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

Factors influencing the efficacy of ultrasound-guided extracorporeal shockwave lithotripsy in the treatment of ureteral stones: a retrospective study

The aim of the study was to analyze the factors influencing the efficacy of ultrasound-guided extracorporeal shockwave lithotripsy (ESWL) in the treatment of ureteral stones. The clinical data of 8102 patients (6083 men and 2019 women) who presented with ureteral stones were retrospectively analyzed. All the patients were treated with ultrasound-guided ESWL. The stone-free rate (SFR) was calculated to evaluate the effect of ESWL. The characteristics of the patients and their stones, and the ESWL parameters applied were compared to identify the factors affecting the treatment outcomes. The SFR and that following one ESWL session were 94.6% (7663/8102) and 75.4% (6107/8102), respectively. Multivariate analysis showed that stone location (OR 0.656, p < 0.001), stone size (OR 1.103, p < 0.001), and degree of hydronephrosis (OR 1.952, p < 0.001) independently affected SFR; and age (OR 1.005, p = 0.022), stone location (OR 0.729, p < 0.001), stone size (OR 1.103, p < 0.001), degree of hydronephrosis (OR 1.387, p = 0.001), maximum energy level(OR 0.691, p < 0.001) independently affected SFR following one session. Ultrasound-guided ESWL is effective in all levels of ureteral stones. Large stone size and moderate hydronephrosis are correlated with treatment failure. Ultrasound-guided ESWL may be the first choice for distal ureteral stones.

Variables measured on three-dimensional computed tomography are preferred for predicting the outcomes of shock wave lithotripsy

PURPOSE

Shock wave lithotripsy (SWL) is used to treat upper urinary tract stones. Recently, some volume analyzers have enabled preoperative assessment using three-dimensional computed tomography (3D-CT). We evaluated the efficacy of 3D-CT variables for predicting the outcomes of SWL.

METHODS

The study population included 193 patients who underwent SWL between November 2014 and August 2020. In addition to conventional two-dimensional computed tomography (2D-CT) assessments, 3D-CT assessments of targeted stones were retrospectively performed, and stone size and stone density (SD) were measured. The successful and unsuccessful treatment groups were compared and risk factors for an unsuccessful first SWL session were investigated. The predictive accuracy of variables measured on 3D-CT was evaluated by receiver operating characteristic curves and multivariate analyses.

RESULTS

The success rate of the first SWL session was 73.1%. Stone volume, mean SD and highest SD on 3D-CT were significantly higher in the unsuccessful group than in the successful group. Stone volume showed a higher area under the curve (AUC) than the estimated volumetric stone burden and stone diameter, which were measured on 2D-CT (0.729, 0.683, and 0.672, respectively). The AUCs of the mean SD and highest SD on 3D-CT were higher than those on 2D-CT (0.699, 0.680, 0.617, and 0.627, respectively). Multivariate analyses identified stone volume (≥ 0.29 ml), mean SD on 3D-CT (≥ 421 HU), and absence of hydronephrosis as independent predictive factors for unsuccessful SWL.

CONCLUSION

3D-CT variables were promising predictors of the outcomes of SWL. Preoperative 3D-CT assessment is helpful for selecting favorable patients for SWL.

The effectiveness and safety of extracorporeal shock wave lithotripsy for the management of kidney stones: A protocol of systematic review and meta-analysis

BACKGROUND

Extracorporeal shockwave lithotripsy (ESWL) has gained worldwide popularity as one of the most commonly used minimally invasive management of urinary tract stones. The objective of this study was to evaluate the efficacy and safety of ESWL for patients with kidney stones (KS).

MATERIALS AND METHODS

This protocol established in this study has been reported following the Preferred Reporting Items for Systematic Review and Meta-Analysis Protocols. Web of Science, PubMed, Embase, Cochrane Library, China Biomedical Literature Database (CBM), China Knowledge Network Database (CNKI), Chinese Scientific Journal Database (VIP), and Wan Fang Database were searched for case-control studies in ESWL treating patients with KS until July 1, 2020. We will use a combination of Medical Subject Heading and free-text terms with various synonyms to search based on the Eligibility criteria. Two investigators independently reviewed the included studies and extracted relevant data. The relative risk (RR) and 95% confidence intervals (CIs) were used as effect estimate. I test, substantial heterogeneity, sensitivity analysis, and publication bias assessment will be performed accordingly. Stata 14.0 and Review Manger 5.3 are used for a meta-analysis.

RESULTS

The results will be published in a peer-reviewed journal.

CONCLUSION

The results of this review will be widely disseminated through peer-reviewed publications and conference presentations. This evidence may also provide helpful evidence of the efficacy and safety of ESWL treating patients with KS.

PROSPERO REGISTRATION NUMBER

CRD42019157243.

Extracorporeal shock wave lithotripsy for distal ureteric stones: which is the ideal approach?

OBJECTIVE

To compare the safety and efficacy of different approaches using ESWL for management of distal ureteric stone in an attempt to select the ideal one.

PATIENTS AND METHODS

This is a prospective randomized single-center study conducted on patients with lower third single radiopaque ureteric stone with size less than 15 mm. Patients were randomized into three groups, group A: Supine transgluteal, group B: Modified prone and group C: Prone position (80 patients each). The success of the procedure was assessed by NCCT and is defined as complete stone removal or had only clinically insignificant fragments (< 3 mm) for a maximum of three sessions. The success rate, rate of complications, pain intensity by visual pain scale and patients' satisfaction rate were compared among the three study groups.

RESULTS

Data of 240 patients were analyzed (80 in each group). Overall, no significant difference has been observed among all groups regarding demographic data, stone and treatment characteristics. The overall success rates for treatment after the last session were 86.3%, 65% and 62.5% in the three study groups, respectively, with a statistically significant difference for group A. Regarding pain perception and complication rate, all groups were comparable. Patient satisfaction is significantly better in group A versus the other two groups.

CONCLUSION

Our study has confirmed better efficacy profile and patients' satisfaction rate of ESWL in the supine position (transgluteal approach) than other different known approaches for the treatment of distal ureteral stones.

Factors affecting success in the treatment of proximal ureteral stones larger than 1 cm with extracorporeal shockwave lithotripsy in adult patients

The aim of the study was to analyze the factors predicting success for the treatment of proximal ureteral stones larger than 1 cm with extracorporeal shockwave lithotripsy (SWL) in adult patients. Between January 2014 and December 2018, 480 adult patients in total underwent SWL and data were retrospectively evaluated. Patients with multiple ureteral stones, solitary kidney, congenital abnormality, skeletal system abnormality, history of previous urinary system surgery and SWL, renal insufficiency, patients who could not tolerate SWL and pediatric patients were excluded from the study. The remaining 415 patients were divided into two groups as success (Group 1, n = 307) and failure (Group 2, n = 108). The overall success rate was 73.9%. The values of stone size, Hounsfield Unit (HU), skin to stone distance (SSD), ureteral wall thickness (UWT), proximal ureter diameter, renal pelvis diameter, hydronephrosis grade, and duration of renal colic were significantly higher in Group 2 compared to Group 1. In binary logistic regression analyses, HU, UWT, and proximal ureter diameter were found to be independent predictors. HU, UWT, and proximal ureter diameter had sensitivity and specificity of 92-92%, 88-23%, and 87-46%, with cutoff values of 740 HU, 2.5 mm and 8.5 mm, respectively. The area under the curve values were 0.96, 0.97, and 0.96 for HU, UWT, and proximal ureter diameter, respectively. The CT-based parameters, including HU, UWT, and proximal ureter diameter are independent predictive factors with excellent accuracy for the treatment of proximal ureteral stones larger than 1 cm with SWL in adult patients. Based on these factors, SWL can be considered for proximal ureteral stones larger than 1 cm.

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.

Factors predictive of shockwave lithotripsy failure for ureteral stones: why we need to hurry

BACKGROUND

The aims of this study are to evaluate the prognostic factors of extracorporeal shockwave lithotripsy in patients with ureteric stones, and to identify which patients might directly benefit of an endoscopic treatment.

METHODS

We performed a prospective study from January 2013 and July 2016 on patients with single ureteric stone and undergoing extracorporeal shockwave lithotripsy (SWL). We divided patients into two groups: first group (success group) included cases resolved with SWL only, and a second group (failure group) including patients with stone not resolved by SWL and requiring an endoscopic treatment. We evaluated age, weight, height, body mass index, stone size, hydronephrosis, laterality, location, days elapsed from onset of symptoms to SWL and stone density when computed tomography was performed. In case of stone fragments >4 mm, the procedure was repeated up to a maximum of three times. SWL was considered as failed if patients had a residual stone of any size after a follow-up of 3 months or if a complication occurred.

RESULTS

274 patients completed follow-up and were enrolled in the study. Mean age was 53.22 years (standard deviation: 13.98). SWL overall success rate was 84.3% (231 patients successfully treated with shockwaves) and failure rate was 15.7% (43 patients underwent auxiliary endoscopic procedure). At the univariate analysis, we observed a statistically significant difference for hydronephrosis (P=0.006), time elapsed from symptoms onset (P=0.013), patients' age (P=0.06) and mean stone density (0.023). In the multivariate logistic regression, patients' age (OR: 1.517), and time elapsed from obstruction to SWL (OR: 3.005) were independent predictive factors for SWL failure. Furthermore, moderate and severe hydronephrosis seemed to be independent predictive factors for SWL failure, presenting an OR of 2.451 and 4.207 respectively. High stone density resulted to be a predictive factor for SWL failure (OR: 2.293 if density was higher than 1100 Hounsfield Units).

CONCLUSIONS

We report a large series of patients undergone primary SWL for ureteric stones. Our data demonstrated the role of hydronephrosis, time elapsed from obstruction onset to treatment and stone density as independent predictive factors of SWL failure.

Single extracorporeal shock-wave lithotripsy for proximal ureter stones: Can CT texture analysis technique help predict the therapeutic effect?

PURPOSE

To explore whether the computed tomography texture analysis (CTTA) technique can help predict the curative effects of a single extracorporeal shock-wave lithotripsy (ESWL) for proximal ureteral stones.

MATERIALS AND METHODS

In all, 100 patients with proximal ureteral stone underwent non-enhanced multi-detector computed tomography (MDCT) before ESWL. The patients were divided into success and failure groups. Success of ESWL was defined as the patients being stone-free or having residual stone fragments of ≤2 mm. Traditional characteristics, such as stone size, body mass index (BMI), and skin-to-stone distance (SSD), and CTTA metrics, such as the mean Hounsfield unit (HU) density, entropy, kurtosis, and skewness, were analyzed and compared between two groups by univariate and multivariate logistic regression analyses. Receiver operating characteristic (ROC) curves were generated to determine Youden index-based cutoff values.

RESULT

Failure of stone removal was observed in 36 patients (36%). Stone height, stone cross-sectional diameter, largest cross-sectional area, stone volume, stone density (mean HU), and CTTA metrics (kurtosis and entropy) were the significant independent predictors of ESWL success on univariate analysis (p < 0.05). On multivariate analysis, mean HU, skewness, and kurtosis were shown to be significant predictors of ESWL success (p < 0.05). In subgroup analysis based on the cutoff value of mean stone density (HU = 857), the only significant independent factor associated with both subgroups was kurtosis (p < 0.05).

CONCLUSIONS

As a quantitative analysis method, CTTA may be helpful in selecting appropriate ESWL patients. High kurtosis and low mean HU values simultaneously indicate a relatively higher ESWL success rate.

Impact of Pretreatment Hydronephrosis on the Success Rate of Shock Wave Lithotripsy in Patients with Ureteral Stone

PURPOSE

To evaluate predictors of the success rate for one session of shock wave lithotripsy (SWL), focusing on the relationships between pretreatment hydronephrosis grade and one-session SWL success rates.

MATERIALS AND METHODS

The medical records of 1824 consecutive patients who underwent an initial session of SWL for treatment of urinary stones between 2005 and 2013 were reviewed. After exclusion, 700 patients with a single, 4-20 mm diameter radiopaque calculus were included in the study.

RESULTS

The mean maximal stone length (MSL) and skin-to-stone distance were 9.2±3.9 and 110.8±18.9 mm, respectively. The average values for mean stone density (MSD) and stone heterogeneity index (SHI) were 707.0±272.1 and 244.9±110.1, respectively. One-session success rates were 68.4, 75.0, 75.1, 54.0, and 10.5% in patients with hydronephrosis grade 0, 1, 2, 3, and 4, respectively. Patients were classified into success or failure groups based on SWL outcome. Multivariate logistic regression analyses revealed that MSL [odds ratio (OR) 0.888, 95% confidence intervals (CI): 0.841-0.934, p<0.001], MSD (OR 0.996, 95% CI: 0.995-0.997, p<0.001), SHI (OR 1.007, 95% CI: 1.005-1.010, p<0.001), and pretreatment hydronephrosis grade (OR 0.601, 95% CI: 0.368-0.988, p=0.043) were significantly associated with one-session success.

CONCLUSION

Pretreatment grades 3 or 4 hydronephrosis were associated with failure of SWL in patients with a single ureteral stone. In the presence of severe hydronephrosis, especially hydronephrosis grade 4; physicians should proceed cautiously in choosing and offering SWL as the primary treatment for ureteral stone.

Has the pelvic renal stone position inside the upper loop of JJ stent any influence on the extracorporeal shock wave lithotripsy results?

Background

JJ stents are often encountered in patients with pelvic renal stones referred for shock wave lithotripsy, most of them being placed either for obstructive renal pelvic stones or for ureteric stones mobilized retrograde during the JJ stent insertion. The aim of the study was to determine whether the relative stone position in the upper loop of the JJ stent during extracorporeal shock wave lithotripsy (SWL) influences the efficiency of the procedure. The study was designed as a prospective cohort study on 162 patients addressing the same urological department, with single renal pelvic stone (primary or mobilized to the renal pelvis during the insertion of JJ stent), smaller than 15 mm, with JJ stent, treated by SWL using a second generation spark gap lithotripter, 18 kV, 3000 waves/session. Patients were divided in three groups according to the relative position of the stone to the upper loop of the JJ stent as appears on plain X-ray: stone-inside-loop, loop-crossing-stone and stone-outside the loop. The SWL success rate was the primary outcome of the study. p Value, Chi square and Kruskal–Wallis tests were used for statistical analysis.

Results

For stone-inside-loop cases, SWL efficiency was 22.7 versus 42 % for all the other cases (p = 0.002). Other factors for decreased SWL success rate were: higher stone radio-opacity, larger JJ of stent and obese patients. Study limitation is represented by the relative small study group and by the evaluation of stone density using plain X-ray instead of computer tomography.

Conclusions

For pelvic renal stones having the same density characteristics studied by plain X-ray, the SWL efficiency is lower in stone-inside-loop cases comparing with the other positions. The overall stone free rate for renal pelvic stones could be explained by the second generation lithotripter used for all procedures.

Clinical Nomograms to Predict Stone-Free Rates after Shock-Wave Lithotripsy: Development and Internal-Validation

PURPOSE

Shock-wave lithotripsy (SWL) is accepted as the first line treatment modality for uncomplicated upper urinary tract stones; however, validated prediction models with regards to stone-free rates (SFRs) are still needed. We aimed to develop nomograms predicting SFRs after the first and within the third session of SWL. Computed tomography (CT) information was also modeled for constructing nomograms.

MATERIALS AND METHODS

From March 2006 to December 2013, 3028 patients were treated with SWL for ureter and renal stones at our three tertiary institutions. Four cohorts were constructed: Total-development, Total-validation, CT-development, and CT-validation cohorts. The nomograms were developed using multivariate logistic regression models with selected significant variables in a univariate logistic regression model. A C-index was used to assess the discrimination accuracy of nomograms and calibration plots were used to analyze the consistency of prediction.

RESULTS

The SFR, after the first and within the third session, was 48.3% and 68.8%, respectively. Significant variables were sex, stone location, stone number, and maximal stone diameter in the Total-development cohort, and mean Hounsfield unit (HU) and grade of hydronephrosis (HN) were additional parameters in the CT-development cohort. The C-indices were 0.712 and 0.723 for after the first and within the third session of SWL in the Total-development cohort, and 0.755 and 0.756, in the CT-development cohort, respectively. The calibration plots showed good correspondences.

CONCLUSIONS

We constructed and validated nomograms to predict SFR after SWL. To the best of our knowledge, these are the first graphical nomograms to be modeled with CT information. These may be useful for patient counseling and treatment decision-making.

Age-related delay in urinary stone clearance in elderly patients with solitary proximal ureteral calculi treated by extracorporeal shock wave lithotripsy

We investigated the effects of aging on the stone-free rate (SFR) after shock wave lithotripsy (SWL) for the treatment of proximal ureteral calculi. A total of 247 consecutive patients were retrospectively selected, classified into seven groups set at 10 year increments (from 20 to 90 years), and examined for SFR after SWL. According to our final analysis, 185 male and 62 female patients with an average age of 54.1 years had stones with a diameter of 11.5 mm and a density of 893.1 Hounsfield units. On average, SFR was 74.9 % at 3 months after 1.7 SWL sessions. SFR gradually reached ≥ 90 % for each age-group after 1.5-2 years. Median durations to achieve 50 % SFR were estimated to be 21 and 86 days for those in their 20 and 80 s, respectively. However, the difference between the two estimates was not significant (p = 0.064). The durations to achieve 50 % SFR for the other groups lay between these two estimates. Aging does not affect long-term SFR, but patients aged ≥ 80 years might experience delayed stone clearance within the first 12 months after SWL.

Two-step minipercutaneous ureterolithotripsy under multimodal analgesia for complicated impacted calculi in proximal ureter

OBJECTIVE

To suggest minipercutaneous ureterolithotripsy using the mininephroscope as an alternative process for impacted stones of the upper ureter because these stones can be challenging to treat and can produce severe symptoms.

MATERIALS AND METHODS

We report our results of cases in which the percutaneous approach using 2-step minipercutaneous ureteroscopy with the mininephroscope was used to achieve relief from the stone, with minimal anesthesia risks. A total of 54 patients (33 men and 21 women) presented with impacted stones in the proximal ureter. The mean stone size was 16.2 mm (range 10-21). All patients were treated with 2-step minipercutaneous antegrade ureterolithotripsy under multimodal analgesia.

RESULTS

The mean operative time was 49 minutes (range 40-110). Placement of the percutaneous drainage tube was quick and was performed with the patient under local anesthesia. The minipercutaneous session followed several days later, with the patient under multimodal anesthesia. The initial stone-free rate was 94%. The stone-free rate 2 months after the procedure was 100%. All procedures were well tolerated by the patients (group mean visual analog scale score 3.1 ± 0.7 standard deviation). No severe adverse events were noted. The mean hospital stay was 5.3 days (range 3-12).

CONCLUSION

In selected emergency cases of impacted proximal ureteral stones, the approach of the initial insertion of a nephrostomy tube followed by a second session of antegrade ureterolithotripsy using the mininephroscope is a safe and effective alternative treatment, especially, because it can be accomplished with minimal anesthesia requirements.

Immediate or delayed SWL in ureteric stones: a prospective and randomized study

The objective is to compare immediate and delayed SWL as a treatment for ureter stones between 5 and 20 mm. Patients who applied to the emergency department with single, radio opaque ureteric stone of 5-20 mm size were included in the study. Patients were randomized into immediate and delayed SWL groups. SWL were carried out after pain relief in the delayed group. Maximum of three SWL sessions were applied to the patients with stones of 5 mm or bigger in diameter, leaving at least 3 days interval in-between. Stone-free rate after first session was similar in two groups. When CIRF was also considered as success, the success rate of SWL in the immediate SWL group was higher after first session (p = 0.02). Immediate SWL had a greater success rate in upper ureteric stones (p = 0.019). Overall average time required for elimination of stones was shorter in immediate SWL group than delayed SWL group (p = 0.033). The success rate after first SWL session (including CIRF) was 59 % for patients with chronic pain in the delayed group and 100 % for patients with acute pain in the immediate group. According to the hydronephrosis grade, success rates were 71 and 44.4 % for patients with grade 1 or no hydronephrosis in the immediate SWL group, and for patients with grade 2 or larger hydronephrosis in the delayed SWL group, respectively, after first SWL session. Immediate SWL insures stone-free status in a shorter time in cases with renal colicky pain and ureteral stones, particularly upper ureteral stones.

Predictive factors of the outcome of extracorporeal shockwave lithotripsy for ureteral stones

Purpose

Extracorporeal Shock Wave Lithotripsy (ESWL) has shown successful outcomes for ureteral stones. We investigated predictive factors for failure of ESWL for treating ureteral stones.

Materials and Methods

A total of 153 patients who underwent ESWL between July 2006 and July 2009 for ureteral stones diagnosed by non-enhanced spiral computed tomography were divided into two groups: (group A, stone size ≤10 mm; and group B, stone size >10 mm). The failure was defined as remnant stones >4 mm. We assessed age, sex, body mass index, stone size, laterality, location, skin-to-stone distance (SSD), Hounsfield unit, and the presence of secondary signs (hydronephrosis, renal enlargement, perinephric fat stranding, and tissue rim sign). We analyzed predictive factors by using logistic regression in each group.

Results

The success rates were 90.2% and 68.6% in group A and B, respectively. In the univariate analysis of each group, stone size, SSD, and all secondary signs showed statistically significant differences in terms of the outcome of ESWL (p<0.05). In the multivariate logistic regression, stone size (odds ratio [OR], 50.005; 95% confidence interval [CI], 6.207 to 402.852) was an independent predictive factor in group A. The presence of perinephric fat standing (OR, 77.634; 95% CI, 1.349 to 446.558) and stone size (OR, 19.718; 95% CI, 1.600 to 243.005) were independent predictive factors in group B.

Conclusions

Stone size is an independent predictive factor influencing failure of ESWL for treating ureteral stones. In larger ureteral stones (>10 mm), the presence of perinephric fat stranding is also an independent predictive factor.

Application of skin electrical conductance of acupuncture meridians for ureteral calculus: a case report

Renal colic is a common condition seen in the emergency department (ED). Our recent study showed that measures of electrical conductance may be used as supplementary diagnostic methods for patients with acute renal colic. Here, we describe the case of a 30-year-old male subject with a left ureteral calculus who presented with frequency and normal-looking urine. He had already visited the outpatient department, but in vain. Normal urinalysis and nonobstructive urogram were reported at that time. Two days later, he was admitted to the ED because of abdominal pain in the left lower quadrant. The urinalysis did not detect red blood cells. Ultrasonography did not indicate hydronephrosis. The meridian electrical conductance and index of sympathovagal balance were found to be abnormal. High level of electrical conductance on the left bladder meridian was found. An unenhanced helical computed tomography was scheduled to reveal a left ureterovesical stone. Ureteroscopic intervention was later uneventfully performed, and the patient's pain was relieved. The follow-up measurements showed that the meridian parameters had returned to normal one month after treatment. This case suggests that bladder meridian electrical conductance might be used as a supplemental method for ureteral calculus diagnosis.

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.

ESWL and Triple Fire Lithotripter

The ideal lithotripter which all companies hope to achieve in the near future, should be characterized by high efficacy, low impact on the patient's sensitivity to pain and least detrimental action on the surrounding tissues. Yet, even the most modern technology seems to be still very far from achieving these goals. For around 1 year our Department has been using the last generation lithotripter Piezolith 3000® (variable triple-focus). Compared to its predecessor, this machine has some changes such as: a) triple focus module that allows to adjust the focal distance to the size of the calculation, b) greater focal depth ranging from 15 cm in Piezolith 3000® fixed focus to 16.5 cm in the new lithotripter, allowing for an easier and more effective treatment of obese patients, c) increase in power by opening the SW variable focal length (F1: 0.20–3.26 mJ/mm2, F2: 0.08–1.64 mJ/mm2, F3: 0.030–0.41 mJ/mm2). The objective of our work is to assess whether the technical characteristics of the new Piezolith 3000® determine a real improvement in management of urinary calculi.

Methods

265 patients undergoing ESWL with variable triple-focus lithotripter from January 2008 to January 2009 (Group A) were compared to 265 patients treated with an equal lithotripter Piezolith 3000® fixed focus (Group B). The two groups were homogeneous as for the following variables: age, size and location of the calculi, which are distributed as follows: superior calyx (6), medium (20), inferior (32), renal pelvis (36), pyeloureteral junction (12), lumbar ureter (50), iliac (12), pelvis (6), iuxtavesical (70), bladder (7), multiple sites (14). The ESWL was performed in both groups with ultrasound exclusive point.

Results

In Group A the time of fragmentation is lower compared to Group B (p<0.01), with fewer days required for fragment expulsion and lower number of re-treatments (p<0.05). The latter result is probably due to increased average energy applied (2.35 mJ/mm2). However, the increase of this energy results in parallel increased perception of pain during ESWL.

Conclusions

Piezolith 3000® represents a real improvement in the effectiveness of fragmentation but there is, compared to the previous model, a significant reduction in the time of expulsion. This suggests that this variable is affected by other factors.

Cost-Effectiveness of Medical Expulsive Therapy Using Alpha-Blockers for the Treatment of Distal Ureteral Stones

OBJECTIVE

Medical expulsive therapy (MET) has recently emerged as an efficacious and safe option for the initial management of ureteral stones. The objective of this study was to assess the cost-effectiveness of MET compared with conservative therapy for the treatment of ureteral stones using international cost data from the United States and four European countries.

MATERIAL AND METHODS

A decision analysis model was built with the use of TreeAge Pro 2004 software with linear success rate assumptions. The likelihood of spontaneous passage of ureteral stones according to their size and location was estimated with the use of data derived from a published meta-analysis. The estimated cost of ureteroscopy (URS) in the United States ($4973) was based on the mean cost of 121 consecutive cases performed at a large metropolitan hospital. URS costs for other countries were obtained from a published international survey. The cost of tamsulosin ($2.08 per day), currently the most commonly used medical expulsive agent, was estimated as a mean of the costs obtained from two national pharmacy chains. MET and conservative therapies were compared with the use of one-way and two-way sensitivity analyses.

RESULTS

In the United States, MET using tamsulosin resulted in a $1132 cost advantage over observation. MET maintained its cost advantage even in countries where the cost of URS is much lower than in the United States. Two-way sensitivity analysis showed that MET remained cost-effective even with very low rates of spontaneous passage, minimal benefit of MET, or low cost of URS.

CONCLUSION

MET is a cost-effective strategy for the management of distal ureteral stones--even those with a low rate of spontaneous passage--providing another incentive for initial "facilitated observation" before embarking on surgical intervention.

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.

Rapid Extracorporeal Shock Wave Lithotripsy for Proximal Ureteral Calculi in Colic versus Noncolic Patients

OBJECTIVES

In delayed extracorporeal shock wave lithotripsy (ESWL) treatment, increasing stone impaction is associated with delayed stone clearance. Whether colic patients treated by rapid ESWL have the same time to stone clearance as noncolic patients, which supports the thesis that stones in both groups are nonimpacted, has not been investigated yet, and was the objective of this study.

METHODS

A total of 82 patients were prospectively enrolled and treated with piezoelectric ESWL for a solitary proximal ureteral stone. Of these, 56 patients experienced at least one colic episode compared with 26 noncolic patients. Hydronephrosis has been assessed with the use of ultrasound and intravenous urography (IVU). Time to stone clearance after the first ESWL and stone-free rates after a follow-up period of 3 mo were recorded.

RESULTS

In colic and noncolic patients, mean stone size was 7.8mm (p=0.7). Ultrasound-detected hydronephrosis was present in 88% versus 39% (p<0.0001), whereas IVU-detected hydronephrosis was present in 60% versus 7.7% (p=0.0001). Mean number of impulses applied was 8000+/-4000 versus 6700+/-3400 (p=0.1). Mean time to stone clearance was 9.5+/-12.1 d versus 4.6+/-3.8 d (p=0.1). Colic and noncolic patients were considered as treatment success in 83% and 81% after 3 mo of follow-up (p=0.9).

CONCLUSIONS

Treatment outcome and time to stone clearance after rapid ESWL in colic patients compared with noncolic patients is comparable and independent of concomitant hydronephrosis. This finding suggests an absence of significant impaction in proximal ureteral stones treated within 24h after a first colic episode, enforcing the concept of performing rapid ESWL in patients harbouring proximal ureteral stones.

Comparative study of extracorporeal shock wave lithotripsy outcomes for proximal and distal ureteric stones

OBJECTIVE

To assess the efficacy of extracorporeal shock wave lithotripsy (ESWL) monotherapy for isolated proximal ureteral calculi and compare it to that for isolated distal calculi.

PATIENT AND METHODS

We treated 68 patients with isolated ureteral stones using MPL 9000. Stones were located in the proximal and distal ureters in 44 and 24 patients, respectively. Patients were stratified according to stone burden and degree of obstruction. Data of all patients were prospectively collected for stone burden, stone localization, number of sessions, number of shock waves, stone-free rates (SFRs), complications, re-treatment rates and auxiliary procedures. Outcomes regarding ureteral localization were compared.

RESULTS

The overall SFR was 85.3% with a 41.2% re-treatment and 17.6% auxiliary procedure rate. The mean number of shock waves applied for each stone was not different among the two ureteral locations. The SFRs were 86.3% and 79.1% for proximal and distal ureteral stones, respectively (P=0.17). For the group with stones <100 mm(2), the SFR was 85.4% and 89.5% for the proximal and distal ureter, respectively. Although the degree of obstruction did not affect SFR of the entire group (P=0.12) and the proximal ureter group (P=0.96), it adversely affected SFR in the distal ureter (P=0.017).

CONCLUSIONS

ESWL outcomes for the ureteral calculi support the use of lithotripsy particularly for stones <100 mm(2). Treatment efficacy was not significantly different among stones localized in proximal and distal ureters. Degree of obstruction did not affect the ESWL outcomes in the proximal ureter, but it adversely affected SFR in the distal ureter.

Limitations of extracorporeal shock wave lithotripsy

PURPOSE OF REVIEW

Extracorporeal shock wave lithotripsy (ESWL) is the preferred modality for the treatment of renal and upper ureteric calculi. The present review focuses on the limitations of ESWL, where recent developments have tried to identify patients who are unlikely to succeed with ESWL and where improvements in shock wave delivery may increase successful stone fragmentation.

RECENT FINDINGS

Evaluation of patients prior to ESWL is especially important, and the use of imaging in the decision process, with the use of computed tomography attenuation values and skin-to-stone distance, can help improve our ability to identify suitable patients for shock wave treatment. Continued research into the methods of shock wave delivery techniques and lithotripter designs will help achieve better stone fragmentation rates with reduced side effects.

SUMMARY

The importance of traditional factors in predicting ESWL success, such as stone size, location, composition and renal anatomy, are well known. More recently, authors have created nomograms to predict stone-free outcome after ESWL. Others have used the information obtained from computed tomography to predict stone comminution. In addition, modifications in shock wave delivery by altering shock rate and voltage have been researched in an effort to improve shock wave efficacy.

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.

ESWL Prediction of Outcome and Failure Prevention

Based on our own experiences and a review of the recent literature, this article evaluates recent developments in predicting outcomes and failures of shockwave lithotripsy when treating patients with urinary tract stones. After a detailed MEDLINE research, the authors identified several variables that influence and predict extracorporeal shockwave lithotripsy (ESWL) success. These variables may be categorized as stone variables, patient variables and operator variables. Only multivariate analysis on a large number of homogenous patients may offer an objective evaluation of the factors conditioning ESWL outcome.

Rapid Extracorporeal Shock Wave Lithotripsy Treatment after a First Colic Episode Correlates with Accelerated Ureteral Stone Clearance

OBJECTIVES

To investigate the relationship between delay in extracorporeal shock wave lithotripsy (ESWL) after a first colic and subsequent time to complete stone clearance.

METHODS

This prospective, non-randomized study included 94 patients treated with ESWL for unilateral solitary proximal ureteral stones after at least one episode of colic pain. Time between the first onset of colic pain and ESWL and stone clearance was recorded. The pretherapeutic degree of hydronephrosis has been assessed using ultrasound.

RESULTS

Mean stone size was 7.9 +/- 2.3 mm and mean time before ESWL after a first colic was 93.4 +/- 143.5 h. At 3 months, 3 patients were lost to follow-up. In 76.9% of patients stones were completely cleared and a further 3.3% harbored residual fragments < or =3 mm. Delay in treatment after a first colic correlated with subsequent time to stone clearance (p < 0.0001). Mean time to stone clearance in patients treated within 24h was 6.4 +/- 6.3 days compared with 16.0 +/- 17.8 days for those treated later (p = 0.008). Maximum stone diameter correlated with time to stone clearance (p = 0.031), but the degree of hydronephrosis did not.

CONCLUSIONS

Rapid ESWL after a first onset of colic pain resulted in accelerated stone clearance independent of the degree of hydronephrosis but had no impact on the need for auxiliary procedures.