Impact of irrigation systems on stone migration

The optimal ratio of endoscope-sheath diameter with negative-pressure ureteral access sheath: an in vitro research

PURPOSE

To maintain safe intrarenal pelvic pressure (IPP), the combination of flexible ureteroscope (fURS) and traditional ureteral access sheath (T-UAS) should maintain a basic rule that is the ratio of endoscope-sheath diameter (RESD) ≤ 0.75. However, the negative-pressure ureteral access sheath (NP-UAS) may break the rule of negative pressure suction. This study aimed to examine the effect of NP-UAS on IPP and flow rate (FR) with varying RESD.

METHODS

In a 3D-printed renal model, flexible ureteroscopy lithotripsy (fURL) was replicated. Six sizes of fURS paired with 12Fr T-UAS and NP-UAS resulted in six distinct RESDs of 0.63, 0.78, 0.87, 0.89, 0.90, and 0.91. While the irrigation pressure (IRP) was set between 100 and 800 cmH2O and the sucking pressure (SP) was set between 0 and 800 cmH2O, the IPP and FR were measured in each RESD.

RESULTS

NP-UASs can reduce the IPP and increase the FR at the same RESD compared to T-UASs. The IPP decreased with increasing SP with NP-UAS. When RESD ≤ 0.78, T-UAS and NP-UAS can maintain IPP < 40 cmH2O in most circumstances. When RESD = 0.87, it is challenging for T-UAS to sustain IPP < 40 cmH2O; however, NP-UAS can do so. When RESD ≥ 0.89, it is difficult to maintain an IPP < 40 cmH2O even with NP-UAS.

CONCLUSION

NP-UAS can decrease IPP and increase FR compared with T-UAS. To maintain a safe IPP, it is recommended that RESD < 0.85 when utilizing NP-UAS.

Clinical Evaluation of Single-Use, Fiber-Optic, and Digital Ureterorenoscopes in the Treatment of Kidney Stones

<b><i>Introduction:</i></b> Indication of ureteroscopy for the treatment of urolithiasis has expanded immensely over the last decade. Fiber-optic and digital reusable instruments present the standard in clinical practice, but various newly available single-use devices might offer an exciting alternative. To date, the evidence is limited to clinical evaluation and efficacy of single-use ureteroscopes (URS) compared to standard instruments. Therefore, we evaluate a single-use instrument’s clinical characteristics and efficacy in direct comparison with a fiber-optic and digital device. <b><i>Methods:</i></b> A prospective study was conducted for patients undergoing endoscopic therapy for urolithiasis at a tertiary care center. We evaluated the different instruments’ clinical performance in categories of visibility, the stability of visibility, irrigation flow, and surgeon’s satisfaction. Statistical analyses were performed by SPSS using the Chi-Quadrat and Kruskal-Wallis test. A <i>p</i> value of <i>p</i> ≤ 0.05 was defined as statistically significant. <b><i>Results:</i></b> A total number of 77 patients were included and distributed as follows: 35 (46.7%) single-use, 19 (25.3%) digital, and 23 (28%) fiber-optic URS. Patients’ characteristics were homogenous over the three cohorts in sex, stone amount, and localization. The stone-free rate was equal in all three cohorts (<i>p</i> = 0.31). We identify stability of visibility, irrigation flow, and satisfaction were equal in all cohorts (<i>p</i> = 0.73; <i>p</i> = 0.20; <i>p</i> = 0.20). We report a significant difference in visibility, with 100% rated excellent in the digital URS group (<i>p</i> = 0.028). <b><i>Discussion/Conclusions:</i></b> Single-use URS achieve comparable clinical outcomes with equal stone-free rates in direct comparison with fiber-optic and digital reusable instruments. Accordingly, single-use devices present an adequate alternative for endoscopic therapy of urolithiasis.

Prevention and Management of Infectious Complications of Retrograde Intrarenal Surgery

Kidney stone disease (KSD) is a commonly encountered ailment in urologic practice. Urinary tract infection (UTI) is commonly associated with KSD, both as an etiology (e.g., struvite and carbonate apatite stones), and as a complication (i.e., obstructive pyelonephritis and post-operative UTI). Indeed, a significant portion of the economic burden of KSD is skewed toward stones associated with infection. UTI is the most common post-operative complication related to stone intervention with progression to urosepsis as a rare but serious consequence. Risk for infection is influenced by a variety of factors including co-morbid conditions, anatomic abnormalities, prior surgical procedures, and local anti-microbial susceptibility. Understanding these risks and the proper steps to mitigate them is an essential component in reducing post-operative morbidity and mortality. Retrograde intrarenal surgery is routinely used for the treatment of KSD. The objective of this review article is to examine the current literature and guidelines for the prevention and management of stone-related infectious complications associated with retrograde intrarenal surgery. Special attention will be given to the incidence, etiology, and antibiotic prophylaxis choice in the management of stone-related infections. Intraoperative risk mitigation techniques will be discussed in conjunction with the management of post-operative infections. Antibiotic stewardship and the potential benefits of reduced empiric antibiotic treatment will also be discussed.

Evaluation of a Novel Female Gender Flexible Ureteroscope: Comparison of Flow and Deflection to a Standard Flexible Ureteroscope

Introduction: The advent of single-use disposable flexible ureteroscopes allows for rapid prototyping of novel endoscopes. In this regard, we sought to develop a female-specific ureteroscope, with a shorter working length, to account for the female anatomy. We hypothesized that the shorter, female-specific single-use flexible ureteroscope would engender higher irrigation flow at a given pressure than that of the standard-length ureteroscope. Methods: An in vitro analysis of a standard 65 cm Dornier Axis™ ureteroscope and a shorter, 45 cm female-specific Dornier Axis ureteroscope was performed. All other aspects of the endoscopes were identical. Each ureteroscope was oriented vertically and connected to a Thermedx^® irrigation system to provide uniform pressurized flow. The average flow rate was computed over five, 2-minute periods at pressure settings of 50, 100, 150, and 200 mm Hg. Data were collected with the working channel unoccupied, after placement of a 200 μm (0.6F) holmium laser fiber and after passage of a 1.7F stone basket. The procedure was then repeated with the endoscopes at maximum deflection. Results: The female gender ureteroscope had significantly higher irrigation flow rates than the standard-length ureteroscope under all conditions by an average of 11% (p < 0.02). The highest average percent increase, 17% (p < 0.001), was seen with the 1.7F NGage^® basket in the working channel with the endoscope straight. The maximum angle of deflection was not significantly different between the female gender and standard ureteroscopes with an open working channel (314° vs 315°, p = 0.86), with the 1.7F NGage basket in place (314° vs 315°, p = 0.15), and with the 200 μm holmium laser in place (316° vs 309°, p = 0.09). Conclusions: A 45 cm female gender ureteroscope allows for a higher irrigation flow rate than the standard-length ureteroscope under all test conditions. There is no added benefit with regard to deflection capabilities.

Evaluation of the Impact of Ureteroscope, Access Sheath, and Irrigation System Selection on Intrarenal Pressures in a Porcine Kidney Model

Introduction: Elevated intrarenal pressure (IRP) during flexible ureterorenoscopy (FURS) is a predictor of postoperative complications. The aim of this study is to evaluate IRP during FURS in a porcine kidney model to determine the safest combination of irrigation device, ureteral access sheath (UAS), and ureteroscope. Methods: Urinary tracts were harvested from Landrace pigs slaughtered for the food chain. Two flexible ureteroscopes, 8.7F and 9.5F, were evaluated. Irrigation systems evaluated included the following: TraxerFlow™ (Rocamed, France), SAPS™ single action pumping system (Boston Scientific), Pathfinder Plus™ (Utah Medical), and a manual "bag squeeze." This experiment was conducted with no UAS, followed by an 11/13F UAS and then a 12/14F UAS. IRPs were measured in the prepared porcine kidney during all possible combinations of scope, UAS, and irrigation system. Results: Pressures were significantly reduced when using 12/14F UAS compared with 11/13F UAS (16.45 ± 5.3 cmH₂O vs 32.73 ± 35.66 cmH₂O, p = 0.006), and when using 11/13F UAS compared with no UAS (32.73 ± 35.66 cmH₂O vs 49.5 ± 29.36 cmH₂O, p = 0.02). Pressures were significantly reduced with the 8.7F scope compared with the 9.5F scope (24.1 ± 21.24 cmH₂O vs 41.68 ± 34.5 cmH₂O, p = 0.001). SAPS generates significantly greater IRP than TraxerFlow, Pathfinder Plus, and a "bag squeeze" (p < 0.05). The most dangerous combination was using the SAPS, no UAS, and larger ureteroscope leading to an IRP of 100.6 ± 16.1 cmH₂O. The safest combination was using Pathfinder Plus with a 12/14F UAS and smaller ureteroscope giving an IRP of 11.6 ± 3.65 cmH₂O. Conclusion: IRPs are reduced by selecting larger UAS and a small ureteroscope. The SAPS generates significantly higher IRPs than other irrigation systems. To maintain safe IRPs during FURS, urologists should use large UAS, narrow ureteroscopes, and be cautious in the selection of an irrigation device.

Frequency and risk factors for antegrade ureteral stone migration after percutaneous nephrolithotomy

Introduction

Percutaneous nephrolithotomy (PCNL) is the minimally invasive procedure of choice for the treatment of large and/or complex nephrolithiasis. Migration of residual fragments (RFs) into the ureter after PCNL is presumed to be uncommon. However, should associated stone-related events (SREs) occur, ancillary procedures may be required. The objective of this study was to describe the frequency and to analyze predictors of antegrade migration of RFs after PCNL.

Material and methods

A case-control study of patients who underwent PCNL for nephrolithiasis and had a postoperative computed tomography available within 48 hours was performed. Descriptive statistics and logistic regression analysis were carried out.

Results

The final sample included 169 interventions. Mean age was 49 ±13 years, median maximum stone size was 26 (7 to 87) mm and mean stone density was 835 (70 to 2022) Hounsfield Units (HUs). 7.1% of the patients experienced migration of RFs into the ureter after PCNL, of whom 41.6% suffered SREs. Lithotripsy was performed using ultrasonic (67.5%), laser (23.7%), and pneumatic (14.8%) technologies. Univariate analysis found female gender (OR 4.1, p = 0.02) height ≥1.68 m (OR 5.52, p = 0.009), middle (OR 6.71, p = 0.01) and upper (OR 3.59, p = 0.04) caliceal location, staghorn calculi (OR 4.72, p = 0.02), stone area (OR 1.001, p = 0.03), lasertripsy (OR 3.61, p = 0.03) and operative time (OR 1.007, p = 0.02) statistically significant for migration of SFs into the ureter after PCNL. Of these, only height ≥1.68 m (OR 7.17, p = 0.01) and staghorn nephrolithiasis (OR 13.27, p = 0.02) remained independent predictors in the multivariate analysis with an area under the curve of 0.69.

Conclusions

71.% of patients undergoing PCNL had a SF migrating to the ureter. Of these 41% suffered a SRE that required ancilliary interventions. Staghorn nephrolithiasis and ≥1.68 mts of height were found to predict this event.

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.

Characterization of intracalyceal pressure during ureteroscopy

PURPOSE

To provide the first report of measuring intracalyceal pressures during ureteroscopy (URS).

METHODS

A prospective single-center clinical study using a cardiac pressure guidewire to measure intracalyceal pressure during flexible URS was performed. Eight patients (45 calyces) undergoing URS for nephrolithiasis were included. A Verrata^® pressure guide wire was passed through the working channel of a dual lumen flexible ureteroscope and into the calyces while irrigation was maintained at 150 mmHg. Pressure was measured in the renal pelvis, upper pole, interpolar, and lower pole calyces both with and without a ureteral access sheath (UAS). The pressure in each location with and without a UAS was compared. The correlation between calyceal pressure and infundibular dimensions (width, length) was determined.

RESULTS

Intracalyceal pressure was significantly lower in each region when a UAS was used. Compared to patients with a 12/14Fr UAS, those with a 14/16Fr UAS had significantly lower pressure in the interpolar (25.3 ± 13.1 vs. 44.0 ± 27.5 mmHg, p = 0.03) and lower pole (16.2 ± 3.5 vs. 49.2 ± 40.3 mmHg, p = 0.004) calyces. Interpolar calyceal pressure in the presence of a UAS was significantly higher than the renal pelvis pressure (RPP) (30.8 ± 19.6 vs. 17.9 ± 11.0 mmHg, p = 0.004).

CONCLUSIONS

During flexible URS, RPP strongly correlates with, but does not uniformly represent, the intracalyceal pressure. With a 14/16Fr UAS and an inflow pressure of 150 mmHg, RPP and intracalyceal pressure never exceed the threshold for renal backflow.

Prospective Randomized Comparison of Standard Hand Pump Infuser Irrigation vs an Automated Irrigation Pump During Percutaneous Nephrolithotomy and Ureteroscopy: Assessment of Operating Room Efficiency and Surgeon Satisfaction

Introduction: The objective of this study was to determine if use of an automated irrigation pump (AIP) during ureteroscopy (URS) and percutaneous nephrolithotomy (PCNL) affects circulating nurse labor, irrigation-related issues, and surgeon and nurse satisfaction when compared to manual hand pump (HP) irrigation. Methods: Eighty consecutive adult patients undergoing unilateral URS or PCNL were prospectively randomized to irrigation with the HP or AIP. Preoperative pump setup time, intraoperative pump maintenance time, total pump time (setup+maintenance), and the number of irrigation-related concerns verbalized by the surgeon intraoperatively were recorded; postoperatively, surgeons and nurses rated their satisfaction with the irrigation system (1 = highly dissatisfied to 10 = highly satisfied). Results: Eighty patients were enrolled (39 AIP and 41 HP); 51 patients underwent URS and 29 patients underwent PCNL. On univariate analysis, the AIP resulted in a significantly reduced total pump time for URS (2.9 vs 5.9 minutes) and PCNL (4.6 vs 33.9 minutes; p < 0.001). The number of irrigation-related concerns was significantly lower in the AIP group during URS (1.2 vs 2.8, p < 0.001), but not during PCNL (1.9 vs 4.0, p = 0.07). The AIP was associated with significantly higher nurse satisfaction during URS (9.2/10 vs 6.5/10, p < 0.001) and PCNL (9.4/10 vs 4.4/10, p = 0.001). There was no significant association between pump type and surgeon satisfaction. On multivariate analysis of URS cases controlling for body mass index and number of stones, use of the AIP was a predictor of total pump time <5 minutes (odds ratio 25.8, 95% confidence interval [CI] 4.0-165.4; p < 0.001) and favorable (8-10/10) nurse satisfaction rating (odds ratio 25.4, 95% CI 4.1-164.0; p < 0.001). Operative time, stone-free rate, and liters of irrigant used with the HP and AIP were similar. Conclusions: During URS and PCNL, the AIP was associated with a significant reduction in irrigation pump time and higher nurse satisfaction.

Retrograde intrarenal surgery for renal stones - Part 1

The main aim in the treatment of renal stones is to clearance of the stones completely with the least morbidity. Parallel to the improvements in technology during recent years, new flexible ureterorenoscopes and effective lithotripters such as holmium laser have been developed, thus retrograde intrarenal surgery (RIRS) has become an efficient and safe option in the management of urinary system stone disease with a gradually increasing popularity. Therewithal, innovations in auxiliary equipment such as guide-wires, ureteral access sheath and stone baskets have made this procedure more effective. With this modality, nowadays, the vast majority of renal stones can be treated successfully without need of open surgery or percutaneous nephrolithotomy. RIRS can be used as a primary treatment in patients with renal stones smaller than 2 cm, in cases with prior unsuccessful shock wave lithotripsy (SWL), infundibular stenosis, renoureteral malformation, musculoskeletal deformity, bleeding diathesis as well as obese patients. The efficiency of this procedure has been also proved in pediatric patients. In the first part of this detailed review for RIRS, history, indications and contraindications, preoperative preparation, antibiotic prophylaxis, anesthesia, surgical technique related to flexible ureteroscopes and auxiliary equipment being used, postoperative care and complications of this operation are discussed with up-to-date literature.

In Vitro Comparison of Maximum Pressure Developed by Irrigation Systems in a Kidney Model

Purpose: To evaluate in vitro the maximum pressure generated in an artificial kidney model when people of different levels of strengths used various irrigation systems. Materials and Methods: Fifteen people were enrolled and divided into three groups based on their strengths. Individual strength was evaluated according to the maximum pressure each participant was able to achieve using an Encore™ Inflator. The irrigation systems evaluated were as follows: T-Flow™ Dual Port, Hiline™, continuous flow single action pumping system (SAPS™) with the system close and open, Irri-flo II™, a simple 60-mL syringe, and Peditrol™. Each irrigation system was connected to URF-V2 ureteroscope, which was inserted into an artificial kidney model. Each participant was asked to produce the maximum pressure possible with every irrigation device. Pressure was measured with the working channel (WC) empty, with a laser fiber, and a basket inside. Results: The highest pressure was achieved with the 60 mL-syringe system and the lowest with SAPS continuous version system (with continuous irrigation open), compared to the other irrigation devices (p < 0.0001). Irrespective of the irrigation system, there was a significant difference in the pressure between the WC empty and when occupied with the laser fiber or the basket inside it (p < 0.0001). The stratification between the groups showed that the most powerful group could produce the highest pressure in the kidney model with all the irrigation devices in almost any situation. The exception to this was the T-Flow system, which was the only device where no statistical differences were detected among these groups. Conclusion: The use of irrigation systems can often generate excessive pressure in an artificial kidney model, especially with an unoccupied WC of the ureteroscope. Depending on the strength of force applied, very high pressure can be generated by most irrigation devices irrespective of whether the scope is occupied or not.

Thulium fiber laser lithotripsy in an in vitro ureter model

Using a validated in vitro ureter model for laser lithotripsy, the performance of an experimental thulium fiber laser (TFL) was studied and compared to the clinical gold standard holmium:YAG laser. The holmium laser (λ = 2120 nm) was operated with standard parameters of 600 mJ, 350 μs, 6 Hz, and 270-μm-core optical fiber. The TFL (λ=1908 nm) was operated with 35 mJ, 500 μs, 150 to 500 Hz, and a 100-μm-core fiber. Urinary stones (60% calcium oxalate monohydrate/40% calcium phosphate) of uniform mass and diameter (4 to 5 mm) were laser ablated with fibers through a flexible video-ureteroscope under saline irrigation with flow rates of 22.7 and 13.7 ml/ min for the TFL and holmium laser, respectively. The temperature 3 mm from the tube's center and 1 mm above the mesh sieve was measured by a thermocouple and recorded throughout each experiment for both lasers. Total laser and operation times were recorded once all stone fragments passed through a 1.5-mm sieve. The holmium laser time measured 167±41 s (n=12). TFL times measured 111±49, 39±11, and 23±4 s, for pulse rates of 150, 300, and 500 Hz, respectively (n=12 each). Mean peak saline irrigation temperatures reached 24±1°C for holmium, and 33±3°C, 33±7°C, and 39±6°C, for TFL at pulse rates of 150, 300, and 500 Hz, respectively. To avoid thermal buildup and provide a sufficient safety margin, TFL lithotripsy should be performed with pulse rates below 500 Hz and/or increased saline irrigation rates. The TFL rapidly fragmented kidney stones due in part to its high pulse rate, high power density, high average power, and observation of reduced stone retropulsion and may provide a clinical alternative to the conventional holmium laser for lithotripsy.

Disposable devices for RIRS: where do we stand in 2013? What do we need in the future?

PURPOSE

Disposable devices for retrograde intrarenal surgery (RIRS) form a significant part of the urologist's armamentarium for the endoscopic management of urologic diseases. Herein, we provide an overview of the literature regarding the advances and controversies of these devices.

METHODS

A PubMed search was used to identify the literature discussing the subject of disposable devices for RIRS. Articles published between 2012 and 2013 were considered.

RESULTS

Ureteral access implements including access sheaths, wires, and dilators are an area of both improvement and controversy regarding their proper use. The safety, effectiveness, and limitations of lithotrites continue to be refined. Stone retrieval devices are undergoing persistent miniaturization, and their use may prove to be cost effective. The debate over perioperative stenting remains, while symptom management is explored. A cost-effective option for disposable flexible ureteroscopy shows promise.

CONCLUSIONS

While rapid advances in technology and knowledge continue, continual improvements are necessary. Disposable equipment needs persistent refinement and possible miniaturization. More efficient fragment retrieval devices are needed. Durability of laser fibers and safety within ureteroscopes needs to be improved. Reducing stent morbidity remains an ongoing challenge. Lastly, costs need to be reduced by the further development of disposable flexible ureteroscopes and in the recyclability of disposable devices to improve availability worldwide.

Simultaneous saline irrigation during retrograde rigid ureteroscopic lasertripsy for the prevention of proximal calculus migration

OBJECTIVE

In this paper, we analyze the clinical efficacy of a simultaneous saline irrigation method in treating upper-mid ureteral stone migration and evaluate its effectiveness during ureteroscopic lasertripsy.

METHODS

We prospectively evaluated 78 patients with a total of 95 upper-mid ureteral stones, which were treated with holmium:YAG lasertripsy. These patients were randomized into 2 groups. In Group 1 (39 cases with 44 ureteral stones), conventional ureteroscopic lasertripsy was performed. In Group 2, (39 cases with 51 ureteral stones), the simultaneous saline irrigation method was used during lasertripsy. There was no significant difference between the groups with regards to stone site, size or state of the upper urinary tract by spiral computed tomography or excretory urography. Data were analyzed regarding stone migration, lengths of time, and ureteral clearing for various stages of each procedure.

RESULTS

One patient in Group 2 (2%) experienced upward stone migration, while this occurred in 8 patients in Group 1 (20%). The operative time in Group 1 ranged from 35 to 55 minutes (mean: 44.8 ± 5.3), while in Group 2 it ranged from 40 to 69 minutes (mean: 50.4±3). There was no significant different in the operative times between the two groups (p < 0.05). Ureteral perforation, urinoma and urosepsis were not seen in both groups.

CONCLUSION

The simultaneous saline irrigation method demonstrated a statistically significant advantage over conventional methods. The operation can be performed persistently under clear vision, and since the stones cannot move upward, fragmented portions are easily flushed out. Our data suggest that this method is simple, safe and effective in preventing proximal stone migration during ureteroscopic lasertripsy.

Systematic evaluation of a novel foot-pump ureteroscopic irrigation system

INTRODUCTION

To evaluate forces exerted on a stone with different ureteroscopic irrigation systems.

METHODS

A 3 mm steel simulated stone was welded to a 3F stone basket and inserted into the working channel of a 4.5F Wolf semirigid ureteroscope. The basket shaft was attached to a 50 g load cell. The urterescope was placed in a ureteral model (14F silicon tubing). Simulated blood (McCormick™ Red Dye, 1 dye drop/15 mL H(2)O) was dripped adjacent to the stone at 12 drops/min. Endoirrigation devices were attached to the ureterscope and irrigation was applied at a rate sufficient to maintain visualization of the stone. Force on the stone was measured with the following endoirrigation systems: Boston Scientific™ Single-Action-Pump System (SAP) hand-pump and NuVista Medical™ Flo-Assist(®) foot-pump.

RESULTS

No significant difference (p=0.19) in the number of pumps required to maintain a clear endoscopic field was found between the SAP (0.20±0.075/second) and Flo-Assist device (0.25±0.056/second). The pump duration of the Flo-Assist was found to be less (1.12±0.40 seconds) than the SAP (1.35±0.31 seconds), but not significantly different (p=0.24). The average maximum impulse was significantly lower (p=0.0002) for the SAP (8.34×10(-5) Ns) than the Flo-Assist (1.96×10(-3) Ns). Total maximum impulse (2.02×10(-5) Ns) for the SAP and total average impulse (5.51×10(-6) Ns) were found to be lower than the Flo-Assist device. The Flo-Assist had a total maximum impulse of 4.49×10(-4) Ns and total average impulse of 8.85×10(-6) Ns, however, these differences were not statistically significant.

CONCLUSION

The hand-pump (SAP) and foot-pump (Flo-Assist) irrigation devices tested require comparable amounts of pumps for similar durations of time to maintain endoscopic visualization. Overall, the SAP device exerts less average maximum force on the stone than the Flo-Assist device.

A comparison of Stone Cone versus lidocaine jelly in the prevention of ureteral stone migration during ureteroscopic lithotripsy

BACKGROUND

Intracorporeal lithotripsy modalities and stone removal devices have been created to facilitate endoscopic management of ureteral stones. These devices, along with improved techniques, have resulted in stone-free rates greater than 95% with low morbidity. However, problems remain that preclude consistent 100% stone-free rates with endoscopic treatment of ureteral calculi. Retrograde migration during ureteroscopic procedures remains a significant problem.

OBJECTIVES

The aim of this study was to compare the Stone Cone device and instillation of lubricating lidocaine jelly as two methods to prevent retrograde stone migration during ureteroscopic lithotripsy.

PATIENTS AND METHODS

This study included patients suffering from ureteral stones that were treated with intracorporeal lithotripsy using the pneumatic Lithoclast. These patients were divided into two groups. In group I, the Stone Cone device was used, while in group II, lidocaine jelly 2% concentration was used.

RESULTS

This study included 40 patients with a mean age of 38.6 ± 9.3 years (20 patients in each group). There was no significant difference between the groups with regards to stone site, size or state of the upper urinary tract by excretory urography. The pneumatic Lithoclast allowed successful fragmentation of all calculi into small fragments. Upward stone migration did not occur in patients in the Stone Cone group, while in the lidocaine jelly group it occurred in three patients (15%). The operative time in the Stone Cone group ranged between 30 and 55 minutes (mean, 41.8 ± 5.3), while in the lidocaine jelly group it ranged between 40 and 71 minutes (mean, 51.4 ± 3.4), and this difference was statistically significant (p < 0.05).

CONCLUSION

The Stone Cone is safe and efficient in preventing proximal stone migration during ureteroscopic pneumatic lithotripsy. It maintained continuous ureteral access and demonstrated a statistically significant advantage over the lidocaine jelly in terms of proximal stone migration, operative time, and the need for auxiliary procedures.

Current status of ureteroscopic treatment for urolithiasis

Intracorporeal treatment of urolithiasis is characterized by continuous technological evolution. In this review we present updated data upon the use of ureteroscopy for the management of urolithiasis. Novel digital flexible ureteroscopes are used in clinical practice. Ureteroscopic working tools are revolutionized resulting in safer and more efficient procedures. Special categories of stone patients such as pregnant women, children and patients on anticoagulation medication can now undergo uneventful ureteroscopy. Routine insertion of stents and access sheaths as well as bilateral ureteroscopy is still a controversial issue. Future perspectives include smaller and better instruments to visualize and treat a stone, while robotic ureteroscopy is becoming a fascinating reality.