 minutes vs 63.9 minutes, p < 0.01) was observed in HP studies. However, stone volume resulted twofold higher (2604 mm3vs 1217 mm3, p = 0.048) in LP studies. Pooled stone-free rate was similar in both LP and HP studies, 81% and 82%, respectively, p > 0.05. No difference in complication rate was observed between the two groups, p = 0.12. Conclusions: HP laser lithotripsy appears to require shorter operative time, with similar stone-free and complication rates as compared with LP traditional lithotripsy. However, when taking into account stone burden, this advantage seems to be lost, or at least not to be comparable with what observed in laboratory studies. Because of the lack of high-level comparative evidence, further clinical studies are needed to elucidate the benefits of using HP laser generators during ureteroscopic stone treatment.

A Rare Presentation of Renal Papillary Necrosis in a COVID-19-Positive Patient.

In this case report we describe an unusual presentation of severe acute papillary necrosis in a COVID-19-positive patient. An emergency flexible ureteroscopy greatly helped in the establishment of the diagnosis. In the international literature, there is a paucity of intraoperative endoscopic images representing severe renal papillary necrosis. We present a case of severe acute renal papillary necrosis in a 49-year-old south-Asian, COVID-19-positive male patient who needed emergency urological intervention for macroscopic hematuria and urinary retention due to clot formation in the urinary bladder. The patient underwent emergency cystoscopy, clot evacuation, and by rigid and flexible ureteroscopy. The diagnosis was only confirmed in the postoperative period, retrospectively. Finally, the patient fully recovered due to the multidisciplinary management. Diagnosis of rare clinical entities can be sometimes challenging in the everyday routine practice. Having atypical clinical course, the surgeon should be prepared and sometimes must take responsible decisions promptly, even if needed intraoperatively, to manage unexpected findings in order to get the right diagnosis without compromising the patient's safety.

Effect of urine pH on the effectiveness of shock wave lithotripsy: A pilot study.

AIM: Shock wave lithotripsy (SWL) is a well-established modality in the treatment of urolithiasis. Studying the effect of urine pH on SWL success is appealing as pH can be manipulated before SWL to insure a better outcome. MATERIALS AND METHODS: This is a prospective study performed at a tertiary medical center. Patients presenting to the SWL unit with a single renal stone <2 cm in size were included in this study. In addition to standard laboratory and radiologic investigations, urine pH measurement was performed on all patients before their procedure. The number of sessions performed, and the stone-free rate (SFR) were assessed. Patients were divided into two groups according to stone clearance. Group 1 was stone-free, whereas Group 2 had residual stones after three sessions of SWL. Data was also classified according to different pH ranges. Influential factors were compared among the study groups and pH ranges. RESULTS: A total of 175 patients were included in this study. The SFR was 54.3%. The mean number of sessions performed was 2.2 ± 0.8. Group 1 included 95 patients, whereas Group 2 had eighty patients. Among all studied factors, stone size (P = 0.03) and skin to stone distance (P = 0.04) significantly affected SFR with SWL. Urine pH was not found to have a statistically significant influence on SWL outcome (P = 0.51). CONCLUSION: Urine pH was not found in this study population to influence the effectiveness of SWL. Further experimental studies are required to help investigate this notion.