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

The effect of stone size on the results of extracorporeal shockwave lithotripsy versus semi-rigid ureteroscopic lithotripsy in the management of upper ureteric stones

Objectives

Patients and methods

Results

Conclusion

Comparison of the effects of retroperitoneoscopic ureterolithotomy and ureteroscopic lithotripsy in the treatment of upper ureteral calculi

ABSTRACT

This study compares the efficacy of retroperitoneoscopic ureterolithotomy (RPUL) and ureteroscopic lithotripsy (URL) in the treatment of upper ureteral calculi.The clinical data of 150 patients with upper ureteral calculi who underwent RPUL and 136 patients who underwent URL between January 2014 and October 2019 were retrospectively analyzed. The operation time, postoperative hospital stay, operation success rate, stone clearance rate, and surgical complications were evaluated between the two groups.For the RPUL and URL groups, respectively, the average operation time was 74.5 ± 24.6 minutes and 54.5 ± 13.2 minutes; the postoperative hospital stay was 5.8 ± 1.4 days and 3.2 ± 1.2 days; the operation success rate was 96.0% (144/150) and 85.3% (116/136); the incidence rate of complications was 3.5% (5/144) and 17.5% (18/103); and the stone clearance rate was 100% (144/144) and 88.8% (103/116), which were all statistically significant (P < .05).Both RPUL and URL had the advantages of low trauma and fast recovery rate for patients with upper ureteral calculi. However, patients who underwent RPUL showed higher success and fewer complication rate. RPUL might be a safe and effective laparoscopic method for the treatment of patients with upper ureteral calculi.

Miniature semi-rigid ureteroscopy with holmium-yttrium-aluminium-garnet laser vs shockwave lithotripsy in the management of upper urinary tract stones >1 cm in children

Objective

To compare the efficacy and safety of miniature semi-rigid ureteroscopy (URS) with holmium (Ho)-yttrium-aluminium-garnet (YAG) laser lithotripsy vs shockwave lithotripsy (SWL) for treating upper urinary tract (UUT) calculi >1 cm in children.

Patients and methods

Children with unilateral single UUT ureteric stones of >1 cm were prospectively enrolled in this study. Patients were randomly divided into two groups: Group 1, treated with SWL; and Group 2, treated with URS (6/7.5 F) and laser lithotripsy. The patients’ characteristics, stones demographics, operative time, adjunctive procedures, stone-free rate (SFR), re-treatment rate, and complications were statistically analysed and compared. Success was defined as stone-free status (no stone residual of ≥0.3 cm) at 1 month from the initial treatment without any auxiliary procedures.

Results

In all, 68 patients with UUT stones met our inclusion criteria. There were no significant differences between the two groups for patient or stone demographics. In Group 1, the SFR was 26/34 (76.4%) and in Group 2 it was 33/34 (97.1%) (P = 0.03). A total of 12 auxiliary procedures in Group 1 and two in Group 2 were needed to reach a 100% SFR (P = 0.014). There were no significant differences between the two groups for operative times, adjunctive procedures, number of complicated cases or complications of Grade ≥III (P = 0.65, P = 0.23, P = 0.77, and P = 0.62, respectively).

Conclusion

Miniature semi-rigid URS with Ho-YAG laser lithotripsy for UUT ureteric stones of >1 cm in children was more effective than SWL in terms of SFR and re-treatment rate, with no significant difference in the rate or grade of complications.

Abbreviations

EQ: efficiency quotient; KUB: plain abdominal radiograph of the kidneys, ureters and bladder; RCT: randomised controlled trial; SFR: stone-free rate; SWL: shockwave lithotripsy; URS: ureteroscopy; US: ultrasonography/ultrasound; URS: ureteroscopy; UUT: upper urinary tract; YAG: yttrium-aluminium-garnet

Does the presence or degree of hydronephrosis affect the stone disintegration efficacy of extracorporeal shock wave lithotripsy? A systematic review and meta-analysis

The aim of this study was to determine whether the presence or degree of hydronephrosis (HN) affects the stone disintegration efficacy of shock wave lithotripsy (SWL). A comprehensive literature search using PubMed, Embase, Cochrane Library, and Web of Science was conducted to retrieve relevant studies. Risk ratios (RRs) and mean differences (MDs) with corresponding 95% confidence intervals (CIs) were calculated for comparisons of outcomes of interest. In total, seven comparative studies with 2033 patients were included. Overall results indicated no significant difference in stone-free rate (SFR) and retreatment rate between two groups. Subgroup analysis further revealed: (1) compared with moderate or severe HN, non-HN SWL brought significantly lower retreatment rate (RR 0.67, 95%CI 0.52-0.87, P = 0.002 and RR 0.55, 95%CI: 0.40-0.76, P = 0.0003, respectively) and shorter clearance time (MD - 3.80, 95%CI - 5.81 to - 1.79, P = 0.0002 and MD - 5.93, 95%CI - 10.29 to - 1.57, P = 0.008, respectively); (2) SWLs performed without stone-induced HN or with artificial HN were associated with significantly higher SFR (RR 1.11, 95%CI 1.04-1.18, P = 0.001 and RR 0.93, 95%CI 0.87-0.99, P = 0.02, respectively); (3) non-HN SWL brought significantly higher SFR than HN group when treating proximal ureteral stones (RR 1.14, 95%CI 1.04-1.24, P = 0.005). Generally, SWLs performed with HN were shown to offer similar stone disintegration efficacy to those without HN. However, it seemed preferable to perform SWL: (1) without severe to moderate HN or stone-induced HN; (2) with artificial HN; (3) without HN when treating proximal ureteral stones.

Spectrum of urinary stone composition in Northwestern Rajasthan using Fourier transform infrared spectroscopy

Introduction:

The aim of this study was to evaluate the chemical composition of urinary stones and pattern of changes according to the patient's age in Northwestern Rajasthan using Fourier transform infrared (FTIR) spectroscopy.

Materials and Methods:

A prospective study of 1005 urolithiasis patients was carried out in two tertiary care centers from September 2012 to September 2016. Chemical composition of urinary stones was analyzed using FTIR spectroscopy, and a subgroup study based on the patient's age was done (8–12 years – Group A, 13–18 years – Group B, and >18 years – Group C).

Results:

Out of 1005 patients, 59 were in Group A, 104 in Group B, and 842 in Group C. Male predominance was found in all age groups. Mixed composition stones were much more common than pure one (74.83% vs. 25.17%). Overall, combination of calcium oxalate monohydrate with dihydrate was the most common composition (58.0%). Calcium oxalate was the predominant chemical composition in 91.54% of stones, followed by uric acid in 4.28%, struvite in 2.29%, calcium phosphate in 1.49%, and cystine in 0.4%. The proportion of calcium oxalate stone was increasing while that of struvite, uric acid, and cystine stone was decreasing with age. Most of the vesical calculi in pediatric age group (Group A; 8–12 years) patients were made up of combination of struvite, calcium phosphate, and uric acid. A total of 85.11% of staghorn calculi were of oxalates.

Conclusion:

In Northwestern Rajasthan, calcium oxalate is the most common composition of urinary stones in all age groups. Mixed stones are more common than pure ones. The incidence of calcium oxalate stone increases while that of struvite, uric acid, and cystine stone decreases with age.

Ureteral stenting can be a negative predictor for successful outcome following shock wave lithotripsy in patients with ureteral stones

Purpose

To evaluate ureteral stenting as a negative predictive factor influencing ureteral stone clearance and to estimate the probability of one-session success in shock wave lithotripsy (SWL) patients with a ureteral stone.

Materials and Methods

We retrospectively reviewed the medical records of 1,651 patients who underwent their first SWL. Among these patients, 680 had a ureteral stone measuring 4–20 mm and were thus eligible for our study. The 57 patients who underwent ureteral stenting during SWL were identified. Maximal stone length (MSL), mean stone density (MSD), skin-to-stone distance (SSD), and stone heterogeneity index (SHI) were determined by pre-SWL noncontrast computed tomography.

Results

After propensity score matching, 399 patients were extracted from the total patient cohort. There were no significant differences between stenting and stentless groups after matching, except for a higher one-session success rate in the stentless group (78.6% vs. 49.1%, p=0.026). In multivariate analysis, shorter MSL, lower MSD, higher SHI, and absence of a stent were positive predictors for one-session success in patients who underwent SWL. Using cutoff values of MSL and MSD obtained from receiver operator curve analysis, in patients with a lower MSD (≤784 HU), the success rate was lower in those with a stent (61.1%) than in those without (83.5%) (p=0.001). However, in patients with a higher MSL (>10 mm), the success rate was lower in those with a stent (23.6%) than in those without (52.2%) (p=0.002).

Conclusions

Ureteral stenting during SWL was a negative predictor of one-session success in patients with a ureteral stone.

Impact of ureteric stent on outcome of extracorporeal shockwave lithotripsy: A propensity score analysis

INTRODUCTION

Extracorporeal shockwave lithotripsy (SWL) is one of the most frequently performed procedures in patients with urolithiasis. For ureter-localized stones, SWL is often preceded by a double J stent insertion. However, fear of serious complications, including sepsis associated with stents, is often expressed. The following study assessed the impact of stent insertions on the results of SWL in patients with ureteric stones.

MATERIAL AND METHODS

The study group consisted of 411 ureteric stone patients who were treated with SWL from January 2010 to December 2014. In 60 cases, treatment was preceded by ureteric stent insertion. A propensity scoring system was used to pair non-stented patients with the stented group. Success rates were assessed and compared using the chi-squared test. Multivariate logistic regression analysis was used to evaluate the influence of particular variables on the stone-free rate.

RESULTS

The overall success rate was 82.2%. After matching, the success rate of the stented group was not significantly different from the control group (85.0% vs. 83.3% respectively, p = 0.80). The mean number of sessions was higher in the stented group (1.88 per patient). Stones located in the lower part of the ureter have the greatest chance of being successfully treated.

CONCLUSIONS

The double J stent has no influence on the outcome of SWL treatment. In view of the greater likelihood of having additional sessions, this approach should be reserved for selected cases.

Laser-induced breakdown spectroscopy is a reliable method for urinary stone analysis

OBJECTIVE

We compared laser-induced breakdown spectroscopy (LIBS) with the traditionally used and recommended X-ray diffraction technique (XRD) for urinary stone analysis.

MATERIAL AND METHODS

In total, 65 patients with urinary calculi were enrolled in this prospective study. Stones were obtained after surgical or extracorporeal shockwave lithotripsy procedures. All stones were divided into two equal pieces. One sample was analyzed by XRD and the other by LIBS. The results were compared by the kappa (κ) and Spearman's correlation coefficient (rho) tests.

RESULTS

Using LIBS, 95 components were identified from 65 stones, while XRD identified 88 components. LIBS identified 40 stones with a single pure component, 20 stones with two different components, and 5 stones with three components. XRD demonstrated 42 stones with a single component, 22 stones with two different components, and only 1 stone with three different components. There was a strong relationship in the detection of stone types between LIBS and XRD for stones components (Spearman rho, 0.866; p<0.001). There was excellent agreement between the two techniques among 38 patients with pure stones (κ index, 0.910; Spearman rho, 0.916; p<0.001).

CONCLUSION

Our study indicates that LIBS is a valid and reliable technique for determining urinary stone composition. Moreover, it is a simple, low-cost, and nondestructive technique. LIBS can be safely used in routine daily practice if our results are supported by studies with larger numbers of patients.

Assessment of Probe-to-Specimen Distance Effect in Kidney Stone Treatment With Hydrodynamic Cavitation

The aim of this study is to focus on the effect of probe-to-specimen distance in kidney stone treatment with hydrodynamic bubbly cavitation. Cavitating bubbles were generated by running phosphate buffered saline (PBS) through stainless steel tubing of inner diameter of 1.56 mm at an inlet pressure of ∼10,000 kPa, which was connected to a 0.75 mm long probe with an inner diameter of 147 μm at the exit providing a sudden contraction and thus low local pressures. The bubbles were targeted on the surface of nine calcium oxalate kidney stones (submerged in a water pool at room temperature and atmospheric pressure) from three different distances, namely, 0.5 mm, 2.75 mm, and 7.75 mm. The experiments were repeated for three different time durations (5 min, 10 min, and 20 min). The experimental data show that amongst the three distances considered, the distance of 2.75 mm results in the highest erosion amount and highest erosion rate (up to 0.94 mg/min), which suggests that a closer distance does not necessarily lead to a higher erosion rate and that the probe-to-specimen distance is a factor of great importance, which needs to be optimized. In order to be able to explain the experimental results, a visualization study was also conducted with a high speed CMOS camera. A new correlation was developed to predict the erosion rates on kidney stones exposed to hydrodynamic cavitation as a function of material properties, time, and distance.

A prospective randomized comparison between shockwave lithotripsy and semirigid ureteroscopy for upper ureteral stones <2 cm: a single center experience

BACKGROUND AND PURPOSE

The best management of upper ureteral calculi is undefined. We performed a prospective randomized comparison between semirigid ureteroscopy (URS) and shockwave lithotripsy (SWL) for upper ureteral stones <2 cm to evaluate safety and efficacy of both procedures.

PATIENTS AND METHODS

Patients with a single radiopaque upper ureteral stone <2 cm undergoing treatment between January 2010 and May 2011 in our department were included. Randomization was performed into two groups-group A: SWL performed as an outpatient procedure using an electromagnetic lithotripter (Dornier Compact Delta); group B: URS performed using an 6/7.5F semirigid ureteroscope with holmium laser intracorporeal lithotripsy. Statistical analysis was performed regarding demographic profile, success rates, retreatment rates, auxiliary procedures, and complications.

RESULTS

There were 90 patients enrolled in each group. Mean stone size: 12.3 mm in group A vs 12.5 mm in group B (P=0.52). The overall 3-month stone-free rate was (74/90) 82.2% for group A vs (78/90) 86.6% for group B (P=0.34). For stone size <10 mm, 3-month stone-free rates were (45/53) 84.9% for group A vs (43/49) 87.7% for group B (P=0.32). For 10 to 20 mm stones, 3-month stone-free rates were (29/37) 78.4% for group A vs (35/41) 85.4% for group B (P=0.12).The re-treatment rate was significantly greater in group A than group B (61.1% vs 1.1%, respectively; P<0.001). The auxiliary procedure rate was comparable in both groups (21.1% vs 17.7%; P=0.45). The complication rate was 6.6% in group A vs 11.1% in group B (P=0.21).

CONCLUSIONS

Both SWL and semirigid URS are safe and highly efficacious for treating patients with proximal ureteral stones <20 mm. For stones <10 mm, SWL was safer, less invasive, and of comparable efficacy with URS. For stones between 10 and 20 mm, however, URS was more effective, with a lesser re-treatment rate.

Analysis of urinary stone composition in Eastern India by X-ray diffraction crystallography

Background:

Stones in the urinary system are common in our country. This study was done to assess the composition of the urinary stones in eastern part of India.

Materials and Methods:

A prospective study was done over a period of thirty months. A total of 90 stones were analyzed in this time period by using X-ray diffraction crystallography.

Results:

Of the 90 stones analyzed, 77 were renal stones, 12 were ureteric stones and one was a bladder stone. Six stones (all renal) did not have properties to be represented by X-ray diffraction crystallography. The overall prevalence of the oxalate containing stones was 85.7% with calcium oxalate monohydrate (COM) being the major constituent. Calcium oxalate dihydrate (COD) was the next most common constituent. Struvite stones constituted 9.5% of the stones analyzed. Pure calcium phosphate stones were found in 4.7% of the cases.

Conclusion:

Our study reveals that the stone composition in the eastern part of India is different from that in other parts of the country. We have a comparatively lower prevalence of oxalate stones while a higher prevalence of phosphate and struvite stones.

Double J stent reduces the efficacy of extracorporeal shock wave lithotripsy in the treatment of lumbar ureteral stones

Introduction

We evaluated the effect of the presence of a double J stent on the efficacy of extracorporeal shock wave lithotripsy (ESWL) in the treatment of lumbar ureteral stones.

Material and methods

Between January 2007 and February 2012, we performed a retrospective cohort study. Forty–four patients were treated by ESWL for lumbar ureteral stones and included into two groups for the analysis: group 1, non–stented (n = 27) and group 2, stented patients (n = 17). Treatment efficacy was evaluated by abdominal X–ray or CT–scan at 1 month. Stone–free patients and those with a residual stone ≤4 mm were considered to be cured.

Results

Mean stone size and density in groups 1 and 2 were 8.2mm/831HU, and 9.7 mm/986HU respectively. Both groups were comparable for age, BMI, stone size and density, number, and power of ESWL shots given. The success rates in groups 1 and 2 where 81.5% and 47.1%, respectively (p = 0.017). There was no difference between the groups for stones measuring 8 mm or less (p = 0.574). For stones >8 mm, the success rates were respectively 76% and 22.2% for groups 1 and 2 (p = 0.030). Logistic regression analysis revealed a higher failure rate when a double J stent was associated with a stone >8 mm (p = 0.033).

Conclusions

The presence of a double J stent affects the efficacy of ESWL in the treatment of lumbar ureteral stones. This effect is significant for stones >8 mm. Ureteroscopy should be considered as the first–line treatment in such patients.

Experience of mini-percutaneous nephrolithotomy in the treatment of large impacted proximal ureteral stones

OBJECTIVES

To evaluate the efficacy and safety of mini- percutaneous nephrolithotomy (PCNL) in the treatment of large impacted proximal ureteral stones.

METHODS

We retrospectively reviewed the outcomes of 163 patients who underwent mini-PCNL between January 2006 and August 2010. Mean age was 48.6 years and mean stone size was 18.4 mm. Hydronephrosis and/or hydroureterosis appeared in all patients. In the prone position, percutaneous access (16-Fr sheath) was established by placement of an access needle into the intended calyx under fluoroscopic guidance or combined with ultrasound guidance for complete obstruction by stones while the contrast agent cannot transit. Pneumatic or ultrasonic probes were used throughout ureterorenoscopy for lithotripsy. The ureteral stents and nephrostomy tube were placed at the end of the procedure. Mean drop in hemoglobin, operative time, success rate, hospital stay, and complications were assessed.

RESULTS

Mini-PCNL operations were performed successfully in all patients. Mean operation time was 37 min. Mean postoperative hospital stay was 3.6 days. All cases were followed up for 6-20 months. No major complications like hemorrhage, perforation or organic injury were noted during the operation or postoperatively. The stone-free rate in all patients was 95.7%. Calculus had no recurrence during the follow-up period. Hydronephrosis and hydroureterosis disappeared or were relieved.

CONCLUSIONS

Mini-PCNL is a safe and effective therapy for large impacted proximal ureteral stones.

Stone clearance after extracorporeal shockwave lithotripsy in patients with solitary pure calcium oxalate stones smaller than 1.0 cm in the proximal ureter, with special reference to monohydrate and dihydrate content

OBJECTIVE

The aim of this study was to assess stone-free rates following extracorporeal shockwave lithotripsy (ESWL) of pure calcium oxalate (CaOx) stones in the proximal ureter.

MATERIAL AND METHODS

The investigators retrospectively examined 53 patients with 5-10 mm pure CaOx stones in the proximal ureter from the medical archives of 593 consecutive patients treated with ESWL. The compositions of calcium oxalate monohydrate (COM) and dihydrate (COD) in a given stone were determined by infrared spectrometry. Stone size, attenuation number and stone-to-skin distance (SSD) were measured using plain radiography and computed tomography (CT). ESWL success was evaluated by stone-free status after the first single session.

RESULTS

On average, calculi were 8.0 × 5.3 mm in size, with an SSD of 11.0 cm. The mean CT attenuation value was 740.1 HU. Attenuation numbers correlated significantly with stone diameter (r = 0.49), but had no correlation with the stone content of COM or COD. A negative correlation was observed between COM and COD content (r = -0.925). With regard to patients' physical characteristics and COM and COD content, no differences were found between study subgroups with stone-free and residual status (n = 38 and 15, respectively). There were also no differences in clinical features between patient subgroups with COM- or COD-predominant stones (n = 22 and 31, respectively).

CONCLUSION

The findings indicated that the differences in COM and COD content of CaOx stones had no impact on stone clearance after ESWL and that a favorable stone-free rate of the stones treated with ESWL may be achieved independently of CaOx hydration.

Treatment of large proximal ureteral stones: extra corporeal shock wave lithotripsy versus semi-rigid ureteroscope with lithoclast

Purpose

Assessment of safety and efficacy of extracorporeal shockwave lithotripsy versus semi-rigid ureteroscope with lithoclast for treatment of large proximal ureteral stones.

Materials and methods

The study included 147 patients with large upper ureteral stones. SWL and ureteroscopy were performed in 71 and 76 patients respectively. Patients in the SWL group were treated with Siemens: - Modularis lithovario under intravenous sedation on an out patient basis. Patients in the ureteroscopy group were treated with (7.5 Fr) semi-rigid ureteroscope and lithoclast under spinal anesthesia on a day care basis.

Results

Stone - free rate for in situ SWL was 58% (41 of 71) patients. For semi-rigid ureteroscope accessibility of the stones was 94% (72 of 76) and the stone free rate was 92% (70 of 76) No major complications were encountered in both groups.

Mean stone size was 1.34 ± 0.03 cm in the SWL group and 1.51 ± 0.04 in the ureteroscopy group.

Conclusions

Our study demonstrates that ureteroscopy with lithoclast can be considered as acceptable treatment modality for large proximal ureteral calculi and can be considered as fist line for treatment of large proximal ureteral stones.

Extracorporeal shock wave lithotripsy in impacted upper ureteral stones: a prospective randomized comparison between stented and non-stented techniques

OBJECTIVES

To assess the need for pre-extracorporeal shock wave lithotripsy (pre-ESWL) stenting in management of impacted upper ureteral stones of size < or = 2 cm and to verify whether stenting would influence the success of therapy.

METHODS

Between 2007 and 2008, a total of 60 patients with solitary, radio-opaque impacted upper ureteral stones measuring < or = 2 cm were divided into 2 equal groups: a stented group with a Double-J stent fixed pre-ESWL and a non-stented group treated by in situ ESWL. All patients were treated by ESWL using Dornier Doli S lithotripter. Results were compared in terms of clearance rates, number of shock waves and sessions, morbidity, and incidence of complications. Pretreatment KUB (kidneys, ureters, and bladder) and intravenous pyelogram and post-treatment KUB were used to evaluate fragmentation and clearance.

RESULTS

Overall stone-free rate was 88.3%. No significant statistical difference was observed in stone-free rate between the stented and non-stented groups being 90% and 86.7%, respectively (P = .346). One session was required in 28.3% of patients, whereas multiple sessions were required in 71.7% of patients. No significant statistical difference was noted in re-treatment rate in the 2 groups. Patients in the stented group significantly complained of side effects attributable to the stent predominantly dysuria, urgency, frequency, and suprapubic pain.

CONCLUSIONS

ESWL is an effective and reasonable initial therapy in the management of impacted upper ureteral stones measuring < or = 2 cm. Pre-ESWL ureteral stenting provides no additional benefit over in situ ESWL. Moreover, ureteral stents are associated with significant patient discomfort and morbidity.

Impact of hydronephrosis on treatment outcome of solitary proximal ureteral stone after extracorporeal shock wave lithotripsy

The purpose of this study was to investigate the impact of hydronephrosis on the treatment outcome of patients with a solitary proximal ureteral stone after extracorporeal shock wave lithotripsy (ESWL). A total of 182 consecutive patients who underwent ESWL for a solitary proximal ureteral stone of between 5 and 20 mm in size in our institution were included in this study. The degree of hydronephrosis was defined by renal ultrasonography. Patient data, stone size, shock wave numbers and shock wave energy were also recorded. Treatment outcome was evaluated 3 months after the first session of ESWL. In multivariate analysis, only the maximal stone length (odds ratio [OR], 0.15; 95% confidence interval [CI], 0.03-0.91; p = 0.04) and the degree of hydronephrosis (OR, 0.40; 95% CI, 0.16-0.98; p = 0.045) were significant predicting factors for stone-free status 3 months after ESWL. For stones < or = 10 mm, the stone-free rate decreased from 80% in patients with mild hydronephrosis to 56.4% in those with moderate to severe hydronephrosis. For stones > 10 mm, the stone-free rate decreased further, from 65.2% in patients with mild hydronephrosis to 33.3% in those with moderate to severe hydronephrosis. In summary, patients with a solitary proximal ureteral stone and a stone > 10 mm, the treatment outcome after ESWL was not good if moderate to severe hydronephrosis was noted on ultrasonography. Alternative treatments, such as ureteroscopic lithotripsy, may be appropriate as initial treatment or after failure of one session of ESWL.

Impact of the degree of hydronephrosis on the efficacy of in situ extracorporeal shock-wave lithotripsy for proximal ureteral calculi

OBJECTIVE

We conducted a prospective randomized study to investigate the relation between the degree of stone-induced hydronephrosis and the outcome of extracorporeal shock-wave lithotripsy (ESWL) in patients with lumbar ureter stones.

MATERIAL AND METHODS

A total of 284 patients with solitary lumbar ureter stones with or without hydronephrosis were treated with ESWL. The degree of hydronephrosis was determined by means of renal ultrasound. Patients were divided into four groups according to the degree of stone-induced hydronephrosis. The results were analyzed by comparing stone-free rates, the number of shock waves, the number of sessions, the incidence of complications, secondary interventions and time to stone clearance.

RESULTS

The mean stone size was 11.4+/-2.6 mm. In the hydronephrotic group, the stone-free rate was 80.3%, compared to 89.1% in patients without hydronephrosis (p=0.12). The mean time to stone clearance was 13.8+/-9.8 days. Differences among the four groups in terms of stone size and treatment outcome were not significant. However, the presence of hydronephrosis was highly associated with repeat treatment (2.4 vs 1.7 treatments; p<0.001) and prolonged clearance time (16.2 vs 11.6 days; p<0.001).

CONCLUSIONS

In cases with solitary lumbar ureter stones, the degree of hydronephrosis caused by the stone does not affect the overall treatment success with ESWL. However, stones in obstructed systems are associated with a tendency for repeat treatment and a prolonged time for stone clearance.

[Management of proximal ureteral stones]

Proximal ureteral stone less than 4-6mm may initially be treated by surveillance. Generally, extracorporeal shockwave lithotripsy (ESWL) is the first line treatment for proximal ureteral stones, specially for stones less than 1cm. For stones greater than 1cm, the results of ureteroscopy (URS) are better than the results of ESWL and in these cases URS may be an option. In case of failure of ESWL, URS can be proposed. URS can be the first line treatment in case of severe ureteral obstruction with no urinary infection. Proximal ureteroscopy must be careful because severe complications are not infrequent. Open surgery has very rare indication. Metabolic check-up and annually follow-up with at least a renal imaging at three months are recommended.

Outpatient basis extracorporeal shock wave lithotripsy for ureter stones: efficacy of the third generation lithotripter as the first line treatment

AIM

We assessed the efficacy of a third generation extracorporeal shock wave lithotripsy (ESWL) machine for ureter stones using the Dornier Lithotriptor Compact Delta.

METHODS

A total of 471 consecutive ureter stones were treated with ESWL using the Dornier Lithotriptor Compact Delta from December 2001 on an outpatient basis. Four hundred and one cases were followed up at least once after the procedure and were included in this study. All of the cases, except one patient who was three years old, were treated without anesthesia, and the procedure was principally performed on outpatient basis.

RESULTS

The overall stone free rate was 94.5% and the mean number of treatment sessions was 1.23. The stone free rates were compared considering various clinical factors and significant differences were observed in the stone length, the stone location and the sex in univariate analysis. However, only the stone length maintained a statistically significant impact in multivariate analysis and the stone free rates were 91.2% and 98.0% respectively in larger stones (length 10mm) and smaller stones (length < 10mm) (p = 0.004). In mid-distal stones, the stone free rate was higher than that of proximal stones (97.5% vs 92.6%, p = 0.04) and not affected by stone length.

CONCLUSIONS

Extracorporeal shock wave lithotripsy performed by the third generation machine achieved an excellent stone free rate with a relatively small number of treatment sessions. This procedure is strongly recommended as the first line therapy for all ureter stones including mid-distal ones.

Matched pair analysis of ureteroscopy vs. shock wave lithotripsy for the treatment of upper ureteric calculi

There is controversy over whether shock wave lithotripsy (SWL) or ureteroscopy (URS) is the best management of ureteric calculi, especially for stones located in the upper ureter. This study compares URS and SWL management of upper ureteric stones directly for the first time using a different analysis tool, the matched pair analysis study design. This method enables meaningful comparisons to be made on a small number of matched patients, using precise like-for-like matching. Adult patients undergoing primary treatment of solitary radiopaque proximal ureteric stones were identified. Patients with stents, nephrostomies or stones at the pelvi-ureteric junction were excluded. Patients had a minimum of 3 months follow-up. Patients treated by primary URS were matched using four parameters (sex, laterality, stone size and location) to patients treated on a Dornier Compact Delta Lithotriptor. A total of 1479 patients had URS or SWL from which 27 upper ureteric stone matched pairs were identified. Three-month stone free rates were 82% for URS and 89% for SWL (McNemar's test, p=0.625). Re-treatment was required in 11% and 26% following URS and SWL respectively (p=0.219). Forty-one per cent of URS patients required an ancillary treatment, such as stent removal, compared with only 22% of SWL patients (p=0.227). Introduction of a holmium:YAG laser for use with URS improved the stone free rate for URS to 100%. Using a robust like-for-like comparison of similar patients with very similar upper ureteric stones the outcomes following SWL and URS were comparable. Choice of treatment should therefore be based on parameters such as availability of equipment, waiting times and patient preference.

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.

Is Pre-Shock Wave Lithotripsy Stenting Necessary for Ureteral Stones With Moderate or Severe Hydronephrosis?

PURPOSE

We performed a prospective, randomized clinical trial to evaluate the outcome of ureteral stents for solitary ureteral stones 2 cm or less in moderately or severely obstructed systems using shock wave lithotripsy.

MATERIALS AND METHODS

Between 2001 and 2004, 186 patients who met study criteria were randomized into 2 groups. Group 1 received a pre-shock wave lithotripsy 6Fr Double-J stent and group 2 had no stent. Patients were treated with a Dornier MFL 5000 lithotripter. Results were compared in terms of clearance rates, number of shock waves and sessions, irritative voiding symptoms, incidence of complications and secondary interventions. Failure was defined as the need for additional procedure(s) for stone extraction.

RESULTS

Overall 164 patients (88.2%) became stone-free after shock wave lithotripsy. Complete stone fragmentation was achieved after 1 to 3 and more than 3 session in 108 (58.1%), 30 (16.1%), 13 (7%) and 14 patients (7.5%), respectively. Ureteral stent insertion did not affect the stone-free rate, which was 84.9% and 91.4% in groups 1 and 2, respectively (p = 0.25). There was no statistical difference in the re-treatment rate, flank pain or temperature in the 2 groups. However, all patients in the stented group significantly complained of side effects attributable to the stent, including dysuria, suprapubic pain, hematuria, pyuria and positive urinary culture.

CONCLUSIONS

Pretreatment stenting provides no advantage over in situ shock wave lithotripsy for significantly obstructing ureteral calculi. Shock wave lithotripsy is reasonable initial therapy for ureteral stones 2 cm or less that cause moderate or severe hydronephrosis.

Forgotten ureteral stents causing renal failure: multimodal endourologic treatment

PURPOSE

To report our experience in managing nine patients with forgotten ureteral stents that resulted in chronic renal failure (CRF).

PATIENTS AND METHODS

We reviewed our stent records from January 1994 to January 2004 to analyze cases of forgotten indwelling ureteral stents in solitary kidneys that had led to CRF (serum creatinine 4-14 mg/dL). These patients had normal renal function prior to the interventions at which stents were placed. They were subjected to multimodal endourologic management, including cystolithotripsy and ureteroscopic and percutaneous lithotripsy, to make them stent and stone free in a single operative session.

RESULTS

The median dwell time of the retained stents was 39 months. Three patients were not aware of the stent, while six chose to ignore it. All patients underwent a temporizing percutaneous nephrostomy with an 8F pigtail catheter and were operated on 2 to 4 weeks later. All nine patients were rendered stone and stent free; however, one patient succumbed to septic complications 3 weeks after the operation. At last follow-up (6-56 months), two patients are on the transplant waiting list, while six are living with mild to moderate renal failure on conservative treatment.

CONCLUSIONS

Chronic renal failure caused by encrusted stents in a functionally solitary kidney is a disastrous complication of forgotten stents. Prevention is, of course, ideal, but such cases are still seen despite increasing awareness. Temporizing percutaneous nephrostomy, renal support, and skilled endourologists are the cornerstones of management of such high-risk cases.

Extracorporeal Shock Wave Lithotripsy in the Treatment of Proximal Ureteral Stones: Does the Presence and Degree of Hydronephrosis Affect Success?

OBJECTIVES

We investigated the relation between the presence and degree of stone induced hydronephrosis and the outcome of extracorporeal shock wave lithotripsy (SWL) in patients with solitary proximal ureteral stones.

METHODS

130 patients with or without hydronephrosis were treated with SWL. The degree of hydronephrosis was defined by renal ultrasound. Patients were divided into four groups according to the degree of stone induced hydronephrosis. Group 0 (24%) had no urinary system dilatation, group 1 (31.2%) had a mild dilatation of the renal pelvis, group 2 (40%) had a moderate and group 3 (4.8%) a severe dilatation of the renal pelvis and calices. The stone size, number of shock waves applied and number of sessions required to achieve stone clearance were recorded.

RESULTS

Mean stone size was 8.2 mm+/-2.5 mm. Mean time to stone clearance was 13.7 days+/-16.3. In 74.4% of patients stone clearance was observed. Additional 4.8% harbored residual fragments < or =3 mm after 3 months. Differences among the four groups in terms of stone size, time to stone clearance and treatment failure were not significant.

CONCLUSIONS

The presence or degree of hydronephrosis caused by a proximal ureteral stone does not affect the time to stone clearance or success rate after SWL.

Therapeutic options for proximal ureter stone: Extracorporeal shock wave lithotripsy versus semirigid ureterorenoscope with holmium: Yttrium-aluminum-garnet laser lithotripsy

OBJECTIVES

To compare the safety and cost-effectiveness of ureterorenoscopic holmium:yttrium-aluminum-garnet (YAG) laser lithotripsy (URSL) with extracorporeal shock wave lithotripsy (ESWL) for proximal ureteral stones.

METHODS

This investigation assessed 220 patients with upper ureteral stones. Those in the ESWL group were treated on an outpatient basis using the Medispec Econolith 2000 (Medispec, Germantown, MD) under intravenous sedation. URSL was performed with a 6/7.5F semirigid tapered ureterorenoscope and holmium:YAG laser under spinal anesthesia on an inpatient basis. A successful outcome was defined as the patient being stone free on radiography 1 month after treatment. The stone size, success rate, postoperative complications, and cost were evaluated in each group.

RESULTS

A total of 220 patients were enrolled in this study. Hematuria and flank pain were the most common complaints in each group. The mean stone burden +/- SD was 58.7 +/- 3.1 mm2 in the ESWL group and 108.4 +/- 10.0 mm2 in the URSL group (P = 0.000). The accessibility of the semirigid ureterorenoscope for upper ureteral stones was 98.1% (101 of 103), and the stone-free rate achieved after one treatment was 83.2% (84 of 101). The initial stone-free rate of in situ ESWL was 63.9% (76 of 119). Significantly, the initial stone-free rate of the URSL group was superior to that of the ESWL group (P = 0.001). The average cost in the URSL group appeared to be lower than that in the ESWL group (P = 0.000).

CONCLUSIONS

The results of this study have demonstrated that URSL achieved excellent results for upper ureter calculi. In terms of cost and effectiveness, this procedure should be the first-line therapy for proximal ureter stones.

COMPARISON BETWEEN EXTRACORPOREAL SHOCK WAVE LITHOTRIPSY AND SEMIRIGID URETERORENOSCOPE WITH HOLMIUM: YAG LASER LITHOTRIPSY FOR TREATING LARGE PROXIMAL URETERAL STONES

PURPOSE

Management of large impacted upper ureteral calculi remains challenging for urologists. These calculi are frequently associated with obstructive uropathy and deteriorated renal function. Extracorporeal shock wave lithotripsy (SWL) is the least invasive treatment but its success rate is decreased for large impacted upper ureteral calculi. According to the American Urological Association guidelines on ureteral stones published in 1997, the appropriateness of ureteroscopy decreases when stone size exceeds 1 cm. However, the application of advanced ureteroscopy and techniques has increased the success rate of treating proximal ureter calculi. In this study we compared the safety and efficacy of ureterorenoscopic holmium:YAG laser lithotripsy (URSL) with SWL for large impacted proximal ureteral stones.

MATERIALS AND METHODS

This study evaluated 82 patients with large impacted upper ureteral stones. Two patients were excluded from study owing to conversion to open surgery. SWL and URSL were performed in 41 and 39 patients, respectively. Those in the SWL group were treated on an outpatient basis with Medispec Econolith 2000 (Medispec, Germantown, Maryland) under intravenous sedation. The URSL was performed with a 6/7.5Fr semirigid tapered ureterorenoscope and holmium:YAG laser with the patient under spinal anesthesia on an inpatient basis. Successful outcome was defined as the patient being stone-free on radiography 1 month after treatment. Stone size, success rate, postoperative complications and cost were analyzed in each group.

RESULTS

A total of 80 patients were enrolled in this study. Hematuria and flank pain were the most common complaints in each group. Mean stone size +/- SD was 1.28 +/- 0.04 cm in the SWL group and 1.51 +/- 0.05 cm in URSL group (p = 0.0009). Accessibility of the semirigid ureterorenoscope for impacted upper ureteral stones was 95.1% (39 of 41) and the stone-free rate achieved after 1 sitting was 92% (36 of 39). The initial stone-free rate of in situ SWL was 61% (25 of 41). Notably, the initial stone-free rate in the URSL group was better than that of the SWL group (p = 0.003). The efficiency quotient was 0.53 for URSL and 0.59 for SWL. The average cost in the URSL group appears to be lower than in the SWL group. Both groups were free of major complications.

CONCLUSIONS

This study demonstrated that URSL achieved excellent results for upper ureteral calculi greater than 1 cm. Thus, this procedure should be considered first line therapy for large proximal ureteral stones.

[Outpatient extracorporeal shock wave lithotripsy. Prospective evaluation of 2937 cases]

PURPOSE

Extracorporeal shock wave lithotripsy (ESWL) is mainly performed on inpatient basis in Germany. It has yet to be considered if outpatient treatment in Germany is indicated when sufficient urological care is guaranteed.

MATERIALS AND METHODS

Between September 1989 and December 2002, a total of 10,505 patients with urolithiasis were treated at the Institut zur Steinzertrümmerung in Troisdorf, Germany with the Siemens Lithostar plus. Of these patients, 2937 (43%) were treated on an outpatient basis. The data were collected prospectively from September 1989. Patient satisfaction was evaluated with a self-developed, non-validated questionnaire.

RESULTS

The overall success rate was 81.8%. The complication rate after ESWL was 40.2%, whereas 4.9% of the patients had to be admitted to a hospital; 73.5% did not need auxiliary treatment before and 78.6% after ESWL, respectively. More than 90% of the patients were satisfied with the result of outpatient treatment.

CONCLUSIONS

Outpatient ESWL can be safely performed as minimally invasive treatment after thorough patient selection in Germany. The success and quality of treatment was not altered because of outpatient treatment. A network of ESWL center and post-interventional care center has to be established to guarantee 24-h service for auxiliary necessities.

Can we improve the prediction of stone-free status after extracorporeal shock wave lithotripsy for ureteral stones? A neural network or a statistical model?

PURPOSE

We evaluated whether an artificial neural network (ANN) can improve the prediction of stone-free status after extracorporeal shock wave lithotripsy (ESWL) (Dornier Medical Systems, Inc., Marietta, Georgia) for ureteral stones compared to a logistic regression (LR) model.

MATERIALS AND METHODS

Between February 1989 and December 1998, 984 patients with ureteral stones, including 780 males and 204 females with a mean age +/- SD of 40.85 +/- 10.33 years, were treated with ESWL. Stone-free status at 3 months was determined by urinary tract plain x-ray and excretory urography. Of all patients 919 (93.3%) were free of stones. The impact of 10 factors on stone-free status was studied using an LR model and ANN. These factors were patient age and sex, renal anatomy, stone location, side, number, length and width, whether stones were de novo or recurrent, and stent use. An LR model was constructed and ANN was trained on 688 randomly selected patients (70%) to predict stone-free status at 3 months. The 10 factors were used as covariates in the LR model and as input parameters to ANN. Performance of the trained net and developed logistic model was evaluated in the remaining 296 patients (30%), who served as the test set. The sensitivity (percent of correctly predicted stone-free cases), specificity (percent of correctly predicted nonstonefree cases), positive predictive value, overall accuracy and average classification rate of the 2 techniques were compared. Relevant variables influencing the construction of the 2 models were compared.

RESULTS

Evaluating the performance of the LR and ANN models on the test set revealed a sensitivity of 100% and 77.9%, a specificity of 0.0% and 75%, a positive predictive value of 93.2% and 97.2%, an overall accuracy of 93.2% and 77.7%, and an average classification rate of 50% and 76.5%, respectively. LR failed to predict any nonstone free cases. LR and ANN identified stone location and stent use as important factors in determining the outcome, while ANN also identified stone length and width as influential factors.

CONCLUSIONS

ANN and LR could predict adequately those who would be stone-free after ESWL for ureteral stones. The neural network has a higher ability to predict those who fail to respond to ESWL.

Does Failure to Visualize the Ureter Distal to an Impacted Calculus Constitute an Impediment to Successful Lithotripsy?

BACKGROUND

A severe degree of ureteral obstruction is viewed as a predictor of poor outcome in shockwave lithotripsy (SWL). Impacted stones are often considered a contraindication to in-situ SWL.

PATIENTS AND METHODS

Impaction in our study was defined as failure to visualize the ureter distal to the calculus with proximal hold-up of contrast for as long as 3 hours on an intravenous urogram (IVU). We evaluated 30 patients with impacted ureteral calculi, who were compared with a second unimpacted group matched for stone size and stone location. The calculi were reorganized into < or =10-mm and >10-mm groups. The results were compared in terms of clearance rates, number of shockwaves, number of sessions, and number of days between the start of SWL and clearance.

RESULTS

Between January 1998 and December 2001, 30 impacted stones were treated with lithotripsy. Complete clearance rates in the impacted as well as the non-impacted group were 76.7%. There was no statistical difference in the number of shockwaves, sessions, or time to clearance. The results were poorer in lower-ureteral than upper-ureteral calculi, but this difference did not reach statistical significance. However, the differences between the < or =10-mm and >10-mm stones were statistically significant.

CONCLUSION

Impaction on an IVU does not affect the results of lithotripsy.

Extracorporeal Shockwave Lithotripsy For Solitary Distal Ureteral Stones: Does the Degree of Urinary Obstruction Affect Success?

BACKGROUND AND PURPOSE

Extracorporeal shockwave lithotripsy (SWL) is a safe and effective way to treat stones in the distal ureter, but the impact of urinary obstruction on outcome is not clear. We investigated the relation between the degree of stone-induced urinary obstruction and the outcome of SWL treatment in patients with solitary distal ureteral stones.

PATIENTS AND METHODS

A series of 165 consecutive patients with solitary distal ureteral stones underwent SWL (Multimed 9200 Lithotriptor, Elmed Medical Systems, Turkey) between October 2002 and September 2003 at two separate centers. Distal ureteral stones were defined as those located below the lower border of the sacroiliac joint. Patients were divided into four groups according to the degree of stone-induced urinary obstruction: group I (N = 62) had no urinary system dilation; group II (N = 40) had mild dilation, group III (N = 35) moderate dilation, and group IV (N = 28) severe dilation. In addition to degree of obstruction, stone size, average fluoroscopy time, total number of shockwaves applied, number of sessions required to achieve stone-free status, and stone clearance time were recorded. Treatment failure was defined as persistence of fragments after three SWL sessions.

RESULTS

Overall, 152 (92.1%) of the patients became stone free after SWL. There were no statistically significant differences among the groups with respect to any of the factors studied.

CONCLUSION

In cases where there is a solitary calculus in the distal ureter, the degree of urinary obstruction caused by the stone does not affect the success of stone clearance with SWL.

The 'modified prone position': a new approach for treating pre-vesical stones with extracorporeal shock wave lithotripsy

OBJECTIVE

To investigate the utility of a new 'modified-prone' position for treating pre-vesical stones with extracorporeal shock wave lithotripsy (ESWL), usually considered an acceptable and effective treatment for such stones, but for which many different body positions have been used in an attempt to increase its efficacy.

PATIENTS AND METHODS

The study included 268 consecutive patients with a solitary pre-vesical stone who underwent ESWL either prone (69) or in the modified-prone position (199) between May 1999 and August 2001. Only those with one stone between the ureteric orifice and 1 cm proximal to the vesico-ureteric junction were included. In each case the stone diameter, days to stone clearance, number of shock waves applied per treatment, and number of sessions required to become stone-free were recorded. If the treatment failed this was also noted. Success rates in the prone and modified-prone groups were compared and analysed to assess which of the variables influenced success with ESWL.

RESULTS

After ESWL, 95.5% of the 268 patients were stone-free; the rates in the prone and modified-prone groups were 89.9% and 97.5%, respectively (P = 0.015). The probability of success with ESWL therapy for pre-vesical calculi in modified-prone position was about five times (odds ratio 4.56, 95% confidence interval 1.2-17.7) greater than that expected with when prone. The modified-prone position was an independent factor most significantly influencing success with ESWL in these patients.

CONCLUSION

The modified-prone position for ESWL is a new and very effective way to treat patients with pre-vesical stones.