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

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

Endoscopic Treatment of Upper Tract Urothelial Carcinoma: Challenging the Definition of the Maximal Lesion Size for Safe Ablation

Introduction: With advances in endoscopic treatment of upper tract urothelial carcinoma (UTUC) lesions, the recommended upper limit of lesion size amenable to laser ablation was set to 2 cm. However, this limit is based on expert opinion only, and debate still exists regarding this definition. Objective: To determine the maximal size of the tissue, for which total endoscopic ablation with laser energy is achievable, from a laser performance perspective. Materials and Methods: Simulating endoscopic surgery conditions, renal tissue blocks from pork kidneys in growing size from 1 cm3 to 3 cm3 were totally ablated with Ho:YAG laser (1 J, 10 Hz). The time to ablation was recorded for each tissue mass. Following the ablation, each sample was inspected microscopically by an expert pathologist to determine the extent to which the tissue was destroyed. Results: Time to ablation ranged from 16.4 min for a 1 cm3 mass, to 69.7 min for a 3 cm3 mass. Histologic evaluation after laser ablation showed that ablation was achieved in all tissue masses, and no &ldquo;unaffected&rdquo; tissue was present, even for lesions with a size of 3 cm3. Conclusions: This study showed that laser ablation can be achieved for tumor lesions up to a size of 3 cm3. The results of this study can contribute to the debate regarding the limits of endoscopic management of UTUC lesions and strengthen the recommended upper limit of 2 cm3 for endoscopic treatment of tumor lesions

Endoscopic Treatment of Upper Tract Urothelial Carcinoma: Challenging the Definition of the Maximal Lesion Size for Safe Ablation

Introduction: With advances in endoscopic treatment of upper tract urothelial carcinoma (UTUC) lesions, the recommended upper limit of lesion size amenable to laser ablation was set to 2 cm. However, this limit is based on expert opinion only, and debate still exists regarding this definition. Objective: To determine the maximal size of the tissue, for which total endoscopic ablation with laser energy is achievable, from a laser performance perspective. Materials and Methods: Simulating endoscopic surgery conditions, renal tissue blocks from pork kidneys in growing size from 1 cm3 to 3 cm3 were totally ablated with Ho:YAG laser (1 J, 10 Hz). The time to ablation was recorded for each tissue mass. Following the ablation, each sample was inspected microscopically by an expert pathologist to determine the extent to which the tissue was destroyed. Results: Time to ablation ranged from 16.4 min for a 1 cm3 mass, to 69.7 min for a 3 cm3 mass. Histologic evaluation after laser ablation showed that ablation was achieved in all tissue masses, and no “unaffected” tissue was present, even for lesions with a size of 3 cm3. Conclusions: This study showed that laser ablation can be achieved for tumor lesions up to a size of 3 cm3. The results of this study can contribute to the debate regarding the limits of endoscopic management of UTUC lesions and strengthen the recommended upper limit of 2 cm3 for endoscopic treatment of tumor lesions

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 cmH$_{2}$O. 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 cmH$_{2}$O. Factors reducing IPP were an irrigation pressure at 40 cmH$_{2}$O, an occupied working channel, and the use of a UAS except with the 10/12Fr at 193 cmH$_{2}$O. Mini-PCNL: IPP values ranged between 2.4 and 39.7 cmH$_{2}$O. Factors reducing IPP were irrigation pressure at 40 cmH$_{2}$O, a large operating sheath (> 15/16Fr). The occupation of the working channel did not affect the IPP at 40 cmH$_{2}$O, while it decreased at 193 cmH$_{2}$O. Standard PCNL: IPP values ranged between 1.4 and 7.3 cmH$_{2}$O. Occupancy of the working channel did not affect IPP at 40 cmH$_{2}$O, while it increased at 193 cmH$_{2}$O. CONCLUSION We recorded for the first time IPP values according to different endourological techniques and configurations. IPP never exceed 50 cmH$_{2}$O irrespectively of the assessed technique/setup. The factors reducing IPP were a low irrigation pressure (40 cmH$_{2}$O), 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

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

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

ABSTRACTObjectives 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