What Do We Mean by "Stone Free," and How Accurate Are Urologists in Predicting Stone-Free Status Following Ureteroscopy?

Under embargo until: 2022-01-12Background and Purpose: No consensus exists on how stone-free rates (SFRs) should be reported after stone treatment. The aim of this study was to assess how accurate urologists predict their patients being stone free after completing ureteroscopy (URS) and to see how various treatment strategies influenced the precision of these predictions. We also wanted to study how different definitions of stone-free status (SFS) affected the results and propose a standard definition of “stone free” to be used in future studies. Materials and Methods: A retrospective evaluation of 1019 URS done for stone treatment at Haukeland University Hospital between 2013 and 2018 was performed. Data on pretreatment status, the surgical procedure, and follow-up were recorded. SFS was defined as either no fragments detected on computed tomography (CT) after 3 months or as practical stone-free status, which also included those with small residual fragments not needing further treatment. Exact chi-squared and independent-samples t-tests were used comparing data between different treatment modalities. Results: The overall SFR, irrespective of treatment strategy and location of stone, using the no residual fragments and practical stone-free definitions were 54.2% and 74.7%, respectively. Urologists predicted intraoperatively that 91.0% of their patients treated with fragmentation and extraction would be stone free compared to 76.8% of patients treated with dusting, p < 0.0001. At follow-up, the actual SFRs with no residual fragments for the two treatment strategies were 68.0% and 35.5%, respectively, p < 0.0001. The practical SFRs for fragmentation and retrieval were 83.1% and 64.8% for dusting, p < 0.0001. Conclusion: The different definitions of SFS have great impact on SFRs. Urologists are far too optimistic predicting their patient being stone free after URS. SFS should be defined as no fragments detected on CT 3 months after the URS procedure when presented in studies.acceptedVersio

Thulium Fibre Laser versus Holmium:YAG for Ureteroscopic Lithotripsy: Outcomes from a Prospective Randomised Clinical Trial

Background Holmium:yttrium-aluminium-garnet (Ho:YAG) laser is the gold standard for ureterorenoscopic (URS) lithotripsy. Thulium fibre laser (TFL) has recently been introduced as a new technology and may challenge Ho:YAG as the preferred laser owing to favourable properties as demonstrated in preclinical studies. Objective To evaluate and compare outcomes after URS lithotripsy with Ho:YAG and TFL. Design, setting, and participants In a prospective randomised trial, patients aged ≥18 yr with ureteral and/or renal stones (≥5 mm) scheduled to undergo day-case URS lithotripsy were invited to participate. In total, 120 consecutively admitted patients with signed consent were included for randomisation. Intervention URS lithotripsy with Ho:YAG or TFL. Outcome measurements and statistical analysis The primary outcome was the stone-free rate (SFR) assessed on noncontrast computed tomography at 3-mo follow-up. Secondary outcomes were the operative time and complications. Outcomes were compared between the groups using the t test and χ2 test. Results and limitations After a single session, the SFR was 67% in the Ho:YAG group and 92% in the TFL group, p = 0.001. For ureteral stones, the SFR was 100% in both groups, and for renal stones; 49% (Ho:YAG) and 86% (TFL), p = 0.001. Operative time was shorter using TFL (49 min) compared to Ho:YAG (57 min), p = 0.008. Bleeding that impaired the endoscopic view was the most frequent intraoperative adverse event and occurred in 13 patients (22%) in the Ho:YAG group and three (5%) in the TFL group, p = 0.014. Conclusions In this study, significantly more patients with renal stones achieved stone-free status and fewer experienced intraoperative complications using TFL compared to Ho:YAG. TFL is the emerging laser of choice for stone lithotripsy. Patient summary We compared outcomes after ureterorenoscopic treatment of kidney and ureteral stones using two different lasers. Our results show that the new thulium fibre laser technology is superior to the current standard laser (holmium:YAG) in clearing kidney stones and reducing operative complications.publishedVersio

Ureteroscopy for stone disease in the paediatric population: lessons learned and outcomes in a Nordic setting

Introduction: Paediatric stone disease is rare in the Nordic communities. Still, the condition can require surgical intervention in the form of ureteroscopy (URS). Here, we report outcomes achieved at a regional (tertiary) centre. Patients and methods: Retrospective analysis was performed of consecutive patients (<18 years of age) undergoing URS for stone disease between 2010 and 2021. Outcomes of interest included stone-free rate (SFR) determined using a definition of no residual fragments ⩾ 3 mm on imaging and complications classified according to Clavien–Dindo system. Results: In total, 23 patients underwent 47 URS procedures for a total of 31 stone episodes. Mean age was 9 (range 1–17) years and male-to-female ratio was 6:17. Overall, 35% had at least one medical comorbidity. Ultrasound determined preoperative stone status in 87%. Mean largest index and cumulative stone sizes were 9 (range 3–40) and 12 (range 3–40) mm, respectively. Overall, 32% had multiple stones. Lower pole was the commonest stone location (39%). No patients underwent elective pre-operative stenting. Ureteral access sheaths were not used in any cases. Access to upper urinary tract at first procedure was successful in 94%. Initial and final SFR was 61% and 90%, respectively. No intra-operative complications were recorded. Overall post-operative complication rate was 17.5%. Urinary tract infection (CD II) was the commonest adverse event (12.5%). Conclusion: Paediatric URS can be delivered in the setting of a regional centre without compromising outcomes. This includes when carried out by adult endourologists, without routine pre-stenting and omitting use of ureteric access sheath.publishedVersio

Holmium and Thulium Fiber Laser Safety in Endourological Practice: What Does the Clinician Need to Know?

Purpose of Review: To summarise the literature on laser safety during endourological practice. Recent Findings: Holmium and Thulium Fiber laser are the two main energy sources in the current clinical practice. The latter may have superior properties, but more clinical studies are needed to formally establish this. Laser injury to urothelium is more dependent on user experience rather than laser type. Smaller laser fibres allow for lower intra-renal temperature profiles. Operators should pay close attention to laser technique including maintaining the safety distance concept and only firing the laser when tip is clearly in view. When adjusting laser settings, pay close attention to resultant power given the associated heat changes. Prolonged periods of laser activation are to be avoided for the same reason. Outflow can be manipulated such as with access sheath to mitigate temperature and pressure changes. There is still limited evidence to support the mandate for compulsory use of eye protection wear during laser lithotripsy. Summary: Lasers are the gold standard energy source for stone lithotripsy. However, the safe clinical application of this technology requires an understanding of core principles as well as awareness of the safety and technical aspects that can help in protecting patient, surgeon and operating staff.publishedVersio

Paediatric kidney stone surgery: state-of-the-art review

While urolithiasis in children is rare, the global incidence is rising, and the volume of minimally invasive surgeries being performed reflects this. There have been many developments in the technology, which have supported the advancement of these interventions. However, innovation of this kind has also resulted in wide-ranging practice patterns and debate regarding how they should be best implemented. This is in addition to the extra challenges faced when treating stone disease in children where the patient population often has a higher number of comorbidities and for example, the need to avoid risk such as ionising exposure is higher. The overall result is a number of challenges and controversies surrounding many facets of paediatric stone surgery such as imaging choice, follow-up and different treatment options, for example, medical expulsive therapy, shockwave lithotripsy, ureteroscopy, and percutaneous nephrolithotomy. This article provides an overview of the current status of paediatric stone surgery and discussion on the key topics of debate

Device Failure and Adverse Events Related to Single-use and Reusable Flexible Ureteroscopes: Findings and New Insights From an 11-Year Analysis of the Manufacturer and User Facility Device Experience Database

Objective To catalog and characterize device failures and adverse events related to flexible ureteroscopes from a national database. Methods Search of the Manufacturer User and Facility Device Experience database was performed for all recorded events related to flexible ureteroscopes between 2012 and 2022. The following information was collected: Problem and cause, timing, complications and injury, prolonged anesthesia, and early termination of procedure. Event severity was graded using a validated tool. Results A total of 206 events were identified (reusable/single use ratio, 2.5:1). There were 20 different problem categories reported, which included image loss (26.7%), difficulty removing scope (13.6%), scope damage from basket (4.4%), detachment of scope tip (5.8%) and contamination (4.9%). Faulty device was the predominant cause for an event related to single-use scopes (86.4%); this was seldom the case for reusable (2%). Patient injury occurred in 21.8%, but these were all in reusable scopes. No deaths were reported, but major complications included complete avulsion of the ureter (3.4%) and fully entrapped scope necessitating open surgery (2.9%). While the safety profile for single-use scopes was superior, they were significantly more likely to result in early termination (71.1% vs 37.3%, P < .001). This was related to 76.3% of the single-use scopes experiencing sudden image loss. Conclusion Flexible ureteroscopes are fragile, and a multitude of problems can occur. Many of these can be avoided through correct surgeon technique and robust maintenance services.publishedVersio

Quantitative PCR Measurement of miR-371a-3p and miR-372-p Is Influenced by Hemolysis

Cell-free microRNAs have been reported as biomarkers for several diseases. For testicular germ cell tumors (GCT), circulating microRNAs 371a-3p and 372-3p in serum and plasma have been proposed as biomarkers for diagnostic and disease monitoring purposes. The most widely used method for quantification of specific microRNAs in serum and plasma is reverse transcriptase real-time quantitative PCR (RT-qPCR) by the comparative Ct-method. In this method one or several reference genes or reference microRNAs are needed in order to normalize and calculate the relative microRNA levels across samples. One of the pitfalls in analysis of microRNAs from serum and plasma is the release of microRNAs from blood cells during hemolysis. This is an important issue because varying degrees of hemolysis are not uncommon in routine blood sampling. Thus, hemolysis must be taken into consideration when working with circulating microRNAs from blood. miR-93-5p, miR-30b-5p, and miR-20a-5p have been reported as reference microRNA in analysis of the miR-371a-373 cluster. We here show how these three microRNAs are influenced by hemolysis. We also propose a new reference microRNA, miR-191-5p, which is relatively stable in serum samples with mild hemolysis. In addition, we show how hemolysis can have effect on the reported microRNA levels in patient samples when these reference microRNAs are used in samples with varying levels of hemolysis

Ureteral Strictures Following Ureteroscopic Stone Treatment

Background and Purpose: Ureteral stricture is a rare, but serious complication following ureteroscopy (URS) for stones. The aim of this study was to investigate how many patients ended up with a ureteral stricture after URS at our hospital and how these were treated. We also wanted to identify potential risk factors for postendoscopic stricture formation. Materials and Methods: A retrospective evaluation of 1001 URSs for stone treatment at the day-case surgery unit between 2013 and 2018 was performed. Data on pretreatment status, the surgical procedure, and follow-up were recorded. Exact χ2 and independent samples t-tests were used comparing data among those who developed strictures and those who did not. Multiple logistic regression was performed analyzing risk factors for stricture formation. Results: In total, 1001 URSs were performed in 725 patients, 289 women and 436 men. Of these, 995 cases were eligible for analysis. At follow-up with CT after 3 months, 28 (3.0%) strictures were identified. Of these, 20 received endourologic treatment with balloon dilatation of which 15 (75%) were effective. Definitive treatment in the 13 patients with failed or unattempted endourologic treatment included nephrectomy, reconstructive surgery, permanent nephrostomy, or observation with no further treatment. In multiple regression analysis, use of ureteral access sheath (UAS; odds ratio [OR] 4.6, p = 0.011), ureteral perforation (OR 11.8, p 60 minutes (OR 5.7, p < 0.005) were found to be risk factors for stricture formation. Conclusion: Ureteral stricture is a rare complication of URS. Balloon dilatation should be the first line of treatment. Use of UAS, perforation, and excessive operating time were found to be risk factors for postendoscopic ureteral stricture formation. Special attention to these risk factors should be given to reduce the incidence of ureteral strictures

Ureteroscopy during pregnancy: Outcomes and lessons learned over 4 decades at a tertiary center in Norway

Abstract. Background. The management of suspected kidney stone disease in pregnancy is challenging. In cases of persistent flank pain and where investigations may have rendered equivocal results, ureteroscopy (URS) is a recognized diagnostic and therapeutic intervention. This study aimed to investigate the safety and outcomes associated with performing URS during pregnancy, as the technique has evolved over the past 4 decades at our center. Materials and Methods. We performed a retrospective analysis of pregnant patients who underwent URS at our tertiary center between 1984 and 2022. Outcomes of interest included anesthetic approach, operative time, hospital stay, and complications. Results. Eighty-seven pregnant patients underwent 96 URS procedures, and 60% (n = 57) of these procedures were performed during the third trimester. Overall, 58% (n = 56) of the procedures were achieved with local anesthesia and light sedation. During the most recent decade, the latter was successfully carried out in 97% of the procedures, with the remainder occurring under spinal anesthesia as per patient choice. Overall, 57% (n = 50) of the whole study group had ureteral calculi found at the time of surgery and in 88% (n = 44) of these cases, fragmentation/extraction was performed. The remainder had insertion of ureteral stent with definitive clearance deferred until postpartum. Mean operative time and postprocedure hospital stay was 33 minutes (range, 7–100 minutes) and 2.2 days (range, 0–16 days), respectively. The overall intraoperative and postoperative complication rates were 2% and 11%, respectively. During the final decade, the latter improved to 6% and all adverse events were minor (Clavien I/II), with the exception of a single case. Regarding exit strategy, ureteral stent was placed in 42% (n = 40) of the procedures, 23% (n = 22) had ureteral catheter inserted, and the remainder (35%, n = 34) had none. Conclusions. Ureteroscopy can be safely performed during pregnancy using anesthetic approach with local anesthesia and light sedation. Development of a local protocol and multidisciplinary management algorithm are instrumental in enabling the delivery of such a service

Thulium Fibre Laser versus Holmium:YAG for Ureteroscopic Lithotripsy: Outcomes from a Prospective Randomised Clinical Trial

Background Holmium:yttrium-aluminium-garnet (Ho:YAG) laser is the gold standard for ureterorenoscopic (URS) lithotripsy. Thulium fibre laser (TFL) has recently been introduced as a new technology and may challenge Ho:YAG as the preferred laser owing to favourable properties as demonstrated in preclinical studies. Objective To evaluate and compare outcomes after URS lithotripsy with Ho:YAG and TFL. Design, setting, and participants In a prospective randomised trial, patients aged ≥18 yr with ureteral and/or renal stones (≥5 mm) scheduled to undergo day-case URS lithotripsy were invited to participate. In total, 120 consecutively admitted patients with signed consent were included for randomisation. Intervention URS lithotripsy with Ho:YAG or TFL. Outcome measurements and statistical analysis The primary outcome was the stone-free rate (SFR) assessed on noncontrast computed tomography at 3-mo follow-up. Secondary outcomes were the operative time and complications. Outcomes were compared between the groups using the t test and χ2 test. Results and limitations After a single session, the SFR was 67% in the Ho:YAG group and 92% in the TFL group, p = 0.001. For ureteral stones, the SFR was 100% in both groups, and for renal stones; 49% (Ho:YAG) and 86% (TFL), p = 0.001. Operative time was shorter using TFL (49 min) compared to Ho:YAG (57 min), p = 0.008. Bleeding that impaired the endoscopic view was the most frequent intraoperative adverse event and occurred in 13 patients (22%) in the Ho:YAG group and three (5%) in the TFL group, p = 0.014. Conclusions In this study, significantly more patients with renal stones achieved stone-free status and fewer experienced intraoperative complications using TFL compared to Ho:YAG. TFL is the emerging laser of choice for stone lithotripsy. Patient summary We compared outcomes after ureterorenoscopic treatment of kidney and ureteral stones using two different lasers. Our results show that the new thulium fibre laser technology is superior to the current standard laser (holmium:YAG) in clearing kidney stones and reducing operative complications