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.     

Progress in the use of helical CT for imaging urinary calculi

Helical CT has become the preferred method to diagnose urinary calculi in patients presenting with abdominal or flank pain. Recent in vitro studies have shown that CT also can display the internal structure in stones with remarkable detail. Because some stones respond better to SWL than others, knowing stone structure at diagnosis could be helpful in choosing among treatment options. This paper examines the potential for CT to be used in this way. Older CT technology proved to be problematic, in that all studies using low-resolution CT will suffer from an artifact in which stone size affects apparent CT attenuation values. Thus, the observation that stones with low measured CT attenuation break more easily than stones with high attenuation could be attributable entirely to an artifact of stone size. Most stones are composed of more than one mineral, and heterogeneity of composition may contribute to variability in stone response to SWL. Older technology is not useful in evaluating stone composition, but current and emerging CT machines have sufficient resolution to determine the composition and structure of stones inside the patient, provided proper viewing windows are used. Continuing improvement in image resolution in helical CT promises to provide information about stone composition and structure that will ultimately lead to better care for patients with stone disease.     

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.     

Urolithiasis in acromegaly

Hypercalcemia, hypercalciuria, and hyperphosphatemia are common findings in acromegaly, yet there are only a few reports on the occurrence of urinary stones in these patients. We reviewed the files of 64 patients with acromegaly. A total of 8 patients had evidence of renal calculi: 4 patients underwent nephrolithotomy, 3 had stones which were seen on intravenous pyelography, and 1 patient voided a stone. Moreover, 2 other patients suffered from recurrent typical episodes of renal colic. In view of the high incidence of urolithiasis in our series we believe that more attention should be paid to detection of urinary stones in acromegalics to avoid further complications and suffering.     

Effect of potassium citrate therapy on stone recurrence and residual fragments after shockwave lithotripsy in lower caliceal calcium oxalate urolithiasis: a randomized controlled trial

BACKGROUND AND PURPOSE: To evaluate the efficacy of potassium citrate treatment in preventing stone recurrences and residual fragments after shockwave lithotripsy (SWL) for lower pole calcium oxalate urolithiasis. PATIENTS AND METHODS: One hundred ten patients who underwent SWL because of lower caliceal stones and who were stone free or who had residual stone 4 weeks later were enrolled in the study. The average patient age was 41.7 years. All patients had documented simple calcium oxalate lithiasis without urinary tract infection and with normal renal morphology and function. Four weeks after SWL, patients who were stone free (N = 56) and patients who had residual stones (N = 34) were independently randomized into two subgroups that were matched for sex, age, and urinary values of citrate, calcium, and uric acid. One group was given oral potassium citrate 60 mEq per day, and the other group served as controls. RESULTS: In patients who were stone free after SWL and receiving medical treatment, the stone recurrence rate at 12 months was 0 whereas untreated patients showed a 28.5% stone recurrence rate (P < 0.05). Similarly, in the residual fragment group, the medically treated patients had a significantly greater remission rate than the untreated patients (44.5 v 12.5%; P < 0.05). CONCLUSION: Potassium citrate therapy significantly alleviated calcium oxalate stone activity after SWL for lower pole stones in patients who were stone free. An important observation was the beneficial effect of medical treatment on stone activity after SWL among patients with residual calculi.     

Recurrence of upper urinary tract calculi

Treatment of upper urinary tract stones has changed greatly. The recurrence of calculi after the discharge was studied in the 634 patients with urolithiasis admitted to our department during the 9 years up to the end of 1984. The recurrence rate in the 325 cases followed for more than 3 months after the disappearance of the original stones, was 15.6% after 2 years, 27.6% after 5 year and 51.4% after 8 years. In recurrent stone formers, the rate of recurrence thereafter was greater than that of primary stone formers. The growth of calculi was rapid in the renal stone former concomitant with urinary tract infection together with a past history of renal surgery. In relation to the composition of the stone, uric acid calculi tended to recur more often than calculi composed of other substances. In view of recurrence, pyelolithotomy is preferred to renal parenchymal incision.     

What radiation exposure can a patient expect during a single stone episode?

PURPOSE: There is increasing concern about the risks of radiation exposure with the advent of new, more complex imaging modalities. For example, computed tomography (CT), with its obvious advantages, is being more commonly used in the investigation of acute flank pain. The likely radiation exposure a patient can expect during a single complete urinary stone episode was studied. PATIENTS AND METHODS: The hospital records of 60 consecutive unselected patients who had become or were rendered stone-free were studied. The effective radiation doses in milliSieverts (mSV) associated with diagnostic imaging modalities such as intravenous urogram studies and CT scans were calculated for St. George's Hospital. By combining these with the published effective doses for interventional examinations, the total effective dose over an entire stone episode was derived. RESULTS: There were a total of 60 patients with 68 stones (15 renal, 9 in the upper, 12 in the middle, and 32 in the lower ureter), with a median stone burden of 4 mm. Thirty-two patients had procedures performed, including extracorporeal shockwave lithotripsy SWL. Total effective doses ranged from 1.18 to 37.66 mSv (median 5.3 mSv; 95% CI of the median 4.13, 7.61). Renal and proximal ureteral stones resulted in the highest radiation exposures. CONCLUSION: In this study the median radiation dose per stone episode was calculated at 5.3 mSv, with higher doses in those with renal stones and those who required CT scans and other interventions. Monitoring and reduction of radiation exposure is advised for all patients presenting with urolithiasis.     

The Dornier Compact Delta lithotripter: the first 500 renal calculi

BACKGROUND AND PURPOSE: Extracorporeal Shockwave Lithotripsy (SWL) is now the best noninvasive treatment for renal calculi, rendering many patients stone free. This prospective study was performed to evaluate the short-term results of patients undergoing SWL with the Dornier Compact Delta lithotripter for all renal calculi. PATIENTS AND METHODS: Between April 1999 and May 2000, there were 500 renal calculi treated in 166 female and 334 male patients with a mean age of 53 +/- 15 years. All patients who completed treatment were entered in the study and assessed at 1 and 3 months with a plain film of the kidneys, ureters, and bladder. Stone-free rate and final outcome have been evaluated. Final outcome is defined as stone free or residual fragments 4 mm or less. Analysis has been made according to stone size, location, number of treatments per stone, and number of shocks per stone. The analgesia requirements during each treatment and complications have also been analyzed. RESULTS: The overall stone-free rate for stones <10 mm was 62% at 1 month and 76% at 3 months. For stones 10 to 20 mm, these rates were 53% and 66%, while the rates for stones >20 mm were 41% and 47%, respectively. The final outcome for stones <10 mm was 90% at 1 month and 93% at 3 months, for stones 10 to 20 mm 73% and 84%, and for stones >20 mm 57% and 67%, respectively. The effectiveness quotient for calculi <10 mm was 60%. For calculi 10 to 20 mm, it was 51%, and for those >20 mm, it was 31%. Oral analgesia was given routinely; however, additional intravenous analgesia was necessary in 22% of treatments. No serious complications have been seen. CONCLUSIONS: These results show that with proper patient selection, good results at 1 and 3 months can be achieved with minimal anesthesia during treatment and low retreatment rates. We do not recommend SWL as primary therapy for stones >20 mm.     

Is intravenous urography a prerequisite for renal shockwave lithotripsy?

PURPOSE: To determine whether intravenous urography (IVU) is a prerequisite for shockwave lithotripsy (SWL) of renal stones by addressing whether using non-contrast-enhanced CT (NCCT) instead of IVU for delineating urinary tract anatomy is associated with post-SWL complications. PATIENTS AND METHODS: Thirty-eight patients treated by SWL (Econolith 2000) for radiopaque renal stones underwent either IVU or NCCT. Twenty patients with normal urinary tracts or with mild hydronephrosis proximal to the stone on urography comprised the IVU group. Eighteen patients who underwent NCCT and plain abdominal (KUB) films and had urinary tract systems similar in appearance to the IVU group comprised the NCCT group. The two groups were of similar mean age (45.75 years, range 24-73 years; and 49.0 years, range 26-72 years, respectively) and had a similar mean stone size (10.1-10.2 mm). Patients with internal ureteral or nephrostomy catheters were excluded. Information on episodes of intractable renal colic, urinary tract infections, and hospitalization was recorded at follow-up 2 to 6 weeks post-SWL. RESULTS: The IVU and NCCT patients had similar mean stone fragmentation rates (80% and 74%, respectively) at 2 to 6 weeks post-SWL. Four IVU patients (20%) had intractable renal colic. One NCCT patient (5.5%) had a urinary infection. Complication and hospitalization rates in the two groups were not significantly different (P = 0.34; Fisher' exact test). CONCLUSIONS: Using only NCCT before SWL was not associated with higher complication rates. Thus, IVU is not a prerequisite for SWL of radiopaque renal stones in patients with a normal urinary tract anatomy as seen on NCCT.     

Management of lower pole renal calculi: shock wave lithotripsy versus percutaneous nephrolithotomy versus flexible ureteroscopy

Current ureteroscopic intracorporeal lithotripsy devices and stone retrieval technology allow for the treatment of calculi located throughout the intra-renal collecting system. Difficulty accessing lower pole calculi, especially when the holmium laser fiber is utilized, is often encountered. Herein we review our experience where lower pole renal calculi were ureteroscopically managed by holmium laser fragmentation, either in situ, or by first displacing the stone into a less dependent position with the aid of a nitinol stone retrieval device. Lower pole stones less than 20 mm can be primarily treated by ureteroscopic means in patients: that are obese; have a bleeding diathesis; with stones resistant to shockwave lithotripsy (SWL); with complicated intra-renal anatomy; or as a salvage procedure after failed SWL. Lower pole calculi are fragmented with a 200 μm holmium laser fiber via a 7.5 F flexible ureteroscope. For those patients where the laser fiber reduced ureteroscopic deflection, precluding re-entry into the lower pole calyx, a 1.9 F nitinol basket is used to displace the lower pole calculus into a more favorable position, thus allowing for easier fragmentation. A nitinol device passed into the lower pole, through the ureteroscope, for stone displacement cause only a minimal loss of deflection and no significant impact on irrigation. Eighty-five percent of patients were stone free by IVP or CT scan performed at 3 months. Ureteroscopic management of lower pole calculi is a reasonable alternative to SWL or percutaneous nephrolithotomy (PNL) in patients with low volume stone disease. If the stone cannot be fragmented in situ, nitinol basket or grasper retrieval, through a fully deflected ureteroscope, allows for repositioning of the stone into a less dependant position, thus facilitating stone fragmentation.     

Extracorporeal shockwave lithotripsy in pediatrics

Since its introduction in 1980, extracorporeal shockwave lithotripsy (SWL) has become the first therapeutic option in most cases of upper-tract urolithiasis, and the technique has been used for pediatric renal stones since the first report of success in 1986. Lithotripter effectiveness depends on the power expressed at the focal point. Closely correlated with the power is the pain produced by the shockwaves. By reducing the dimensions of the focus, it becomes possible to treat the patient without anesthesia or analgesia but at the cost of a higher re-treatment rate. Older children often tolerate SWL under intravenous sedation, and minimal anesthesia is applicable for most patients treated with second- and third-generation lithotripters. Ureteral stenting before SWL has been controversial. Current data suggest that preoperative stent placement should be reserved for a few specific cases. Stone-free rates in pediatric SWL exceed 70% at 3 months, with the rate reaching 100% in many series. Even the low-birth-weight infant can be treated with a stone-free as high as 100%. How can one explain the good results? Possible explanations include the lesser length of the child's ureter, which partially compensates for the narrower lumen. Moreover, the pediatric ureter is more elastic and distensible, which facilitates passage of stone fragments and prevents impaction. Another factor is shockwave reproduction in the body: there is a 10% to 20% damping of shockwave energy as it travels through 6 cm of body tissue, so the small body volume of the child allows the shockwaves to be transmitted with little loss of energy. There are several concerns regarding the possible detrimental effect of shockwaves on growing kidneys. Various renal injures have been documented with all type of lithotripters. On the other hand, several studies have not shown adverse effects. In general, SWL is considered to be the method of choice for managing the majority of urinary stones in children of all ages. Re-treatments improve the stone-free rate, often raising it to 100%. Among the predictors of success, stone size seems to be the most important. In the absence of guidelines, selecting the appropriate treatment modality for each child requires planning and depends on instrument availability and local expertise.     

Extracorporeal shock wave lithotripsy as first line treatment for urinary tract stones in children: outcome of 500 cases

Purpose

The continued evolution of stone treatment modalities, such as endourologic procedures, open surgery and shock wave lithotripsy, makes the assessment of continuous outcomes are essential. Pediatric urolithiasis are an important health problem allover the world, especially in Middle East region. We evaluate the safety, efficacy and factors affecting success rate and clearance of stones in children treated with shock wave lithotripsy.

Patient and methods

Between 2005 and 2010, a total of 500 children with stones in the upper urinary tract at different locations were treated by Extracorporeal shock wave lithotripsy (ESWL) in our department, Sohag University, Egypt. We have used the Siemn??s Lithostar Modularis machine, Germany. A total of 371 boys and 129 girls with the average age of 8.63?±?5?years, and a range from 9?months to 17?years were included in this study. Diagnosis of their urinary calculi was established either by the use of abdominal ultrasound, plain X-ray, intravenous urography, or CT scan. The stones were located in the kidney in 450 (90%) patients; 298 (66%) pelvic, 26 (5.7%) upper calices, 57 (12.6%) mid calices, and lower calices in 69 (15.3%) patients. The average of their stone sizes was 12.5?±?7.2?mm. The other 50 children their stone were located in the proximal ureteral stones in 35 patients (70%); middle third in 5 (10%) patients and in the distal ureter in 10 (20%) patients. The average ureteral stone size was 7.5?±?3.2?mm. All children were treated under general anesthesia with adequate lung and testes shielding using air foam. We treated the distal ureteral stones of young children in the supine position through greater sciatic foramen and lesser sciatic foramen as the path of shockwave instead of prone position, which is not a comfortable or natural position and could adversely affect cardiopulmonary function especially under general anesthesia. Localization was mainly done by ultrasound, and X-ray was only used to localize ureteral calculi. For follow-up, we have used abdominal ultrasound, plain X-ray, and CT scan if needed to confirm stone disintegration and clearance.

Results

The overall success rate for renal and ureteral calculi was 83.4 and 58.46%, respectively. The re-treatment rate was 4% in renal group and 28% for the ureteral group. No serious complications were recorded in our patients. Minor complications occurred in 15% of our patients; renal colic was reported in 10% of our treated patients, and repeated vomiting was reported in 5% that respond to antiemetics. In the renal group; children with history of pervious urologic surgical procedures had low success rate of stone clearance after ESWL. In the ureteral group stone burden, stone location, had a significant impact on stone clearance outcome.

Conclusion

This study showed that SWL in pediatric age group for both renal and ureteral stone is cost effective, safe with an acceptable re-treatment rate; however children with large stone burden or previous urologic surgery have low success rate.     

Minimal-invasive PCNL (Mini-Perc)

Extracorporeal shock wave lithotripsy (SWL) is the current treatment modality of choice for upper urinary tract calculi. For stones with a diameter >2 cm and in lower calyceal stones and diverticular stones, the stone-free rate of SWL is rather poor. In these cases, conventional percutaneous nephrolithotomy (PCNL) leads to an increased stone-free rate, but morbidity with conventional PCNL is significant higher than in SWL. With the invention of miniaturized nephroscopes (mini-perc), new treatment options are available. The experience based on hundreds of treatments using mini-perc show comparable results of mini-perc to conventional PCNL and a complication rate comparable to that for SWL. These favorable results are independent of stone size, stone location, and patient age. In summary, mini-perc can be recommended as a primary approach to stones of the upper urinary tract exceeding 1 cm, larger lower-pole stones, and calyceal diverticular stones. Mini-perc can be regarded as an alternative treatment modality to conventional PCNL.     

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.     

Treatment of urinary calculi with ureteroscopy and Swiss lithoclast pneumatic lithotripter: report of 150 cases

PURPOSE: To present our clinic experience with the Swiss Lithoclast pneumatic lithotripter in the endoscopic management of urinary calculi. PATIENTS AND METHODS: From August 1994 to December 1997, 145 patients with ureteral calculi and 5 patients with urethral calculi were treated with the Swiss Lithoclast. RESULTS: In the ureteral stone group, ureteroscopic addressing of the stones was successful in 133 patients. In 27 patients, the stones were partially fragmented and remained in situ or were pushed back to the calices. They were subsequently treated successfully with SWL. Stones were fragmented in a single session in 101 cases. Complications associated with the procedure included five perforations and four urinary tract infections. All of the five urethral stone patients were treated successfully with pneumatic lithotripsy. The overall successful fragmentation rate thus was 70.7% (106 of 150) and 88.7% (133 of 150) in combination with adjuvant SWL. CONCLUSIONS: We have found Swiss Lithoclast pneumatic lithotripsy to be a safe, effective, and economical treatment method for urinary calculi. If combined with other modalities such as SWL, this treatment will be even more effective.     

影响第二次冲击波碎石术治疗上尿路结石患者成功的因素分析

目的 探讨影响第二次冲击波碎石术（extracorporeal shock wave lithotripsy, ESWL）治疗上尿路结石患者成功的因素。方法 回顾性分析2008年1月至2012年12月来本院接受第二次ESWL治疗的上尿路结石患者120例。根据患者上尿路结石有无完全排出分为成功组（n=80）和失败组（n=40）。回顾性分析所有患者的病历资料,相关因素分析包括性别、年龄、病程、BMI、结石侧别、结石位置、结石长度、结石宽度、结石数目、肾绞痛、血尿、肾积水程度、非增强螺旋CT值、冲击次数、冲击能量等指标。应用单因素、多因素非条件Logistic回归分析上尿路结石患者第二次ESWL治疗成功与否的危险因素分析。结果 120例上尿路结石患者临床特征显示,两组在病程、BMI、结石长度、结石宽度、结石数量、肾绞痛、肾积水程度、CT值、冲击次数方面差异有统计学意义（P＜0.05）,在性别、年龄、结石侧别、结石位置、血尿、冲击能量方面差异无统计学意义（P＞0.05）。经单因素、多因素 Logistic 回归分析结果显示,BMI偏高、结石长度＞2 cm、存在肾绞痛、肾积水程度严重、CT值＞750 HU会增加上尿路结石患者第二次ESWL治疗失败的风险（P＜0.05）。结论 临床医师利用ESWL第二次治疗上尿路结石患者过程中,应格外注意患者BMI、结石长度、肾绞痛、肾积水程度、CT值等关键指标。     

Low-dose computed tomography for the evaluation of flank pain in the pregnant population

BACKGROUND: Evaluation of the pregnant patient with suspected renal colic is complex. Fetal irradiation concerns have traditionally prohibited the use of CT in this population. We report our institution's experience using low-dose CT in the evaluation of pregnant patients with refractory flank pain. PATIENTS AND METHODS: A retrospective review of all patients who underwent low-dose CT evaluation of the urinary tract for suspected urinary tract stones was performed. Data obtained included gestational age, urinalysis and ultrasonography results, CT findings, and calculated fetal radiation exposure. RESULTS: Between April 2004 and December 2006, 20 patients with an average gestational age of 26.5 weeks presented to our institution with acute, refractory flank pain consistent with a diagnosis of urolithiasis. All patients underwent renal ultrasonographic evaluation before unenhanced CT of the abdomen and pelvis using a low-dose protocol. The average radiation exposure was 705.75 mrads (range 210-1372; SD +/- 338.66 mrads). Of the 20 patients, CT demonstrated urinary stones (1-12 mm) in 13. Of those patients with documented stones, 4 were treated conservatively, 2 underwent intrapartum stent placement, 5 had ureteroscopy with stone extraction, and 2 were treated postpartum. CONCLUSION: Low-dose CT is highly sensitive and specific for the detection of urinary calculi in the pregnant population. CT confers a low risk of fetal harm and can improve patient care when used judiciously.     

Is the gravity effect of radiographic anatomic features enough to justify stone clearance or fragments retention following extracorporeal shock wave lithotripsy (SWL)

We determined whether the gravity effect of radiographic anatomic features on the preoperative urography (IVP) are enough to predict fragments clearance after shock wave lithotripsy (SWL). A Total of 282 patients with mean age 45.8 ± 13.2 years (189 male, 93 female), who underwent SWL due to renal calculi between October 2005 and August 2009 were enrolled. The mean calculi load was 155.72 ± 127.66 mm2. The patients were stratified into three groups: patients with pelvis calculi (group 1); patients with upper or middle pole calculi (group 2) and patients with lower pole calculi (group 3). Three angles on the pretreatment IVP were measured: the inner angle between the axis of the lower pole infundibular and ureteropelvic axis (angle I); the inner angle between the lower pole infundibular axis and main axis of pelvis-ureteropelvic (UP) junction point (angle II) and the inner angle between the lower pole infundibular axis and perpendicular line (angle III). Multivariate analysis was used to define the significant predictors of stone clearance. The overall success rate was 85.81%. All angles, sessions number, shock waves number and stone burden were significant predictors of success in patients in group 1. However, in group 2 only angle II and in group 3 angles I and II had significant effect on stone clearance. Radiographic anatomic features have significant role in determining the stone-free rate following satisfactory fragmentation of renal stones with SWL. The measurement of infundibulopelvic angle in different manner helps to predict the stone-free status in patients with renal calculi located not only in lower pole, but also in renal pelvis and upper or middle pole. Gravity effect is not enough to justify the significant influence of the radiographic anatomic features on the stone clearance and fragments retention after 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.     

Extracorporeal Shock Wave Lithotripsy as First Line Treatment Alternative for Urinary Tract Stones in Children: A Large Scale Retrospective Analysis

PurposeManagement of urinary tract stones in children represents a challenging problem. In this study we retrospectively analyzed our experience with extracorporeal shock wave lithotripsy (SWL) in children.Materials and MethodsDuring a 12-year period 408 urinary tract calculi in 344 children (mean age 8.7 ± 3.9 years, range 6 months to 14 years) were managed with the Lithostar Plus lithotriptor (Siemens Medical Systems, Iselin, New Jersey). There were 57 caliceal stones, 167 in the renal pelvis, 31 in the proximal ureter, 16 in the mid ureter and 121 in the distal ureter, and 16 bladder stones.ResultsAll patients were treated on an outpatient basis, with intravenous sedation being used in 138 (40.1%), general anesthesia in 132 (38.4%) and no anesthesia in 74 (21.5%). A maximum of 3,500 shocks and 18 kV per session was given. A total of 780 SWL sessions were applied (mean 1.9 sessions per stone). Overall, a stone-free rate of 79.9% and clinically insignificant residual fragments in 13.2% of cases were observed at 3-month followup with a re-treatment rate of 53.9%. Overall efficacy quotient was 50.9%. Significantly more favorable results were achieved in ureteral calculi and stones 2 cm or smaller (p <0.05). Complications were observed in 33 patients (9.6%).ConclusionsOur results indicate that SWL, with satisfactory stone-free rates and efficacy quotients in stones 2 cm or smaller can be offered as a first line treatment in children.