Evaluation and comparison of scoring systems for predicting stone-free status after flexible ureteroscopy for renal and ureteral stones

OBJECTIVE

To evaluate four predictive scores for stone-free rate (SFR) after flexible ureterorenoscopy (f-URS) with holmium-YAG laser fragmentation of renal and ureteral lithiasis.

METHODS

We carried out a retrospective analysis of 800 f-URS procedures performed in our institution between January 2009 and December 2016. For each procedure, a single surgeon calculated the following scores: S.T.O.N.E score; Resorlu Unsal Stone Score (RUSS); modified Seoul National University Renal Complexity (S-ReSC) score; and Ito's score.

RESULTS

Overall SFR was 74.1%. Univariate analysis demonstrated that stone size (p<0.0001), stone volume (p<0.0001), stone number (p = 0.004), narrow lower pole infundibulopelvic angle (IPA) (p = 0.003) and lower pole location + IPA <45° (p = 0.011) were significantly associated with SFR. All scores differed between the stone-free and non-stone-free groups. Area under the curve of the receiving operator characteristics curve was calculated for each score: 0.617 [95%CI: 0.575-0.660] for the S.T.O.N.E score; 0.644 [95%CI: 0.609-0.680] for the RUSS; 0.651 [95%CI: 0.606-0.697] for the S-ReSC score; and 0.735 [95%CI: 0.692-0.777] for Ito's nomogram.

CONCLUSION

All four scores were predictive of SFR after f-URS. Ito's score was the most sensitive. However, the performance of all scores in this analysis was lower than in developmental studies.

Effect of Stone Composition on the Outcomes of Semi-Rigid Ureteroscopy Using Holmium: Yttrium-Aluminum-Garnet Laser or Pneumatic Lithotripsy

OBJECTIVE

To compare the effectiveness of laser lithotripsy (LL) and pneumatic lithotripters (PL) in calcium oxalate (CaOx) and calcium phosphate (CaP) stones and assess whether these stone compositions affect the outcomes of LL and PL.

STUDY DESIGN

Comparative, descriptive study.

PLACE AND DURATION OF STUDY

Istanbul Training and Research Hospital, Turkey, from August 2010 to August 2015.

METHODOLOGY

A total of 114 patients underwent ureteroscopy using LL and PL. Fifty-eight (50.9%) had CaOx stones and 56 (49.1%) had CaP stones. The lithotripters were compared in stone composition groups, and stone compositions were compared in lithotripter groups. Patient characteristics, perioperative parameters, and postoperative complications were compared.

RESULTS

The baseline patient and stone characteristics were similar in all groups. The operation time of the PL and LL for the patients with CaP stones (68.75 ±32.88 and 44.48 ±34.37 minutes, respectively) was significantly shorter than the operation time of the PL and LL for the patients with CaOx stones (91.56 ±30.54 and 65.75 ±37.74 minutes, (p=0.012 and p=0.009, respectively). Moreover, the patients with CaOx or CaP treated with LL 65.75±37.74 and 44.48 ±34.37 minutes, respectively) had significant shorter operation time than the PL (91.56 ±30.54 and 68.75 ±32.88 minutes, (p=0.046 and p=0.01, respectively). Stone-free rates were similar in all groups. The PL for the patients with CaP stones caused more postoperative fever and infection than the other groups (p=0.050).

CONCLUSION

Though both PL and LL are effective in the treatment of CaOx and CaP stones, LL had a significantly shorter operation and hospitalization time and complication rates in patients with CaOx and CaP stones. So LL is a more feasible and safer modality in the treatment of recurrent CaP stones.

[A Case of Atazanavir Urolithiasis Diagnosed by Stone Analysis]

A 70-year-old man was referred to our hospital for right back pain. His past history included human immunodeficiency virus infection, which had been treated with atazanavir for 7 years. Abdominal and pelvic computed tomographic scan showed right hydronephrosis due to a strongly suspected right ureteral radiolucent stone. He underwent indwelling of a right ureteral stent because of obstructive pyelonephritis due to the ureteral stone. After improvement of the pyelonephritis, he underwent transurethral ureterolithotripsy for the right ureteral stone. Stone analysis showed the atazanavir stone. He has been followed up for 8 months without evidence of recurrence. Herein, we report this rare case of an atazanavir stone in Japan, which was confirmed by calculus analysis, and present a review of the literature.

[Modern conservative (citrate) therapy for urate calculi in the ureters]

The results of conservative citrate therapy of 35 patients with urate calculi in ureter are presented. Due to the violation of the passage of urine in the upper urinary tract, the vast majority of patients (31 (88%)) underwent ureteral stenting to restore adequate flow of urine before treatment. In four patients, drainage of the upper urinary tract was not required. Citrate therapy allowed to achieve complete dissolution of calculi within 2 months in 25 (72%) patients. Another 14% of patients were able to reduce the size of the calculi, and in combination with contact ureterolithotripsy achieve complete discharge of calculi. Only in 14% of patients with urate calculi in ureter litholysis was ineffective. The used treatment option allows to avoid surgery in a large number of patients with urate lithiasis.

Case series demonstrating the clinical utility of dual energy computed tomography in patients requiring stents for urinary calculi

Dual energy computed tomography (DECT) utilizes the material change in attenuation when imaged at two different energies to determine the composition of urinary calculi as uric acid or non-uric acid. We discuss a series of case reports illustrating DECT's ability to provide immediate determination of uric acid versus non-uric acid calculi and facilitate more informed clinical decision-making. Further, these cases demonstrate a unique population of patients with ureteral stents and percutaneous nephrostomy tubes that benefit from DECT's ability to create a virtual color contrast between an indwelling device and the stone material and thereby significantly impacting patient morbidity.

Predictors of success in shock wave lithotripsy of renal and ureteral stones

In many centers, shock wave lithotripsy (SWL) is a commonly used modality for the treatment of both renal and ureteral calculi. It is non-invasive, may be performed using minimal anesthesia, and has a high level of patient acceptance. The focus of the present review is to highlight patient and stone characteristics which affect the outcomes of SWL, in order to define which patients are proper candidates for this treatment.

[Two cases of infants with acute renal failure due to bilateral obstructive ureteral stones associated with rotavirus gastroenteritis]

We report on 2 infants with acute renal failure caused by bilateral obstructive ureteral stones associated with rotavirus gastroenteritis. A 28-month boy and a 13-month boy with several days history of watery diarrhea and vomiting were referred to our hospital because of anuria. They were diagnosed acute post-renal failure due to obstructive bilateral ureteral stones based on the findings of ultrasound scan and computed tomography. Immediately, percutaneous nephrostomy tubes were inserted for urinary drainage, serum levels of creatinine and uric acid returned to normal within several days. Sandy stones were excreted through the nephrostomy tubes with urine after urinary alkalization, which were proved to be mainly ammonium acid urate. Ammonium acid urate is rare in developed countries, but some cases of bilateral urolithiasis causing acute renal failure in infants with rotavirus gastroenteritis were reported in recent years. It has been known that the cause of acute renal failure is renal azotemia resulting from sustained hypovolemia, but post-renal causes due to ammonium acid urate stones should be taken into consideration.

[Clinico-experimental rationale of choice of optimal contact pneumatic ureterolithotripsy]

We studied morphobiomechanical properties of the ureters of 134 adult people, results of treatment of 178 patients suffering from ureterolithiasis which were divided into two groups: the comparison group (n = 97) in which contact lithotripsy was carried out without power dosage lithotripter and the study group (n = 81) in which stone decomposition results were analysed with account of impulse duration and power of the shock wave estimated with special tables for an individual patient. We developed expert tables presenting optimal regimens for power pneumatic lithotriptor for fragmentation of a concrement with the least traumatic effect taking into account sex, age of the patient, size, chemical composition and location of the concrement. The above expert tables can be used in urological departments practicing contact ureterolithotripsy for ureterolithiasis, and in medical high schools for teaching students.

Evidence suggesting a genetic contribution to kidney stone in northeastern Thai population

Genetic factor may play a role in the pathogenesis of kidney stone that is found in the northeastern (NE) Thai population. Herein, we report initial evidence suggesting genetic contribution to the disease in this population. We examined 1,034 subjects including 135 patients with kidney stone, 551 family members, and 348 villagers by radiography of kidney-ureter-bladder (KUB) and other methods, and also analyzed stones removed by surgical operations. One hundred and sixteen of 551 family members (21.05%) and 23 of the 348 villagers (6.61%) were affected with kidney stone. The relative risk (lambda(R)) of the disease among family members was 3.18. Calcium stones (whewellite, dahllite, and weddellite) were observed in about 88% of stones analyzed. Our data indicate familial aggregation of kidney stone in this population supporting that genetic factor should play some role in its pathogenesis. Genetic and genomic studies will be conducted to identify the genes associated with the disease.

Diagnosis of urolithiasis

Diagnostic imaging is usually required to determine the presence of urolithiasis. Double-contrast cystography is more accurate than survey radiography and approximately as accurate as ultrasonography. Knowledge of the mineral composition of calculi helps direct appropriate management of urolithiasis, and signalment can help predict composition with about 70% accuracy. In cats, about half of cystic calculi are struvite and half are calcium oxalate; most nephroliths and ureteroliths are calcium oxalate. In female dogs, struvite uroliths are the predominant type found in the bladder. In male dogs, breed plays a strong role in prediction of bladder urolith type. It is difficult to predict the composition of nephroliths and ureteroliths based on signalment alone in dogs. Urinalysis and imaging findings can help in predicting urolith composition, although chemical analysis is necessary for definitive diagnosis.

Impact of Stone Size, Location, Composition, Impaction, and Hydronephrosis on the Efficacy of Holmium:YAG-Laser Ureterolithotripsy

OBJECTIVES

The impact and outcome of holmium:YAG-laser (Ho:YAG) ureterolithotripsy in treating proximal and distal ureteral stones was investigated.

METHODS

A total of 543 patients harbouring proximal (n=194) or distal (n=349) ureteral stones underwent semirigid Ho:YAG ureterolithotripsy. The degree of hydronephrosis; stone size, location, impaction, and composition; and complication and stone-free rates were recorded.

RESULTS

Mean stone size for proximal and distal stones was 7.1+/-3.6 mm and 6.2+/-2.5 mm, respectively. The stone-free rate on the first postoperative day was 79.4% for proximal and 96.8% for distal stones (p<0.0001). For proximal stones <10mm and > or =10mm, respectively, the stone-free rate was 80.5% and 74.3% (p=0.4) and for distal stones 97.3% and 94.3% (p=0.2). Stone-free rates for radio-opaque versus radiolucent stones in proximal stones were 79.6% versus 77.9% (p=0.8) and 97.6% versus 96.2% in distal stones (p=0.5). Impaction correlated significantly with stone-free rates (p<0.0001). Stone-free rates for nonimpacted versus impacted proximal stones were 85.8% versus 67.2% (p=0.003) and for distal stones 99.2% versus 91.4% (p<0.003), respectively. The presence or degree of hydronephrosis did not correlate with treatment success (p=0.4, p=0.8). The presence of intraoperative complications correlated significantly with proximal compared to distal ureteral stone location (p=0.004). Auxiliary measures in proximal versus distal stones were performed in 20.6% versus 2.9% (p<0.0001).

CONCLUSIONS

In this series, stone-free rates in Ho:YAG ureterolithotripsy were significantly higher in distal and nonimpacted stones but were independent of stone size and composition and the degree of hydronephrosis. Ureterolithotripsy in proximal stones was associated with higher intraoperative complication and retreatment rates compared to distal stones.

[Economic aspects of evidence-based metaphylaxis]

The calculation model which we developed for the cost of stone therapy and metaphylaxis in Germany some years ago with a social health insurance company is based on estimates of stone incidence, types and recurrence rates, actual costs for stone removal, and metaphylaxis (based on data from a district of the social health care system). There are 200,000 stone recurrences per year in Germany. Costs for treatment of these stones amount to $687,000,000. Stone metaphylaxis reduces the recurrence rate by some 40%. The annual cost for stone removal could be lowered by $275,300,000. Metabolic evaluation/metaphylaxis amount to $70,100,000 per year, resulting in a net saving of $205,200,000. In 1997, there were 96 days off work per stone patient resulting in 5,800,000 days off work in Germany per year. Metaphylaxis is not only medically effective in stone formers but also can lower health care cost significantly. Although health care conditions may vary from country to country, in principle this calculation model is applicable also to other countries.

The Silence of the Stones: Asymptomatic Ureteral Calculi

PURPOSE

We investigated the characteristics and diagnosis of primary asymptomatic ureteral calculi.

MATERIALS AND METHODS

During a period of 12 years asymptomatic ureteral stones were prospectively investigated at the Urological Stone Center. We studied mode of diagnosis, stone size, localization, composition, hydronephrosis grade and patient characteristics.

RESULTS

Between 1995 and 2006 a total of 40 patients with asymptomatic ureteral stones were identified among 3,711 patients with ureteral stones (1.1%). Mean age of the 33 male and 7 female asymptomatic patients was 58.3 years (range 28.1 to 87.1). Localization of stones was 19 proximal, 3 mid and 18 in the distal ureter. Mean stone size was 10.0 mm (+/-6). Mode of diagnosis of asymptomatic calculi was randomly diagnosed hydronephrosis in 10 patients (25%), microscopic hematuria in 8 (20%), randomly diagnosed stone on other than urological x-ray examination in 13 (32.5%) and stone diagnosed during followup after previous nephrolithiasis in 9 patients (22.5%). Primary therapy was extracorporeal shock wave lithotripsy in 35 patients (87.5%), ureterorenoscopic lithotripsy in 4 (10%), spontaneous stone passage before scheduled treatment in 1 and open ureteroneocystostomy in 1 patient.

CONCLUSIONS

De novo asymptomatic ureteral calculi do exist. Characteristics of this small group of patients with ureterolithiasis have not been described thus far. Diagnosis is usually made during routine health care examinations, during the evaluation of nonurological diseases and during followup of patients who previously had nephrolithiasis. A large proportion of patients exhibit some degree of hydronephrosis as a sign of silent obstruction.

[Secondary uroliths after surgical correction of urinary bladder extrophy]

The analysis of long-term results of complex surgical correction of urinary bladder extrophy in 83 patients has shown that 21 (25.3%) patients had concrements in the urethra. Multiple bacteriological tests detected urease-producing flora which was managed with specific antibacterial therapy. Two patients were exposed to extracorporeal shock-wave lithotripsy. Low-invasive lithotripsy was low effective and all the patients were operated. Chemical structure of the removed concrements was determined with x-ray difractometry. Recurrent concrements were found in 7 (33.3%) of 21 patients who had not received specific antibacterial therapy. All the stones detected were struvite. Thus, struvite concrements' risk in patients after surgical correction of urinary bladder extrophy can be reduced under the following conditions: suppression of urease-producing flora activity, catheterization regime compliance, systemic sanation of the artificial urinary bladder.

Evaluation of trends in urolith composition in cats: 5,230 cases (1985–2004)

OBJECTIVE

To determine trends in urolith composition in cats.

DESIGN

Retrospective case series.

SAMPLE POPULATION

5,230 uroliths.

PROCEDURES

The laboratory database for the Gerald V. Ling Urinary Stone Analysis Laboratory was searched for all urolith submissions from cats from 1985 through 2004. Submission forms were reviewed, and each cat's age, sex, breed, and stone location were recorded.

RESULTS

Minerals identified included struvite, calcium oxalate, urates, dried solidified blood, apatite, brushite, cystine, silica, potassium magnesium pyrophosphate, xanthine, and newberyite. During the past 20 years, the ratio of calcium oxalate stones to struvite stones increased significantly. When only the last 3 years of the study period were included, the percentage of struvite stones (44%) was higher than the percentage of calcium oxa-late stones (40%). The most common location for both types of uroliths was the bladder. The number of calcium oxalate-containing calculi in the upper portion of the urinary tract increased significantly during the study period. The number of apatite uroliths declined significantly and that of dried solidified blood stones increased significantly, compared with all other stone types. No significant difference in the number of urate stones was detected.

CONCLUSIONS AND CLINICAL RELEVANCE

The increasing proportion of calcium oxalate uroliths was in accordance with findings from other studies and could be a result of alterations in cats' diets. However, the decreased percentage of calcium oxalate calculi and increased percentage of struvite calculi observed in the last 3 years may portend a change in the frequency of this type of urolith.

Structural features of three ureterocele calculi

Ureterocele calculi are developed in cavities with urinary retention but far from the upper renal cavities. The structural features of three ureterocele calcium oxalate stones were observed by scanning electron microscope coupled with X ray microanalysis. The urinary parameters of the three patients were also determined. The stone A consisted of loose structure of large calcium oxalate dihydrate crystals and small spheres of hydroxyapatite. The interior contains disorganized plate-like calcium oxalate monohydrate crystals. The stone B was formed by a compact outer layer of calcium oxalate monohydrate columnar crystals. The structure of stone interior was similar to the stone A. The stone C was formed by concentric layers composed of either calcium oxalate monohydrate columnar crystals or hydroxyapatite. The core consisted of agglomerated calcium oxalate monohydrate crystals, hydroxyapatite and organic matter. From the urinary biochemical data it was deduced that two ureterocele patients (who formed A and B stones) were hypercalciuric (calcium > 300 mg/24 h), being 6.5 the urinary pH value of the patient that formed the A stone, and 7.0 the urinary pH of the patient that formed the C stone. The rest of urinary parameters for the three patients were normal. Thus, one of the requisite conditions for unattached stone development is the existence of a place inside the urinary tract where the solid particles that act as calculus initiator of the stone can be retained enough time to exert this action.

Does Degree of Hydronephrosis Affect Success of Extracorporeal Shock Wave Lithotripsy for Distal Ureteral Stones?

OBJECTIVES

To investigate the relation between the degree of stone-induced hydronephrosis and the outcome of shock wave lithotripsy in patients with distal ureter stones.

METHODS

A total of 215 patients with a solitary distal ureter stone with or without hydronephrosis were treated with shock wave lithotripsy. The degree of hydronephrosis was determined by renal ultrasonography. The patients were divided into four groups according to the degree of stone-induced hydronephrosis. Group 0 (44.2%) had no urinary system dilation, group 1 (32.5%) had mild dilation, group 2 (16.3%) had moderate dilation, and group 3 (7%) had severe dilation. The patients were treated with the Dornier MFL 5000 lithotripter. The results were compared in terms of the stone-free rates, number of shock waves, number of sessions, incidence of complications, number of secondary interventions, and time to stone clearance.

RESULTS

The mean stone size was 11.2 +/- 2.5 mm. In the hydronephrotic group, the stone-free rate was 74% compared with 83% in patients without hydronephrosis (P = 0.27). The mean time to stone clearance was 16.3 +/- 9.2 days. The differences among the four groups in terms of stone size and treatment outcome were not significant. However, the presence of hydronephrosis was significantly associated with repeat treatment (2.2 versus 1.6, P <0.001) and prolonged clearance time (18.7 versus 15.4 days, P <0.001).

CONCLUSIONS

The results of our study have shown that in patients with solitary distal ureter stones, the degree of hydronephrosis caused by the stone does not affect the overall treatment success with shock wave lithotripsy. However, stones in obstructed systems tended to require repeat treatment and prolonged time for stone clearance.

A comparison of the FREDDY and holmium lasers during ureteroscopic lithotripsy

BACKGROUND AND OBJECTIVE

Two laser devices that are used today in endoscopic treatment of renal and ureteral calculi are the frequency-doubled double-pulse neodynium:YAG (FREDDY) and Holmium:YAG lasers. The mechanism of action of these lasers differs, thus conferring potentially different safety and efficacy profiles. The in vitro efficacy of these lasers in treating urinary stones has been explored, but to our knowledge no study compares the in vivo efficacy. The purpose of this study is to compare the stone-free and complication rates of the FREDDY and holmium lasers.

STUDY DESIGN/MATERIALS AND METHODS

Subjects were included in the study (from January 2004 to September 2006) if they had adequate documentation of stone size and location, postoperative stone burden, and perioperative complications. Stone-free status was determined based on intraoperative findings and postoperative imaging. Complications included bleeding, ureteral perforation, any intraoperative event necessitating termination of the procedure, ureteral stricture, hydronephrosis, and admission to the hospital with a diagnosis related to the procedure.

RESULTS

Sixty patients with adequate follow-up were identified. Thirty patients were treated with FREDDY and 30 patients with Holmium laser. Fisher's exact test was employed for statistical analysis. There was no significant difference in the average stone size between the FREDDY and Holmium groups, which were 6.7 mm and 6.1 mm, respectively. Stone-free rates in the FREDDY and Holmium groups were 76.7% and 93.3%, respectively, P = 0.149. The complication rates were 17.4% in the FREDDY group and 10% in the Holmium group, P = 0.667.

CONCLUSION

The complication and stone-free rates did not significantly differ between the FREDDY and Holmium lasers, though there was a trend toward a higher stone-free rate and lower complication rate with the holmium laser. Holmium laser may be more effective than the FREDDY laser in fragmenting calcium oxalate monohydrate stones. The device and laser fiber costs were comparable.

Extracorporeal shock wave lithotripsy in the management of pediatric urolithiasis

The main objective of this paper was to evaluate the efficacy and safety of the management of pediatric urolithiasis by extracorporeal shock wave lithotripsy (ESWL). Between November 1988 and July 2000, 165 renal stones, 53 ureteral stones, and 5 bladder stones were treated in 126 pediatric patients using Siemens Lithostar lithotriptor. The ESWL treatments ranging from 1 to 7 were needed per patient (mean: 2.1). One ESWL session was performed for 49.6% of stones, two for 24.6%, three for 13.0 %, four for 5.6% and > 4 for 8.2%. The success rate for renal stone units (asymptomatic fragments less than 4 mm) was 88.2%, stone-free rate was 49.0%. The stone-free rate for ureteral stone units was 87.5%, but was 75% for bladder stones. The overall results of ESWL treatment in 126 children was satisfactory: the success rate was 90.5%, stone-free rate was 51.6%, residual fragments > 4 mm were 9.5%. General anesthesia was required in 65 children (136 treatments) under the age of 10, and only in 18 children (40 treatments) in the age 11-14. Auxiliary procedures, such as double J stent and percutaneous nephrostomy (PCN) were used in 19 and 7 patients, respectively. Perirenal hematoma in one patient and hematomas in enteric wall in another one patient were the only major complications managed conservatively without consequences. Low energy lithotripsy with the Siemens Lithostar in our series of pediatric patients was safe and relatively effective.

Aging assessment by dynamic mechanical analysis of in vivo encrusted polymeric urinary stents

PURPOSE

To investigate the viscoelastic properties of plastic pigtail stents after removal from patients using the method of dynamic mechanical analysis (DMA).

MATERIALS AND METHODS

Dynamic mechanical analysis was performed in 12 polymeric pigtail stents left indwelling for various periods of time (0-120 days). The encrustations were characterized by infrared spectroscopy, and their morphology was observed using scanning electron microscopy.

RESULTS

Softening and stiffening behavior was observed. Stiffening was found specifically in the stents with heavy mineral deposits.

CONCLUSIONS

Material degradation becomes obvious after certain periods of time. The effect of stent degradation appeared in two forms: softening of the stent polymer, possibly through interaction with urine, and stiffening of the stent secondary to the formation of various insoluble mineral deposits covered by layers of organic matrix.

[Matrix stone: a case report]

Here, we report a case of matrix stone in a 32-year-old man with diabetes, gout, and chronic renal failure. The patient complained of pain in the left flank. He had undergone an operation for bilateral vesicoureteral reflex at the age of 17 and matrix stone discharge was repeated. Computed tomography revealed a soft tissue mass in the right hydroureter. Percutaneous ureteral lithotripsy was performed successfully. Analysis of the stone components revealed the stone to be composed entirely of protein. Radiological imaging of matrix stones may be difficult to separate from urothelial cancers.

[Two cases of silicate urolithiasis]

Case 1: A 31-year-old woman with the chief complaint of right back pain was referred to our hospital. She was diagnosed with a right ureteral stone and it was delivered spontaneously after conservative medical therapy. The stone was found to consist of silicate by infrared spectrometry. Case 2: A 71-year-old man with the chief complaint of asymptomatic macrohematuria was referred to our hospital. No tumor was observed by cystourethroscopy, but a right ureteral stone was found by computerized tomography. Subsequently, it was delivered immediately and infrared spectrometry of the stone demonstrated silicate containing a small amount of calcium oxalate monohydrate. We analyzed and discussed 44 cases of silicate urolithiasis reported in Japan.

Can ureteral stent encrustation analysis predict urinary stone composition?

OBJECTIVES

To determine the value of mid-infrared spectroscopy (MIRS) of ureteral stent encrustations in predicting urinary stone composition.

METHODS

A retrospective study analyzed the composition of stent encrustations and urinary stones by MIRS in patients who had had a stent for ureteral obstruction between 2001 and 2003. The overall correlation was evaluated. The correlation coefficient kappa for agreement between the proportions of each component was calculated.

RESULTS

A total of 72 stents and 72 stones from 72 patients were analyzed. The mean stent indwelling time was 55.5 days (range 14 to 102). The stents had been placed for fever (52 cases, 72%), pain refractory to analgesics (15 cases, 21%), and impairment of kidney function (5 cases, 7%). The overall correlation between stone composition and stent encrustation was 71.4%, excluding biofilm analysis. The kappa value was 0.78 for the main component (n = 72; P < 0.0005), 0.61 for the secondary component (n = 72; P < 0.0005), and 0.91 for the agreement between the composition of encrustations at each end of a stent (n = 30; P < 0.0005).

CONCLUSIONS

MIRS analysis of stent encrustations is a reliable method of predicting stone composition when the stone cannot be retrieved. Systematic MIRS analysis of stent encrustations is not recommended but can be very useful in clinical situations in which no stone is available.

[Silica-containing urinary stones--clinical issues to keep in mind]

Formation of calculi in efferent urinary passages is always due to supersaturation of urinary calculi substances and associated increased crystallization. Apart from the typical calculi, consisting of calcium oxalate, inorganic phosphates, uric acid or cystine, there are occasional signs of rare substance classes. Although more than 50 silicate stones have already been reported internationally, this stone entity remains relatively unknown. In particular, the occurrence of silicate stones in the absence of magnesium trisilicate abuse is extremely rare. A medium-sized left-sided ureterolith was removed from a 54-year-old male patient using a ureteroscope. X-ray diffraction showed it to be a compound stone consisting of 40% silicate. The patient, who in 1986 was living close to the nuclear reactor accident in Chernobyl, showed no signs of a constant uptake of magnesium trisilicate. However, he had undergone partial (2/3) gastrectomy 4 months before for a drug-refractory gastric ulcer, which had been diagnosed at the end of the 1980s and treated with excessive dosages of a magnesium trisilicate antacid preparation until the time of the operation. The patient had also been suffering from unstable angina pectoris since 1986 and treated with Pentalong (pentaerythrityltetranitrate) for 17 years. We were also able to detect silicium dioxide in components of this drug using X-ray diffraction. Silicate uroliths are extremely rare but they can be clearly identified by X-ray diffraction or infrared spectroscopy and distinguished from artifacts or quartz pebbles. Formation of calculi can be prevented by increasing diuresis as well as switching to a different drug and reducing the dosage.

Stone disease in the Hmong of Minnesota: initial description of a high-risk population

BACKGROUND AND PURPOSE

The Hmong are an ethically distinct refugee population from the highlands of Laos. Metropolitan Minneapolis-St. Paul, Minnesota is home to the largest population of Hmong ( 40,000) outside Asia. A clinical impression that the Hmong have a high rate of uric acid stone disease was evaluated.

PATIENTS AND METHODS

A retrospective chart review was performed. All adult Hmong patients seen between January 1, 2000, and December 31, 2001, by a large urology group practice (N = 205) were compared with a similar number of non-Hmong patients (N = 204).

RESULTS

Of these patients, 94 Hmong (46%) and 23 non-Hmong (11%) patients had stone disease (P < 0.001). After addition of 75 non-Hmong stone patients to create a suitable comparison group, a total of 86 Hmong and 88 non-Hmong stone patients had complete records. Sex (57% v 60% male) and mean age (47.9 v 47.3 years) were similar. Staghorn calculi were found in 21 Hmong (24%) and 0 non-Hmong patients (P < 0.001). Surgical treatments differed between Hmong and non-Hmong (P = 0.004): SWL (16 v 35), ureteroscopy (24 v 29), percutaneous nephrolithotomy (19 v 7), and nephrectomy (5 v 0). Treatment for staghorn calculi was refused by 9 Hmong patients (43%). Stone composition was available in 40 Hmong and 39 non-Hmong. Uric acid (>10%) was found in 50% of Hmong and 10% of non-Hmong stones (P < 0.001).

CONCLUSIONS

Hmong patients who come to urologic attention tend to do so for stone disease and tend to have uric acid calculi. The frequent requirement for invasive therapy, including nephrectomy, in the Hmong is of concern.

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.

Dissolution of ureteral uric acid calculi with local litholytic irrigation

This study was designed to evaluate the efficacy of local litholytic irrigation (LLI) in the treatment of ureteral uric acid calculi. Fourteen cases of ureteral uric acid calculi were diagnosed by abdominal plain radiography (KUB), retrograde urography, ultrasonography (B-mode ultrasound), spiral computerized tomography(CT) and blood biochemical examinations. A ureteral catheter was passed retrogradely across ureteral calculi by cystoscopy. LLI with tromethamine-E (THAM-E) was performed via the ureteral catheter after the improvement of renal function and general situation and the control of urinary tract infection under the condition of intravenous application of antibiotics. The irrigation rate varied from 1000 to 1500 ml per day. Retrograde pyelography demonstrated complete dissolution of all the stones, 13 cases within 10 days and 1 within 12 days. Mild hematuria was observed in the majority of the cases and temporary aggravated lumbago in 1 case, with no other side effects. It is concluded that LLI is a practical and effective method in the treatment of ureteral uric acid calculi for its advantages of shorter duration,lower cost, less physical suffering and no severe complications.

Ureteroscopy for pediatric urolithiasis: An evolving first-line therapy

OBJECTIVES

To present in a retrospective report a contemporary series of patients aged 14 years and younger who were treated for stones with ureteroscopy at our institution from 1991 to 2002. With the improvement and miniaturization of ureteroscopes and ancillary instruments, the endoscopic treatment of renal and ureteral calculi in children has become more feasible.

METHODS

A retrospective chart review was performed of 23 patients aged 14 years and younger who had undergone ureteroscopy for the treatment of ureteral or renal calculi at our institution.

RESULTS

A total of 27 stones were treated in 23 patients. Of the 27 stones, 18 were in the distal ureter, 5 in the mid ureter, 2 in the proximal ureter, and 2 in the renal pelvis. Ureteral dilation was performed in 4 (17.4%) of the 23 patients. The lithotripsy modalities used were holmium:yttrium-aluminum-garnet laser in 16 (69.6%), electrohydraulic lithotripsy in 3 (13%), a combination of holmium laser and electrohydraulic lithotripsy in 2 (8.7%), and basket extraction alone in 2 (8.7%) of 23 patients. Ureteral stents were placed in 21 (91.3%) of 23 patients. The average operative time was 46.9 minutes (range 15 to 92). In 21 (91.3%) of 23 patients, postoperative imaging was available and revealed that 20 (95.2%) of the 21 patients were rendered stone free. Two patients were lost to follow-up. No intraoperative complications occurred. One patient was treated postoperatively with intravenous antibiotics for transient fever.

CONCLUSIONS

Ureteroscopy is safe and effective in the management of ureteral and renal calculi in children. In our institution, it has emerged as a valid first-line therapy for the treatment of pediatric urolithiasis.

[Ammonium acid urate stone due to laxative abuse: a case report]

We report a case of ammonium acid urate stone due to laxative abuse. A 27-year-old female complained of left flank pain. Computed tomography revealed bilateral ureter stones (right 16.5 x 9.0 mm; left 4 mm), while left ureter stone was radiolucent on the plain X ray film. Bilateral hydronephrosis was seen, but no therapy was performed for the right stone, because 99mTc-MAG3 scintigraphy revealed that right kidney had no function. The left stone was successfully removed by transurethral approach. The stone was revealed to be an ammonium acid urate by infrared spectrophotometry. She had been taking many laxatives (bisacodyl, sennoside, aloe extract) for 12 years to control her body weight. Ammonium acid urate stones are rarely seen in developed countries. We have reviewed 9 cases in Japan, describing ammonium acid urate stones due to laxative abuse. Among these patients, 24-hour urine volume and excretion in urinary sodium were decreased, and serum aldosterone was increased. The involvement of laxative abuse should be considered when ammonium acid urate is formed in a woman with a low body mass index.

Stone fragility: its therapeutic implications in shock wave lithotripsy of upper urinary tract stones

OBJECTIVE

To analyse the impact of stone composition on stone fragility (fragmentation) and clearance of upper urinary tract stones after shock wave lithotripsy (SWL).

MATERIAL AND METHODS

Between 1st July 1998 and 31st July 2001, 300 renal and ureteric units of 290 patients (10 being bilateral) underwent SWL for upper urinary tract calculi. The degree of fragmentation was divided into four types: (I) Excellent, (II) Good, (III) Fair and (IV) No fragmentation. Stone composition was done by X-ray diffraction crystallography. A statistical comparison was made between degree of fragmentation, number of shock waves delivered, voltage setting, number of sessions required and requirements of adjuvant procedures according to the stone composition.

RESULTS

Stone analysis revealed that 90% of the patients had calcium oxalate stones. Of these 80% were calcium oxalate monohydrate (COM) and 20% calcium oxalate dehydrate (COD). Struvite, apatite and uric acid stones comprised of 6%, 3% and 1% respectively. Type-I fragmentation was achieved up to 63.96%, 50% and 100% in COD, struvite and uric stones respectively as compared to 44.9% and 44.44% for COM and apatite stones. Type-III fragmentation was seen up to 8.79% and 33.3% respectively in COM and apatite as compared to 5.55% or less in other types of the stones suggesting that COM and apatite stones produce larger fragments. The mean number of shock waves, voltage and number of treatments was significantly higher for COM and apatite stones (p value < 0.005) with a stone free rate of only 65-66% and 65-68% respectively at three months (p value < 0.001). Similarly the number of adjuvant procedures required in COM alone was more, i.e. 31 as compared to 17 procedures in rest of the other kinds of stones (p value < 0.05).

CONCLUSION

Stone composition in Indian subcontinent is different from the western world. Fragility of a stone varies with the composition of the stone and affects the therapeutic results.

Bilateral guaifenesin ureteral calculi

We report on a patient with bilateral ureteral calculi composed of guaifenesin metabolite as determined by infrared spectroscopy. These stones may be associated with excessive guaifenesin intake related to the current popularity of ephedrine preparations.

[Extracorporeal shockwave lithotripsy in the treatment of distal ureteral stones larger than 10 mm in diameter]

Optimal treatment for distal ureteral stones remains controversial. During a period of 10 years, from December 1992 to December 2002, 103 distal ureteral stones larger than 10 mm in diameter were treated at our institution with extracorporeal shock wave lithotripsy (ESWL) using the Siemens Lithostar. Only 2 patients had a ureteral stent in place at the time of treatment. The overall stone-free rate was 98% with 1-12 session and 3-month stone-free rate was 95.1%. These data reveal that a high success rate was achieved in multisession ESWL. Therefore, ESWL is considered to be acceptable as first-line therapy for fragmentation of distal ureteral stones larger than 10 mm in diameter.

[The clinical significance of 50 cases of percutaneous nephroureteral lithotripsy]

Percutaneous nephroureteral lithotripsy (PNL) was conducted in 50 patients with renal or ureteral calculi between March 2000 and August 2002. The mean age of patients was 56.6 years (range 25-82 years) and they included 29 males (58.0%) and 21 females (42.0%). The calculi were renal calculi in 38 patients (76.0%) and ureteral calculi in 12 patients (24.0%). The mean number of calculi was 1.5 (1-10 calculi, median number 1). The mean of the maximum calcule diameter was 30.9 mm (15.0-83.0 mm) for the renal calculi and 17.4 mm (8.0-27.0 mm for the ureteral calculi. The lithotripsy device was an ultrasonic lithotriptor (ALOKA) or Lithoclast (SWISS), as appropriate, and was used with a 24 Fr rigid endoscope (TAKEI). All operations were performed under lumbar spinal anesthesia. Eighteen of the 38 renal calculus patients were treated with PNL alone. In the other 19 PNL was combined with postoperative extracorporeal shock wave lithotripsy (ESWL). Seven of the 12 patients with ureteral calculi were treated with PNL alone, and 5 with PNL combined with postoperative ESWL. After 3 months, the treatment results were Tx(3)-0 in 45 patients (90.0%), and Tx(3)-2 in 5 patients (10.0%). The mean period of postoperative hospitalization was 30.3 days (10-86 days), with a median of 26 days. Complications were renal pelvis perforation in 1 patients and fever of 38.0 degrees C or above in 16 patients, but there was no hemorrhaging that required transfusion or other serious complications. PNL is a safe and reliable treatment method, and should be considered as a treatment option in cases of large calculi when a short treatment period is desired.

Endoscopic management of milk of calcium-filled ureterocele stump

A 38-year-old woman with a duplicated right collecting system and a history of right upper-pole heminephrectomy was referred for persistent dysuria and right lower-quadrant abdominal discomfort. Imaging identified a remnant ureter and a ureterocele filled with what appeared to be a large homogenous stone. At cystoscopy, the ureterocele was incised with a holmium:YAG laser, releasing a large quantity of white milky fluid (milk of calcium). There was no evidence of any solid material. Endoscopic evaluation should be the first step in patients with stones in a ureteral stump because milk of calcium may be the etiology of what appears to be a large stone burden in an obstructed system.

Extracorporeal shock wave lithotripsy for cystine urolithiasis in children: outcome and complications

The Siemens Lithostar Litotriptor was used to treat 6 children with cystine nephrolithiasis, previously treated by open surgery. Five children had renal calculi (3 multiple caliceal, 2 pelvis) and one had ureteral calculus. Stone size ranged from 0.2-2.5 cm in diameter, and stone burden was from 0.24 to 10.81 cm3 per kidney. From one to 4 ESWL sessions per unit were applied, with a total of 1,800 to 12,000 shock waves. The stone free rate at 3 months was 50%. A complete elimination was obtained with cystine stones in renal pelvis and ureter, however, up to 4 ESWL treatments failed in caliceal stones. Rather location of cystine calculi than previous surgery was associated with ESWL success rate. Two patients with positive urine cultures were successfully treated with appropriate antibiotics before ESWL was attempted. Perirenal hematoma was major complication demonstrated by radionuclide scintigraphy in one patient, and resolved spontaneously by 3 months. In the combined treatment of cystine urolithiasis in children ESWL, as auxillary procedure, was safe and effective in pelvis stone but failed in caliceal stones. Medical dissolution for retained fragments was found effective.

Obstructive nephropathy secondary to sulfasalazine calculi

The incidence of drug-induced stone disease is 0.44%. A 57-year-old woman with ulcerative colitis presented with obstructive nephropathy and pyelonephritis. She underwent cystoscopy, bilateral retrograde pyelography, and bilateral ureteral stent placement. A 6-cm bladder calculus and two 3-mm right distal ureteral calculi were discovered. Later, cystolithotomy was performed. The stone analysis demonstrated sulfapyridine, a sulfasalazine metabolite. Patients with inflammatory bowel disease can develop urolithiasis owing to acidic urine and low-volume urine production. Patients receiving aminosalicylates are at an increased risk of urolithiasis and may benefit from oral hydration and urinary alkalization.

University of Wisconsin experience using the Doli S lithotriptor

OBJECTIVES

To present our initial results using the Dornier Doli S lithotriptor with the 220 electromagnetic shock wave emitter to treat urinary calculi. At present, there is no published report of the efficacy of this instrument in service in the United States.

METHODS

We retrospectively reviewed the outcome of shock wave lithotripsy in 270 consecutive patients with solitary renal and/or ureteral stones treated from September 1998 to October 2001 with the Dornier Doli S lithotriptor. Data were collected with respect to stone size, location, and fragmentation.

RESULTS

Of the 270 patients treated, 204 had renal stones and 66 had ureteral stones. All patients had solitary stones. The renal stones averaged 9.7 mm in size (range 4 to 26). The ureteral stones averaged 7.8 mm (range 4 to 17). Of the renal stones, 51% were located in the renal pelvis, with 18%, 5%, and 25% located in the upper, middle, and lower poles, respectively. Of the ureteral stones, 68% were located in the proximal ureter, with 14% and 18% in the mid and distal ureter, respectively. In the renal group, 176 (86%) of 204 patients achieved clinical success. Of these patients, 148 were stone free (73%) and 28 had residual fragments less than 4 mm in size (14%). In the ureteral group, 52 (79%) of 66 patients achieved clinical success. Of these patients, 50 were stone free (76%) and 2 (3%) patients had fragments less than 4 mm in size. Thirteen (6%) of 204 patients in the renal group required retreatment. Four (6%) of 62 patients in the ureteral group required retreatment. Of the patients in whom treatment failed and who had stone analysis, 16 (76%) of 21 had stones composed of predominantly calcium oxalate monohydrate. Four patients developed steinstrasse. Two were treated with retrograde stent placement, and the other two with placement of percutaneous nephrostomy. One patient developed a known perinephric hematoma but did not require a blood transfusion.

CONCLUSIONS

Shock wave lithotripsy using the Doli S in appropriately selected patients is an effective instrument for treating urinary calculi throughout the urinary tract.

[2,8-dihydoroxyadenine (DHA) urolithiasis: a case report]

We report a case of 2,8-dihydroxyadenine (DHA) urolithiasis in a 28-year old female. She was admitted to our hospital complaining of a sudden pain in the left lumbar region. Abdominal X-ray (kidney-ureter-bladder; KUB) and computed tomography (CT) demonstrated a radiolucent left ureteral (8 x 6 mm2) and a renal (15 x 10 mm2) stone. In the repetitive procedure of transurethral ureterolithothripsy (TUL) and extracorporeal shock wave lithotripsy (ESWL), the stones had been removed successfully. The spectrophotometric analysis of the stone fragments revealed an absorption spectrum for 2,8-DHA. Adenine phosphoribosyltransferase (APRT) enzyme activity was lowered to 0.8 nmol/hr/mg protein. Thus, we diagnosed the illness as 2,8-DHA urolithiasis originating from APRT deficiency. A molecular analysis of the APRT gene by the polymerase chain reaction (PCR) method revealed the genotype to be APRT*J/APRT*Q0.

[Urologic interventional therapy of kidney calculi (I)--extracorporeal shockwave lithotripsy]

With a prevalence of around 5% in western countries, urolithiasis is a frequently occurring disease but with a poorly understood pathogenesis. Effective prevention is not possible for most stone types, in particular for calcium-containing stones, which occur most frequently. Additionally, after occurrence, patient compliance is often inadequate. Interventional therapy becomes necessary after stone manifestation within the urinary tract. Not all stone compositions respond to a drug treatment. Whereas in the seventies, stone treatment meant open surgery newly developed minimally-invasive procedures have displaced this treatment. The clinical introduction of extracorporal shock wave lithotripsy (ESWL) has played a crucial role in this process. Today, more than 80% of all urinary stones can be treated by modern lithotripters. Combination with other minimally-invasive procedures further improve stone free rate. This article provides an overview of technique, application and results of ESWL treatment.

Clinical association with urinary glycosaminoglycans and urolithiasis

OBJECTIVES

To determine the clinical association between urinary glycosaminoglycan (GAG) concentration and kidney stone disease.

METHODS

Thirty-five patients (14 women and 21 men) with a history of stone disease and 37 controls (13 women and 24 men) were evaluated for urinary GAG concentration. By using a new dye-binding assay, the total GAG concentration in the urine was measured and corrected to urinary creatinine levels (micrograms of GAG per milligram creatinine).

RESULTS

The mean urinary GAG concentration in those with stones was significantly lower (31.5 +/- 2.6 microg GAG/mg creatinine) than in the controls (43.8 +/- 3.8 microg GAG/mg creatinine, P = 0.01). Male patients with stones also had a significantly lower mean GAG concentration (26.1 +/- 1.8) than did the female patients (39.6 +/- 5.3, P = 0.009). The mean GAG concentration between ureteral (n = 13) versus renal (n = 22), single (n = 19) versus multiple (n = 16), family history (n = 11) versus no family history (n = 24), large (n = 13) versus small (n = 20), and the presence (n = 22) versus absence (n = 13) of residual stones did not show any significant differences. However, patients with recurrent stone formation (n = 21) had significantly lower mean GAG levels (26.4 +/- 1.6) compared with those with single stone formation (n = 14; 39.2 +/- 5.5, P = 0.01).

CONCLUSIONS

Lower urinary GAG levels are more common in patients with stone formation. This may play a more determinant role in male patients and those with recurrent stone formation.

Utility of oral dissolution therapy in the management of referred patients with secondarily treated uric acid stones

OBJECTIVES

Uric acid stones are best managed by chemolysis. Some patients with acutely symptomatic stones opt for endourologic therapies. The radiolucent nature of these stones makes secondary interventions difficult to plan. Computed tomography becomes the modality of choice to identify stone locations and size in these patients. We analyzed patients with uric acid stones referred to our stone center after primary treatment had failed to establish the efficacy of oral alkalinization therapy.

METHODS

Eleven patients presented after one or more failed attempts to intervene for uric acid stones. Charts were reviewed for age, sex, time with stone before referral, medical therapies undertaken, number of antecedent urologic interventions, number of radiographic studies performed, subsequent procedures performed, and outcomes with a minimal follow-up of 6 months.

RESULTS

Eight patients were men and four presented with bilateral stone disease (overall, 15 involved upper tracts). Sixty-seven percent of patients had right-sided solitary calculi. All patients at presentation filled out urinary pH diaries. Of the 11 patients, 4 stated they had been prescribed oral alkaline therapy but were found to be noncompliant, 4 were never prescribed this therapy, and 3 took the medication sporadically. All patients were counseled on self-dosing to maintain their urinary pH between 6.0 and 6.5 and to continue the diaries. Computed tomography scans were done in 9 patients, and intravenous urography and ultrasonography in the other 2 patients confirmed the stone burden. Only 3 patients (27%) required subsequent interventions (ureteroscopic laser lithotripsy).

CONCLUSIONS

Secondarily referred patients with uric acid stones are best treated with medical therapy. These findings suggest that the initial medical regimens had failed because of noncompliance or lack of effective follow-up by the primary urologist. Seventy-three percent of these patients had dissolution of the stones, requiring no further endourologic intervention.

Impact of power index, hydroureteronephrosis, stone size, and composition on the efficacy of in situ boosted ESWL for primary proximal ureteral calculi

OBJECTIVES

The efficacy, safety, feasibility, and outcome of in situ treatment applied to select proximal ureteral calculi was assessed and analyzed with a view to avoiding auxiliary interventions and providing high clearance rates in the shortest possible time. We studied the impact of several clinically important variables, including power index, degree of hydroureteronephrosis (HDUN), stone size, and composition on the efficacy of sequential in situ boosted extracorporeal shock wave lithotripsy (ESWL) in a select group. The power index requirement for the in situ boosted protocol and the impact of the stone size/composition, degree of HDUN, and clearance rates were also analyzed.

METHODS

An in situ (no instrumentation) boosted protocol was applied to 130 primary unimpacted proximal ureteral calculi with no prior intervention. A typical session with the Siemens Lithostar Plus comprised 3000 shock waves, in installments of 500, deployed at a power setting of 1 to 4 kV with a gradual stepwise escalation. Sequential boosted additional sessions of ESWL were administered on days 2, 7, and 14, tailored to the degree of fragmentation, clearance status, and amount of residual stone bulk. Several parameters (shock waves, kilovolts used, fluoroscopy time, number of sessions, stone size, composition, fragmentation, clearance, and HDUN) were recorded and the results analyzed statistically.

RESULTS

The results were excellent in 83.8%, with a mean duration to complete clearance of 11.3 days. In situ ESWL failed in 7.69%, and the auxiliary intervention rate was 10.7%. Pre-ESWL HDUN was present in 78.3%, the mean power index was 184.6/session/case, and the average stone burden was 8.9 mm(2). Calcium oxalate monohydrate was the most common stone (56%). Renal colic was the most common side effect observed. The power index, fragmentation at the first session, and stone size were found to be the most favorable significant variables affecting stone clearance. The degree of HDUN, number of sessions, and stone composition did not significantly impact the clearance rates.

CONCLUSIONS

In situ boosted ESWL should be the first-line therapeutic modality in select unimpacted primary proximal ureteral stones.

Current evaluation and management of renal and ureteral stones

A systematic clinical approach is required for the diagnosis and management of renal and ureteral stones. The presenting symptoms, past medical history, medications, and physical examination all provide clues to the diagnosis of urinary stones. In the acute setting, noncontrast helical computerized tomography has emerged as the first line imaging test for renal colic. More traditional imaging tests are also important in the management of stone disease. After making the diagnosis of a urinary stone, the urologist should discuss the advantages and disadvantages of all treatment options with the patient. For most stone patients today, many equally effective treatment approaches can exist for the same problem. To help direct surgical management, guidelines for stone management have been devised. With technologic advances, stone treatment has improved and complications have decreased. While patient care has been significantly impacted by use of effective endourologic techniques, patients should complete imaging tests following surgery to assure a stone-free state. In addition, recurrent stone formers should complete a medical stone evaluation to identify treatable causes of their stones.

Transurethral ureterolithotomy in 100 lower ureteral stones

A total of 100 patients with lower ureter stones received transurethral ureterolithotripsy (TUL) using a pulsed dye laser and/or a pneumatic lithotriptor. Extracorporeal shock wave lithotripsy treatment was added in 15 patients because fragments larger than 4 mm had been pushed back to the renal pelvis. The median stone size was 8 mm (range 3-22 mm). Operative time ranged between 3 and 157 min with a median of 30 min. Stone size correlated well with impaction, when impaction was defined as the inability of a guidewire to pass over the stone. Complete removal was defined as total clearance at 1 month without retreatment. The overall stone-free rate was 93%. Among the 7 not-stone-free cases, 5 cases were considered to have been treated successfully because asymptomatic residual fragments were smaller than 4 mm, 1 case required retreatment to become stone free, and 1 case with a silent residual fragment of 8 mm had been followed up for 3 months. The success rate was 98% when successful treatment was defined as total clearance or the presence of asymptomatic residual fragments of 4 mm or less without retreatment. Impaction was not a significant determining factor of stone-free rate (95.7 and 86.7%, respectively, p > 0.05) and in situ stone-free rate (TUL alone; 85.7 and 76.7%, respectively, p > 0.05). Two minor ureteral perforations were encountered. No patient required percutaneous nephrostomy or open surgery, or showed any late complications. TUL is a safe and successful method in managing lower ureteral stones.

Stone recurrence after endopyelotomy

OBJECTIVES

The purpose of this study was to evaluate whether repair of the ureteropelvic junction (UPJ) obstruction reduces the incidence of stones in stone-forming patients with concurrent UPJ obstruction.

METHODS

We performed a retrospective study evaluating 90 patients with UPJ obstruction who underwent endopyelotomy and simultaneous stone extraction (group A) and 80 patients without UPJ obstruction who underwent only stone extraction (group B). Group A consisted of 52 men and 38 women with an average age of 54.4 years (range 15 to 82), and group B of 46 men and 34 women with an average age of 53.5 years (range 8 to 94). Metabolic evaluation was available in 47 patients of group A and 42 patients of group B.

RESULTS

We achieved a stone-free state in all patients of both groups. Stone recurrence was observed in 7 patients (8%) in group A and in 32 patients (40%) in group B. Nine of 47 patients (19%) in group A showed metabolic abnormalities. In group B we found 30 of 42 patients (71.4%) with metabolic abnormalities.

CONCLUSIONS

Our results suggest that correction of the anatomic obstruction facilitates the drainage of the previously entrapped urine, and thus decreases the incidence of recurrent urinary stone formation.