Extracorporeal shock wave lithotripsy in children

PURPOSE: We analyzed the efficacy of extracorporeal shock wave lithotripsy in children. MATERIALS AND METHODS: Between 1987 and 2000, 15,423 patients with urinary calculi were treated at our institution, of whom 86 (0.56%) children 3 to 14 years old underwent lithotripsy using the Siemens Lithostar Plus (Siemens Medical Systems, Iselin, New Jersey). A total of 121 calculi in 90 urinary tracts were treated requiring 149 extracorporeal shock wave lithotripsy sessions. The stones were caliceal in 62 cases, renal pelvic in 35, ureteral in 18 and staghorn in 6. Followup consisted of nephrotomogram or ultrasound 1 day and 1 to 3 months postoperatively. RESULTS: Complete removal of all stone fragments was achieved in 97.6% of the stones after 3 months. Re-treatment was necessary in 24 patients (27.9%). All patients were treated as outpatients with intravenous sedation in 54 (62.8%), general anesthesia in 13 (15.1%) and no anesthesia in 19 (22.1%). Complications were present in 8 patients (10.7%) who had colic and received medical treatment followed by uneventful recovery. CONCLUSIONS: Extracorporeal shock wave lithotripsy using the Lithostar Plus has been demonstrated to be an effective noninvasive procedure to treat radiopaque and even radiolucent or slightly opaque urinary calculi in children.     

In vitro comparison of shock wave lithotripsy machines

PURPOSE: We tested the hypothesis that shock wave lithotripsy machines vary in the ability to fragment stones to small size. MATERIALS AND METHODS: Calcium oxalate monohydrate, calcium hydrogen phosphate dihydrate, cystine and magnesium ammonium phosphate hexahydrate calculi were fragmented in vitro with the 22 kV. Dornier HM3, section sign 20 kV. Storz Modulith SLX, parallel, 15.6 kV. Siemens Lithostar C, paragraph sign 24 kV. Medstone STS-T,** 26 kV. HealthTronics LithoTron 160,daggerdagger 20 kV. Dornier Doli section sign and 22.5 kV. Medispec Econolithdouble daggerdouble dagger lithotriptors. Stones were given 500 or 2,000 shocks, or the Food and Drug Administration limit. Post-lithotripsy fragment size was characterized using sequential sieves and compared. RESULTS: Stone mass was statistically similar in the cohorts (p >0.94). Fragment size decreased as the number of shocks increased when the machine and stone composition were constant. Magnesium ammonium phosphate hexahydrate calculi were completely fragmented by all devices. At Food and Drug Administration treatment limits the mean incidence per device of calcium hydrogen phosphate dihydrate, calcium oxalate monohydrate, cystine and magnesium ammonium phosphate hexahydrate stones rendered into fragments greater than 2 mm. was 0% for the HM3, Modulith SLX and Lithostar C, 10% for the STS-T, 3% for the LithoTron 160, 29% for the Doli and 18% for the Econolith (p = 0. 04); 0% for the HM3, Modulith SLX, Lithostar C, STS-T and LithoTron 160, 4% for the Doli and 9% for the Econolith (p = 0.15); 1% for the HM3, 0% for the Modulith SLX, 1% for the Lithostar C, 10% for the STS-T, 14% for the LithoTron 160, 3% for the Doli and 9% for the Econolith (p = 0.44); and 1% for the HM3, 0% for the Modulith SLX, 1% for the Lithostar C, 10% for the STS-T, 14% for the LithoTron 160, 3% for the Doli and 9% for the Econolith (p = 0.44), respectively. CONCLUSIONS: Shock wave lithotriptors vary in fragmentation ability. The HM3, Modulith SLX and Lithostar C machines yield smaller fragments than other machines.     

Extracorporeal shock wave lithotripsy in children: Results and short-term complications

AIM: The introduction of extracorporeal shock wave lithotripsy represented an important evolution in urinary tract lithiasis management. The aim of this study is to describe the results of extracorporeal shock wave lithotripsy for the treatment of urinary tract lithiasis in children, focusing on the index of elimination of the calculi and the complications occurring during the procedure and during the following three months. METHODS: From September 1991 to July 2002, 135 children between one and 12 years, suffering from urinary tract lithiasis underwent extracorporeal shock wave lithotripsy. A retrospective analysis of these patients was carried out. RESULTS: One hundred and ninety-five calculi ranging in size from 5.0 mm to 20.0 mm were treated, out of which 147 were found in the kidneys and 48 in the ureter. Urinary tract dilation was presented by 30% of the children at the time of the procedure. After extracorporeal shock wave lithotripsy 75.8% of the calculi were eliminated: 64.1% were stone-free and 11.7% had < or = 4 mm stones. Ureteral calculi and 5-10 mm stones responded better than the kidney and 11-20 mm stones (P = 0.027 and P = 0.012, respectively). No differences were detected according to the calculi location, whether in the ureter or kidney (P = 0.637 and P = 0.703, respectively). The shock wave intensity of 14kv was as efficient as the higher voltage. Short-term complications were observed in 23.7%, characterized by fever and pain. CONCLUSION: In children, extracorporeal shock wave lithotripsy proved to be able to eliminate 75.8% of the treated calculi and 83.7% of the patients presented a complete or partial response. Complications were observed in 23.7% of patients, and pain was the most frequent symptom.     

低能量体外冲击击波碎石术研究进展

复式脉冲低能量体外冲击波碎石术治疗尿路结石成功率高,复打率低,副作用少,无严重并发症。本文就低能量体外冲击波碎石术提高成功率、减轻结石周围组织损伤及预防结石再复发的研究进展作一综述。     

Hounsfield units on computerized tomography predict stone-free rates after extracorporeal shock wave lithotripsy

PURPOSE: Studies suggest that HU values on non-contrast computerized tomography may predict the ability to fragment urinary calculi. We determined whether the HUs of in vivo urinary stones could be used to predict the stone-free rates after extracorporeal shock wave lithotripsy. MATERIALS AND METHODS: We evaluated 50 patients who underwent extracorporeal shock wave lithotripsy for 5 to 10 mm. upper urinary tract stones. Chemical analyses and HU calculations were performed for each stone and posttreatment radiographic assessment categorized patients into a stone-free or a residual stone group. Statistical analysis was performed using the Student t test to compare mean HU values in the 2 groups. RESULTS: Of the patients 32 (64%) were stone-free and 18 (36%) had residual stones. Mean values +/- SEM for the stone-free and residual stone groups were significantly different (551.20 +/- 46.66 versus 926.20 +/- 51.42 HU, p <0.0001). A total of 30 calculi (60%) were located in the ureter, including 21 in the stone-free group and 9 in the residual stone group with a mean value of 505.10 +/- 46.66 and 888.70 +/- 102.00 HU, respectively, which was significantly different (p = 0.0005). A total of 20 calculi (40%) were located in the kidney, including 11 in the stone-free group and 9 in the residual stone group with a mean value of 558.40 +/- 62.38 and 905.10 +/- 61.49 HU, respectively, which was significantly different (p = 0.001). CONCLUSIONS: These findings suggest that HU measurement of urinary calculi on pretreatment non-contrast computerized tomography may predict the stone-free rate. This information may be beneficial for selecting the preferred treatment option for patients with urinary calculi.     

Risk factors for the formation of a steinstrasse after extracorporeal shock wave lithotripsy: a statistical model

PURPOSE: We studied the various stone, renal and therapy factors that could affect steinstrasse formation after extracorporeal shock wave lithotripsy (ESWL), Dornier Medical Systems Inc., Marietta, Georgia to define the predictive factors for its formation. Thus, steinstrasse could be anticipated and prophylactically avoided. MATERIALS AND METHODS: Between February 1989 and May 1999, 4,634 patients were treated with a Dornier MFL 5000 lithotriptor (Dornier Med Tech, GmbH, Germany). Renal stones were encountered in 3,403 patients and ureteral stones in 1,231. Steinstrasse were recorded in 184 patients, of whom 74 required intervention and formed the "complicated group." All patient data, stone and renal characteristics, and data of ESWL were reviewed. Univariate and multivariate statistical analyses of patients, stones and therapy characteristics in correlation with the incidence of steinstrasse formation were performed to assign the factors that had a significant impact on steinstrasse formation. RESULTS: The overall incidence of steinstrasse was 3.97%. The steinstrasse was in the pelvic ureter in 74% of the cases, lumbar ureter in 21.7% and iliac ureter in 4.3%. Steinstrasse incidence significantly correlated with stone size and site, the power level (kV.) used during therapy and radiological renal features. Steinstrasse was more common with renal stones more than 2 cm. in diameter in a dilated system, especially with the use of high power (greater than 22 kV.) for disintegration. A statistical model was constructed to estimate the risk of steinstrasse formation accurately. CONCLUSIONS: Stone size and site, renal morphology and shock wave energy are the significant predictive factors controlling steinstrasse formation. If a patient has a high probability of steinstrasse formation, close followup with early intervention or prophylactic pre-ESWL ureteral stenting is indicated.     

Fate of residual fragments after successful extracorporeal shock wave lithotripsy

PURPOSE: The aim of the present study was to investigate the reason residual fragments from upper urinary tract calculi failed to clear after successful extracorporeal shock wave lithotripsy (ESWL). METHODS: Risk factors were analyzed in 161 patients with residual fragments (< or = 4 mm) that had remained for more than 3 months after ESWL. The factors examined in the present study were gender, a history of urolithiasis, the number, location and size of stones, hydronephrosis 3 months after ESWL and bacteriuria before ESWL. The mean follow-up period was 20.0 months (range 6-69 months). RESULTS: The overall stone-free rate was 14.3%. The stone-free rate in patients with multiple stones or hydronephrosis 3 months after ESWL was significantly lower than that in patients without these conditions (P < 0.05 and P < 0.01, respectively). The cumulative non-clearance rate in patients with hydronephrosis was significantly higher than in patients without this condition (P < 0.05). Results of Cox's proportional hazards model indicated that hydronephrosis was the most important and only significant factor for failure to clear of the seven factors investigated (P < 0.05). CONCLUSION: Hydronephrosis was most highly correlated with the fate of residual fragments after ESWL.     

Slow versus fast shock wave lithotripsy rate for urolithiasis: a prospective randomized study

PURPOSE: We determined the effect of shock wave lithotripsy (SWL) rate on treatment outcome in patients with renal and ureteral stones. MATERIALS AND METHODS: A total of 156 patients were prospectively randomized to receive SWL using a slow (60 pulses per minute) or fast wave rate (120 pulses per minute). Inclusion criteria were patients with a single radiopaque renal or ureteral stone not exceeding 30 mm in maximum diameter. Patient characteristics, stone and therapy features were reviewed, and the relation to success rate and total number of shock waves required was assessed using the chi-square, Fisher exact and Mann-Whitney tests. Factors proven to be significant in univariate analysis were entered in a multivariate logistic regression analysis. RESULTS: The study included 114 male (73.1%) and 42 female (26.9%) patients with a mean age +/- SD of 42.1 +/- 13.3 years. Stone length measured in maximum diameter was 13.2 +/- 5.9 mm (range 5 to 30). Renal stones were encountered in 94 (60.3%) patients and ureteral stones in 62 (39.7%). The slow SWL rate was used in 76 (48.7%) patients and the fast rate in 80 (51.3%). Baseline variables were comparable in both groups. However, the total number of shock waves required was statistically significantly lower in the slow rate group (p = 0.004) and the treatment time was significantly longer (p = 0.000). The rate of success, defined as being completely stone-free or having clinically insignificant gravel less than 2 mm, was significantly higher with the slow rate (p = 0.034), an increased number of sessions (p = 0.001), decreased stone length (p = 0.000) and greater total number of shock waves (p = 0.011). However, only the slow SWL rate and stone length maintained a statistically significant impact in multivariate analysis. CONCLUSIONS: The slow SWL rate is associated with a significantly higher success rate at a lower number of total shock waves compared to the fast SWL rate.     

体外震波碎石治疗肾结石

目的探讨体外震波碎石(ESWL)治疗肾结石的有效性。方法1997年8月至2001年8月应用德国DornierCompacts型体外震波碎石机治疗802例肾结石(直径为0.5～2.5cm)门诊病人。结果结石直径≤0.8cm(196例)、0.9～1.9cm(574例),≥2.0cm(32例),在二月内的排出率分别为62.7%、52.6%、20.5%;总排出率为54.9%。并发症少见,2例肾包膜下血肿,采用保守治疗;19例肾绞痛及24例“石街”形成,采用输尿管镜、再次碎石或保守治疗,结石完全排出。结论ESWL是治疗肾结石(直径<2.0cm)的有效方法,对大于2.0cm的结石,应首先行开放手术或经皮肾镜碎石(PCNL)治疗。     

Three-dimensional assessment of urinary stone on non-contrast helical computed tomography as the predictor of stonestreet formation after extracorporeal shock wave lithotripsy for stones smaller than 20 mm

The incidence of stonestreet formation after extracorporeal shock wave lithotripsy (ESWL) rises with increasing stone burden. However, stonestreet after ESWL is often experienced even in stones smaller than 20 mm. To examine whether the non-contrast helical computed tomography (CT) data could predict stonestreet formation in these stones, 53 radiopaque stones of 5-20 mm treated with ESWL were evaluated. Maximal dimension was measured on plain radiograph. From an attenuation value histogram graphed from the CT data, total stone volume and mean attenuation value were calculated. Seven stonestreets longer than 25 mm developed. There was no significant difference in maximal dimension and total stone volume between stones that did and stones that did not develop stonestreet. Mean attenuation value was the sole significant predictive factor. Application of mean attenuation value with cut-off level of 650 HU would anticipate stonestreet formation with a sensitivity of 85.7% and a specificity of 71.7%. The estimated risk of stonestreet formation is high in the treatment of stones with higher mean attenuation value.     

ESWL治疗儿童尿路结石的临床效果和远期随访(附54例报告)

为探讨体外冲击波碎石术（ESWL）治疗儿童尿路结石的远期效果，采用ESWL治疗儿童尿路结石54例，成功率为96．3％，术后无严重并发症。并对其中16例患儿进行了24～91个月（平均56．5个月）的远期随访，结果尿常规、尿素氮、肾功能及形态均正常，仅14．3％的患儿有结石复发，另外2例未排净的残石中有1例再生。由此表明，ESWL对患儿的血压远期影响不大，亦不影响患儿的肾脏功能及其生长发育。     

Pediatric staghorn calculi: the role of extracorporeal shock wave lithotripsy monotherapy with special reference to ureteral stenting

PURPOSE: Treatment for staghorn calculi in children represents a unique challenge. We assessed the efficacy of extracorporeal shock wave lithotripsy (ESWL) (Dornier Medical Systems, Inc., Marietta, Georgia) monotherapy for the management of staghorn calculi in children with special reference to ureteral stenting. MATERIALS AND METHODS: From June 1992 to January 2001 we treated 42 children 9 months to 12 years old with staghorn stones using the Piezolith 2501 (Richard Wolf GmBH, Knittlingen, Germany) lithotriptor. The initial group of 19 patients underwent ESWL without prophylactic ureteral stenting, while in the latter group of 23 a Double-J (Medical Engineering Corp., New York, New York) ureteral stent was inserted immediately before the first ESWL session. Mean patient age, stone size, number of shock waves and ESWL sessions, hospital stay, stone-free rate and major complications were compared in the 2 groups. RESULTS: Overall 33 children (79%) were stone-free after 3 months. The 2 groups were comparable in regard to patient age, stone size, number of shock waves and ESWL sessions, and stone-free rates. Major complications developed in 21% of the unstented group, whereas none were observed in stented cases. This difference was statistically significant (p = 0.035). Seven post-ESWL auxiliary procedures were required in the unstented group to manage complications. Hospital stay was significantly longer in the unstented compared with the stented group (p = 0.022). At a followup of 9 to 102 months (mean 47) stones recurred in 2 children, who were treated with further ESWL. CONCLUSIONS: ESWL monotherapy was an efficient and safe modality for the treatment of staghorn calculi in children. Stented patients had fewer major complications and a shorter hospital stay. Prophylactic ureteral stenting is advisable before ESWL for staghorn calculi in children.     

Evaluation of a synchronous twin-pulse technique for shock wave lithotripsy: the first prospective clinical study

OBJECTIVE: To present the results of the first clinical study of a synchronous twin-pulse technique for extracorporeal shock-wave lithotripsy (ESWL), which is effective for in vitro stone fragmentation and safe when assessed in vivo on animal tissue. PATIENTS AND METHODS: Fifty patients with urinary stones (35 men and 15 women) were enrolled and treated with the TWINHEADS lithotripter. The entry criteria were: age > or = 18 years, with a radio-opaque single stone in the kidney or upper ureter, a normal laboratory profile (serum creatinine, liver function, blood, bleeding and clotting times, and prothrombin concentration). The exclusion criteria included lower ureteric stones, patients with urinary tract infection, obstructed urinary tract distal to the stones, or congenital abnormalities. All patients received one session and were evaluated by ultrasonography (US), urinary tract plain X-ray, and complete laboratory investigations before and immediately after treatment, and after 2, 14 and 30 days. Patients requiring re-treatment at the 14-day visit received a second session and were re-evaluated after 7 and 14 days. RESULTS: The mean (sd, range) stone size (longest diameter) was 12.3 (2.6, 9-18) mm. Intravenous sedation was used in 30 patients. There was mild haematuria in 25 patients on the day of treatment. During the follow-up there was no evidence of haematoma, gross renal injury, upper urinary tract obstruction or significant changes in the laboratory investigations. After 14 days, 17 patients (34%) were free of stones, with residual stones of < or = 5 mm in 20 (40%); they were free of stones at the 1-month follow-up. Thirteen patients (26%) had residual stones of 6-9 mm, but the stones were half or less of the original size. Patients with residual stones of > 5 mm had another ESWL session and were free of stones within 14 days. Thus all patients were rendered stone-free within 1 month. CONCLUSIONS: Synchronous twin-pulse ESWL is promising, seems safe and effective for treating patients with renal and upper ureteric lithiasis.     

影响体外冲击波碎石术疗效的因素分析

目的　探讨影响体外冲击波碎石术(ESWL)疗效的因素。　方法　回顾ESWL治疗尿路结石患者234例的临床资料。分析患者性别、年龄、病程、结石大小、位置、X线形态及合并肾积水情况等因素与治疗成功率的关系。ESWL术后3个月接受KUB、IVU和B超检查,剩余结石<2mm为碎石成功, >2mm为治疗不成功。　结果　234例碎石成功率78. 6% (184 /234)。男性组和女性组治疗成功率分别为80. 3% (122 /152)和75. 6% (62 /82),P>0. 05。治疗不成功组与成功组病程分别为(1262. 6±1742. 1)d、(722. 9±1364. 6)d,P>0. 05;结石直径分别为(1. 1±0. 6)cm、(1. 0±0. 4)cm,P>0. 05;年龄分别为(58. 8±13. 6)岁、(42. 8±12. 2)岁,P<0. 05。肾盂结石(22. 7%, 10 /44)与肾盏结石(40. 0%, 8 /20),肾盂结石与输尿管结石( 18. 8%, 32 /170 ),输尿管上段结石( 15. 8%, 18 /114)与下段结石(25. 0%, 14 /56)间不成功率比较,差异无统计学意义(P>0. 05)。均匀高密度结石(20. 0%, 6 /30)与杂色结石(21. 6%, 44 /204)不成功率两组比较差异无统计学意义(P>0. 05)。结石直径0. 3~1. 0cm者(1. 9%, 2 /108), 1. 0 ~2. 0cm者(29. 8%, 28 /94), >2. 0cm者(62. 5%, 20 /32)不成功率3组两两比较P<0. 05。结石大小与治疗剂量呈正相关(r=0.28,P=0. 006)。     

Extracorporeal shock wave lithotripsy for lower pole calculi: Our experience

INTRODUCTION: This study was performed in order to evaluate the immediate and long-term outcome of patients undergoing extracorporeal shock wave lithotripsy (ESWL) for isolated lower pole calculi. METHODS: Three hundred and seventy renal units of 350 patients (240 men and 110 women; mean age 55 years) with isolated lower pole renal stones of smaller than 2 cm2 were studied. Follow up ranged from 1 to 52 months (mean, 15 months) to time of censorship, significant period of secondary urologic evaluation. RESULTS: Out of 370 renal units in 350 patients, 212 (57, 29%) were stone-free 1 month after ESWL and 21 (5.67%) spontaneously became stone-free within another 1-52 months (mean, 15 months). Intervention was required after 1-52 months (mean, 17.5 months) and accomplished by ESWL alone (30/350 patients 8.57%) or combined with retrograde endoscopy (10/350 patients 2.85%) while retrograde manipulation was necessary in two of the 350 patients (0.57%). CONCLUSION: Extracorporeal shock wave lithotripsy is the initial treatment of choice in patients with lower pole stones < 2 cm2, because the overall stone-free rate is acceptable and because even in the residual calculi, the risk of suffering symptomatic episodes requiring secondary intervention is low.     

Stone measurement by volumetric three‐dimensional computed tomography for predicting the outcome after extracorporeal shock wave lithotripsy

OBJECTIVE

To evaluate the efficacy of stone volume measured using a three‐dimensional (3D) reconstruction of preoperative non‐contrast computed tomography (NCCT) as an independent predictor of success after extracorporeal shock wave lithotripsy (ESWL) of upper urinary tract calculi.

PATIENTS AND METHODS

We evaluated preoperative NCCT in 94 patients who had ESWL for solitary upper urinary tract calculi of 4–20 mm in diameter. Axial images were used to measure the skin‐to‐stone distance (SSD), Hounsfield Unit (HU) density and axial stone diameter. Stone volume was calculated on a volume‐rendered 3D image for each stone. Maximum stone length was determined by comparative measurements of each stone in coronal, sagittal and axial planes, and was also measured on a plain abdominal film before ESWL. For ESWL we used the DoliS lithotripter (Dornier Medical Systems, Marrietta, GA, USA). A plain film at 6 weeks was used to categorize patients as stone‐free (SF) or with residual stone.

RESULTS

In all, 58 (62%) patients were SF and 36 (38%) had RS; the mean stone volume was significantly different between these groups (274 vs 464 µL, P = 0.002). Logistic regression analysis showed that stone volume was the strongest predictor of SF status (P < 0.001), compared to peak HU (P = 0.015), mean HU (P = 0.04) and axial stone diameter (P = 0.006). The body mass index, SSD and maximum stone length on NCCT or a plain film did not predict success. A stone volume of <500 µL best predicted treatment success (P < 0.001) with 72% of patients with a stone volume of <500 µL having a successful outcome, vs only 27% with a stone volume of >500 µL.

CONCLUSION

Our study suggests that stone volume is an optimal predictor of SF status after ESWL of solitary upper urinary tract calculi.     

Pain in extracorporeal shock wave lithotripsy

Pain tolerance has long been identified as a factor influencing successful treatment of renal calculi by shock wave lithotripsy (SWL). We aimed to clarify which factors directly influence pain tolerance to predict which patients are likely to undergo successful treatment. We analysed retrospectively 179 patients who received their first SWL for a solitary kidney stone. All patients were on a non-opioid analgesia protocol and were treated on an outpatient basis. The target was to deliver 4,000 shock waves at an energy level of 4. In total, 53% of patients could tolerate the targeted shock wave number and energy and were retrospectively allocated into group A. Those who required a reduction in either energy levels or shock wave number were allocated in group B. Multivariate and univariate analysis showed that female patients, who are young with thin body habitus, have lower pain tolerance to SWL. 11th international symposium on urolithiasis, Nice, France, 2–5 September 2008 Urological Research (2008) 36:157–232. doi:. .     

Ureteroscopy and pneumatic lithotripsy, followed by extracorporeal shock wave lithotripsy for the treatment of distal ureteral stones

BACKGROUND: We retrospectively reviewed our experience with retrograde ureteroscopy (URS) and a pneumatic lithotriptor in 160 patients with distal ureteral stones to determine whether prior extracorporeal shock wave lithotripsy (ESWL) is a limiting factor in the ureteroscopic procedure. METHODS: From January 1999 to September 2000, we performed URS and pneumatic lithotripsy in 160 patients with distal ureteral stones. Seventy-four patients were treated with URS primarily (Group 1), while the remaining 86 patients received URS only after ESWL had failed (Group 2). For URS and lithotripsy, we used a 9.5 French rigid instrument and vibrolith (Elmed, Ankara, Turkey). RESULTS: In Group 1, 73 of 74 patients (98.6%) were treated successfully by URS alone, as were 81 of 86 patients (94.4%) in Group 2. Impacted stones were also observed in 17 patients from Group 2. In these patients, endoscopic observation revealed edematous inflammation above and below the calculus. Ureteral perforation occurred in one patient from Group 2, which required surgical repair. There was no significant difference in the stone-free rates of the two groups t = 1.4 < 1.96t( infinity,0.05). CONCLUSION: Our data demonstrate that when ESWL fails, URS and pneumatic lithotripsy is as safe and effective as primary URS. Pneumatic lithotripsy also seems to be an effective treatment modality for impacted stones.