Appropriate kidney stone size for ureteroscopic lithotripsy: When to switch to a percutaneous approach

Impact of pulse duration alterable laser ureterorenoscopic lithotripsy for upper urinary tract calculi

To assess the effectiveness of a pulse duration alterable Holmium-YAG (Ho:YAG) laser on the stone-free rate (SFR) compared to a conventional pulse duration fixed laser after ureterorenoscopic lithotripsy (URSL). The medical records from patients with upper urinary tract calculi of ≥ 9 mm and < 30 mm were retrospectively investigated. URSL using a conventional Ho:YAG Laser (group C) or a pulse duration alterable Ho:YAG system (group A) was included. In total, 228 and 188 patients were enrolled in groups C and A, respectively. A 272 µm optical core bare-ended, reusable laser fiber was used, and the laser system was set to a standard 0.8 J and 10 Hz (8 W of average power) in both groups. URSL adopts active fragmentation using an extraction approach. SF was defined as the complete absence of stone fragments on computed tomography (CT) 1-2 months after URSL. Sex, BMI, stone length, stone volume, stone density, and the number of patients with positive preoperative urine cultures were not significantly different between the groups. However, age, rate of preoperative febrile urinary tract infection (fUTI), and pre-stenting were significantly higher in group A, and the operative times and incidence of postoperative fUTI were comparable. The SFRs were 71.5% and 80.3% in groups C and A, respectively (P = 0.035). Multivariate logistic regression revealed that the use of conventional laser was associated with non-SF (odds ratio [OR] 1.090, 95% confidence interval [CI] 1.01-1.18, P = 0.040). The present study revealed the superior performance of a pulse duration alterable Ho:YAG laser on the SFR after URSL compared to a conventional pulse duration fixed laser delivery system.

Semirigid Ureteroscopy Therapy against Childhood Kidney Stones

Objective

The purpose of the current study was to assess the effectiveness of semirigid ureterorenoscopy (URS) as first-line therapy for early childhood patients with <20 mm stones in the pelvic, middle, or upper calices.

Methods

In all, 61 pediatric kidney stone patients who had flexible ureteroscopy (fURS) between January 1, 2010, and December 31, 2019, were included in this study. Before fURS, semirigid URS employed the UreTron or holmium: YAG (Ho : YAG) laser was conducted. When semirigid URS was unsuccessful, fURS was used for retrograde intrarenal surgery (RIRS). All participants were monitored clinically for a minimum of three months after each procedure.

Results

The patient's mean age was 4.52 ± 1.53 years, and 52 (83.61%) participants underwent semirigid URS successfully. Mean procedural duration of semirigid URS was 36.49 ± 7.72 min. The stone-free rate after semirigid URS was 92.16% (47/51). During the postprocedural medical observation, there were no serious adverse effects.

Conclusions

Based on the present study's findings, semirigid URS is a low-risk, effective therapy for kidney stones in selected pediatric patients.

Robotic management of large stone disease: a case series

The gold standard for urologic management of large stone disease traditionally has been percutaneous nephrolithotomy (PCNL). An alternative to PCNL is robotic pyelolithotomy (RP), which continues to gain traction. This study is a retrospective review of ten cases performed over a 2 year period presenting operative outcomes for large stone disease treated with RP. The mean and standard deviation were calculated for age, body mass index, stone volume, stone diameter, pre-operative creatinine, operative time, robot-docked time, length of stay, post-operative creatinine, and estimated blood loss. In addition, results were collected for post-operative complications and secondary procedure requirements. Complete stone clearance was successful in 9 of 10 cases. The average renal function remained stable from a pre-operative creatinine of 0.917 mg/dL to a post-operative creatinine level of 0.943 mg/dL. This case series demonstrates that robotic assisted surgery has practical application when managing large stone disease.

A Novel Semirigid Ureterorenoscope with Vacuum Suctioning System for Management of Single Proximal Ureteral and Renal Pelvic Stones: An Initial Experience

INTRODUCTION

A novel semirigid ureterorenoscope, named the Sotn ureterorenoscope, was designed with a vacuum suction system. The present study aimed to evaluate the feasibility and safety of using the Sotn ureterorenoscope to manage single proximal ureteral or renal pelvic stones.

PATIENTS AND METHODS

Data were retrospectively collected from consecutive patients treated with a Sotn ureterorenoscope between February 2010 and August 2015 at Sun Yat-sen Memorial Hospital of Sun Yat-sen University and Jiangmen Wuyi Traditional Chinese Medicine Hospital in China. The primary outcome was the primary stone-free rate (SFR) in 1 month. The secondary outcomes were the final SFR and the perioperative complication rate.

RESULTS

A total of 386 patients were evaluated, including 240 males and 146 females. The median (interquartile range [IR]) age was 50 (40-59) years. There were 96 and 290 stones located in the renal pelvis and proximal ureter, respectively. The median (IR) operative time and console time for all patients were 40 (30-70) and 20 (12-38) minutes, respectively. The primary overall SFR was 86.5%, whereas the SFRs for stones with a diameter of ≤1, 1 to 2, and 2 to 3 cm were 95.7%, 86.9%, and 69.0%, respectively. Complications occurred in 90 patients (23.3%); these complications were classified as Clavien-Dindo grades 1 to 2 (minor) in 79 (20.5%) patients, and grades 3 to 4 (major) in 11 (2.8%).

CONCLUSIONS

The novel semirigid Sotn ureterorenoscope featuring a vacuum suction system is effective and safe for managing proximal ureteral and renal pelvic stones.

Characteristics of current digital single-use flexible ureteroscopes versus their reusable counterparts: an in-vitro comparative analysis

Background

Single-use flexible ureterorenoscopes (fURSs) have been recently introduced aiming to offer solutions to the sterilization, fragility and cost issues of the reusable fURSs. In order to be a viable alternative, the single-use scopes must prove similar capabilities when compared to their reusable counterparts. The goal of our in-vitro study was to compare the current reusable and single-use digital fURSs regarding their deflection, irrigation and vision characteristics.

Methods

We compared in-vitro 4 single-use fURSs-LithoVue™ (Boston Scientific, Marlborough, Massachusetts, USA), Uscope™ (Zhuhai Pusen Medical Technology Co. Ltd., Zhuhai, Guangdong Province, China), NeoFlex™ (NeoScope Inc, San Jose, California, USA) and ShaoGang™ (YouCare Technology Co. Ltd., Wuhan, China) versus 4 reusable fURSs-FLEX-X^c (Karl Storz SE & Co KG, Tuttlingen, Germany), URF-V2 (Olympus, Shinjuku, Tokyo, Japan), COBRA vision and BOA vision (Richard Wolf GmbH, Knittlingen, Germany). Deflection and irrigation abilities were evaluated with different instruments inserted through the working channel: laser fibres (200/273/365 µm), retrieval baskets (1.5/1.9/2.2 Fr), guide wires [polytetrafluoroethylene (PTFE) 0.038 inch, nitinol 0.035 inch] and a biopsy forceps. A scoring system was designed to compare the deflection impairment. Saline at different heights (40/80 cm) was used for irrigation. The flow was measured with the tip of the fURS initially straight and then fully deflected. The vision characteristics were evaluated (field of view, depth of field, image resolution, distortion and colour representation) using specific target models.

Results

Overall, the single-use fURSs had superior in-vitro deflection abilities than the reusable fURSs, in most settings. The highest score was achieved by NeoFlex™ and the lowest by ShaoGang™. PTFE guide wire had most impact on deflection for all fURSs. The 200 µm laser fibre had the lowest impact on deflection for the single-use fURSs. The 1.5 Fr basket caused the least deflection impairment on reusable fURSs. At the end of the tests, deflection loss was noted in most of the single-use fURSs, while none of the reusable fURSs presented deflection impairment. ShaoGang™ had the highest irrigation flow. Increasing the size of the instruments occupying the working channel led to decrease of irrigation flow in all fURSs. The impact of maximal deflection on irrigation flow was very low for all fURSs. When instruments were occupying the working channel, the single-use fURSs had slightly better in-vitro irrigation flow than the reusable fURSs. The field of view was comparable for all fURSs, with LithoVue™ showing a slight advantage. Depth of field and colour reproducibility were almost similar for all fURSs. ShaoGang™ and Uscope™ had the lowest resolution. FLEX X^c had the highest image distortion while LithoVue™ had the lowest. Partial field of view impairment was not for Uscope™ and ShaoGang™.

Conclusions

In-vitro, there are differences in technical characteristics of fURSs. It appears that single-use fURSs deflect better than their reusable counterparts. Irrespective of deflection, the irrigation flow of the single-use fURSs was slightly superior to the flow of the reusable fURSs. Overall, reusable fURSs had better vision characteristics than single-use fURSs. Further in-vivo studies might be necessary to confirm these findings.

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

Objective

To evaluate the efficacy and safety of sheathless and fluoroscopy-free flexible ureterorenoscopic laser lithotripsy (FURSL) for treating renal stones.

Methods

Between May 2015 and May 2017, 135 patients with renal stones treated with sheathless and fluoroscopy-free FURSL were prospectively evaluated. Our technique involved a semi-rigid ureteroscopic assessment of the ureter, and the guidewire was left in situ to railroad the flexible ureteroscope. A holmium laser was used to fragment and dust the stones; fragments were neither grasped nor collected.

Results

The study population consisted of 135 patients including 85 males (62.96%) and 50 females (37.04%) with a mean age of 40.65 years (range: 3–70 years) were evaluated. The mean stone size was 17.23 mm (range: 8–41 mm). Complete stone-free status was achieved in 122 (90.37%) patients and clinically insignificant residual fragments (CIRF) in two (1.48%), while residual stones were still present in 11 (8.15%) patients. Postoperative complications occurred in 23 (17.4%) cases and were mostly minor, including fever in 17 (12.6%), pyelonephritis in four (3.0%), subcapsular hematoma in one (0.7%) and steinstrasse in one (0.7%). These complications were Clavien I-II, GI in 17 (12.6%) patients, GII in five (3.7%), and Clavien IIIb in one (0.7%). No major complications were observed. Stone size ≥2 cm, operative time ≥30 min, and lasing time ≥20 min were significantly associated with a higher rate of complications and lower stone-free rates upon univariate analysis (p<0.05).

Conclusion

Sheathless and fluoroscopy-free FURSL are effective and safe for renal stone management, especially for stones under 2 cm in diameter. This process is a feasible option for avoiding sheath complications, which can protect surgeons from the negative effects of radiation.

Enterorenal Fistula as an Unusual Complication from Ureteroscopic Lithotripsy: A Case Report

Background: This case highlights an enterorenal fistula as a rare complication from ureteroscopic lithotripsy. Case Presentation: A 56-year-old woman with significant obesity, decompensated cirrhotic and ascitic liver disease, hypertension, type 2 diabetes mellitus, and nephrolithiasis treated with five prior ureteroscopic lithotripsies for a partial left staghorn stone presented to the emergency department (ED) with worsening left flank pain and sepsis. A CT scan of the abdomen and pelvis with contrast showed a large left perinephric hematoma. She underwent drain placement and during fluoroscopic imaging, there was a fistula from the left subcapsular hematoma/abscess to the proximal descending colon. The patient wished to proceed with a surgical course involving nephrectomy with hemicolectomy despite extensive counseling regarding her high mortality risk. However, because of worsening nutritional status as well as several other high-risk comorbidities, a shared decision was made with the patient to postpone the procedure. The patient was discharged to a skilled nursing facility for nutritional optimization and prehabilitation; however, she continued to decline with recurrent sepsis and cirrhosis-related complications and unfortunately passed away. Conclusion: A subscapular hematoma evolving into a perinephric abscess is a rare but known complication of ureteroscopic lithotripsy; however, this patient developed an enterorenal fistula that has yet to be reported after repeated ureteroscopy.

Accuracy of Ex Vivo Semiautomatic Segmentation of Urinary Stone Size in Computed Tomography Compared With Manual Size Estimation in Radiographic Correlation

OBJECTIVE

To evaluate the accuracy of semiautomated segmentation of urinary stone size in computed tomography (CT) compared with manual measurement.

MATERIALS AND METHODS

A total of 103 patients (32f, 71m ; mean age 52 years±18 that were diagnosed with urolithiasis and collected stones received standardized ex vivo CT-scans and radiography of the stones. Stone size was segmented semiautomatically using commercial software (syngo.via, Siemens, Germany) and compared with manual caliper measurement on digital radiography.

RESULTS

Mean size was 4.4 mm in CT and 4.6 mm in radiography. Depending on number of stones analyzed per patient, estimation of stone size showed moderate to excellent correlation for both methods. There was no significant difference in overall size measurement.

CONCLUSION

Semiautomatic segmentation of urinary stone size in CT is possible and reduces measurement errors, allowing more precise estimation especially for smaller concrements. Neighboring stones may hamper segmentation of stone size.

Predictive risk factors for systemic inflammatory response syndrome following ureteroscopic laser lithotripsy

The objective of this study was to investigate risk factors for the development of systemic inflammatory response syndrome following ureteroscopic laser lithotripsy. We retrospectively collected data of 469 patients who underwent ureteroscopic laser lithotripsy at our single institution from February 2008 to June 2016. Details for the patient, the stone, and the surgical factors that potentially contributed to postoperative infection were extracted. Using a logistic regression model, we analyzed how the clinical factors affected the incidence of systemic inflammatory response syndrome. Twenty-seven patients (5.7%) were postoperatively diagnosed with systemic inflammatory response syndrome; of these, 25 patients were diagnosed within 24 h after ureteroscopy. One patient required intensive care unit admission, but no death was reported. A preoperative stent was significantly associated with postoperative systemic inflammatory response syndrome only on univariate analysis, and the reasons for stenting were varied. Multivariate analysis revealed that obstructive pyelonephritis, a positive preoperative bladder urine culture result, and female gender were significantly associated with postoperative systemic inflammatory response syndrome. Patients who experienced obstructive pyelonephritis preceding ureteroscopic laser lithotripsy or had a positive preoperative bladder urine culture result were at an increased risk of systemic inflammatory response syndrome despite receiving appropriate preoperative antibiotic therapy. Regarding the impact of a preoperative stent on postoperative infection, further investigation focusing on reasons for stenting is needed.

Burden of Urolithiasis: Trends in Prevalence, Treatments, and Costs

CONTEXT

The recent evolution of management options for urolithiasis has presented a unique dilemma for the modern urologist. A comprehensive understanding of epidemiological trends along with current provider preferences in treating urinary stones would be beneficial.

OBJECTIVE

To review trends in the prevalence, treatments, and costs of urolithiasis worldwide.

EVIDENCE ACQUISITION

A literature review was performed using the MEDLINE database, the Cochrane Library Central search facility, Web of Science, and Google Scholar between 1986 and 2016. Keywords used for the search were "urolithiasis" and "prevalence; treatment; and cost".

EVIDENCE SYNTHESIS

The incidence and prevalence of urinary stones are rising around the world, including regions that have historically had low rates of urolithiasis. Common theories explaining this trend involve climate warming, dietary changes, and obesity. Shockwave lithotripsy (SWL) has been the preferred mode of treatment since its introduction in the 1980s. However, ureteroscopy (URS) has become increasingly popular for small stones regardless of location because of lower recurrence rates and costs. Developing countries have been slower to adopt URS technology and continue to use percutaneous nephrolithotomy at a steady rate.

CONCLUSIONS

URS has recently challenged SWL as the treatment modality preferred for small upper urinary tract stones. In some cases it is less expensive but still highly effective. As the burden of stone disease increases worldwide, appropriate selection of stone removal therapies will continue to play an important role and will thus require further investigation.

PATIENT SUMMARY

Urinary stones are becoming more prevalent. Recent advances in technology have improved the management of this disease and have decreased costs.

Retrospective Analysis of Ultrasound-guided Flexible Ureteroscopy in the Management of Calyceal Diverticular Calculi

Background:

Percutaneous nephrolithotomy (PCNL) is the most widely recommended treatment for calyceal diverticular calculi, providing excellent stone-free results. However, its invasiveness is not negligible considering its major complication rates. Flexible ureteroscopy (FURS) is currently used to treat calyceal diverticula. However, the greatest drawback of FURS is locating the diverticulum since its neck is narrow and concealed. In such a case, the FURS procedure must be converted to PCNL. The aim of this study was to evaluate ultrasound-guided flexible ureteroscopy (UFURS) identifying diverticulum and the management of calyceal diverticular calculi.

Methods:

A retrospective analysis was conducted on 24 patients who had calyceal diverticular calculi. In all 12 patients in the UFURS group, direct FURS failed to find evidence of calyceal diverticula but were confirmed with imaging. The other 12 patients in the PCNL group received PCNL plus fulguration of the diverticular walls.

Results:

Puncture of calyceal diverticulum was successful in all 12 UFURS patients. Two patients in this group had postoperative residual calculi and two patients developed fever. In the PCNL group, percutaneous renal access and lithotomy were successful in all 12 patients. One patient in this group had residual calculi, one had perirenal hematoma, and two patients developed fever. No significant difference was found in the operating time (UFURS vs. PCNL, 91.8 ± 24.2 vs. 86.3 ± 18.7 min), stone-free rate (UFURS vs. PCNL, 9/12 vs. 10/12), and rate of successful lithotripsy (UFURS vs. PCNL, 10/12 vs. 11/12) between the two groups (all P > 0.05). Postoperative pain scores in the FURS group were significantly lower than that in the PCNL group (2.7 ± 1.2 vs. 6.2 ± 1.5, P < 0.05). Hospital stay in the UFURS group was significantly shorter than that in the PCNL group (3.4 ± 0.8 vs. 5.4 ± 1.0 days, P < 0.05). All patients were symptom-free following surgery (UFURS vs. PCNL, 10/10 vs. 12/12).

Conclusion:

Ultrasound-guided puncture facilitates identification of calyceal diverticula during FURS and improves the success rate of FURS surgery.

Salvage Percutaneous Nephrolithotomy: Analysis of Outcomes following Initial Treatment Failure

PURPOSE

Percutaneous nephrolithotomy has high potential for morbidity or failure. There are limited data regarding risk factors for failure and to our knowledge no published reports of surgical outcomes in patients with prior failed attempts at percutaneous stone removal.

MATERIALS AND METHODS

We identified patients referred to 3 medical centers after prior failed attempts at percutaneous nephrolithotomy. A retrospective chart review was performed to analyze reasons for initial failure and outcomes of salvage percutaneous nephrolithotomy. Outcomes were compared to those in a prospectively maintained database of more than 1,200 patients treated with a primary procedure.

RESULTS

Salvage percutaneous nephrolithotomy was performed in 31 patients. Unsuitable access to the stone was the reason for failure in 80% of cases. Other reasons included infection, bleeding and inadequate instrument availability in 6.5% of cases each. Compared to patients who underwent primary percutaneous nephrolithotomy those treated with salvage were more likely to have staghorn calculi (61.3% vs 31.4%, p <0.01) and a larger maximum stone diameter (3.7 vs 2.5 cm, p <0.01), and require a secondary procedure (65.5% vs 42.1%, p <0.01). There was no significant difference between the cohorts in the remaining demographics or perioperative outcomes. All patients were deemed completely stone free except one who elected observation for a 3 mm nonobstructing fragment.

CONCLUSIONS

Despite the more challenging nature and prior unsuccessful attempts at treatment, the outcomes of salvage percutaneous nephrolithotomy were no different from those of primary percutaneous nephrolithotomy when performed by experienced surgeons.

Outcomes of flexible ureteroscopy and laser fragmentation for treatment of large renal stones with and without the use of ureteral access sheaths: Results from a university hospital with a review of literature

OBJECTIVE

The aim of this study was to analyse prospective data on flexible ureteroscopy and laser fragmentation (FURSL) of large stones (> 2 cm) to assess whether a ureteral access sheath (UAS) is necessary for the treatment of large renal stones.

MATERIALS AND METHODS

Between March 2012 and October 2014, 43 patients with large stones underwent FURSL. Data were collected on a prospective database for patient demographics, stone characteristics and outcomes of FURSL with and without a UAS.

RESULTS

There were 27 men and 16 women with a mean age of 54 years (range 7-84 years). The cumulative stone diameter was 2.92 cm (range 2-5 cm), with an overall stone-free rate (SFR) of 83.7%. A total of 68 procedures was needed (average 1.58 procedures/patient). The overall complication rate was 8.8% (n = 6); these were Clavien class II complications associated with urinary tract infections treated with additional antibiotics. UAS was not used in 28 procedures (41.2%). Comparing outcomes in those who had a UAS versus those who did not, there were no statistical differences in SFR, complication rate or average number of procedures per patients.

CONCLUSION

Use of a UAS does not make any difference to the SFR or complication rate for FURSL in large stones (> 2 cm) and may not be routinely needed in all cases.