The Effect of Pre-Stenting on Bleeding-Related Complications Following Ureteroscopy in Patients on Anticoagulation or Antiplatelet Therapy.

Introduction: The American Urological Association guidelines state that continuing anticoagulant (AC) and antiplatelet (AP) agents during ureteroscopy (URS) is safe. Through a multi-institutional retrospective study, we sought to determine whether pre-stenting in patients on AP or AC was associated with fewer URS bleeding-related complications. Methods: A series of 8614 URS procedures performed across three institutions (April 2010 to September 2017) was electronically reviewed for AC/AP use at time of URS. Records indicating AC or AP use at time of URS were then manually reviewed to characterize intraoperative and 30-day postoperative (intraoperative bleeding, postoperative hematuria, emergency department visits, hospital readmission, unplanned reoperation, phone calls, and other minor 30-day complications). Results: A total of 293 identified URS procedures were completed on patients on AC/AP therapy-112 cases were on AC only (38 were pre-stented), 158 on AP only (51 pre-stented), and 23 on both AP and AC (8 pre-stented). Patient characteristics and comorbidities were similar between the pre-stented and non-pre-stented groups. For AC and AP subjects, pre-stenting did not decrease the composite risk of bleeding complications (10.3% pre-stent vs 12.2% non-prestent, p = 0.6). Pre-stented patients did have a significantly lower likelihood of requiring an unplanned reoperation (1.0% vs 5.6%, p = 0.04). In the subgroup of patients on AP alone, pre-stented patients had significantly fewer episodes of intraoperative bleeding (0% vs 9%, p = 0.04), unplanned reoperations (0% vs 6.5%, p = 0.02), and 30-day complications (14% vs 27%, p = 0.05). In the subgroup of patients on AC alone, there were no significant differences in outcomes based on stent status. Conclusions: In this multi-institutional study, we found that pre-stenting before URS was not associated with fewer bleeding complications. However, pre-stenting appeared to be associated with improved outcomes for those patients on AP therapy. These results suggest a need for prospective studies to clarify the role of pre-stenting for URS.

The impact of smart technology on adherence rates and fluid management in the prevention of kidney stones.

Smart technology (ST) can enhance chronic disease management, yet little is known about the benefits of ST on kidney stone prevention. Our aim was to prospectively evaluate the impact of ST on follow-up adherence rates and urine output (UOP) in patients with nephrolithiasis. Kidney stone patients with low UOP (< 2.5 L/24 h) were randomized into three intervention groups: (1) standard dietary/medical counseling alone (control), (2) control + smartphone fluid management application (app), and (3) control + smart water bottle (bottle). Demographics, adherence rates, kidney stone events, and 24 h urine data were collected and analyzed at baseline, 3-6, and 12 months. We randomized 111 patients (37 per group), of which 20 (55%), 8 (26%), and 10 (33%) patients completed the 12 month follow-up in the control, app, and bottle groups respectively. Control group patients were the most likely to adhere to follow-up (p = 0.004). Overall mean UOP increased by 0.4 L in each group (p < 0.05), with no difference in mean baseline 24 h UOP (1.6 L) and 12 month 24 h UOP (2.0 L) between groups (p > 0.05). Twenty-nine percent of patients achieved a daily UOP goal of > 2.5 L across the treatment groups (p < 0.001). In this prospective study, the 24 h UOP improved across all groups compared to baseline, although adherence to follow-up remained low. Furthermore, the use of ST did not further augment UOP, underscoring the importance of dietary/medical counseling for kidney stone prevention.

Can CT-Based Stone Impaction Markers Augment the Predictive Ability of Spontaneous Stone Passage?

Introduction: A number of clinical and radiological predictors of either stone impaction or ureteral stone passage (SP) have been proposed. We aimed at identifying the key predictors of successful SP by using readily available CT-based tools/measurements. Methods: Patients presenting to the emergency department from February 2017 to February 2018 with an acute unilateral ureteral stone confirmed on non-contrast CT and managed conservatively were followed for SP. Patients with renal impairment, sepsis or requiring emergent intervention were excluded. Patients were followed at 1 month to confirm SP (stone collection/repeat imaging) or failure of passage. The CT variables analyzed included: Stone factors [location, size, volume, HU density (HUD)], impaction factors [ureteral HUD above and below the stone, maximal ureteral wall thickness (UWT) at the stone site, contralateral UWT, and ureteral diameter above and below the stone]. Binary logistic regression analysis was performed to identify predictors of SP. Results: Forty-nine patients met study inclusion criteria, of whom 32 (65.3%) passed the stone without further intervention. Patients with successful passage were more likely to have smaller, lower volume and less dense stones located in the distal ureter (p < 0.01). Lower ureteral HUD below the stone, lower maximal UWT, and lower ureteral diameter above the stone were associated with successful passage (p < 0.01). On multivariable logistic regression analysis, only maximal UWT at the stone site was a significant independent predictor of SP outcome (p = 0.01). Youden's criterion identified 2.3 mm as the optimal UWT cut-off point, which will accurately predict SP with 82.4% sensitivity and 87.5% specificity. Conclusions: Maximal UWT at the stone site was the most significant predictor of successful passage in acute unilateral ureteral stones, with an optimal cut-off point of 2.3 mm. Further prospective studies are needed to accurately predict spontaneous SP.

Comparison of automated irrigation systems using an in vitro ureteroscopy model.

INTRODUCTION: Two automated irrigation systems have been released for use during endoscopic procedures such as ureteroscopy: the Cogentix RocaFlow® (CRF) and Thermedx FluidSmart® (TFS). Accurate pressure control using automated systems may help providers maintain irrigation pressures within a safe range while also providing clear visualization. Our objective was to directly compare these systems based on their pressure accuracy, pressure-flow relationships, and fluid heating capabilities in order to help providers better utilize the temperature and pressure settings of each system. MATERIALS AND METHODS: An in vitro ureteroscopy model was used for testing, consisting of a short semirigid ureteroscope (6/7, 5F, 31cm Wolf 425612) connected to a continuous digital pressure transducer (Meriam m1550). Each system pressure output and flow-rate, via 100mL beaker filling time, was measured using multiple trials at pressure settings between 30 and 300mmHg. Output fluid temperature was monitored using a digital thermometer (Omega DP25-TH). RESULTS: The pressure output of both systems exceeded the desired setting across the entire tested range, a difference of 15.7±2.4mmHg for the TFS compared to 5.2±1.5mmHg for the CRF (p < 0.0001). Related to this finding, the TFS also had slightly higher flow rates across all trials (7±2mL/min). Temperature testing revealed a similar maximum temperature of 34.0°C with both systems, however, the TFS peaked after only 8 minutes and started to plateau as early as 4-5 minutes into the test, while the CRF took over 18 minutes to reach a similar peak. CONCLUSIONS: Our in vitro ureteroscopy testing found that the CRF system had better pressure accuracy than the TFS system but with noticeably slower fluid heating capabilities. Each system provided steady irrigation at safe pressures within their expected operating parameters with small differences in performance that should not limit their ability to provide steady irrigation at safe pressures.

Endoscopic guided PCNL in the prone split-leg position versus supine PCNL: a comparative analysis stratified by Guy's stone score.

INTRODUCTION: The optimal patient positioning for percutaneous nephrolithotomy (PCNL) based on the complexity of stone burden is not yet defined. Thus, we aimed to evaluate the intraoperative parameters, effectiveness and complications of patients undergoing PCNL between the endoscopic-guided prone split-leg PCNL (ePSL) and the supine PCNL by stratifying patients according to Guy's stone score (GSS). MATERIALS AND METHODS: A retrospective chart review was conducted of patients undergoing PCNL at two high-volume tertiary referral centers. At one center, patients underwent PCNL using the ePSL technique, while at the second center, patients underwent PCNL in supine. Patient demographics and stone characteristics, operative details, complications and effectiveness were compared between groups. The impact of obesity was also investigated. RESULTS: Of 830 subjects, a total of 449 (54%) underwent PCNL in ePSL and 381 (46%) in supine. The ePSL group had a greater mean age and body mass index. No statistical differences were found in gender, serum chemistry and Charlson comorbidity index. After stratifying patients by GSS, the differences in baseline stone burden between PSL and supine lost significance and both groups could be compared. Complications were not statistically different between both groups. Univariate analysis demonstrated that multiple tracts and lower pole access were more prevalent in supine. In addition, for GSS1-3, ePSL was correlated with reduced operative time, radiation exposure, length of hospital stay and need for secondary procedure. Multivariate analysis correlated ePSL with lower radiation exposure and need for secondary procedures (p = 0.01). In comparison to the whole trial population, the same tendencies were appreciated for obese cohort. CONCLUSIONS: This is the first report focusing on the performance differences between ePSL and supine PCNL stratified by GSS. Both techniques are safe, with a low rate of complications. For GSS1-3, ePSL reduces radiation exposure and requires less need for both multiple access and secondary procedure.

The Impact of Thiazides and Potassium Citrate on Bone Mineral Density Evaluated by CT Scan in Stone Formers.

INTRODUCTION: Thiazides and citrate prevent kidney stones and improve bone mineral density (BMD). The objective of this study was to opportunistically utilize the noncontrast CT (NCCT) scan used for stone detection to identify those with low BMD and follow the impact of potassium citrate and thiazides on longitudinal BMD measurements. MATERIALS AND METHODS: A retrospective analysis was performed on 299 kidney stone patients treated with thiazides and/or potassium citrate for a minimum of 1 year. For each patient, BMD was estimated at L1 with CT attenuation measured in HU. A level of 160 HU was chosen to distinguish normal from low BMD. Pairwise t-test was used to compare the continuous outcomes before and after treatment for the whole cohort and the low BMD subgroup. Linear regression was performed to find if any association exists between the duration of follow-up and the changes in HU. A matched pair t-test was performed to compare among the medications used and the impact of their doses on the HU outcomes. RESULTS: Patients with low BMD (HU <160) comprised (n = 186, 62.2%) the cohort. A total of 16.1% normalized after 1 year of treatment and 68% had an increase in HU. The mean change in HU was 8.6 (p = 0.0001). Linear regression demonstrated no association between the duration of treatment and the HU changes (p = 0.64). Hydrochlorothiazide (HCTZ) 50 mg was more effective at improving BMD (HU +19.7, p = 0.04) compared with 25 mg (+2.9) or 12.5 mg (HU +6.4). Majority of the low BMD subgroup were either postmenopausal women (n = 88) or men with age older than 60 (n = 74) and both showed a significant increase in HU (3.125, 10.731), p-value (0.0453, 0.0007), respectively. CONCLUSION: Stone health and bone health are synergistic. The impact of thiazides and citrates on BMD can be monitored opportunistically with the NCCT scan.

Transurethral Pneumatic Cystolithotripsy: A Novel Approach.

OBJECTIVE: Various endoscopic instruments used in treating renal stones have been used in managing bladder calculi. Our aim is to evaluate the use of transurethral ureteroscopic pneumatic cystolithotripsy for the management of large bladder calculi. PATIENTS AND METHODS: In a retrospective study conducted between May 2005 and July 2011, 53 patients with solitary bladder stones were subjected to our technique, transurethral ureteroscopic pneumatic cystolithotripsy. The mean patient age was 54.3 years. The mean stone size was 4.8 cm. Diagnostic cystoscopy was performed first. A semirigid ureteroscope with a pneumatic probe was introduced through the cystoscope sheath, and pneumatic lithotripsy was performed. The cystoscope sheath works as a draining channel, allowing bladder evacuation. The bladder collapses over the stone and, subsequently, prevents stone migration, which shortens the lithotripsy's duration. Stone immobilization allows the transmission of full pneumatic power to the stone. The stone fragments were removed through periodic bladder irrigation using an Ellick evacuation-irrigation system, and a 16F Foley catheter was placed at the end of the procedure. RESULTS: Our technique was effective in all cases, including stone-free bladders. No surgical complications were detected. The mean operative time was 83 ± 21.0 minutes, which is comparable to that of standard management. The mean duration of lithotripsy and evacuation was 29.7 ± 18.4 minutes. In the postoperative period, patients were followed up for 18 months, with no urethral stricture being reported in any case. CONCLUSION: The transurethral ureteroscopic pneumatic cystolithotripsy procedure is a safe technique for the management of large bladder calculi. It allows the bladder to collapse over the stone, leading to stone immobilization and, subsequently, decreasing lithotripsy duration. Our procedure is associated with a minimal chance of postoperative urethral injury because all stone fragments are evacuated through the cystoscope sheath, without contact with the urethral urothelium.