Piezoelectric shockwave lithotripsy of urinary calculi: comparative study of stone depth in kidney and ureter treatments

PURPOSE: The aim of this prospective study was to assess the relation between stone depth and the efficiency of piezoelectric extracorporeal shockwave lithotripsy (SWL). PATIENTS AND METHODS: A total of 150 patients presenting with 25 pelvic, 75 caliceal, and 25 upper and 25 lower ureteral calculi were treated using the EDAP LT02 lithotripter. All of the stones were easy to localize with sonographic and radiographic systems, and their largest diameter ranged from 4 to 25 mm (mean 8.5 mm). Renal and upper ureteral calculi were treated with the patient in the supine position and lower ureteral stones in prone position. On the basis of a meticulous stone localization and focusing, depth measurements were carried out under real-time ultrasonic guidance, the minimal distance between the cutaneous plane and the focal point being recorded only for definitely localized calculi. RESULTS: Ureteral calculi were significantly deeper than renal stones (p < 0.0001), but the distance from the cutaneous plane was statistically similar for upper and lower ureteral calculi. Stone depth was statistically affected by body mass index (BMI), patients with a BMI >25 having significantly deeper renal and ureteral calculi than subjects with a BMI < or =25 (p < 0.00001 and 0.01, respectively). Renal stones resisting SWL were significantly deeper than successfully treated calculi (p < 0.03). At the level of the ureter, the success rate after one SWL session was 85% for stones with a depth < or =110 mm and 57% for deeper stones, the difference being significant (p < 0.05). CONCLUSION: Stone depth has a significant influence on treatment outcome after piezoelectric SWL for both renal and ureteral calculi. We recommend particular attention be given to corpulent patients presenting with ureteral stones.     

Prospective, randomized trial comparing shock wave lithotripsy and ureteroscopy for lower pole caliceal calculi 1 cm or less

PURPOSE: The optimal management of lower pole renal calculi is controversial. We compared shock wave lithotripsy (SWL) and ureteroscopy (URS) for the treatment of patients with small lower pole stones in a prospective, randomized, multicenter trial. MATERIALS AND METHODS: A total of 78 patients with 1 cm or less isolated lower pole stones were randomized to SWL or URS. The primary outcome measure was stone-free rate on noncontrast computerized tomography at 3 months. Secondary outcome parameters were length of stay, complication rates, need for secondary procedures and patient derived quality of life measures. RESULTS: A total of 67 patients randomized to SWL (32) or URS (35) completed treatment. The 2 groups were comparable with respect to age, sex, body mass index, side treated and stone surface area. Operative time was significantly shorter for SWL than URS (66 vs 90 minutes). At 3 months of followup 26 and 32 patients who underwent SWL and URS had radiographic followup that demonstrated a stone-free rate of 35% and 50%, respectively (p not significant). Intraoperative complications occurred in 1 SWL case (unable to target stone) and in 7 URS cases (failed access in 5 and perforation in 2), while postoperative complications occurred in 7 SWL and 7 URS cases. Patient derived quality of life measures favored SWL. CONCLUSIONS: This study failed to demonstrate a statistically significant difference in stone-free rates between SWL and URS for the treatment of small lower pole renal calculi. However, SWL was associated with greater patient acceptance and shorter convalescence.     

Evaluating the importance of mean stone density and skin-to-stone distance in predicting successful shock wave lithotripsy of renal and ureteric calculi

Shock wave lithotripsy (SWL) is considered the first line treatment for the majority of patients with renal and ureteric calculi, with success rates from contemporary series varying from 60 to 90%. Success is dependent on many patient and stone-related factors. We conducted a retrospective analysis of mean stone CT density (MSD) and skin-to-stone distance (SSD) to determine their influence on the success of SWL of renal and ureteric calculi. Data from all patients treated at the St. Michael’s Hospital Lithotripsy Unit from May 2004 to June 2009 were reviewed. Analysis was restricted to those patients with a pre-treatment non-contrast CT scan conducted at our center demonstrating a solitary renal or ureteric calculus ≤20 mm in maximal diameter. Successful treatment of renal stones was defined as those patients who were stone free or had asymptomatic, clinically insignificant residual fragments ≤4 mm in diameter, as measured by KUB X-ray, 3 months after a single SWL treatment. Successful treatment of ureteric stones was defined as being stone free on KUB X-ray, 2-weeks post-SWL. Demographic, stone, patient, treatment and follow-up data were collected from a prospective database and review of CT and KUB imaging by two independent urologists and one radiologist. Data were analyzed with logistic regression, Chi square analysis and ANOVA where appropriate. 422 patients (69.7% male) with a mean age of 51.4 years (SD 12.9) and mean BMI 27.0 kg/m² (SD 4.9) were analyzed. Mean stone size was 78.9 mm² (SD 77.3) for ureteral stones and 66.1 mm² (SD 63.2) for renal stones, with 95 (43.6%) of the renal stones located in the lower pole. The single-treatment success rates for ureteral and renal stones were 62.3% and 68.8%, respectively. On univariate analysis, predictors of SWL success, regardless of stone location, were age (p = 0.01), BMI (p = 0.01), stone size (p < 0.01), MSD (p < 0.01) and SSD (p < 0.01). On multivariate analysis, MSD >900 HU (OR = 0.49, CI: 0.32–0.75) and SSD >110 mm (OR = 0.49, CI: 0.31–0.78) were both significant predictors of outcome. We have identified in a large series of renal and ureteric calculi that both MSD and SSD can reliably predict SWL outcomes. This data can be used in combination with other patient and stone-related factors to facilitate optimal treatment-based decisions and provide patients with more accurate single-treatment success rates for SWL.     

Endoscopy vs. extracorporeal shockwave lithotripsy in the treatment of distal ureteral stones: ten years' experience.

BACKGROUND: The lower third is the location of the great majority of ureteral stones. Treatment of these stones remains controversial: in situ extracorporeal shockwave lithotripsy (SWL) vs. ureteroscopy (URS). METHODS: During the last decade, 633 distal ureteral calculi were treated at our institution using in situ SWL (Siemens Lithostar electromagnetic lithotripter) in 395 patients and URS (with 11.5F instrument and ultrasonic lithotripsy) in 228 patients. The patients' age and stone size were similar in the two groups. All SWL therapies were performed on an outpatient basis. RESULTS: The overall success rate was 99% for SWL, and the efficiency quotient (EQ) was 92.4%. The treatment was more effective for <10 mm calculi. In the URS group, there was a 92% overall success rate with an EQ at 91.2%. Compared with SWL, URS was more time consuming, at least for the initial cases; often required intravenous sedation; entailed routine placement of a ureteral stent; and more often led to hospitalization. On the other hand, stone clearance was rapid after URS, although most of the SWL patients were stone free at the end of 6 weeks. The cost was similar in the two groups. CONCLUSION: We believe that multiple factors should be considered when deciding the most appropriate approach to distal ureteral calculi. In situ SWL provides optimal first-line treatment for calculi < 10 mm, whereas URS is better reserved for stones >10 mm.     

Complications and outcomes following extracorporeal shock wave lithotripsy: a prospective study of 3,241 patients

Extracorporeal shock wave lithotripsy (SWL) has become the least invasive treatment modality with high success rates for urinary calculi; however, its established efficacy has been associated with a number of side effects and complications. This study sought to further evaluate the incidence rate and management of the post-SWL complications and also the efficiency of procedure in a large scale of patients. During a 51-month period, 3,241 consecutive adult patients with the mean age of 38.1 years (range 15–75) and urinary calculi (≥4 mm) underwent SWL at our referral center and were followed for 3 months prospectively. Overall, 3,614 stones [kidneys (83.5%), ureters (15.8%) and bladder (0.7%)] in 3,241 patients were treated requiring 7,245 SWL sessions. Stone-free state occurred in 71.5% calculi and success rate in 79.8% patients. The re-treatment was necessary in 37.2% patients. Auxiliary procedure and efficiency quotient were 5.6% and 0.50, respectively. SWL success rate decreased as the stone size increased (P < 0.0001). The stone-free rate was correlated with the location of the stone. During the study period, 4,075 complications occurred in our patients. Colicky pain (40%) was the most frequent symptom followed by gross hematuria (32%) and steinstrasse (24.2%). Symptomatic bacteriuria developed in 9.7% patients; Escherichia coli (30.4%) was the most causative organism. In conclusion, the complication rate following SWL was high in our study; however, the majority was mild and managed conservatively or with the minimal intervention. Moreover, the management of urinary calculi in adults using SWL was proved to be safe and efficient, particularly for ureteral stones <10 mm, renal pelvic stones <20 mm, and bladder stones <30 mm.     

Pediatric urolithiasis: 15 years of local experience with minimally invasive endourological management of pediatric calculi

PURPOSE: We sought to identify whether changes in technology and local practice have improved outcomes in the minimally invasive management of pediatric stone disease. MATERIALS AND METHODS: We reviewed retrospectively case notes and imaging from 1988 to 2003, noting treatment modality, stone-free rates, ancillary therapy and complications. RESULTS: A total of 122 children (140 renal units) with a mean age of 7.7 years underwent 209 extracorporeal shock wave lithotripsy (SWL) sessions. Stone size ranged from 6 to 110 mm. Stone-free rates were 84% for cases involving stones smaller than 20 mm, and 54% for those involving stones 20 mm or greater. For complex calculi 40% of patients were stone-free and 45% required ancillary procedures, with an overall complication rate of 26%. A total of 37 children (43 renal units) with a mean age of 6.4 years underwent 46 percutaneous nephrolithotomies (PCNLs). Stone size ranged from 8 to 155 mm. The overall stone-free rate was 79%. Of these patients 34% required ancillary procedures, with a major complication rate of 6%. A total of 35 children (35 renal units) with a mean age of 5.9 years underwent 53 ureteroscopies. Holmium laser was the most effective treatment modality in this group, with a 100% stone-free rate and no complications. CONCLUSIONS: For most renal stones smaller than 20 mm SWL was the most effective primary treatment modality. There was no statistical difference between the 2 lithotriptors for stone-free or ancillary procedure rate. The stone-free rate was dependent on stone size rather than type of lithotriptor. For renal stones 20 mm or greater and staghorn calculi we switched from SWL to PCNL as primary treatment, as stone-free rates were higher and the ancillary procedure and re-treatment rates were lower with PCNL. Electrohydraulic lithotripsy and pulse dye laser were initially used to treat ureteral stones. However, with the introduction of holmium laser technology we achieved higher stone-free rates and lower complication rates. Holmium laser lithotripsy is now used as a primary treatment modality for ureteral stones.     

Management of ureteral stones with pneumatic lithotripsy: report of 500 patients

PURPOSE: To evaluate the results of pneumatic lithotripsy (PL) with ureteroscopy in the treatment of ureteral stones. PATIENTS AND METHODS: We reviewed, retrospectively, the records of 500 patients (366 male, 134 female) with ureteral calculi treated by PL with the Swiss Lithoclast. Of these patients, 124 (24.8%) were treated primarily and 376 (75.2%) were treated secondarily after unsuccessful extracorporeal shockwave lithotripsy (SWL). The results were evaluated 3 months after treatment by excretory urography, ultrasonography, or both. RESULTS: The over-all stone-free and fragmentation rates were 94.6% and 96.8%, respectively. These values were 97.1% and 98.5% for stones 10 mm, respectively. The main complications were stone migration (2.0%), urosepsis (3.0%), and ureteral perforation (1.4%). CONCLUSIONS: While SWL is generally excepted as a first-line treatment option in ureteral stones because of its noninvasive nature, in situ lithotripsy, and especially PL, has higher success rates with minimal morbidity. Thus, PL seems to be a good alternative in patients in whom SWL was unsuccessful or not indicated and in patients who need early stone removal.     

Piezoelectric lithotripsy of ureteral stones: influence of shockwave frequency on sedation and therapeutic efficiency.

OBJECTIVE: The aim of this randomized study was to assess the relation between shockwave frequency, sedation, and efficiency in piezoelectric extracorporeal shockwave lithotripsy (SWL) for ureteral calculi. METHODS: A random sample of 114 patients aged between 15 and 74 (mean 45) years were treated at the shockwave frequencies of 1 (N = 57) or 4 (N = 57) per second using the EDAP LT 02 lithotripter at maximum energy. The stones' largest diameter ranged from 5 to 18 mm (mean 7.6 mm). Lower ureteral stones were treated with the patient in the prone position and upper ureteral stones in supine position. The duration of SWL sessions and stone measurements were statistically similar for patients treated at low and high frequencies. The levels of required sedation (none, intramuscular analgesia, intravenous sedation-analgesia) and stone-free rates after one session were analyzed by Student's t-test or Fisher's exact test. RESULTS: Sedation did not differ statistically with SWL frequency for mid and lower ureteral calculi. However, the use of intravenous sedation-analgesia was less common for patients with upper ureteral stones treated at low rather than high frequency (19% and 100%, respectively; P < 0.0001). The success rate was significantly lower (P = 0.04) for lower ureteral calculi treated at low v high frequency (65 % and 89%, respectively) but was not statistically affected by frequency for upper ureteral stones. CONCLUSION: We recommend high frequency for piezoelectric SWL of lower ureteral calculi, especially for stones with a maximum diameter > or =8 mm. On the other hand, low-frequency SWL appears to be suitable for the treatment of upper ureteral stones.     

Extracorporeal piezoelectric shockwave lithotripsy of ureteral stones: are second-generation lithotripters obsolete?

BACKGROUND: The role of extracorporeal shockwave lithotripsy (SWL) for ureteral calculi is still being debated. We evaluated our results in a large series to clarify the role of this modality. PATIENTS AND METHODS: A total of 478 patients with solitary ureteral stones were treated by in situ piezoelectric extracorporeal shockwave lithotripsy (SWL) using a Wolf Piezolith 2300 ultrasound-guided lithotripter. Two hundred fifty stones (52.3%) were located in the upper ureter and 228 (47.7%) in the distal ureter. Seventy of the upper ureteral stones were located in the ureteropelvic junction and 180 in the lumbar ureter. The diameter of the stones ranged from 5 to 30 mm. Four hundred sixty-seven patients were followed up for a mean of 4 months. RESULTS: Four hundred forty patients (94.2%) were stone free after in situ SWL alone. Complete removal of all stone fragments was achieved in 95.4% of the 216 patients with calculi of 5 to 10 mm in diameter, in 94.3% of the 229 with stones of 11 to 20 mm, and in 81.8% of the 22 with calculi of 21 to 30 mm. In situ treatment completely removed 61 of 69 ureteropelvic junction stones (88.4%), 166 of 175 lumbar stones (94.8%), and 213 of 223 distal ureteral stones (95.5%). In situ treatment failed in 27 stones (5.8%). After 4 months, 12 stone fragments and 15 unfragmented stones persisted despite retreatments and required endoscopic procedures. The mean number of sessions and shockwaves per patient was 1.8 and 4884, respectively. Morbidity was low. Renal colic in 57 patients (11.9%) was managed successfully by analgesics. In 36 patients, stone fragments obstructed the ureter; in 28 of these 36 (78%), the obstruction was resolved and the patients were stone free after in situ retreatments alone. All these results were achieved on an outpatient basis without sedation or local or general anesthesia. CONCLUSION: Piezoelectric SWL is an effective and noninvasive method for eliminating ureteral stones. Second-generation ultrasound-guided lithotripters are not yet obsolete.     

The Dornier Compact Delta lithotripter: the first 150 ureteral calculi

BACKGROUND AND PURPOSE: Shockwave lithotripsy (SWL) is the least invasive treatment for ureteral calculi and is the best accepted by patients and clinicians. This prospective study was performed to evaluate the results of SWL for all ureteral calculi. PATIENTS AND METHODS: Between April 1999 and May 2000, there were 150 SWL treatments for ureteral calculi at our center. All patients who completed treatment (24 females, 126 males with an average age of 54 +/- 14 years) were entered in the study and were assessed at 1 and 3 months with a plain film of the kidneys, ureters, and bladder and an ultrasound scan or intravenous urogram if clinically indicated. The outcome has been analyzed according to stone size, location (lower ureter [LU], midureter [MU], and upper ureter [UU], number of treatments per stone, number of shocks per stone, and stone-free rate (SFR). The analgesia requirements during each treatment and complications have also been analyzed. RESULTS: The SFR in the UU was 77% at 1 month and 85% at 3 months. The SFR in the MU was 74% at both 1 and 3 months. The SFR in the LU was 65% at 1 month and 74% at 3 months. Overall, the SFR for all calculi was 72% at 1 month and 79% at 3 months. Ureteroscopic extraction was necessary in 19% of the patients and conservative management for the remaining asymptomatic fragments, which were 2 mm or smaller. All of these asymptomatic fragments were seen to have passed spontaneously on follow-up imaging studies. Ureteral stents were not placed routinely prior to SWL, but there were 32 calculi (21%) for which stents had been placed prior to SWL: 29 (19%) in the UU, 3 (2%) in the MU, and 0 in LU. There was no difference in the SFR or ureteroscopy rate in UU calculi treated with or without stents and no difference in the number of treatments needed to achieve these SFRs. The efficiency quotient for the UU was 55%, 45% for the MU, and 45% for the LU. Oral analgesia was given routinely; however, additional intravenous analgesia was necessary in 24% of treatments. No serious complications were seen. CONCLUSIONS: The Dornier Compact Delta lithotripter provides an effective noninvasive treatment for ureteral calculi that is achieved with minimal anesthesia and a low complication rate. Placement of ureteral stents prior to SWL does not enhance the SFR or obviate intervention if SWL fails. We recommend a low threshold for ureteroscopic treatment if significant progress is not made in fragmenting the stone with SWL.     

Analgesia in piezoelectric SWL: comparative study of kidney and upper ureter treatments.

BACKGROUND: The development of newer-generation lithotripters has reduced the pain associated with SWL, but many patients still require some form of sedation. We prospectively compared the analgesic requirements for kidney and upper ureteral treatments. Predictive factors for pain during piezoelectric SWL were also studied. PATIENTS AND METHODS: A total of 102 consecutive patients without any previous experience of SWL were treated for renal (N = 70) or upper ureteral (N = 32) calculi using the EDAP LT02 lithotripter. The stones' largest diameter ranged from 4 to 30 mm (mean 9 mm). Patients were given an oral dose of 60 mg of dextropropoxyphene hydrochloride and 800 mg of paracetamol associated with 100 mg of ketoprofene per rectum 30 minutes before treatment. The SWL session was begun at low intensity and increased to the maximal range of energy as rapidly as could be tolerated by the patient. The amount of pain during treatment was recorded according to a visual analogue scale (VAS). Further analgesia using intravenous alfentanil was given as required by the severity of the pain. Visual analog pain scores, additional sedation requirements, and success rates after one session were analyzed. RESULTS: The VAS scores and intravenous sedation requirements were significantly lower for patients with upper ureteral stones than for those with renal calculi (P < 0.01). The stone-free rates after one session were, respectively, 90% and 73% (P < 0.05). On the other hand, SWL tolerance was significantly lower for women presenting with renal stones (P < 0.05). CONCLUSION: Piezoelectric SWL without intravenous sedation is suitable for the treatment of upper ureteral calculi. However, such an approach is less efficient in the management of kidney stones, especially for female patients.     

Comparative results of shockwave lithotripsy for renal calculi in upper, middle, and lower calices

BACKGROUND AND PURPOSE: To assess the results of shockwave lithotripsy (SWL) for renal calculi in upper, middle, and lower calices according to the stone burden. PATIENT AND METHODS: A series of 52 female and 66 male patients with a mean age of 47.8 years and isolated single caliceal stones who underwent SWL monotherapy were enrolled. Stone burden, stone location, number of sessions/shockwaves, and auxiliary procedures were noted for each patient. Stones were located in the upper, middle, and lower calices of 35, 43, and 40, patients respectively, with mean stone burdens of 81.4 mm2, 75.2 mm2, and 96.3 mm2, respectively. Patients were evaluated with intravenous urography, plain film, or ultrasonography. Success was determined 3 months after the last session. Re-treatment rates were calculated. The effect of anatomic factors on the success of treatment for lower-caliceal stones also was determined. RESULTS: The mean stone burden, median number of treatment sessions, and mean number of shockwaves were 84.2 mm2, 2, and 4344, respectively. The auxiliary procedure rate was 16.1%, and the re-treatment rate was 71.2%. Failure was noted in 26 patients (22%). The stone-free rates for stones in the upper, middle, and lower calices were 82.8%, 83.4%, and 67.5%, respectively (P = 0.14). The stone-free rates for stones <100 mm2 and 100 to 200 mm2 were 91.2% and 65.5%, respectively (P = 0.001). The efficiency quotient was 49.8, 44.8, and 32.5 for upper-, middle-, and lower-caliceal stones, respectively. Infundibular length (P = 0.006) and infundibular width (P + 0.036) were significant in determining the stone-free rate after treatment of lower-caliceal stones. CONCLUSIONS: We recommend SWL as the first choice for treatment of stones <200 mm2 in the upper and middle calices. Extracorporeal lithotripsy is one of the options for lower-caliceal stones <200 mm2 but has high re-treatment and auxiliary-procedure rates in these cases.     

Pneumatic lithotripsy for large ureteral stones: is it the first line treatment?

Objective To evaluate the effectiveness of pneumatic lithotripsy (PL) with ureteroscopy in the treatment of large ureteral stones. Methods We reviewed, retrospectively, the records of 156 patients (122 male, 34 female) who had ureteral calculi larger than 10 mm that were treated with PL. Of these patients, 41 (26.3%) were treated primarily with PL and 115 (73.7%) were treated secondarily after unsuccessful extracorporeal shock wave lithotripsy (SWL). The mean stone diameter was 12.87 mm (range 10–20.5 mm). Results were evaluated 3 months after treatment by excretory urography and/or ultrasonography. Results The overall stone-free and fragmentation rates (FRs) were 85.2 and 92.3%, respectively. Corresponding values were 60 and 84% for upper ureteral stones, 79.5 and 89.7% for middle ureter stones and 94.5 and 95.6% for lower ureteral stones, respectively. The main complications were migration of a complete stone or of fragments (7.1%), urosepsis (4.5%) and ureteral perforation (1.3%). Conclusions Although SWL is generally accepted as the first treatment option for ureteral stones because of its non-invasive nature, PL with ureteroscopy seems to be a good alternative with the advantage of higher success rates and quick stone clearance. Especially when we take the importance of quick stone removal into account for larger ureteral stones, which are more likely to have obstruction, impaction, or infection, we believe that PL may be chosen as the first line treatment rather than SWL for stones larger than 10 mm.     

Primary treatment of ureteral stones by new multiline lithotripter.

BACKGROUND AND OBJECTIVES: During the last 15 years, a second and a third generation of lithotripters have been developed. We present the results achieved by primary extracorporeal shockwave lithotripsy (SWL) of ureteral calculi treated with the new Multiline Lithotripter (Siemens). PATIENTS AND METHODS: From April 1996 until February 1997, 50 men and 17 women ages 19 to 82 (mean 50.9) years, underwent SWL as a primary treatment of ureteral stones at the Department of Urology, University of Düsseldorf. Data were analyzed retrospectively. More than half (60%) of the 67 patients had left ureteral stones. The most frequent site was proximal (46%) followed by distal (37%). The mean stone diameter was 9 mm. A total of 118 treatments were performed. RESULTS: The success rates of SWL monotherapy for upper, mid, and lower ureteral calculi were 71%, 82%, and 72%, respectively. Although in 62% of the cases, complete, and in 33% partial, stone disintegration was achieved, auxiliary procedures (ureteral stenting, nephrostomy, and ureteroscopy) were necessary in 43% of the patients. Renal hematoma occurred in two patients, who were treated for upper ureteral calculi. Two thirds of the patients were discharged from the hospital free of stones. CONCLUSIONS: Primary SWL treatment of ureteral stones with the new Multiline showed good results in about 84% of cases, although 43% of patients required auxiliary procedures. The occurrence of renal hematoma after the treatment of upper ureteral stones is an unexpected complication and makes reduction of the applied energy necessary if the kidney lies within the field of shockwave application.     

The concentration of Zn,Mg and Mn in calcium oxalate monohydrate stones appears to interfere with their fragility in ESWL therapy

Extracorporeal shockwave lithotripsy (SWL) has remained the preferred method of treatment of urinary stones since its introduction in 1980. Although SWL is classified as a potential first-line treatment for renal stones smaller than 2 cm and its overall success rate is higher than 85% for stone clearance, not all renal calculi are successfully fragmented after SWL. Among the urinary stones, calcium oxalate monohydrate (COM) stone is one of the hardest stones to fragment. Several factors interfering with stone fragility are known to exist. In addition to technical properties for SWL to increase the quality and rate of stone disintegration, the composition of stones such as trace element levels may also interfere with the efficacy of SWL. Therefore, in the present study, we aimed to elucidate the correlation, if it exists, between fragmentation of renal stones and their trace element (Cu, Zn, Mg, Fe, Pb, Mn, Cr) concentrations. For this purpose, the patients admitted to our department who were identified with urinary stones (740 patients) and underwent SWL sessions were evaluated prospectively. Patients having 5–20 mm of solitary COM stone in the renal pelvis were included in this study. The trace element concentrations of renal stones that were successfully fragmented with SWL (SWL-S) were compared with those that were unsuccessfully fragmented after three SWL sessions (SWL-US) and removed surgically. Our measurements showed that the concentrations of Cu, Fe, Pb, and Cr were similar in both groups; by contrast, the concentration of Zn, Mg and Mn was significantly lower in SWL-US renal stones. The present results suggest that low concentrations of Zn, Mg and Mn in COM stones appear to make them resistant to SWL fragmentation and may offer a critical distinction for the choice of a treatment program.     

Retrograde intra-renal surgery for stone extraction

OBJECTIVE: To assess various clinical parameters affecting the efficacy and safety profile of retrograde intra-renal surgery (RIRS) for stone extraction. MATERIAL AND METHODS: Between the years 2001 and 2003, 63 patients underwent RIRS in our department for renal calculi, including 25 who had stones >/=20mm in size. RESULTS: Among the 63 patients who underwent the operation, 19 (30%) had infectious complications postoperatively. Although neither preoperative stenting nor stone burden were found to have any direct implication on postoperative course, a trend was seen as 64% of the infected patients had initially had large renal stones (>/=20mm in diameter) and 59% had been preoperatively drained. CONCLUSIONS: RIRS is currently considered to be a safe standard retrograde endoscopic procedure for treating renal calculi. However, patients with stones>20 mm in diameter or multiple small calculi, especially in the presence of pre-existing tubes or following prior urinary tract infections, represent a subgroup of patients that are, in general, at higher risk of remarkable infectious complication rates and are likely to experience less satisfying stone-free rates when RIRS surgery is performed.     

Current practice patterns in the management of upper urinary tract calculi in the north central United States

PURPOSE: To determine the current practice patterns in the management of upper urinary tract calculi in a large group of urologists in the north central United States. MATERIALS AND METHODS: An email survey was sent to 790 practicing members of the North Central Section of the American Urological Association. The survey consisted of questions pertaining to practice and training background, and case scenarios with treatment options for upper urinary tract calculi of different sizes at various locations. The responses were then statistically analyzed to determine practice trends. RESULTS: Seven urologists did not fill out the survey, as they did not manage patients with stone disease. The overall response rate was 23% (167/783). Although more than 75% of urologists were trained to perform extracorporeal shockwave lithotripsy (SWL), ureteroscopy (URS), and percutaneous nephrolithotomy (PCNL) during their residency, only 61% and 17% were trained to perform open stone surgery (OSS) and medical expulsive therapy (MET), respectively. Twelve percent of respondents were fellowship trained in endourology. Observation was most commonly recommended for asymptomatic renal calculi <5 mm in size (92%). Although SWL continues to be the most commonly utilized therapy for renal (43%-92%) and proximal ureteral calculi <20 mm in size (29%-51%), and PCNL for renal calculi >20 mm in size (72%-92%), many urologists (48%) favored PCNL for lower pole calculi 10 to 20 mm in size. Use of URS was mostly favored for distal (44%-90%) and proximal ureteral calculi (23%-46%), while MET was recommended for small ureteral calculi <5 mm in size (25%-32%). Fellowship-trained endourologists, academic urologists, and urologists in practice for less than 5 years were more likely to utilize URS, PCNL, and MET, and less likely to utilize SWL for urinary calculi. CONCLUSION: The results of this survey suggest that practice patterns for treatment of stone disease match the treatment approach recommended in the published literature. This information can be further utilized for assessment of guidelines for the treatment of stone disease.     

Predictors of clinical significance of residual fragments after extracorporeal shockwave lithotripsy for renal stones

PURPOSE: To determine the predictors of the clinical outcome of residual fragments after extracorporeal shockwave lithotripsy (SWL). PATIENTS AND METHODS: During the last 10 years, residual fragments < or =5 mm were present in 99 male and 55 female patients (mean age 43.1 years) for >3 months after SWL for renal stones. Follow-up with history, urine examination, and non-contrast CT scanning was carried out every 6 months or when symptoms developed. Clinically insignificant residual fragments were diagnosed in patients who became stone free or had asymptomatic fragments of the same size during follow-up. A clinically significant outcome was considered to have occurred in patients requiring secondary intervention for regrowth of the fragments or medical treatment for frequent symptomatic episodes. Univariate (Kaplan-Meier) and multivariate (Cox-regression) analyses were performed to determine significant predictors of the outcome. The mean follow-up was 31 months (range 6-80 months). RESULTS: Stone-free status, regrowth of fragments, and persistence of fragments of the same size were present in 21 (13.6%), 52 (33.8%), and 81 (52.6%) patients, respectively. A clinically significant outcome was documented in 75 patients (48.7%) as percutaneous nephrolithotomy was needed in 2, repeat SWL in 50, and medical treatment for symptomatic episodes in 23 patients. Significant independent predictors of a clinically significant outcome were fragment size > or =4 mm and history of recurrent stone disease (P < 0.001). CONCLUSION: The term "clinically insignificant residual fragments" is not appropriate for all patients with post-SWL fragments, as 48.7% of patients had fragments that became clinically significant. Fragments of 4 to 5 mm and recurrent stone disease predicted clinical significance.     

Modern Stone Management in Children

Shock wave lithotripsy (SWL) for the treatment of pediatric stone disease was initiated almost three decades ago, ushering in a new era of noninvasive techniques for stone disintegration in children. Initially, all urinary stones—regardless of their size, site, or composition—were treated by this modality, eliminating the necessity of open surgery. SWL became less painful and more accessible for children when modern modular lithotripters, with smaller foci and better stone-targeting options, were introduced. Stone-free rates (SFRs) vary between 46% and 100%, depending on patient, lithotripter, and stone factors. Short- and long-term complications are rare. Recent refinements in endoscope design and intrarenal and ureteral imaging have added percutaneous nephrolithotomy (PCNL) and ureteroscopy (URS) as alternatives to SWL for stone disintegration in children and infants. The main advantage of these modalities over SWL is their ability to actively remove stone fragments from the urinary system to achieve better SFRs compared with SWL in ureteral and large renal calculi. Current stone management guidelines for children have been established and updated by the European Association of Urology. Hand- and robot-assisted laparoscopic pyelolithtomy have recently been introduced for special cases. We conclude that SWL is an effective and safe treatment modality for small renal stones and for upper ureteral calculi but not for cysteine stones. URS is very efficient for distal ureteral stones and recently has become more popular for renal stones. PCNL is the first-line treatment for large or staghorn calculi.     

Extracorporeal shockwave lithotripsy for stones in abnormal urinary tracts: analysis of results and comparison with normal urinary tracts.

PURPOSE: We reviewed our experience with SWL for stones in abnormal urinary tracts and compared the results with those in normal urinary tracts. PATIENTS AND METHODS: The study group was composed of 2566 renal units (RU) treated on the Siemens Lithostar lithotripter at our SWL unit whose treatment and follow-up at 10 to 12 weeks were completed. Sixty-eight RUs (2.7%) belonged to 52 patients who had congenital upper urinary tract abnormalities. Logistic regression analysis was performed to analyze the impact of age, stone size, location, and the type of abnormality on the outcome of the SWL in the abnormal RU. The student t-, chi-square, and Fisher's exact tests were used for the comparison of stone load, number of treatment sessions, catheter placement, and success rates of the patients with normal and abnormal RU. Results of long-term follow-up for available patients (38 RU; 56%) were also evaluated. RESULTS: Age, stone load, stone location, and the type of abnormality did not have a statistically significant impact on the outcome of SWL for abnormal RU. The average stone load was 2.1 +/- 2.8 cm2 in the abnormal and 1.4 +/- 1.3 cm2 in the normal RU. Thus, the stone load was significantly higher in the abnormal RU (P < 0.05). In the abnormal group, 56% of the RU became stone free, 37% had nonobstructive and noninfectious clinically insignificant residual fragments < or = 4 mm (CIRF), and SWL failed in 7%. In the normal group, 78% of the RU became stone-free, 18.5% had CIRF, and SWL failed in 4%. There was no significant difference in the success rates in the groups if success was defined as stone free and CIRF together (P > 0.05). However, there was significant a difference when stone-free, CIRF, and failure rates were evaluated separately (P < 0.05). Recurrence, regrowth, and retreatment rates in abnormal RU were 50%, 37%, and 34%, respectively. CONCLUSIONS: Although the fragmentation rates were similar, clearance of the fragments was hampered in abnormal urinary tracts. Thus, especially for large stones, other endourologic treatment options should be considered. High recurrence and regrowth rates warrant careful monitoring and consideration for medical treatment during follow-up.