Retrograde Stone Migration Research Articles

Lidocaine jelly with the Dormia Stone Basket: Preventing Retrograde Ureteric Stone Migration During Pneumatic Lithotripsy

Background: Ureteroscopy for kidney stones has undergone a great deal of improvement over time, but stone migration is still an issue. Dormia TM stone baskets and lidocaine jelly installations are a few of the methods for prevention. Objectives: To compare the effectiveness of the Dormia™ stone basket and lidocaine jelly installation proximal to the ureteral stone for prevention of retrograde migration and improvement of stone-free rate. Methods: 185 patients were divided into three groups based on retrospective analysis of data from Aga Khan Hospital in Dar es Salaam: Group 1 (Dormia basket), Group 2 (Lidocaine jelly), and Group 3 (no intervention). Two weeks and 24 hours later, follow-up radiological imaging was performed. Our finding: The three groups' sizes of stones and demographics were similar. In Groups 1, 2, and 3, stone-free rates were 98.4%, 92.5%, and 80.4%, respectively, whereas stone fragment migration occurred in 1.6%, 6.5%, and 19.6% of cases. In comparison to the no-intervention group, stone fragment migration was significantly different in the intervention group (p = 0.002 for Group 1 and p = 0.050 for Group 2). Group 1 versus Group 3 (p = 0.001) and Group 2 vs Group 3 (p = 0.030) showed statistically significant differences between the groups. However, there was no significant difference between Group 1 and Group 2 (p = 0.365). Conclusions: Compared to lidocaine jelly, Dormia basket increased the rate of stone migration, although the difference was not statistically significant. Both approaches considerably increased stone movement and stone-free state as compared to no intervention, with a higher correlation shown with the Dormia basket. Our study showed a significant reduction in stone migration and an improved stone-free rate with the use of a Dormia basket or lidocaine jelly during ureteroscopy as compared to the no-intervention group. Dormia could be adapted as a cost-effective technique in resource-limited settings such as ours. Keywords: Retrograde stone migration, Dormia basket, and lidocaine jelly, Ureteroscopy

Clinical application of flexible ureteroscopic sheath with controllable intraluminal pressure in treating ureteral stones

ObjectiveThe purpose of the study was to assess the clinical efficacy and safety of a combined perfusion suction platform with pressure feedback control function and an ureteroscopic suction sheath that can measure the ureteropelvic pressure in implementing lithotripsies. MethodsFifty-two patients who underwent lithotripsy under intelligent monitoring of ureteral intraluminal pressure from June 2016 to January 2018 were retrospectively recruited. The inclusion standard was stone diameter >1.5 cm but <2.5 cm. After the 12/14 Fr suction sheath was placed, manometer interface and suction interface of the sheath were connected to the platform via the pressure sensor and suction tube, respectively. The ureteroscope was connected to the platform perfusion pump, and the crushed stones were aspirated out under negative pressure. ResultsAccording to the location of the stone, 21 (40.4%) cases were classified as upper ureteral stones, 19 (36.5%) were midureteral stones, and 12 (23.1%) were lower ureteral stones. Forty-seven patients underwent successful primary sheath placement and lithotripsy with a mean operative time of 34.5 (standard deviation 18.3) min. Retrograde stone migration did not occur. There were eight patients with hematuria postoperatively. Serious complication was 1.9% with one case of ureteral perforation. Stone clearance was 95.7% at Day 1–2 postoperatively, and 100% at Day 30 postoperatively. ConclusionUreteroscopic lithotripsy with intelligent pressure control using our device improved the efficiency of the lithotripsy and rate of stone clearance. The safety of the operation can be ensured. It is worth popularization and application in clinical practice.

Contact Pneumatic Ureterolithotripsy Using LMA StoneBreaker Lithotriptor and Search for Opportunities to Increase Effectiveness

The objective: to evaluate the effectiveness of portable pneumatic contact lithotripter LMA StoneBreaker in endoscopic contact ureterolithotripsy of ureteral stones of different localization depending on their density and search for opportunities to increase it. Materials and methods. Contact pneumatic ureterolithotripsy was performed in 89 patients (49 men, 40 women), 39 (43.8%) patients (I group) underwent standard contact pneumoureterolithotripsy, and 50 (56.2%) patients (11 group) – modified (with prior fixation of the stone in the ureter loop Dormia), which allowed urethrolithotripsy in situ and prevented the migration of stones and their fragments proximally. The number of strokes required to initiate fragmentation, complete fragmentation, and total ureterolithotripcy time for stones of different localization and density were determined. The integrity of the stones was determined by computed tomography in units of Haunsfield (HU). The mineral composition of stone fragments after their removal was diagnosed by X-ray diffraction analysis. The effectiveness of the applied methods was evaluated in groups of patients by complete (100%) removal of stone fragments from the ureter and by the number of cases of retrograde migration of stones into the renal cavity. Results. No intraoperative complications were observed. The number of strokes for the initial and complete disintegration of the stone, regardless of the method of ureterolithotripsy and their localization, depended on their density, ie its mineral composition. The minimum number of strokes for start and complete fragmentation of the stone was recorded in patients with a stone density of 480+54 HU and diagnosed as phosphates. Oxalate and uric acid stones, as well as their combinations (density 1310–1580 HU) required the maximum number of blows. Stone migration was noted in 8 (8.99%) patients. Thanks to intraoperative stone fixation was able to reduce the average time of lithotripsy (from 15,65±6.9 min to 12.3±6,15 min) and reduce the frequency of retrograde stone migration from 15.4% (in 6 patients of group 1) to 4% (2 patients of ІI group). The dependence of lithotripsy efficiency on stone localization is established. It was highest in patients with stones of the lower third of the ureter (95% in patients of group 1 and 100% of patients in group II) and with low density (480–840 HU). The lowest efficacy was observed in patients whose stones were localized in the upper third of the ureter (66.3% in group I and 90% in group II) and had a high density (more than 1200 HU). Due to the fixation of the stone with modified pneumoureterolithotripsy, the overall effectiveness of the method increased from 84.6% to 96%. Conclusions. Traneurethral contact pneumoureterolithotrysis using a portable pneumatic lithotripter LMA Stonebreaker – is effective, safe, minimally costly and easy to use. The effectiveness of contact pneumatic ureterolithotripsy depends on the location and density of the stone. The number of strokes required for the initial and complete fragmentation of the stone directly depends on the density of the stone and does not depend on its location and method of performing pneumoureterolithotripsy. The use of a modified technique with fixation of the stone in the ureter during the process of lithotripsy reduces the time of the operation and increases its effectiveness.

Inadvertent Stone Migration During Pneumatic Lithotripsy: Still a Conundrum in the 21st Century.

Currently, an ideal gadget to stop retrograde stone migration remains a holy grail, and the hunt for such a device is still ongoing in the 21st century. The quest for an ideal instrument is driven by the need to reduce cost, minimize ancillary procedure rates, reduce the device's operative time, and improve the stone-free rate. The purpose of the present review is to provide an update on the use of preventive measures that are used to stop retrograde stone migration during pneumatic lithotripsy for ureteric stone management.

Efficacy and Safety of NTrap® Stone Entrapment and Extraction Device for Ureteroscopic Lithotripsy.

NTrap® stone entrapment and extraction device (NTrap®) is a device used to extract and remove stones from the urinary tract and to minimize retrograde stone migration during ureterolithotripsy (URS). This study aimed to evaluate the efficacy and safety of NTrap® in URS. From Jan 2014 to June 2017, 148 patients underwent URS with the aid of NTrap® (Group A), and 209 patients underwent standard URS without any anti-retropulsion device (Group B). Their demographics, operation time, complications, stone migration rate, and stone-free rate (SFR) were recorded for comparison. Compared with group B, Group A had a significantly shorter operative and lasering time (P = 0.003, P<0.001, respectively). There was no significant difference between the 2 groups in overall complications, a decrease in mean hemoglobin, and length of stay (LOS) (P = 0.426, P = 0.097, P = 0.058, respectively). The incidence of stone migration was significantly lower in Group A than Group B (P = 0.035). The postoperative auxiliary procedure rate (in patients with stones retropulsion during the operation) was significantly lower in Group A compared to Group B (P = 0.024). The SFR was considerably higher in Group A than Group B (P = 0.009). URS, with the aid of NTrap®, is an effective and safe method for treating ureteric stones. It may prevent stones from retropulsion and shorten the operative time.

Evaluation the result of warm normal saline irrigation in ureteral endoscopic surgeries.

Transurethral lithotripsy (TUL) is a major modality for the endoscopic management of ureteral stones. Ureteral spasm makes access for ureters difficult, which causes impaction of the ureteroscope, ureteral dislodge, and a low success rate of endoscopic surgeries. This study described the outcomes of a new endoscopic surgical experience by use of 40-degree warm saline irrigation during TUL compaired with routine ambient air irrigation in TUL. In this randomized clinical trial from 2014 to 2015, 150 patients with ureteral stone with balanced randomization were divided into two parallel groups. Patients underwent TUL in the first group with 20-25 degree saline irrigation and in the second group with 40-degree saline irrigation. One surgical team with the same semi-rigid instrument performed all TULs and the other steps were similar in both groups. Complete stone fragmentation was measured as the primary outcome and the duration of procedure, retrograde stone migration and all and any intraoperative complications were the secondary measurements. While comparing warm saline irrigation with cold saline irrigation, the rate of access to upper ureter was 95% versus 72%, stone retropulsion frequency was 10.7% versus 30.7% and the stone-free rate was 96% versus 76% respectively (P < .05). There was no ureteroscope impaction and ureteral dislodge in both groups. Using warm saline irrigation in endoscopic surgeries results in better surgical outcomes including a lower ureteral spasm rate, greater ureteral muscle relaxation and better access to the upper ureteral zone, and a lower rate of complications, such as ureteroscope impaction, ureteral dislodge and stone retropulsion.

Transurethral contact ureterolithotripsy in gas (СО2) medium.

Transurethral intracorporeal lithotripsy is the modality of choice for the endoscopic disintegration of large, long-standing, radiolucent or high-density stones. Despite several advantages and proven benefits of contact ureterolithotripsy/ureterolithoextraction (CULT), the application of irrigation carries significant risks of untoward perioperative events including retrograde stone migration and postoperative pyelonephritis. We describe a new technique - endoscopic intracorporeal lithotripsy in the gas (СО2) medium. It is a prospective randomized, single blinded pilot study that included total of (n = 60) patients with urolithiasis who were allocated to either experimental or control group. Out of the total pool of patients, 30 underwent treatment with the new approach (experimental group) and other 30 (control group) had contact ureterolithotripsy in a standard of care 0.9% NaCL medium. We included patients >18 years old, with known symptomatic renal calculi disease who were eligible and scheduled for CULT and free from significant coexisting pathologies of urinary tract. No retrograde migration of the stone fragments into the kidney was reported in the experimental group [complications rate 0%, confidence interval (CI): 0-11.6%]. In the control group, complications were observed in eight cases (complications rate 26.7%, CI: 14.7-42.3%); retrograde migration was in five patients (16.6%), and acute pyelonephritis/exacerbation of chronic pyelonephritis was seen in three (10%) patients. There was not any acute pyelonephritis in the experimental group. Reliability of frequency differences - p = 0.0023 (χ2). The novel method of contact ureterolithotripsy is a safe and promising alternative to the conventional contact ureterolithotripsy in a fluid medium in a carefully selected patient population.

The \u201cGuidewire-Coil\u201d-Technique to prevent retrograde stone migration of ureteric calculi during intracorporeal lithothripsy

BackgroundStone retropulsion represents a challenge for intracorporeal lithotripsy of ureteral calculi. The consequences are an increased duration and cost of surgery as well as decreased stone-free rates. The use of additional tools to prevent proximal stone migration entails further costs and risks for ureteral injuries. We present the simple technique of using a coil of the routinely used guidewire to prevent stone retropulsion.MethodsWe retrospectively evaluated all patients with mid-to-proximal ureteral stones in 2014, which were treated by ureteroscopic lithotripsy (Ho: YAG and/or pneumatic lithotripsy). The preoperative stone burden was routinely assessed using low dose CT scan (if available) and/or intravenous pyelogram.ResultsThe study population consisted of 55 patients with 61 mid-to-proximal calculi. Twentyseven patients underwent semirigid ureterorenoscopy using the “Guidewire-Coil-Technique”, the second group (n = 28) served as control group using the guidewire as usual. There has been a statistically significant reduction of accidental stone retropulsion (2/27 vs. 8/28, p < 0.05) as well as a decreased use of auxiliary procedures (p < 0.05) compared to the control group. No difference was observed in operative time. One ureteral injury in the control group required a prolonged ureteral stenting.ConclusionThe “Guidewire-Coil-Technique” is a simple and safe procedure that may help to prevent proximal calculus migration and therefore may increase stone-free rates without causing additional costs.

Preventing stone retropulsion during intracorporeal lithotripsy

Several studies of ureteroscopic treatment for ureteral stones have reported that most stone clearance failures can be attributed to stone fragment retropulsion. Stone retropulsion can result in increased operative time and cost-resulting from the need to change from the semi-rigid ureteroscope to a flexible instrument to chase migrated calculi-and additional procedures to treat residual migrated fragments are often required. The degree of migration depends mainly on the energy source used for lithotripsy; pneumatic and electrohydraulic lithotripters are associated with a greater degree of retropulsion than lasers. Different stone-trapping strategies and devices have been developed to minimize stone migration. Novel devices include the Lithovac(®) suction device, the Passport(™) balloon, the Stone Cone(™), the PercSys Accordion(®), the NTrap(®), and stone baskets such as the LithoCatch(™), the Parachute(™), and the Escape(®). Some authors have also reported on the use of lubricating jelly and BackStop(®) gel (a reverse thermosensitive polymeric plug); these devices are instilled proximal to the stone prior to the application of kinetic energy in order to prevent retrograde stone migration.

Cost-Effectiveness of Anti-Retropulsion Devices for Ureteroscopic Lithotripsy

We evaluated the cost-effectiveness of anti-retropulsion devices used during ureteroscopic lithotripsy. A decision analysis model was constructed to compare the cost-effectiveness of ureteroscopic lithotripsy with vs without an anti-retropulsion device. The risk of stone retropulsion was determined from published data in the English language literature. Expected value calculations were used to determine whether the additional cost of a device would be cost-effective to prevent secondary procedures used to treat retropulsed stones. Device cost was determined using the average cost of all commercially available devices. It became cost-effective to use an anti-retropulsion device at or above a 6.3% retropulsion rate. The weighted probability of retropulsion with vs without an anti-retropulsion device was 98.1% vs 83.7%. The estimated costs of secondary procedures needed to treat retropulsed stones were $5,290 for shock wave lithotripsy and $6,390 for ureteroscopy. Average device cost was $278. Thus, the average additional cost of ureteroscopic lithotripsy with vs without an anti-migration device would be $384 vs $952. It is cost-effective to use an anti-retropulsion device at a retropulsion rate of greater than 6.3%.

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

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. 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. 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. 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). 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.

E40 The fibre tow technique: A novel maneuver to retrieve ureteric calculi

Abstract Introduction Retrograde stone migration, during ureteroscopic lithotripsy, poses a problem. We describe the fiber tow technique, a novel maneuver to retrieve such stones to facilitate pulv...

A Randomized Prospective Controlled Study for Assessment of Different Ureteral Occlusion Devices in Prevention of Stone Migration During Pneumatic Lithotripsy

To compare the safety and efficacy of two different ureteral occlusion devices (stone cone and entrapment net) in preventing retrograde stone migration during ureteroscopic pneumatic lithotripsy. Proximal migration of stone fragments during ureteroscopic lithotripsy is a common problem, especially when the pneumatic lithotripter is used for stone fragmentation. A total of 195 patients with proximal ureteric stones were prospectively randomized into one of three groups in this study, with 65 patients in each group. In group I, the Stone Cone was used as a ureteral occlusive device; in group II, the N-Trap was used; and in group III (control group), the patients underwent pneumatic lithotripsy without any ureteral occlusive device. The ureteroscopic procedure was completed successfully in 180 patients; 63 patients in group I, 59 patients in group II, and 58 patients in group III. Patients in group I showed significantly lower incidence of stone migration compared with the other 2 groups (P <.05). Both ureteral occlusive devices significantly lowered the incidence of residual fragments (>3 mm), ureteral trauma, operative time, and the need for ureteral stenting compared with control group. The stone-free rate at 3 weeks was 95.24%, 83.05%, and 72.41% in groups I, II, and III, respectively. The patients in group I had a statistically significant stone-free rate compared with the other two groups (P <.05). Auxiliary procedures were required in 3 (4.76%), 10 (16.94%), and 16 cases (27.58%) in groups I, II, and III, respectively. The use of Stone Cone or N-Trap is valuable during ureteroscopic pneumatic lithotripsy for treatment of proximal ureteral stones. Both devices significantly diminish residual fragments, the incidence of ureteral wall trauma, and the need for the auxiliary procedure. However, the stone cone was more effective in preventing proximal stone migration and the subsequent stone-free rate.

Intrarenal Pressures Generated During Deployment of Various Antiretropulsion Devices in an Ex Vivo Porcine Model

Pressurized saline irrigation is commonly used during ureteroscopy, which can cause an increase in intrarenal pressure leading to postoperative pain, sepsis, and renal injury due to pyelovenous and pyelolymphatic backflow. To prevent retrograde stone migration during ureteroscopic lithotripsy, antiretropulsion devices can be deployed, which may or may not protect the kidney against high intrarenal pressures. This study compares the intrarenal pressures generated during the use of two antiretropulsion devices in an ex vivo porcine model. Using an ex vivo porcine model of the urinary system, flexible ureteroscopy was performed at the proximal, mid, and distal ureter. Intrarenal pressures were measured in the absence and presence of a coil-based antiretropulsion device and a multifold film-based device. Intrarenal pressure measurements were obtained while using saline irrigation at a gravity of 84 cm H(2)O and pressures of 150 and 300 mm Hg. The deployment of a coil device resulted in a significant increase in intrarenal pressures during ureteroscopy with pressurized irrigation when compared with intrarenal pressures without a device. The use of a multifold film device that occluded the ureter during ureteroscopy resulted in a decrease in intrarenal pressures at an irrigation pressure of 300 mm Hg when compared with pressures without a device. In the remaining configurations, the intrarenal pressures were only minimally elevated. When comparing the two devices to each other, the multifold film device had significantly lower intrarenal pressures at each configuration. This has potential implications in preventing renal injury and/or sepsis during ureteroscopy. The use of a multifold film antiretropulsion device during ureteroscopy with high-pressure irrigation can potentially protect the kidney from elevated intrarenal pressures.

THE USE OF A NOVEL THERMOSENSITIVE POLYMER (BACKSTOP™) TO PREVENT PROXIMAL URETERIC STONE RETROPULSION DURING INTRACORPOREAL LITHOTRIPSY: A PROSPECTIVE RANDOMIZED CONTROLLED CLINICAL STUDY

INTRODUCTION AND OBJECTIVES: We present a randomized controlled prospective study using BackStopTM (Pluromed Inc, Woburn, MA), a novel reverse thermosensitive, water soluble polymer that is injected above the stone as a low viscosity gel, and which rapidly transitions to a high viscosity gel at body temperature, thereby occluding the ureter and preventing retrograde stone migration during intracorporeal lithotripsy. After fragmentation is completed and concretions extracted, conventional irrigation with saline dissolves the polymer, which is then flushed out. METHODS: A total of sixty-eight eligible subjects have been consented and randomly assigned to either the experimental group (BackStopTM) or the control group (no anti-retropulsion device). All subjects were indicated for ureteroscopic lithotripsy to treat single, radiopaque stones located in the proximal ureter. Primary endpoints include a determination of the effectiveness of BackStopTM in preventing retrograde stone migration during intracorporeal lithotripsy and an assessment of its “removal” via dissolution. The volume used, stone free rates and necessity of secondary procedures, if any, were also documented. RESULTS: The rate of stone retropulsion in the BackStop group was 8.8% (3/34) compared to 52.9% (18/34) in the control group (p=.0002). CONCLUSIONS: BackStop safely and significantly reduces the incidence of retropulsion of ureteral stones during intracorporeal lithotripsy.

A Randomized Clinical Trial of Lidocaine Jelly for Prevention of Inadvertent Retrograde Stone Migration During Pneumatic Lithotripsy of Ureteral Stone

We studied the efficacy of lidocaine jelly instillation proximal to the ureteral stone during intracorporeal lithotripsy using a semirigid ureteroscope for the prevention of retrograde migration and improvement in stone-free rate. From November 2006 to September 2007, 50 patients with 5 to 18 mm ureteral stones undergoing ureteroscopic removal using pneumatic lithotripsy were randomized into 2 groups. Group 1 (25 patients) had lidocaine jelly instilled proximal to the stone before and after fragmentation, and group 2 was the control group (25 patients). Ureteroscopy was performed using an 8 or 6.4Fr semirigid ureteroscope. A 5Fr ureteral stent was advanced beyond the stone. Lidocaine jelly (2 ml) was instilled and lithotripsy was performed with a Swiss LithoClast . A 5Fr ureteral catheter was left in place for 24 hours. Patients were followed at 24 hours with plain x-ray of the kidneys, ureters and bladder, and at 2 weeks with noncontrast enhanced computerized tomography of the kidneys, ureters and bladder. The 2 groups were comparable with regard to age and stone size. Stone or stone fragment migration occurred in 4% and 28% of patients in groups 1 and 2, respectively, and this difference was statistically significant (p = 0.002). At 2 weeks followup with imaging the stone-free rate was 96% and 72% in groups 1 and 2, respectively, and this difference was also statistically significant (p = 0.045). Although the mean operative time was slightly longer in the treatment group (33.56 +/- 13 vs 35.84 +/- 12.5 minutes) the difference was not significant (p = 0.450). Lidocaine jelly instillation proximal to ureteral calculi during lithotripsy is an effective method of preventing retrograde stone displacement as well as significantly improving the stone-free rate.

Prevention of retrograde stone migration during ureteroscopy

Retrograde stone migration during ureteroscopy leads to longer operating times, more-invasive endoscopy, and an increase in residual stones and the need for secondary procedures. In this Viewpoint, the author describes his experience with the various devices developed to prevent stone migration, focusing on the Stone Cone.

Prevention of retrograde calculus migration with the Stone Cone

Retrograde calculus migration during ureteroscopic lithotripsy remains a problem in 5-40% of cases. We assessed the safety and efficacy of the Stone Cone device, in comparison with the standard flat wire basket. A total of 56 consecutive patients with ureteral calculi, suitable for ureteroscopic extraction and/or lithotripsy, where included in this prospective study. Patients were randomly allocated into two groups. In group A (30 patients), we used the Stone Cone, while in group B (26 patients) we used the standard flat wire basket. The Stone Cone was placed through a cystoscope under fluoroscopic guidance, or when necessary under direct ureteroscopic control. Whenever necessary, intracorporeal electrohydraulic lithotripsy took place in both groups. Statistical significance was assessed by the paired t-test. The mean operative time was 48.5 min in group A, and 42.4 min in group B. Intact calculus extraction was possible in 16.6% in group A, and in 7.6% in group B (P < 0.01). Retrograde stone migration was revealed in 23% in group B only (P < 0.001). Also, residual fragments > 3 mm were recorded in 30.7% in group B only (P < 0.001). None of the patients in group A required auxiliary procedures, in contrary to 23% in group B (P < 0.001). No major complications were recorded in group A, while in group B a case of major ureteral mucosal abrasion was recorded. The Stone Cone is safe and efficient in preventing retrograde stone migration and in minimizing residual fragments during ureteroscopic lithotripsy in comparison with the flat wire basket.

542 Prevention of retrograde ureteral stone migration

542 Prevention of retrograde ureteral stone migration

The Dretler Stone Cone: A Device to Prevent Ureteral Stone Migration—The Initial Clinical Experience

Retrograde stone migration during ureteroscopic lithotripsy occurs in 5% to 40% of proximal and distal ureteral stone cases. This migration increases morbidity and the need for auxiliary procedures. The Dretler stone cone (Medsource, Norwell, Massachusetts) is a novel device to prevent proximal stone migration and facilitate fragment extraction during ureteroscopic lithotripsy. We assessed the safety and efficacy of the Dretler stone cone in the clinical setting and compared it prospectively with a conventional flat wire basket during ureteroscopy for ureteral calculi. To our knowledge we report the initial clinical use of the Dretler stone cone in 50 consecutive patients with ureteral calculi undergoing ureteroscopic extraction. Calculi were situated above the sacroiliac joint in 24 cases, over the sacroiliac joint in 15 and below the sacroiliac joint in 11. Pneumatic lithotripsy was done in 42 cases. In the remaining 8 cases ureteroscopic (3) or fluoroscopic (5) intact stone extraction was performed. The later 23 cases using the Dretler stone cone were prospectively compared with 20 of ureteroscopic intracorporeal lithotripsy using a standard flat wire basket. The Dretler stone cone was successfully placed in all 50 cases. In 41 patients it was placed via cystoscopy under fluoroscopic guidance, while 9 impacted stones required ureteroscopic placement. Six patients in whom the Dretler stone cone was used had residual fragments less than 3 mm. No patient required auxiliary procedures. In the prospective trial no patients in Dretler stone cone group had residual fragments greater than 3 mm. or required auxiliary procedures. However, in the flat wire basket group residual stones greater than 3 mm. were present in 6 cases (30%, p <0.001), while auxiliary procedures were required in 4 (20%, p <0.01). The Dretler stone cone represents a new generation of basketry that minimizes proximal ureteral stone migration and allows safe extraction of fragments during ureteroscopic lithotripsy. In our experience it is associated with a lower incidence of significant residual fragments and fewer auxiliary procedures than conventional flat wire baskets.