Management of calyceal calculi

PCNL vs RIRS in management of stones in calyceal diverticulum: outcomes from a global multicentre match paired study that reflects real world practice

INTRODUCTION

Calyceal diverticulum (CD) is the outpouching of a calyx into the renal parenchyma, connected by an infundibulum. Often associated with recurrent stones, common surgical options include percutaneous nephrolithotomy (PCNL) or retrograde intrarenal surgery (RIRS). We aim to present the real-world practises and outcomes comparing both approaches and the technical choices made.

MATERIALS AND METHODS

Retrospective data including 313 patients from 11 countries were evaluated. One hundred and twenty-seven underwent mini-PCNL and one hundred and eighty-six underwent RIRS. Patient demographics, perioperative parameters, and outcomes were analysed using either T test or Mann-Whitney U test. Categorical data between groups were analysed using the Chi-squared test. Propensity score matching (PSM) was performed matching for baseline characteristics. Subgroup analyses for anomalous/malrotated kidneys and difficult diverticulum access were performed.

RESULTS

After PSM, 123 patients in each arm were included, with similar outcomes for stone-free rate (SFR) and complications (p < 0.001). Hospitalisation was significantly longer in PCNL. Re-intervention rate for residual fragments (any fragment > 4 mm) was similar. RIRS was the preferred re-intervention for both groups. Intraoperative bleeding was significantly higher in PCNL (p < 0.032) but none required transfusion. Two patients with malrotated anatomy in RIRS group required transfusion. Lower pole presented most difficult access for both groups, and SFR was significantly higher in difficult CD accessed by RIRS (p < 0.031). Laser infundibulotomy was preferred for improving diverticular access in both. Fulguration post-intervention was not practised.

CONCLUSION

The crux lies in identification of the opening and safe access. Urologists may consider a step-up personalised approach with a view of endoscopic combined approach where required.

Percutaneous management of caliceal diverticula: a narrative review

PURPOSE OF REVIEW

Caliceal diverticula are relatively uncommon within urologic practice and may be difficult to diagnose and treat. We aim to highlight contemporary studies examining surgical interventions for patients with caliceal diverticula, with a focus on percutaneous intervention, and provide updated practical recommendations for the management of these patients.

RECENT FINDINGS

Studies within the last 3 years examining surgical treatment options for caliceal diverticular calculi are limited. When flexible ureteroscopy (f-URS) and percutaneous nephrolithotomy (PCNL) are examined within the same observational cohorts, PCNL is associated with improved stone-free rates (SFRs), lower requirement for re-intervention, and longer lengths of stay (LOS). Retrograde f-URS for the treatment of caliceal diverticula and diverticular calculi is associated with satisfactory safety and efficacy outcomes. There are no studies in the last 3 years that provide supporting evidence to use shock wave lithotripsy to treat caliceal diverticular calculi.

SUMMARY

Recent studies examining surgical interventions for patients with caliceal diverticula are limited to small observational studies. Heterogeneity in LOS and follow-up protocol limits comparisons between series. Despite technological advancements in f-URS, PCNL appears to be associated with more favorable and definitive outcomes. PCNL continues to be the preferred treatment strategy for patients with symptomatic caliceal diverticula when deemed technically feasible.

The effect of stone and patient characteristics in predicting extra-corporal shock wave lithotripsy success rate: A cross sectional study

Introduction

We determine the effect of patient characteristics (age, sex, and body mass index BMI) and stone characteristics (density, location, and size) by non-contrast computed tomography of the kidneys, ureters, and bladder (CT-KUB) in predicting the success of extracorporeal shock wave lithotripsy (ESWL) in the treatment of kidney and ureteric stones. We present this study to further enrich the knowledge of physicians towards the effect of different patient characteristics upon predicting extra-corporal shock wave lithotripsy success rates.

Methods

We evaluated 155 patients who received ESWL for renal and ureteric stone measuring 3–20 mm (mm), over a 3-month period. The stone size in millimeters, density in Hounsfield units (HU) and its location was determined on pre-treatment CT-KUB. ESWL was successful if post-treatment residual renal stone fragments were ≤3 mm and for ureteric stones should be totally cleared.

Results

The overall success of ESWL treatment was observed in 65.8% of the 155 patients. There was no significant difference seen when the effect of patients age, sex and BMI were studied with ESWL outcome with P values were 0.155, 0.101 and 0.415 respectively. Also, stone location either in the kidney or ureter has no statistically significant effect on ESWL response rate. while stone density and size determined on CT KUB have statistically significant effect on the success rate of ESWL with a P-value of 0.002 and 0.000 respectively.

Conclusions

This study shows that determination of stone density and stone size on CT KUB pre ESWL can help to predict the outcome of ESWL. We propose that stone density <500 HU and stone size < 5 mm are highly likely to result in successful ESWL.

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Previous studies have reported a wide variation of ESWL success rate ranging from 46% to 91%.

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Failure of ESWL results in unnecessary exposure of renal parenchyma to shock waves and complications like renal hematoma.

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Increasing Efforts have been made to determine factors that predict ESWL outcome and improve patients' selection.

Calyceal Diverticula Disease: Diagnosis and Management Options in the Era of Non-Contrast CT Scan

INTRODUCTION

Calyceal diverticula (CD) are traditionally diagnosed by contrast studies. However, non-contrast CT is the standard imaging modality for kidney stones. Therefore, we aimed to determine if the lack of contrast imaging affected outcomes of the management of symptomatic CD with stone.

MATERIALS AND METHODS

This is a retrospective study of patients diagnosed with CD with intracalyceal stone from 2000 to 2017 analyzing demographics, clinical data, and success of different treatment options. The timing of CD diagnosis is correlated to the success of the first treatment.

RESULTS

Forty-eight patients were found. CD was diagnosed prior to intervention in 20 (42%) cases and intraoperatively during flexible ureteroscopy in 17 (35%) and 11 (23%) cases were diagnosed after failed intervention, mainly ESWL. We found that the success rate of treatment was highly affected by the timing and modality of diagnosis. Preoperative diagnosis of CD was associated with 69% success rate of the first intervention. In contrast, there was a 0% success rate of first treatment if CD was not diagnosed with contrast imaging. Furthermore, univariate analysis showed no significant association between sociodemographics and clinical variables and success treatment (p > 0.05).

CONCLUSIONS

The delay in diagnosing CD with stone contributes significantly to the success rate and the number of treatments.

The utility of automated volume analysis of renal stones before and after shockwave lithotripsy treatment

This study aimed to evaluate the additional utility of an automated method of estimating volume for stones being treated with shockwave lithotripsy (SWL) using computed tomography (CT) images compared to manual measurement. Utility was assessed as the ability to accurately measure stone burden before and after SWL treatment, and whether stone volume is a better predictor of SWL outcome than stone diameter. 72 patients treated with SWL for a renal stone with available CT scans before and after treatment were included. Stone axes measurement and volume estimation using ellipsoid equations were compared to volume estimation using software using CT textural analysis (CTTA) of stone images. There was strong correlation (r > 0.8) between manual and CTTA estimated stone volume. CTTA measured stone volume showed the highest predictive value (r² = 0.217) for successful SWL outcome on binary logistic regression analysis. Three cases that were originally classified as ‘stone-free with clinically insignificant residual fragments’ based on manual axis measurements actually had a larger stone volume based on CTTA estimation than the smallest fragments remaining for cases with an outcome of ‘not stone-free’. This study suggests objective measurement of total stone volume could improve estimation of stone burden before and after treatment. Current definitions of stone-free status based on manual measurements of residual fragment sizes are not accurate and may underestimate remaining stone burden after treatment. Future studies reporting on the efficacy of different stone treatments should consider using objective stone volume measurements based on CT image analysis as an outcome measure of stone-free state.

Systematic Review of Caliceal Diverticulum

PURPOSE

We performed a systematic review of the literature regarding the diagnosis and treatment of caliceal diverticulum (CD).

METHODS

The search strategy was conducted according to the Cochrane review guidelines for systematic reviews and Preferred Reporting Items for Systematic reviews and Meta-Analyses checklist.

RESULTS

In total 1189 titles and abstracts were reviewed, of which 101 were selected for article evaluation. Of these 101 articles, 40 were selected for inclusion after full article evaluations. In the extracted article, intravenous urography (IVU), rather than CT urography, was the main imaging tool for diagnosis, although many articles had failed to provide any imaging modality information. The extracted articles included 88, 153, and 487 patients who underwent shock wave lithotripsy (SWL), flexible ureteroscopy/retrograde intrarenal surgery (fURS/RIRS), and percutaneous nephrolithotomy (PCNL), respectively. Stone-free rates were 21.3% (SWL), 61.4% (fURS/RIRS), and 83.0% (PCNL). The complication rates were 8.0% (SWL), 3.3% (fURS/RIRS), and 11.9% (PCNL). There was incomplete and inconsistent reporting of even basic clinical parameters, such as the size and location of the CD, number of stones, outcomes, and complications. There was a striking lack of follow-up data, despite a known high recurrence rate. The literature on laparoscopic management was too sparse to analyze.

CONCLUSIONS

This meta-analysis revealed that there are not enough high-quality studies to evaluate the ideal strategy for the diagnosis and treatment of CDs. This systematic review emphasizes (a) the importance of contrast imaging for CD diagnosis, (b) higher success rates but also higher complication rates in PCNL compared with SWL and FURS, and (c) the need for standardized reporting of outcomes to include complications, number of interventions, symptom resolution, stone clearance, and CD ablation.

Robot-Assisted Laparoscopic Management of Caliceal Diverticular Calculi

Standard treatment modalities of caliceal diverticular calculi range from extracorporal shockwave lithotripsy (SWL) over retrograde intrarenal surgery (RIRS), percutaneous nephrolithotomy (PNL) and laparoscopic stone removal. A 55-year-old woman presented with a history of pyelonephritis based on a caliceal diverticular calculus. Due to the narrow infundibulum and anterior location, a robot-assisted laparoscopic calicotomy with extraction of the calculi and fulguration of the diverticulum was performed, with no specific perioperative problems and good stone-free results. This article shows technical feasibility with minimal morbidity of robot-assisted laparoscopic stone removal and obliteration of a caliceal diverticulum.

The usefulness of stone density and patient stoutness in predicting extracorporeal shock wave efficiency: Results in a North African ethnic group

INTRODUCTION

We determine the role of stone density and skin-to-stone distance (SSD) by non-contrast computed tomography of the kidneys, ureters and bladder (CT-KUB) in predicting the success of extracorporeal shock wave lithotripsy (ESWL).

METHODS

We evaluated 89 patients who received ESWL for renal and upper ureteric calculi measuring 5 to 20 mm, over a 12-month period. The mean stone density in Hounsfield units (HU) and mean SSD in mm was determined on pre-treatment CT-KUB at the CT workstation. ESWL was successful if post-treatment residual stone fragments were ≤3 mm.

RESULTS

ESWL success was observed in 68.5% of patients. Mean stone densities were 505 ± 153 and 803 ± 93 HU in the ESWL successful and failure groups, respectively (p < 0.001, student's t-test). The mean SSD were 10.6 ± 2.0 and 11.2 ± 2.6 cm in ESWL successful and failure groups, respectively; this was not statistically significant.

CONCLUSIONS

This study shows that stone density can help to predict the outcome of ESWL. We propose that stone density <500 HU are highly likely to result in successful ESWL. Conversely, stone densities >800 HU are less likely to be successful.

Percutaneous management of caliceal diverticuli

BACKGROUND AND PURPOSE

Caliceal diverticula are rare congenital abnormalities that can become symptomatic if associated with a calculus or infection. We review percutaneous management of caliceal diverticula.

METHODS

Pathogenesis, clinical evaluation, management options, and recommended follow-up for symptomatic caliceal diverticula are reviewed. We present our single-stage and prepercutaneous nephrolithotomy opacification techniques for the management of caliceal diverticula. This involves complete extraction of all stone particles and ablation of the diverticular cavity without infundibular identification or dilation. Comparison of outcomes between our current ablative technique and our previous dilation technique is evaluated.

RESULTS

Percutaneous management of caliceal diverticula offers the highest symptomatic relief and stone-free rate of available management options. We identified 106 patients with caliceal diverticula who were treated with a percutaneous approach. Review of 85 of these patients demonstrated that most procedures can be performed with a small nephrostomy tube in place for 24 hours and an overnight hospital stay. Minimal complication and stone recurrence rates were observed. Patients treated with caliceal diverticular ablation experienced a shorter hospital stay, fewer complications, and a higher stone-free status than those patients who were treated with dilation of the diverticular infundibulum.

CONCLUSIONS

Percutaneous management of caliceal diverticula using cavity ablation is a minimally invasive technique that offers long-term symptomatic relief with minimal complications.

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

BACKGROUND AND PURPOSE

To assess the results of shockwave lithotripsy (SWL) for renal calculi in upper, middle, and lower calices according to the stone burden.

PATIENT AND METHODS

A series of 52 female and 66 male patients with a mean age of 47.8 years and isolated single caliceal stones who underwent SWL monotherapy were enrolled. Stone burden, stone location, number of sessions/shockwaves, and auxiliary procedures were noted for each patient. Stones were located in the upper, middle, and lower calices of 35, 43, and 40, patients respectively, with mean stone burdens of 81.4 mm2, 75.2 mm2, and 96.3 mm2, respectively. Patients were evaluated with intravenous urography, plain film, or ultrasonography. Success was determined 3 months after the last session. Re-treatment rates were calculated. The effect of anatomic factors on the success of treatment for lower-caliceal stones also was determined.

RESULTS

The mean stone burden, median number of treatment sessions, and mean number of shockwaves were 84.2 mm2, 2, and 4344, respectively. The auxiliary procedure rate was 16.1%, and the re-treatment rate was 71.2%. Failure was noted in 26 patients (22%). The stone-free rates for stones in the upper, middle, and lower calices were 82.8%, 83.4%, and 67.5%, respectively (P = 0.14). The stone-free rates for stones <100 mm2 and 100 to 200 mm2 were 91.2% and 65.5%, respectively (P = 0.001). The efficiency quotient was 49.8, 44.8, and 32.5 for upper-, middle-, and lower-caliceal stones, respectively. Infundibular length (P = 0.006) and infundibular width (P + 0.036) were significant in determining the stone-free rate after treatment of lower-caliceal stones.

CONCLUSIONS

We recommend SWL as the first choice for treatment of stones <200 mm2 in the upper and middle calices. Extracorporeal lithotripsy is one of the options for lower-caliceal stones <200 mm2 but has high re-treatment and auxiliary-procedure rates in these cases.

Preoperative nomograms for predicting stone-free rate after extracorporeal shock wave lithotripsy

PURPOSE

Extracorporeal shock wave lithotripsy is currently accepted as a first line treatment modality for urolithiasis. In obtaining informed consent it is important to inform patients of the stone-free rate with extracorporeal shock wave lithotripsy before surgery. The present study was performed to develop preoperative nomograms for predicting stone-free rates after extracorporeal shock wave lithotripsy.

MATERIALS AND METHODS

A total of 435 patients with 507 urinary stones were treated with extracorporeal shock wave lithotripsy with a Dornier Lithotripter D. Patient age, sex, body mass index, number of stone(s) in each treatment, stone length, side and location were evaluated before extracorporeal shock wave lithotripsy, and treatment efficacies were evaluated at 3 months after each session. The treated stones were divided into 2 groups, those in cases that were stone-free with a single extracorporeal shock wave lithotripsy session and those in all other cases. Multivariate analysis was performed using a logistic regression model. The nomograms were developed by repeating the analysis on 200 bootstrap samples.

RESULTS

Stone length, location and number were identified as significant variables on multivariate analysis, and a logistic regression model was developed using these variables. The nomograms predicting stone-free rate at 3 months after single extracorporeal shock wave lithotripsy treatment were finally developed from 200 bootstrap samples. In these nomograms the stone-free probability was highest for solitary proximal ureteral stones less than 5 mm in size (93.8%) and lowest for multiple caliceal stones greater than 21 mm (10.5%).

CONCLUSIONS

This study demonstrated that stone size, location and number are significant predictors of extracorporeal shock wave lithotripsy outcome. We have developed nomograms for predicting the stone-free rate of extracorporeal shock wave lithotripsy, which is useful for counseling patients with urolithiasis before surgery.

Prognostic factors of success of extracorporeal shock wave lithotripsy (ESWL) in the treatment of renal stones

OBJECTIVES

To evaluate the factors that affect the success rate of extracorporeal shock wave lithotripsy (ESWL) for treatment of renal stones.

PATIENTS AND METHODS

Between January 2000 and December 2003, 427 patients with single or multiple renal stones (< 30 mm, largest diameter) underwent ESWL monotherapy using Storz SL 20 lithotriptor. The results of treatment were evaluated after 3 months of follow-up. Treatment success was defined as complete clearance of the stones or presence of clinically insignificant residual fragments < 4 mm. The success rate was correlated with the characteristics of the patients, conditions of the urinary tract and stone features.

RESULTS

At 3-month follow-up, the overall success rate was 333/427 (78%). Repeat treatment was needed in 226 patients (53.1%). Post-ESWL auxiliary procedures were required in 36 patients (8.4%). Post-ESWL complications were recorded in 16 patients (3.7%). Of the 10 prognostic factors studied, 5 had a significant impact on the success rate, namely: renal morphology, congenital anomalies, stone size, stone site and number of treated stones. Other factors including age, sex, nationality, stone nature (de novo or recurrent) and ureteric stenting had no significant impact on the success rate.

CONCLUSIONS

The success rate of ESWL for the treatment of renal stones could be predicted by stone size, location and number, radiological renal features and congenital renal anomalies.

Surgical management of urolithiasis

Pediatric patients with urolithiasis present unique challenges. Interventional techniques developed for adult patients have been adopted and adapted to facilitate effective and safe treatment in this population. Management must be stratified and individualized, taking into account the many factors described in this article. Long-term follow-up and metabolic evaluation are essential components of the overall treatment strategy. Interventional management will continue to evolve with progressive refinements in instrumentation and techniques.

Metabolic abnormalities associated with calyceal diverticular stones

OBJECTIVE

To review the metabolic analyses of patients with calyceal diverticular stones who had surgical treatment of their calculi and to examine the effect of selective medical therapy on stone recurrence, as recent reports suggest that metabolic abnormalities contribute to stone development.

PATIENTS AND METHODS

In all, 37 patients who had endoscopic treatment of symptomatic calyceal diverticular calculi were retrospectively reviewed. Stone composition and initial 24-h urine collections (24-h urinary volumes, pH, calcium, sodium, uric acid, oxalate, citrate, and the number of abnormalities/patient per collection) were compared with 20 randomly selected stone-forming patients (controls) with no known anatomical abnormalities. Stone formation rates before and after the start of medical therapy were calculated in the patients available for follow-up.

RESULTS

Twelve of the diverticulum patients (five men and seven women) had complete 24-h urine collections, all of whom had at least one metabolic abnormality. Seven patients had hypercalciuria, four had hyperuricosuria and three had mild hyperoxaluria. The most common abnormality was a low urine volume; 11 of the 12 patients had urine volumes of <2000 mL/day (range 350-1950). Ten patients had hypocitraturia in at least one of the two 24-h urine samples; seven had low urinary citrate levels (172-553 mg/day) on both samples. The findings were similar in the control group. The diverticulum patients had 3.1 abnormalities/patient, and the controls had 2.9 abnormalities/patient (P > 0.05). No patients had gouty diathesis and none developed cystine stones. Stone analyses were similar in the two groups; both developed either calcium oxalate or mixed calcium oxalate/calcium phosphate stones. Six patients were followed for a mean of 23.1 months while on selective medical therapy; only one passed any additional stones, thought to be existing calculi, for a remission rate of five of six (83%).

CONCLUSIONS

All patients with symptomatic calyceal diverticular stones who had comprehensive metabolic evaluation had metabolic abnormalities. There were similar abnormalities in the control random stone-formers. The abnormalities were corrected with selective medical therapy, as shown by the high remission rate. We recommend that, for patients with symptomatic calyceal diverticular calculi, a metabolic evaluation should be considered to determine stone forming risk factors.

Percutaneous endoscopic treatment for calyceal diverticular calculi

A 29-year-old man complaining of gross hematuria was referred to our department. DIP demonstrated calyceal diverticular calculi of the left kidney. The patient requested ESWL, but the stone had not been discharged after two treatments. He then underwent PNL with dilation of the narrow neck of the calyceal diverticulum under fluoroscope. The neck of the diverticulum was dilated using an amplats dilator. Three months after the surgery, DIP demonstrated that the diverticulum was completely free from calculi and the size of the diverticulum was reduced. He was doing well 24 months after the operation. Calyceal diverticular calculi should be managed not only with ESWL and PNL but also with dilation of the narrow neck of the calyceal diverticulum.

Laparoscopy-Assisted Transperitoneal Percutaneous Nephrolithotomy for Renal Caliceal Diverticular Calculi

BACKGROUND AND PURPOSE

There are a variety of options for the management of symptomatic calculi in caliceal diverticula, each with utility in particular situations. Herein, we describe a laparoscopy-assisted transperitoneal percutaneous nephrolithotomy (PCNL) technique to address the unusual combination of an anterior caliceal diverticulum together with multiple branched calculi having segments both within and proximal to the diverticulum.

TECHNIQUE

With the patient in a modified lithotomy position, standard transperitoneal laparoscopy was performed utilizing three 10-mm trocars. After mobilization of the colon medially, the cystic diverticulum was opened. An additional 12-mm trocar was placed to allow transperitoneal PCNL within the diverticulum. Rigid nephroscopy, holmium laser lithotripsy, and stone extraction were performed, including laser enlargement of the diverticular neck and removal of the stone burden proximal to the neck. A double-pigtail ureteral stent and Jackson-Pratt drain were placed.

RESULTS

This procedure was successful in the only patient in whom it has been used to date. As far as we know, this is the first report of laparoscopy-assisted transperitoneal PCNL for the management of caliceal diverticular calculi.

CONCLUSION

Laparoscopy-assisted transperitoneal PCNL is a safe and effective alternative for the management of symptomatic stones in anterior cystic caliceal diverticula with a narrow neck and complex branched calculi.

Predictions of outcomes of renal stones after extracorporeal shock wave lithotripsy from stone characteristics determined by unenhanced helical computed tomography: a multivariate analysis

The aim of our study is to analyze the relationships between the characteristics of renal stones determined by unenhanced helical computed tomography (UHCT) and their outcomes after extracorporeal shock wave lithotripsy (ESWL) as well as to predict ESWL outcomes of renal stones by their UHCT characteristics with the use of multivariate analysis. During a 7-month period, 80 adult patients with renal stones underwent ESWL as well as UHCT both before and 3 months after ESWL. Of the 80 patients, 42 patients were classified as ESWL successes and 38 as ESWL failures based on their post-ESWL UHCT findings. For pre-ESWL UHCT, a stone number of more than 2 (P=0.0236), a maximal stone size of greater than 12 mm (P<0.0001), a stone burden of more than 700 mm3 (P<0.0001), a maximal stone density of more than 900 HU (P=0.0008) and nonround/oval stones (P=0.0007) were associated with ESWL failure outcomes. Multivariate analysis demonstrated that a stone burden of more than 700 mm3 (P=0.0003), the presence of nonround/oval stones (P=0.0072) and a maximal stone density of more than 900 HU (P=0.0430) were statistically significant predictors of a failure outcome for ESWL. Thus, the analysis of stone characteristics of renal stones by UHCT is helpful in selecting appropriate patients undergoing ESWL for favorable outcomes and reduces the overall costs of the treatment of renal stones.

Management of Caliceal Diverticula

Although most caliceal diverticula are asymptomatic, they can be associated with pain, and concomitant calculi are common. When treatment is indicated, a variety of surgical options are available, although the management is often a challenge even to the most experienced surgeon. We review the indications, surgical options, and outcomes for the treatment of caliceal diverticula.

Prediction of success rate after extracorporeal shock-wave lithotripsy of renal stones--a multivariate analysis model

OBJECTIVES

To define prognostic factors that affect the success rate after extracorporeal shock-wave lithotripsy (ESWL) of renal calculi and to estimate the probability of stone-free status using a regression analysis model.

MATERIAL AND METHODS

Between February 1992 and February 2002, 2954 patients with single or multiple radiopaque renal stones (<30 mm) underwent ESWL monotherapy. The results of treatment were evaluated after 3 months of follow-up. Treatment success was defined as complete clearance of the stones with no residual fragments. The stone-free rate was correlated with stone features and patient characteristics using the chi2 test. Factors found to be significant using the chi2 test were further analyzed using multivariate regression analysis.

RESULTS

At 3-month follow-up, the overall stone-free rate using ESWL monotherapy was 86.7%. Failure to disintegrate the stones was observed in 7.3% of cases (n = 216) and failure to clear the fragmented stones occurred in 6% (n = 177). Repeat ESWL was needed in 53% of cases. Static steinstrasse occurred in 4.9% of cases (n = 146) and post-ESWL auxiliary procedures were required in 4% (n = 118). Using the chi2 test, patient age (p < 0.001), stone size (p < 0.001), location (p < 0.001), number (p < 0.001) and nature (p = 0.003), radiological renal picture (p < 0.001) and congenital renal anomalies (p < 0.001) had a significant impact on the stone-free rate. Multivariate analysis excluded stone nature from the logistic regression model while other factors maintained their statistically significant effect on success rate, indicating that they were independent predictors. A regression analysis model was designed to estimate the probability of stone-free status after ESWL. The sensitivity of the model was 83%, the specificity 91% and the overall accuracy 87%.

CONCLUSION

Patient age, stone size, location and number, radiological renal features and congenital renal anomalies are prognostic factors determining stone clearance after ESWL of renal calculi. Our regression model can predict the probability of the success of ESWL with an accuracy of 87%.

Is lower pole caliceal anatomy predictive of extracorporeal shock wave lithotripsy success for primary lower pole kidney stones?

PURPOSE

The management of lower pole kidney stones is controversial. We examined whether lower pole caliceal anatomy could predict the success of extracorporeal shock wave lithotripsy of primary lower pole kidney stones 20 mm. or less.

MATERIALS AND METHODS

From December 1997 to June 2001, 246 adults with a single, 20 mm. or less radiopaque lower pole renal stone were treated with the Doli 50 lithotriptor (Dornier Medical Systems, Marietta, Georgia) while under general anesthesia. Of the 246 patients 190 (77%) had excretory urography available for review. Lower pole infundibular length and width, lower pole infundibulopelvic angle and caliceal-pelvic height were measurable on 161 (85%), 129 (68%), 128 (67%) and 163 (86%) excretory urograms, respectively. Extracorporeal shock wave lithotripsy was considered a failure if residual stone fragments remained after 1 month, or an auxiliary procedure or re-treatment was required. RESULTS The overall stone-free rate was 78% (32 of 41) for stones 5 mm. or less, 73% (98 of 135) for stones 6 to 10 mm., 43% (22 of 51) for stones 11 to 15 mm. and 30% (7 of 19) for stones 16 to 20 mm. in maximum linear dimension. The stone-free rates grouped according to stone surface area were 76% (48 of 63 stones) for stone surface area 25 mm.2 or less, 69% (97 of 141) for 26 to 100 mm.2 and 33% (14 of 42) for 101 to 400 mm.2. Caliceal anatomy was not predictive of success even with stones grouped as 10 or less or 11 to 20 mm. Grouping patients with favorable (lower pole infundibulopelvic angle 70 degrees or greater, lower pole infundibular length 30 mm. or less and lower pole infundibular width greater than 5 mm.) versus unfavorable (70 degrees or less, greater than 30 mm. and 5 mm. or less, respectively) anatomy was also not predictive of success.

CONCLUSIONS

On the Doli 50 machine stone size rather than caliceal anatomy is predictive of treatment outcome. Initial treatment failures with this machine should be managed by alternative endoscopic procedures if necessary rather than by repeat shock wave lithotripsy.

Endoscopic management of symptomatic caliceal diverticula: a retrospective comparison of percutaneous nephrolithotripsy and ureteroscopy

BACKGROUND AND PURPOSE

A myriad of minimally invasive options exist for managing symptomatic caliceal diverticula, including shockwave lithotripsy, percutaneous surgery, retrograde ureteroscopy, and laparoscopy. Yet no direct comparisons have been made in the literature of the relative treatment efficacy of ureteroscopy (URS) and percutaneous nephrolithotripsy (PNL). A retrospective review of our patients was performed to determine the most appropriate endoscopic management option for patients with symptomatic caliceal diverticula.

PATIENTS AND METHODS

Between November of 1994 and April 2001, 39 patients presented with symptomatic caliceal diverticula, 37 of which contained calculi. Twenty-two patients (56%) underwent PNL, and 17 patients (44%) were managed by URS. Of the PNL group, 82% required the creation of a neoinfundibulotomy. The stone burden in the PNL group averaged 11.4 x 12.0 mm and that in the URS group 12.7 x 13.0 mm (p > 0.05). Pain, recurrent urinary tract infections, and nausea and vomiting were the presenting complaints in both subgroups of patients, with pain being by far the most common symptom. The average hospital stay was 2.8 days for the PNL group. All the URS procedures were performed on a same-day-surgery basis. Results, including stone-free, symptom-free, and complication rates, were compared for the two groups.

RESULTS

Thirty-five percent of the URS group were symptom free at 6 weeks' follow-up, with an additional 29% reporting an improvement in pain, whereas 86% of the PNL group was completely symptom free at 6 weeks' follow-up. Only 19% of the URS group were stone free on follow-up intravenous urography v 78% of those undergoing PNL (three patients failed to return for follow-up imaging). It was not possible to identify the ostium of the stenotic infundibulum in 4 patients (24%) undergoing URS, and 7 patients (41%) eventually went on to PNL with ultimate success. The PNL was statistically better than URS in producing stone-free results for diverticula located in the upper pole and for stones <11 mm (p < 0.05). No complications occurred in the URS group; however, complications were identified in four patients after PNL. One patient developed clot urinary retention necessitating Foley catheterization and manual bladder irrigation; one patient experienced significant bleeding necessitating early cessation of the procedure. Two patients sustained intrathoracic complications, one a pneumothorax and the other a pneumohemothorax after supra-11(th) rib access. Both were managed successfully with tube thoracostomy.

CONCLUSIONS

Our review clearly suggests an advantage of percutaneous management over ureteroscopy for complex posterior symptomatic caliceal diverticula, although with a slightly increased risk of complications. Therefore, PNL should be considered the primary modality for managing these difficult processes. In cases where the stenotic infundibulum cannot be traversed with a guidewire, creation of a neoinfundibulotomy permitted secure access to the collecting system while providing effective results.

[Extracorporeal shock-wave lithotripsy. An established treatment]

Extracorporeal shock wave lithotripsy (ESWL) is the most required urinary stone therapy in our country and in the rest of the world. In a way it has replaced the alternative treatments (open surgery, percutaneous nephrolithectomy, ureteroscopy). Nevertheless these therapeutic approaches have still its own indications. Although there is no a definitive agreement, it should be desirable a world-wide consensus where each therapy will have a exactly defined land with all potential of each management improved. We review ESWL technical aspects, its literature-based most accepted indications, adverse bioeffects and last, future improvements are considered.

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

BACKGROUND AND PURPOSE

To evaluate the efficacy of potassium citrate treatment in preventing stone recurrences and residual fragments after shockwave lithotripsy (SWL) for lower pole calcium oxalate urolithiasis.

PATIENTS AND METHODS

One hundred ten patients who underwent SWL because of lower caliceal stones and who were stone free or who had residual stone 4 weeks later were enrolled in the study. The average patient age was 41.7 years. All patients had documented simple calcium oxalate lithiasis without urinary tract infection and with normal renal morphology and function. Four weeks after SWL, patients who were stone free (N = 56) and patients who had residual stones (N = 34) were independently randomized into two subgroups that were matched for sex, age, and urinary values of citrate, calcium, and uric acid. One group was given oral potassium citrate 60 mEq per day, and the other group served as controls.

RESULTS

In patients who were stone free after SWL and receiving medical treatment, the stone recurrence rate at 12 months was 0 whereas untreated patients showed a 28.5% stone recurrence rate (P < 0.05). Similarly, in the residual fragment group, the medically treated patients had a significantly greater remission rate than the untreated patients (44.5 v 12.5%; P < 0.05).

CONCLUSION

Potassium citrate therapy significantly alleviated calcium oxalate stone activity after SWL for lower pole stones in patients who were stone free. An important observation was the beneficial effect of medical treatment on stone activity after SWL among patients with residual calculi.

Renal collecting system anatomy: its possible role in the effectiveness of renal stone treatment

The anatomy of the kidney collecting system may play a role in the selection of the best method of kidney stone treatment for a specific patient. Also, an analysis of the collecting-system anatomy would indicate the likely effectiveness of each method of treatment. For stones located in the lower pole, the clearance rate after shockwave lithotripsy has been uniformly low relative to that of calculi elsewhere. Some special anatomical findings suggest that retention of what are considered to be 'passable stone fragments' (4 mm in diameter or less) in the inferior pole might be a consequence not only of the gravity-dependent position of lower calices but also of particular anatomical features of the inferior pole collecting system. The aspects reviewed and discussed are the angle formed between the main lower infundibulum and the renal pelvis (the infundibulopelvic angle), the lower infundibula diameters, the lower infundibulum length and height, and the lower calices spatial distribution. Also, the presence of minor calices perpendicular to the surface of the collecting system and drainage of superior and inferior poles are reviewed and discussed in the context of their importance to the effectiveness of renal stone treatment.

Renal calculi. Percutaneous management

Percutaneous nephrolithotomy has established indications and is performed with high success and minimal morbidity. Patients who have large or hard stones or stones associated with urinary obstruction are candidates for a percutaneous procedure. When the certainty of the final result is important, the patient should have a PNL. In general, the best treatment for SWL failure is not more SWL; such patients usually should have an endoscopic procedure.

Retroperitoneoscopic technique for treating symptomatic caliceal diverticula

Calculous disease in a caliceal diverticulum is a rare entity. The standard treatment currently is endoscopic surgery with marsupialization or fulguration or both with dilatation of the neck of the diverticulum. We present the fifth reported case of retroperitoneoscopic management of a caliceal diverticulum in a patient with a long history of flank pain and suggest that this treatment offers a stone-free rate comparable to that of open surgery with less morbidity than is associated with endoscopic treatments.

Renal calculus disease

We have seen an explosion in technical innovations for the management of urolithiasis. Today, the endourologist possesses an assortment of minimally invasive tools to treat renal stones. Most patients receive fast, safe and effective treatment in the outpatient setting. Despite the many technical advances, however, anatomical malformations and complex stones still provide significant challenges in diagnosis, access to a targeted stone, fragmentation, and clearance of the resulting fragments. This review examines a variety of urinary stone presentations and treatment strategies for cost-effective management.