Management of kidney stones

Do the residual fragments after shock wave lithotripsy affect the quality of life?

OBJECTIVE

To evaluate the possible effects of residual fragments on the health-related quality of life in patients undergoing extracorporeal shockwave lithotripsy for renal stones.

PATIENTS AND METHODS

Seventy-one patients with residual fragments were divided into 2 further groups; group 1 (n = 42; fragment size, ≤ 4 mm) and group 2 (n = 29; fragment size, >4 mm). During 3-month follow-up, spontaneous passage rates; number of emergency department visits, amount of the analgesic required, additional procedures, and the changes in the quality of life were evaluated. Quality of life was evaluated using the Short Form 36 survey. Statistical analyses included independent sample t tests.

RESULTS

Of the 42 cases with fragments ≤ 4 mm, although 92.8% patients passed the fragments spontaneously, fragments resided until 3 months in 4.8% patients. Again, after 2 sessions of extracorporeal shockwave lithotripsy, of the 29 cases with fragments >4 mm, 55% were stone free, whereas 14% still had residual fragments. Mean number of emergency department visit was found to be 0.07 and 0.5 in both groups, respectively. Mean analgesic need was 138.75 mg in group 1 and 375 mg in group 2. Although significantly lower scores were noted only for one parameter during 1-month evaluation in cases with larger fragments, they were present in all 8 parameters during 3-month evaluation.

CONCLUSION

Larger residual fragments could significantly affect the quality of life. Emergency department visits and colic attacks are the causes of discomfort. Effective stone disintegration by an experienced urologist should be aimed to limit the negative effects of residual fragments on the quality of life.

A novel minimally invasive percutaneous nephrolithotomy technique: safety and efficacy report

OBJECTIVE

The aim of this study was to evaluate the outcome and determine the complications of ultrasound-guided 16 F tract percutaneous nephrolithotomy (PCNL) by review of over 1000 cases in a Chinese hospital.

MATERIAL AND METHODS

A total of 1368 patients underwent 16 F tract PCNL in the hospital between March 2007 and July 2013. Surgery was performed under general anesthesia in all cases. Central venous puncture was chosen as a puncture device. Complications, residual stones, stone clearance and the need for auxiliary treatments were evaluated. Management experience was evaluated with respect to the complications.

RESULTS

Complications occurred in 275 out of 1368 patients (20.1%). There were 102 Clavien grade 1 (7.4%), 121 grade 2 (8.8%) and 48 grade 3 (3.5%) complications, but no grade 4 or 5 complications. Access to the kidney was established in 99.7% of cases and 82.0% of cases had complete stone clearance without undergoing further PCNL. Auxiliary treatments included shockwave lithotripsy in 135 patients, second-phase PCNL in 49 patients and ureteroscopy in 63 patients. Three cases of rare complications occurred, including a double-J stent translocated to the chest, and intraoperative acute pulmonary edema and heart failure. Severe intraoperative or postoperative complications should be managed immediately.

CONCLUSION

An ultrasound-guided mini-tract PCNL is safe and convenient, even for patients with complicated stones.

Renal stones in pregnancy

Diagnosis and treatment of renal stones during pregnancy is a complex problem. Risks to the fetus from ionising radiation and interventional procedures need to be balanced with optimising clinical care for the mother. Management of such patients requires a clear understanding of available options, with a multidisciplinary team approach. In this review, we discuss the role of different diagnostic tests including ultrasound, magnetic resonance urography, and computerized tomography. We also provide an update on recent developments in the treatment of renal stones during pregnancy. Expectant management remains first-line treatment. Where definitive treatment of the stone is required, new evidence suggests that ureteroscopic stone removal may be equally safe, and possibly better than traditional temporising procedures.

Results of retrograde intrarenal surgery in the treatment of renal stones greater than 2 cm

OBJECTIVE

To analyze the results of retrograde intrarenal surgery (RIRS) in patients with ≥2 cm stones treated in our center.

MATERIAL AND METHODS

A retrospective review of 106 patients with renal calculi underwent RIRS ≥2 cm (period January 2009-December 2011). The procedures were performed under general anesthesia as a source of fragmentation using the holmium laser (30 W Litho Quantasystem) and flexible ureteroscopes (X2 Flex Storz, Olympus P5) through ureteral access sheaths. It discusses demographic variables (age, medical history, antiplatelet or anticoagulant treatment, treatment of urolithiasis, BMI, ASA), treated stones variables (size, number, Hounsfield units, biochemical composition) and intra-and postoperative variables (operative time, number of pulses, hospital stay, complications) with the completion of a descriptive analysis of the same. To define our results we consider success to the complete absence of fragments or residual <5 mm posterior imaging tests.

RESULTS

The mean stone size was 2.46 cm treated, being the only stone in 87.7% of cases. The most frequent location was the renal pelvis stones (44%) followed by the lower calyx (39%). The postoperative complication rate was 6.7%, with all of little relevance. The success rate with a single procedure was 79.4% to 94.1% with retreatment.

CONCLUSION

RIRS is a valid alternative for the treatment of kidney stones ≥2 cm for its high success rate and few complications if performed in specialized centers.

Percutaneous nephrolithotomy increases the risk of diabetes: a 5-year follow-up study

OBJECTIVE

To examine the risk of diabetes mellitus within a 5-year period among patients with nephrolithiasis undergoing percutaneous nephrolithotomy .

METHODS

A total of 304 patients who underwent percutaneous nephrolithotomy were included in the study cohort. A total of 3040 patients with nephrolithiasis who did not undergo percutaneous nephrolithotomy were used as a comparison cohort. All participants included in the present study were individually tracked for a 5-year period in order to identify those who developed diabetes mellitus during this timeframe.

RESULTS

The incidence rate of diabetes mellitus was 3.03 per 100 person-years in participants who underwent percutaneous nephrolithotomy and 1.65 per 100 person-years in participants who did not undergo percutaneous nephrolithotomy. After adjusting for the participants' monthly income, geographic location, urbanization level, hypertension, hyperlipidemia and alcohol abuse/alcohol dependence syndrome, the hazard ratio of receiving a first diagnosis of diabetes mellitus during the 5-year follow-up period was 1.96 (95% confidence interval 1.40-2.77) for participants who underwent percutaneous nephrolithotomy. Furthermore, compared with extracorporeal shock wave lithotripsy or endoscopic intervention, participants who underwent percutaneous nephrolithotomy had a significantly increased hazard of developing diabetes mellitus (adjusted hazard ratio 1.79 for a percutaneous nephrolithotomy vs extracorporeal shockwave lithotripsy, and adjusted hazard ratio 1.71 for a percutaneous nephrolithotomy vs an endoscopic intervention).

CONCLUSIONS

The present results suggest an association between patients with nephrolithiasis who undergo a percutaneous nephrolithotomy and a subsequent diabetes mellitus diagnosis.

Retrograde intrarenal surgery vs extracorporeal shock wave lithotripsy for intermediate size inferior pole calculi: a prospective assessment of objective and subjective outcomes

OBJECTIVE

To assess objective and subjective outcomes of retrograde intrarenal surgery (RIRS) and extracorporeal shock wave lithotripsy (SWL) for the treatment of intermediate size (1-2 cm) inferior calyceal (IC) stones in a prospective randomized fashion.

METHODS

Between March 2011 and January 2013, 70 symptomatic adults who had isolated IC stone between 10 and 20 mm underwent RIRS or SWL by computer-generated pseudorandom assignment (1:1). Success rate, mean procedure time, hospital stay, pain score on day 1 and 2 using visual analog scale, analgesic requirement after discharge, complications, retreatment rate, auxiliary procedure, and patient-reported outcomes (using self-made nonvalidated questionnaire) were compared.

RESULTS

Baseline parameters and mean stone size (SWL 16.45 ± 2.28 mm, RIRS 15.05 ± 3.56 mm; P = .0542) were comparable. Success rate was significantly higher after a single session of RIRS compared with 3 sessions of SWL (85% vs 54%; P = .008). Retreatment rate (65% vs 5.7%; P = .0001) and auxiliary procedure (45% vs 8%; P = .0009) were significantly higher in SWL. Pain score on postoperative day 1 and 2 was significantly higher in RIRS, but patients with SWL required significantly more analgesics afterward. Most of the complications were of Clavien grade I and/or II in both groups. Average time to return to normal activity and voiding symptoms were significantly higher in RIRS. Overall satisfaction score (2.17 ± 1.24 vs 2.82 ± 1.17; P = .026) was significantly higher in RIRS than SWL.

CONCLUSION

For the treatment of intermediate size IC calculi, RIRS is superior to SWL in terms of objective and subjective outcomes.

The success of extracorporeal shock-wave lithotripsy based on the stone-attenuation value from non-contrast computed tomography

Objective

To determine the utility of the urinary stone-attenuation value (SAV, in Hounsfield units, HU) from non-contrast computed tomography (NCCT) for predicting the success of extracorporeal shock-wave lithotripsy (ESWL).

Patients and methods

The study included 305 patients with renal calculi of ⩽30 mm and upper ureteric calculi of ⩽20 mm. The SAV was measured using NCCT. Numerical variables were compared using a one-way analysis of variance with posthoc multiple two-group comparisons. Univariate and multivariate regression analysis models were used to test the preferential effect of the independent variable(s) on the success of ESWL.

Results

Patients were grouped according to the SAV as group 1 (⩽500 HU, 81 patients), group 2 (501–1000 HU, 141 patients) and group 3 (>1000 HU, 83 patients). ESWL was successful in 253 patients (83%). The rate of stone clearance was 100% in group 1, 95.7% (135/141) in group 2 and 44.6% (37/83) in group 3 (P = 0.001).

Conclusions

The SAV value is an independent predictor of the success of ESWL and a useful tool for planning stone treatment. Patients with a SAV ⩾956 HU are not ideal candidates for ESWL. The inclusion criteria for ESWL of stones with a SAV <500 HU can be expanded with regard to stone size, site, age, renal function and coagulation profile. In patients with a SAV of 500–1000 HU, factors like a body mass index of >30 kg/m² and a lower calyceal location make them less ideal for ESWL.

Managing caliceal stones

The natural course of untreated asymptomatic caliceal calculi has not been clearly defined, especially in terms of disease progression, and the indications for and outcomes of surgical intervention are not precise. Caliceal stones may remain asymptomatic but, in case of migration, ureteral calculi can cause acute ureteric colic with severe complications. The decision for an active treatment of caliceal calculi is based on stone composition, stone size and symptoms. Extracorporal shock-wave lithotripsy (ESWL) has a low complication rate and is recommended by the current guidelines of the European Association of Urology as a first-line therapy for the treatment of caliceal stones <2 cm in diameter. However, immediate stone removal is not achieved with ESWL. The primary stone-free rates (SFR) after ESWL depend on stone site and composition and, especially for lower pole calculi, the SFR differ widely from other caliceal stones. Minimally-invasive procedures including percutaneous nephrolithotomy and ureteroscopy are alternatives for the treatment of caliceal stones, associated with low morbidity and high primary SFR when performed in centers of excellence.

Cumulative sum analysis for experiences of a single-session retrograde intrarenal stone surgery and analysis of predictors for stone-free status

INTRODUCTION

This study investigated the learning curve of a single-session retrograde intrarenal surgery (RIRS) in patients with mid-sized stones. Competence and trainee proficiency for RIRS was assessed using cumulative sum analysis (CUSUM).

MATERIALS AND METHODS

The study design and the use of patients' information stored in the hospital database were approved by the Institutional Review Board of our institution. A retrospective review was performed for 100 patients who underwent a single-session RIRS. Patients were included if the main stone had a maximal diameter between 10 and 30 mm. The presence of a residual stone was checked on postoperative day 1 and at one-month follow-up visit. Fragmentation efficacy was calculated "removed stone volume (mm(3)) divided by operative time (min)". CUSUM analysis was used for monitoring change in fragmentation efficacy, and we tested whether or not acceptable surgical outcomes were achieved.

RESULTS

The mean age was 54.7±14.8 years. Serum creatinine level did not change significantly. Estimated GFR and hemoglobin were within normal limits postoperatively. The CUSUM curve tended to be flat until the 25th case and showed a rising pattern but declined again until the 56th case. After that point, the fragmentation efficacy reached a plateau. The acceptable level of fragmentation efficacy was 25 ml/min. Multivariate logistic regression analyses showed that stone-free rate was significantly lower for cases with multiple stones than those with a single stone (OR = 0.147, CI 0.032 - 0.674, P value  = 0.005) and for cases with higher number of sites (OR = 0.676, CI 0.517 - 0.882, P value  = 0.004).

CONCLUSIONS

The statistical analysis of RIRS learning experience revealed that 56 cases were required for reaching a plateau in the learning curve. The number of stones and the number of sites were significant predictors for stone-free status.

Material decomposition images generated from spectral CT: detectability of urinary calculi and influencing factors

RATIONALE AND OBJECTIVES

To evaluate the detectability of urinary calculi on material decomposition (MD) images generated from spectral computed tomography (CT) and identify the influencing factors.

MATERIALS AND METHODS

Forty-six patients were examined with true nonenhanced (TNE) CT and spectral CT urography in the excretory phase. The contrast medium was removed from excretory phase images using water-based (WB) and calcium-based (CaB) MD analysis. The sensitivity for detection on WB and CaB images was evaluated using TNE results as the reference standard. The signal-to-noise ratio (SNR) and contrast-to-noise ratio (CNR) on MD images were evaluated. Using logistic regression, the influences of image noise, attenuation, stone size, and patient's body mass index (BMI) were assessed. Threshold values with maximal sensitivity and specificity were calculated by means of receiver operating characteristic analyses.

RESULTS

One hundred thirty-six calculi were detected on TNE images; 98 calculi were identified on WB images (sensitivity, 72.06%) and 101 calculi on CaB images (sensitivity, 74.26%). Sensitivities were 76.92% for the 3-5-mm stones and 84.51% for the 5-mm or larger stones on both WB and CaB images but reduced to 46.15% on WB images and 53.85% on CaB images for small calculi (<3 mm). Compared to WB images, CaB images showed lower image noise, higher SNR but similar CNR. Larger stone sizes (both >2.71 mm on WB and CaB) and greater CT attenuation (>280 Hounsfield units [HU] on WB, >215 HU on CaB) of the urinary stones were significantly associated with higher stone visibility rates on WB and CaB images (P ≤ .003). Image noise and BMI showed no impact on the stone detection.

CONCLUSIONS

MD images generated from spectral CT showed good reliability for the detection of large (>2.71 mm) and hyperattenuating (>280 HU on WB, >215 HU on CaB) urinary calculi.

Radiopacity and hounsfield attenuation of cystine urolithiasis: case series and review of the literature

OBJECTIVES

Given the high recurrence rate of cystine urolithiasis, understanding of the radiographic stone characteristics is important in following cystine stone formers over their lifetime. However, due to their infrequent incidence, in vivo radiographic properties of cystine stones have not been well characterized. The purpose of our study is to characterize the in vivo radiographic properties of cystine urolithiasis.

METHODS

Patients with a cystine stone analysis and noncontrast computed tomography (NCCT) were extracted from our stone clinic database. Stone attenuation in Hounsfield units (HU) was measured for each stone and plain abdominal films (kidney, ureter, and bladder radiograph [KUB]) within 30 days of the NCCT prior to any intervention were reviewed by a blinded radiologist to assess whether urolithiasis could be visualized.

RESULTS

Twenty patients met our study inclusion criteria. When plotted by attenuation, two distinct groups of stone attenuation were noted for cystine stone formers (p<0.001). The largest group (n=16) had an attenuation of <550 HU (424±106 HU), while a distinct second group (n=4) was >850 HU (972±134 HU). Sixteen patients had a KUB, with 88% of the stones being visualized by a blinded radiologist. Stone size and attenuation were not significantly different between visualized and nonvisualized stones via KUB, however, the body mass index was significantly higher in the nonvisualized group (34.4 vs 26.9 kg/m(2), p=0.03).

CONCLUSIONS

Cystine stones were visualized by KUB, which has implications in post-treatment follow-up imaging. Though most cystine stones had an attenuation of <550 HU, a second distinct group of cystine stones were noted to have a high attenuation of >850 HU. HU measurements alone are not sufficient to differentiate cystine stones from other stone compositions.

Does computed tomographic scan affect diagnosis and management of patients with suspected renal colic?

BACKGROUND

Patients with renal colic commonly present to the emergency department (ED) and are usually treated with analgesics, antiemetics and hydration. Computed tomographic (CT) scan is commonly utilized in evaluating patients with suspected renal colic.

OBJECTIVES

We compared diagnosis and treatment plans before and after CT in patients with suspected renal colic with the aim to evaluate how often changes in diagnosis, treatment and disposition are made.

METHODS

In this prospective observational study, we enrolled a convenience sample of clinically Stable ED patients older than 17 with suspected renal colic for whom CT was planned. Exclusion criteria were: chronic kidney disease, urinary tract infection, recent CT and history of previous kidney stone. Pre-CT and Post-CT surveys were completed by the treating provider.

RESULTS

The discharge diagnosis was renal colic in 62 of 93 enrolled patients (67%). Urinalysis showed blood in 52 of these patients (84%). CT confirmed obstructing kidney or bladder stone in 50 patients. There were five cases of alternative diagnoses noted on CT scan. After CT scan, 7 patients had changes in disposition. Sixteen providers felt that CT would not change management. In these cases, CT offered no alternative diagnosis and didn't change disposition.

CONCLUSION

CT scan didn't change management when providers did not expect it would. This indicates that providers who are confident with the diagnosis of renal colic should consider forgoing a CT scan. CT scan did occasionally find important alternative diagnoses and should be utilized when providers are considering other concerning pathology.

Slow vs rapid delivery rate shock wave lithotripsy for pediatric renal urolithiasis: a prospective randomized study

PURPOSE

We compared slow vs fast shock wave frequency rates in disintegration of pediatric renal stones less than 20 mm.

MATERIALS AND METHODS

Our study included 60 children with solitary 10 to 20 mm radiopaque renal stones treated with shock wave lithotripsy. Patients were prospectively randomized into 2 groups, ie those undergoing lithotripsy at a rate of 80 shock waves per minute (group 1, 30 patients) and those undergoing lithotripsy at a rate of 120 shock waves per minute (group 2, 30 patients). The 2 groups were compared in terms of treatment success, anesthesia time, secondary procedures and efficiency quotient.

RESULTS

Stone clearance rate was significantly higher in group 1 (90%) than in group 2 (73.3%, p = 0.025). A total of 18 patients in group 1 (60%) were rendered stone-free after 1 session, 8 required 2 sessions and 1 needed 3 sessions, while shock wave lithotripsy failed in 3 patients. By comparison, 8 patients (26.6%) in group 2 were rendered stone-free after 1 session, 10 (33.3%) required 2 sessions and 4 (13.3%) needed 3 sessions to become stone-free. Mean general anesthesia time was significantly longer in group 1 (p = 0.041). Postoperatively 2 patients in group 1 and 4 in group 2 suffered low grade fever (Clavien grade II). Significantly more secondary procedures (percutaneous nephrolithotomy, repeat shock wave lithotripsy) were required in group 2 (p = 0.005). The predominant stone analysis was calcium oxalate dihydrate in both groups. Efficiency quotient was 0.5869 and 0.3437 for group 1 and group 2, respectively (p = 0.0247).

CONCLUSIONS

In children with renal stones slow delivery rates of shock wave lithotripsy have better results regarding stone clearance than fast delivery rates.

Percutaneous nephrolithotomy guided solely by ultrasonography: a 5-year study of >700 cases

OBJECTIVE

To evaluate the safety and efficacy of percutaneous nephrolithotomy (PCNL) solely guided by ultrasonography (US).

PATIENTS AND METHODS

From May 2007 to July 2012, 705 24-F-tract PCNL procedures were performed (679 patients, of whom 26 had bilateral stones). Calyceal puncture and dilatation were performed under US guidance in all cases. The procedure was evaluated for access success, length of postoperative hospital stay, complications (modified Clavien system), stone clearance and the need for auxiliary treatments.

RESULTS

The mean (sd) operating time was 66 (25) min, with a mean (sd) postoperative hospital stay of 3.98 (1.34) days. The patients experienced a mean (sd) haemoglobin level decrease of 2.24 (2.02) g/day and the overall stone-free rate at 4 weeks after surgery was 92.6% in patients with a single calculus and 82.9% in patients with staghorn or multiple calculi. Auxiliary treatments, including shockwave lithotripsy in 52 patients, re-PCNL in 41 patients and ureteroscopy in 18 patients, were performed 1 week after the primary procedure in 111 (15.7%) cases for residual stones >4 mm in size. The sensitivities of intra-operative US-guidance and flexible nephroscopy for detecting significant residual stones and clinically insignificant residual fragments were 95.3 and 89.1%, respectively. There were 94 grade 1 (13.3%), 17 grade 2 (2.4%), and two grade 3 (0.3%) complications, but there were no grade 4 or 5 complications.

CONCLUSION

Total US-guided PCNL is safe and convenient, and may be performed without any major complications and with the advantage of preventing radiation hazards and damage to adjacent organs.

High carbonate level of apatite in kidney stones implies infection, but is it predictive?

The presence of infectious microorganisms in urinary stones is commonly inferred from stone composition, especially by the presence of struvite in a stone. The presence of highly carbonated apatite has also been proposed as a marker of the presence of bacteria within a stone. We retrospectively studied 368 patients who had undergone percutaneous nephrolithotomy (PCNL), and who also had culture results for both stone and urine. Urine culture showed no association with stone mineral content, but stone culture was more often positive in struvite-containing stones (73 % positive) and majority apatite stones (65 %) than in other stone types (54 %, lower than the others, P < 0.02). In 51 patients in whom the carbonate content of apatite could be measured, carbonate in the apatite was weakly predictive of positive stone culture with an optimal cutoff value of 13.5 % carbonate (sensitivity 0.61, specificity 0.80). In positive cultures of stones (all mineral types combined), organisms that characteristically produce urease were present in 71 % of the cases, with no difference in this proportion among different types of stone. In summary, the type of mineral in the stone was predictive of positive stone culture, but this correlation is imperfect, as over half of non-struvite, non-apatite stones were found to harbor culturable organisms. We conclude that mineral type is an inadequate predictor of whether a stone contains infectious organisms, and that stone culture is more likely to provide information useful to the management of patients undergoing PCNL.

Impact of stone density on outcomes in percutaneous nephrolithotomy (PCNL): an analysis of the clinical research office of the endourological society (CROES) pcnl global study database

OBJECTIVE

This study aimed to explore the relationship between stone density and outcomes of percutaneous nephrolithotomy (PCNL) using the Clinical Research Office of the Endourological Society (CROES) PCNL Global Study database.

MATERIAL AND METHODS

Patients undergoing PCNL treatment were assigned to a low stone density [LSD, ≤ 1000 Hounsfield units (HU)] or high stone density (HSD, > 1000 HU) group based on the radiological density of the primary renal stone. Preoperative characteristics and outcomes were compared in the two groups.

RESULTS

Retreatment for residual stones was more frequent in the LSD group. The overall stone-free rate achieved was higher in the HSD group (79.3% vs 74.8%, p = 0.113). By univariate regression analysis, the probability of achieving a stone-free outcome peaked at approximately 1250 HU. Below or above this density resulted in lower treatment success, particularly at very low HU values. With increasing radiological stone density, operating time decreased to a minimum at approximately 1000 HU, then increased with further increase in stone density. Multivariate non-linear regression analysis showed a similar relationship between the probability of a stone-free outcome and stone density. Higher treatment success rates were found with low stone burden, pelvic stone location and use of pneumatic lithotripsy.

CONCLUSIONS

Very low and high stone densities are associated with lower rates of treatment success and longer operating time in PCNL. Preoperative assessment of stone density may help in the selection of treatment modality for patients with renal stones.

Kidney stone volume estimation from computerized tomography images using a model based method of correcting for the point spread function

PURPOSE

We propose a method to improve the accuracy of volume estimation of kidney stones from computerized tomography images.

MATERIALS AND METHODS

The proposed method consisted of 2 steps. A threshold equal to the average of the computerized tomography number of the object and the background was first applied to determine full width at half maximum volume. Correction factors were then applied, which were precalculated based on a model of a sphere and a 3-dimensional gaussian point spread function. The point spread function was measured in a computerized tomography scanner to represent the response of the scanner to a point-like object. Method accuracy was validated using 6 small cylindrical phantoms with 2 volumes of 21.87 and 99.9 mm(3), and 3 attenuations, respectively, and 76 kidney stones with a volume range of 6.3 to 317.4 mm(3). Volumes estimated by the proposed method were compared with full width at half maximum volumes.

RESULTS

The proposed method was significantly more accurate than full width at half maximum volume (p <0.0001). The magnitude of improvement depended on stone volume with smaller stones benefiting more from the method. For kidney stones 10 to 20 mm(3) in volume the average improvement in accuracy was the greatest at 19.6%.

CONCLUSIONS

The proposed method achieved significantly improved accuracy compared with threshold methods. This may lead to more accurate stone management.

A new scoring system for predicting stone-free rate after retrograde intrarenal surgery: the "resorlu-unsal stone score"

OBJECTIVE

To investigate the prognostic factors associated with the treatment efficacy of retrograde intrarenal surgery (RIRS) and develop a scoring system for predicting the stone-free rate after this surgery.

METHODS

We performed a retrospective analysis of 207 patients who underwent RIRS for renal stones between January 2009 and September 2011. Patient age, gender, body mass index, stone size, stone side, stone location, stone composition, number of stones, lower pole infundibulopelvic angle, using anticoagulant therapy, abnormal skeletal anatomy, and abnormal renal anatomy were investigated as potential preoperative predictive factors.

RESULTS

The present study included 111 (53.6%) men and 96 (46.4%) women. Mean patient age was 32.9 ± 18.8 years (range 1-74) and mean stone size was 16.2 ± 4.1 mm (range 8-40). Overall, 178 of the 207 (86%) patients were stone free after the initial treatment. Univariate analysis showed that stone size (P <.001), stone location (P = .025), stone composition (P = .01), stone number (P = .049), renal malformations (P = .042), and lower pole infundibulopelvic angle (P = .003) had significant influence on the stone-free rate after RIRS. Multivariate analysis excluded stone location from the logistic regression model, whereas other factors maintained their statistically significant effect on success rate, indicating that they were independent predictors.

CONCLUSION

Our study demonstrated that stone size, stone number, stone composition, infundibulopelvic angle, and renal malformations are significant predictors of RIRS outcome. A scoring system based on these factors helps separate patients into outcome groups and facilitates treatment planning.

Flexible ureteroscopy and laser lithotripsy for bilateral multiple intrarenal stones: is this a valuable choice?

OBJECTIVE

To demonstrate the safety and efficacy of flexible ureteroscopy (FURS) and holmium laser lithotripsy as a valuable treatment of bilateral multiple intrarenal stones and stratify the efficacy by stone burdens ≤ 20 and >20 mm.

METHODS

Twenty-five patients with bilateral multiple intrarenal stones were treated with FURS and holmium lithotripsy at a single clinic. The operative time, stone-free rates (SFRs) per renal unit, stone compositions, number of procedures, serum creatinine, and complications were evaluated. The SFRs were evaluated with computed tomography and plain X-rays of the kidneys, ureters, and bladder. Renal ultrasound was performed 30 days after double-J stent removal to identify hydronephrosis and absence of stones. We defined a stone-free status as the absence of fragments in the kidney or fragments of <1 mm.

RESULTS

The total stone number was 128 with a mean stone burden per patient of 24 ± 5 (range 17-37 mm). The overall SFRs per renal unit after 1, 2, and 3 procedures were 70.0%, 92.0%, and 92.0%, respectively. The overall SFRs per renal unit for patients with a preoperative stone burden ≤ 20 and >20 mm were 100% and 85.7%, respectively. No major intraoperative or postoperative complications occurred. There were only 4 minor postoperative complications (16%).

CONCLUSION

Our study results firmly suggest that FURS with holmium laser lithotripsy represents a favorable alternative to external shock wave lithotripsy or percutaneous nephrolithotomy for select patients with bilateral multiple intrarenal stones, which have a satisfactory efficacy and low morbidity.

The relationship between ureteral stone characteristics and secondary signs in renal colic

PURPOSE

To assess correlations between stone size/location and severity of secondary signs for ureteral obstruction.

METHODS

Unenhanced multi-detector computed tomography examinations of 150 patients with acute renal colic were reviewed. Stone size, location in the ureter, kidney size and Hounsfield unit values, perinephric edema, and degree of hydronephrosis were assessed.

RESULTS

Pale kidney sign was detected in 36%. Hydronephrosis was mild in 63% and severe in 21%; severe hydronephrosis was associated with larger stones. Mid-ureter and ureteropelvic junction stones were more likely to cause hydronephrosis. Perinephric edema (56%) was not correlated with stone size/location.

CONCLUSION

Only severe hydronephrosis was significantly associated with larger stone size.

Does the radiologic technologist or the fluoroscopy time affect treatment success with shockwave lithotripsy?

BACKGROUND AND PURPOSE

The minimally invasive nature and effectiveness of shockwave lithotripsy (SWL) has made it one of the primary treatment modalities for urinary tract calculi. Several factors determining the success of SWL treatment have been studied, including stone factors (ie, location, size, and composition) and patient factors (ie, patient habitus and skin-to-stone distance). Our objective was to determine if either the assisting radiologic technologist or the amount of fluoroscopy time used has an impact on SWL success.

PATIENTS AND METHODS

We compared the outcome of 536 SWL treatments across three radiologic technologists. We also evaluated the average amount of fluoroscopy time used in treatment success vs failures in this same cohort. The outcomes measured were stone-free and successful fragmentation rate at 2 weeks and 3 months. Successful fragmentation was defined as being either stone free, having residual sand, or with an asymptomatic fragment ≤ 4 mm on radiography of the kidneys, ureters, and bladder.

RESULTS

The patients treated by the three different radiologic technologists were comparable with respect to body mass index, stone side and location, presence of ureteral stent, and mean stone area (mm(2)). The stone-free and successful fragmentation rates at 2 weeks and 3 months between the three radiologic technologists were not significantly different. When examining fluoroscopy time, we found a significantly greater mean fluoroscopy time was used in treatments with successful fragmentation at 2 weeks (3.16 min vs 2.72 min, P=0.0001) and 3 months (3.12 min vs 2.75 min, P=0.0015) compared with treatment failures.

CONCLUSION

The radiologic technologist did not have a significant impact on SWL treatment outcome at 2 weeks and 3 months. Successful SWL fragmentation at 2 weeks and 3 months, however, was associated with a greater amount of fluoroscopy time, suggesting that using fluoroscopy to ensure accurate targeting during SWL is important for successful fragmentation.

Medical management and prevention of nephrolithiasis

Kidney stones have increased in prevalence and pose a significant burden on the US health care expenditure. This article is intended to help primary care physicians in their office management of stone disease by providing an update on the recent advances made in this field.

Medical management of renal stone

Kidney stone is a common clinical problem faced by clinicians. The prevalence of the disease is increasing worldwide. As the affected population is getting younger and recurrence rates are high, dietary modifications, lifestyle changes, and medical management are essential. Patients with recurrent stone disease need careful evaluation for underlying metabolic disorder. Medical management should be used judiciously in all patients with kidney stones, with appropriate individualization. This chapter focuses on medical management of kidney stones.

A 970 Hounsfield units (HU) threshold of kidney stone density on non-contrast computed tomography (NCCT) improves patients' selection for extracorporeal shockwave lithotripsy (ESWL): evidence from a prospective study

What's known on the subject? and What does the study add? Stone density on non-contrast computed tomography (NCCT) is reported to be a prognosis factor for extracorporeal shockwave lithotripsy (ESWL). In this prospective study, we determined that a 970 HU threshold of stone density is a very specific and sensitive threshold beyond which the likelihood to be rendered stone free is poor. Thus, NCCT evaluation of stone density before ESWL may useful to identify which patients should be offered alternative treatment to optimise their outcome.

OBJECTIVE

• To evaluate the usefulness of measuring urinary calculi attenuation values by non-contrast computed tomography (NCCT) for predicting the outcome of treatment by extracorporeal shockwave lithotripsy (ESWL).

PATIENTS AND METHODS

• We prospectively evaluated 50 patients with urinary calculi of 5-22 mm undergoing ESWL. • All patients had NCCT at 120 kV and 100 mA on a spiral CT scanner. Patient age, sex, body mass index, stone laterality, stone size, stone attenuation values (Hounsfield units [HU]), stone location, and presence of JJ stent were studied as potential predictors. • The outcome was evaluated 4 weeks after the ESWL session by NCCT. • ESWL success was defined as patients being stone-free (SF) or with remaining stone fragments of <4 mm, which were considered as clinically insignificant residual fragments (CIRF).

RESULTS

• Our survey concluded that 26 patients (52%) were SF, 12 (24%) had CIRF and 12 (24%) had residual fragment on NCCT after a one ESWL treatment. • Stones of patients who became SF or had CIRF had a lower density compared with stones in patients with residual fragments [mean (sd) 715 (260) vs 1196 (171) HU, P < 0.001]. • The Youden Index showed that a stone density of 970 HU represented the most sensitive (100%) and specific (81%) point on the receiver-operating characteristic curve. • The stone-free rate for stones of <970 HU was 96% vs 38% for stones of ≥ 970 HU (P < 0.001). A linear relationship between the calculus density and the success rate of ESWL was identified.

CONCLUSION

• The use of NCCT to determine the attenuation values of urinary calculi before ESWL helps to predict treatment outcome, and, consequently, could be helpful in planning alternative treatment for patients with a likelihood of a poor outcome from ESWL.

Development of a method for the quantitative analysis of urinary stones, formed by a mixture of two components, using infrared spectroscopy

OBJECTIVES

The analysis of urinary stones is used for the diagnosis of the etiology of an episode of nephrolithiasis. The technique considered as standard for this purpose is infrared spectroscopy (IR). However, when the urinary stone is formed by a mixture of components, only semi-quantitative information can be achieved using IR. The objective of this work is the development of a quantitative method.

DESIGN AND METHODS

Bands in the IR spectra of several mixtures were studied, in order to design a calibration model useful to determine the quantitative composition of the urinary stones. For mixtures of two components, four mathematical models were proposed. To assess the validity of these models, nine series of mixtures of two components were prepared, using the most frequently compounds found in urinary stones, for analyzing by ATR-FTIR spectroscopy (Attenuated Total Reflection Fourier Transformed Infrared).

RESULTS

Nine series of nine mixtures of two components were prepared for this work. The IR spectrum was recorded for each mixture and the absorbance intensities at selected wave numbers were used to apply the proposed mathematical models. There were good linear correlations between the analytical signals (IR absorbances) and the analytical responses (weight fractions) using the calibration lines. The validity of the method was checked by the comparison between the weight fractions resulted from the calibration lines and the real weight fractions obtained by weighing, presenting good correlation parameters.

CONCLUSIONS

The method developed in this work has been useful for the quantification of compounds which are commonly found in urinary stones. This method allows a total characterization of the urinary stones (qualitative and quantitative) by means of IR spectroscopy.

X-ray diffraction and SEM study of kidney stones in Israel: quantitative analysis, crystallite size determination, and statistical characterization

Urinary calculi have been recognized as one of the most painful medical disorders. Tenable knowledge of the phase composition of the stones is very important to elucidate an underlying etiology of the stone disease. We report here the results of quantitative X-ray diffraction phase analysis performed on 278 kidney stones from the 275 patients treated at the Department of Urology of Hadassah Hebrew University Hospital (Jerusalem, Israel). Quantification of biominerals in multicomponent samples was performed using the normalized reference intensity ratio method. According to the observed phase compositions, all the tested stones were classified into five chemical groups: oxalates (43.2%), phosphates (7.7%), urates (10.3%), cystines (2.9%), and stones composed of a mixture of different minerals (35.9%). A detailed analysis of each allocated chemical group is presented along with the crystallite size calculations for all the observed crystalline phases. The obtained results have been compared with the published data originated from different geographical regions. Morphology and spatial distribution of the phases identified in the kidney stones were studied with scanning electron microscopy (SEM) and energy-dispersive X-ray spectroscopy (EDS). This type of detailed study of phase composition and structural characteristics of the kidney stones was performed in Israel for the first time.

A clinical nomogram to predict the successful shock wave lithotripsy of renal and ureteral calculi

PURPOSE

Although shock wave lithotripsy is dependent on patient and stone related factors, there are few reliable algorithms predictive of its success. In this study we develop a comprehensive nomogram to predict renal and ureteral stone shock wave lithotripsy outcomes.

MATERIALS AND METHODS

During a 5-year period data from patients treated at our lithotripsy unit were reviewed. Analysis was restricted to patients with a solitary renal or ureteral calculus 20 mm or less. Demographic, stone, patient, treatment and 3-month followup data were collected from a prospective database. All patients were treated using the Philips Lithotron® lithotripter.

RESULTS

A total of 422 patients (69.7% male) were analyzed. Mean stone size was 52.3±39.3 mm2 for ureteral stones and 78.9±77.3 mm2 for renal stones, with 95 (43.6%) of the renal stones located in the lower pole. The single treatment success rates for ureteral and renal stones were 60.3% and 70.2%, respectively. On univariate analysis predictors of shock wave lithotripsy success, regardless of stone location, were age (p=0.01), body mass index (p=0.01), stone size (p<0.01), mean stone density (p<0.01) and skin to stone distance (p<0.01). By multivariate logistic regression for renal calculi, age, stone area and skin to stone distance were significant predictors with an AUC of 0.75. For ureteral calculi predictive factors included body mass index and stone size (AUC 0.70).

CONCLUSIONS

Patient and stone parameters have been identified to create a nomogram that predicts shock wave lithotripsy outcomes using the Lithotron lithotripter, which can facilitate optimal treatment based decisions and provide patients with more accurate single treatment success rates for shock wave lithotripsy tailored to patient specific situations.

Percutaneous nephrolithotomy versus extracorporeal shock wave lithotripsy for moderate sized kidney stones

OBJECTIVE

To compare the outcomes of percutaneous nephrolithotomy (PNL) and extracorporeal shock wave lithotripsy (ESWL) for moderate sized (1-2 cm) upper and middle pole renal calculi in regards to stone clearance rate, morbidity, and quality of life.

METHODS

All patients diagnosed with moderate sized upper and middle pole kidney stones by computed tomography (CT) were offered enrollment. They were randomized to receive either ESWL or PNL. The SF-8 quality of life survey was administered preoperatively and at 1 week and 3 months postoperatively. Abdominal radiograph at 1 week and CT scan at 3 months were used to determine stone-free status. All complications and outcomes were recorded.

RESULTS

PNL established a stone-free status of 95% and 85% at 1 week and 3 months, respectively, whereas ESWL established a stone-free status of 17% and 33% at 1 week and 3 months, respectively. Retreatment in ESWL was required in 67% of cases, with 0% retreatment in PNL. Stone location, stone density, and skin-to-stone distance had no impact on stone-free rates at both visits, irrespective of procedure. Patient-reported outcomes, including overall physical and mental health status, favored a better quality of life for patients who had PNL performed.

CONCLUSION

PNL more often establishes stone-free status, has a more similar complication profile, and has similar reported quality of life at 3 months when compared with ESWL for moderate-sized kidney stones. PNL should be offered as a treatment option to all patients with moderate-sized kidney stones in centers with experienced endourologists.

Predictors of clinical outcomes of flexible ureterorenoscopy with holmium laser for renal stone greater than 2 cm

Objective. To evaluate the clinical outcome of flexible ureterorenoscopy (F-URS) with holmium laser in managing renal stone greater than 2 cm. Patients and Methods. Records of 120 patients (123 renal units) with renal stone greater than 2 cm who underwent F-URS with holmium laser iwere evaluated. The mean stone size was 26.3 mm. Patient and stone characteristics, perioperative outcomes and complications were evaluated. The outcome was determined at 4 weeks on plain radiograph (KUB) and Non-contrast CT scan (NCCT). Follow-up visit was up to 6 months to evaluate the clinical outcome and patients symptoms. Results. Stone burden was an independent predictor of FURS results. After first session of treatment, success rate was obtained in 72 renal units (58.5%). On the other hand, significant residual fragment was encountered in 51 renal units (41.5%). This was improved with “staged-therapy” to 87% and 96.7% after second and third session of treatment, respectively. Complications were recorded. They were managed in proper manner accordingly. Conclusion. This is an attractive, safe and effective technique. It is an ideal option for low volume complex stone with average burdens of 2 to 3 cm. Patient should be informed and consented about staged-therapy.

An atypical case of nephrolithiasis with transient remission of symptoms following spinal manipulation

OBJECTIVE

Nephrolithiasis is a common condition with symptoms similar to common mechanical lesions of the lumbar spine and pelvis. The purpose of this report is to outline a case of nephrolithiasis that closely mimicked sacroiliac joint syndrome in subjective report, objective findings, and reduction of symptoms with spinal manipulation.

CLINICAL FEATURES

A 41-year-old obese male patient with mild pain over the left posterior sacroiliac joint, penile paresthesia, and the penile sensation of urinary urgency presented for chiropractic care. Subjective history and objective evaluation suggested sacroiliac joint syndrome.

INTERVENTION AND OUTCOME

A trial of conservative management including spinal manipulation was initiated. Following each treatment, the patient reported temporary relief of all symptoms (4 hours to 2 days). After unsuccessful permanent resolution of symptoms, a urinalysis was performed; and a follow-up computerized tomography scan revealed a large renal calculus obstructing the left ureter. Laser lithotripsy produced obliteration of the stone and complete resolution of symptoms.

CONCLUSIONS

This report outlines the potential overlap of symptoms of visceral and somatic lesions in both presentation and response to care. In this case, a favorable response to spinal manipulation masked the most likely underlying symptom generator. This encounter demonstrates the potential need for further clinical examination in the instance of the unresponsive mechanical lesion. This report also supports the need for future research into spinal manipulation as a possible adjunct for visceral pain management.

The Clinical Research Office of the Endourological Society Percutaneous Nephrolithotomy Global Study: indications, complications, and outcomes in 5803 patients

PURPOSE

To assess the current indications, perioperative morbidity, and stone-free outcomes for percutaneous nephrolithotomy (PCNL) worldwide.

PATIENTS AND METHODS

The Clinical Research Office of the Endourological Society (CROES) collected prospective data for consecutive patients who were treated with PCNL at centers around the world for 1 year. PCNL was performed according to study protocol and local clinical practice guidelines. Stone load and location were recorded, and postoperative complications were graded according to the modified Clavien grading system.

RESULTS

Between November 2007 and December 2009, 5803 patients were treated at 96 centers in Europe, Asia, North America, South America, and Australia. Staghorn calculus was present in 1466 (27.5%) patients, and 940, 956, and 2603 patients had stones in the upper, interpolar, and lower pole calices, respectively. The majority of procedures (85.5%) were uneventful. Major procedure-related complications included significant bleeding (7.8%), renal pelvis perforation (3.4%), and hydrothorax (1.8%). Blood transfusion was administered in 328 (5.7%) patients, and fever >38.5°C occurred in 10.5% of patients. The distribution of scores in modified Clavien grades was: No complication (79.5%), I (11.1%), II (5.3%), IIIa (2.3%), IIIb (1.3%), IVa (0.3%), IVb (0.2%), or V (0.03%). At follow-up. the 30-day stone-free rate was 75.7%, and 84.5% of patients did not need additional treatment.

CONCLUSION

With a high success rate and a low major complication rate, PCNL is an effective and safe technique overall for minimally invasive removal of kidney stones.

Label-free quantitative proteomics reveals differentially regulated proteins influencing urolithiasis

Urinary proteins have been implicated as inhibitors of kidney stone formation (urolithiasis). As a proximal fluid, prefiltered by the kidneys, urine is an attractive biofluid for proteomic analysis in urologic conditions. However, it is necessary to correct for variations in urinary concentration. In our study, individual urine samples were normalized for this variation by using a total protein to creatinine ratio. Pooled urine samples were compared in two independent experiments. Differences between the urinary proteome of stone formers and nonstone-forming controls were characterized and quantified using label-free nano-ultraperformance liquid chromatography high/low collision energy switching analysis. There were 1063 proteins identified, of which 367 were unique to the stone former groups, 408 proteins were unique to the control pools, and 288 proteins were identified for comparative quantification. Proteins found to be unique in stone-formers were involved in carbohydrate metabolism pathways and associated with disease states. Thirty-four proteins demonstrated a consistent >twofold change between stone formers and controls. For ceruloplasmin, one of the proteins was shown to be more than twofold up-regulated in the stone-former pools, this observation was validated in individuals by enzyme-linked immunosorbent assay. Moreover, in vitro crystallization assays demonstrated ceruloplasmin had a dose-dependent increase on calcium oxalate crystal formation. Taken together, these results may suggest a functional role for ceruloplasmin in urolithiasis.

Nutcracker syndrome with urolithiasis

The nutcracker syndrome, caused by compression of the left renal vein between the superior mesenteric artery and the aorta, usually manifests with hematuria, flank pain and proteinuria. We report on a 9-year-old boy who was previously diagnosed with urolithiasis but had significant proteinuria, not explained by this diagnosis. On further investigation by renal Doppler ultrasonography it was found that he had nutcracker syndrome. We would like to emphasize that this syndrome should be considered where there is no obvious cause of proteinuria and hematuria.