Fabio Cesar Miranda Torricelli

Percutaneous Nephrolithotomy Versus Retrograde Intrarenal Surgery: A Systematic Review and Meta-analysis

CONTEXT Recent advances in technology have led to the implementation of mini- and micro-percutaneous nephrolithotomy (PCNL) as well as retrograde intrarenal surgery (RIRS) in the management of kidney stones. OBJECTIVE To provide a systematic review and meta-analysis of studies comparing RIRS with PCNL techniques for the treatment of kidney stones. EVIDENCE ACQUISITION A systematic literature review was performed in March 2014 using the PubMed, Scopus, and Web of Science databases to identify relevant studies. Article selection proceeded according to the search strategy based on Preferred Reporting Items for Systematic Reviews and Meta-analysis criteria. A subgroup analysis was performed comparing standard PCNL and minimally invasive percutaneous procedures (MIPPs) including mini-PCNL and micro-PCNL with RIRS, separately. EVIDENCE SYNTHESIS Two randomised and eight nonrandomised studies were analysed. PCNL techniques provided a significantly higher stone-free rate (weighted mean difference [WMD]: 2.19; 95% confidence interval [CI], 1.53-3.13; p<0.00001) but also higher complication rates (odds ratio [OR]: 1.61; 95% CI, 1.11-2.35; p<0.01) and a larger postoperative decrease in haemoglobin levels (WMD: 0.87; 95% CI, 0.51-1.22; p<0.00001). In contrast, RIRS led to a shorter hospital stay (WMD: 1.28; 95% CI, 0.79-1.77; p<0.0001). At subgroup analysis, RIRS provided a significantly higher stone-free rate than MIPPs (WMD: 1.70; 95% CI, 1.07-2.70; p=0.03) but less than standard PCNL (OR: 4.32; 95% CI, 1.99-9.37; p=0.0002). Hospital stay was shorter for RIRS compared with both MIPPs (WMD: 1.11; 95% CI, 0.39-1.83; p=0.003) and standard PCNL (WMD: 1.84 d; 95% CI, 0.64-3.04; p=0.003). CONCLUSIONS PCNL is associated with higher stone-free rates at the expense of higher complication rates, blood loss, and admission times. Standard PCNL offers stone-free rates superior to those of RIRS, whereas RIRS provides higher stone free rates than MIPPs. Given the added morbidity and lower efficacy of MIPPs, RIRS should be considered standard therapy for stones <2 cm until appropriate randomised studies are performed. When flexible instruments are not available, standard PCNL should be considered due to the lower efficacy of MIPPs. PATIENT SUMMARY We searched the literature for studies comparing new minimally invasive techniques for the treatment of kidney stones. The analysis of 10 available studies shows that treatment can be tailored to the patient by balancing the advantages and disadvantages of each technique.

Flexible Ureteroscopy With a Ureteral Access Sheath: When to Stent?

OBJECTIVE To compare intra- and postoperative data of patients who underwent ureterorenoscopy (URS) with an access sheath, with and without postoperative stenting. METHODS We retrospectively identified patients who underwent flexible URS with a ureteral access sheath between January 2102 and January 2013. Two surgeons performed all cases; one who routinely stents after flexible ureteroscopy and a second who selectively stents. Fifty-one patients who were stented and 51 patients not stented after URS were enrolled in this study. Patients were matched by operative time as a surrogate measure of complexity of the procedure. Intra- and postoperative data were compared. We also analyzed if preoperative stenting or sheath diameter had any effect on postoperative pain score for each group. RESULTS Patients in the stented group were older (P <.001), had larger ureteral access sheaths (P <.001), and greater stone burden (P <.001). Despite this, the stented group had lower pain scores (4.5 ± 3.2 vs 8.9 ± 3.2; P = .025) and were less likely to seek medical assistance for pain than the unstented patients (26.3% vs 3.9%; P = .007). Patients who were prestented before ureteroscopy had lower pain scores than those who were not prestented in the group that did not receive a postoperative stent (4.2 ± 3.4 vs 6.6 ± 2.8; P = .047). CONCLUSION Postoperative stenting after flexible URS with a ureteral access sheath seems to decrease postoperative pain. Patients might be selected for no ureteral stent if they were prestented before the procedure, and the URS was uneventful.

Accuracy of ultrasonography for renal stone detection and size determination: is it good enough for management decisions?

To determine the sensitivity and specificity of ultrasonography (US) for detecting renal calculi and to assess the accuracy of US for determining the size of calculi and how this can affect counselling decisions.

Dyslipidemia and Kidney Stone Risk

PURPOSE We studied the impact of dyslipidemia on 24-hour urinalysis and stone composition. MATERIALS AND METHODS We retrospectively identified patients with nephrolithiasis who underwent 24-hour urinalysis and lipid profile evaluation within 3 months. Patients were divided into groups based on total cholesterol, high density lipoprotein, nonhigh density lipoprotein and triglycerides. The groups were compared based on demographic data, diabetes, hypertension and each component of 24-hour urinalysis and stone composition. Multivariate analysis and linear regression were performed to control for potential confounders, including age, gender, body mass index, diabetes and hypertension. RESULTS A total of 2,442 patients with a mean age of 51.1 years were included in study. On multivariate analysis patients with high total cholesterol had significantly higher urinary potassium and calcium, those with low high density lipoprotein or high triglycerides had significantly higher urinary sodium, oxalate and uric acid with lower pH, and those with high nonhigh density lipoprotein had higher urinary sodium and uric acid. Regarding stone composition, high total cholesterol and triglycerides were significantly associated with a higher uric acid stone rate (p = 0.006 and <0.001, respectively). Linear regression showed a significant association of nonhigh density lipoprotein with higher urinary sodium (p = 0.011) and uric acid (p <0.001) as well as triglycerides and higher uric acid (p = 0.017), and lower urinary pH (p = 0.005). CONCLUSIONS There is a link between dyslipidemia and kidney stone risk that is independent of other components of metabolic syndrome such as diabetes and obesity. Specific alterations in the patient lipid profiles may portend unique aberrations in urine physicochemistry and stone risk.

Type-2 Diabetes and Kidney Stones: Impact of Diabetes Medications and Glycemic Control

OBJECTIVE To evaluate the impact of diabetic medications and glycemic control on the urine pH, 24-hour urine stone risk profile, and stone composition. PATIENTS AND METHODS We retrospectively reviewed our database searching for type-2 diabetic patients with kidney stones from July 2002 to January 2013. Patients were divided in 2 groups according to their diabetic medications: insulin vs oral antihyperglycemics. Patients were compared based on their urine collections and stone composition. A linear regression was done to assess which variables could predict a low urine pH. In a subgroup analysis, patients on thiazolidinediones (ie, pioglitazone) were compared with patients on other oral antihyperglycemics. RESULTS We analyzed 1831 type-2 diabetic patients with stone disease; 375 (20.5%) were included in the insulin group and 1456 (79.5%) in the antihyperglycemics group. Linear regression revealed male gender (P = .011) and insulin therapy (P <.001) as protective factors of low urine pH, whereas HbA1c level (P <.001) was inversely related to the urine pH (odds ratio, -0.066; 95% confidence interval, -0.096 to -0.036; P <.001). There were no significant differences in other 24-h urine stone risk parameters or stone composition between the groups. There were also no significant differences in the subgroup analysis. CONCLUSION Urine pH is inversely related to HbA1c level. Insulin therapy is associated with higher urine pH than oral antihyperglycemic agents despite higher HbA1c suggesting that insulin may modify urine pH independent of glycemic control.

Hydrophilic Guidewires: Evaluation and Comparison of Their Properties and Safety

OBJECTIVE To compare physical and mechanical properties of 10 commercially available hydrophilic guidewires. METHODS In vitro testing was performed to evaluate 10 different straight hydrophilic guidewires (5 regular and 5 stiff wires): Glidewire, NiCore, EZ Glider, Hiwire, and Zipwire. The forces required for tip perforation, tip bending, shaft bending, and friction during movement were measured for all 10 wires. The tip contour was measured using high power light microscopy. RESULTS The Glidewire required the greatest force to perforate our model (P = .01). The EZ Glider, Zipwire, and Glidewire had the lowest tip bending forces (P <.001). The Glidewire had the stiffest shaft (P <.001). The EZ Glider and Glidewire required the greatest forces in the friction test (P <.001). Regarding the stiff guidewires, the GlidewireS required the greatest force in the perforation test (P ≤.05). The GlidewireS and EZ GliderS required the lowest tip bending force (P ≤.004). The ZipwireS and NiCoreS had the stiffest shafts (P ≤.01). The GlidewireS required the greatest force in the friction test (P <.001). Measurement of the tip contour showed the Zipwire, HiwireS, and EZ GliderS had the roundest tips. CONCLUSION Each wire has unique properties with advantages and disadvantages. The Glidewires (both stiff and regular) have the lowest potential for perforation, although they are less slippery. The Glidewire and EZ Glider required the least tip force to bend around a point of obstruction.

Semi-rigid ureteroscopic lithotripsy versus laparoscopic ureterolithotomy for large upper ureteral stones: a meta – analysis of randomized controlled trials

ABSTRACT Introduction: To provide a systematic review and meta-analysis of randomized controlled trials (RCT) comparing semi-rigid ureteroscopic lithotripsy (URS) with laparoscopic ureterolithotomy (LU) for the treatment of the large proximal ureteral stone. Materials and methods: A systematic literature review was performed in June 2015 using the PubMed, Scopus, and Web of Science databases to identify relevant studies. Article selection proceeded according to the search strategy based on Preferred Reporting Items for Systematic Reviews and Meta-analysis criteria. Results: Six RCT including 646 patients were analyzed, 325 URS cases (50.3%) and 321 LU cases (49.7%). URS provided a significantly shorter operative time (weighted mean difference [WMD] = −31.26 min; 95%CI −46.88 to −15.64; p<0.0001) and length of hospital stay (WMD = −1.48 days; 95%CI −2.78 to −0.18; p=0.03) than LU. There were no significant differences in terms of overall complications (OR = 0.78; 95%CI 0.21-2.92; p=0.71) and major complications – Clavien ≥3 – (OR = 1.79; 95%CI 0.59-5.42; p=0.30). LU led to a significantly higher initial stone-free rate (OR = 8.65; 95%CI 4.18-17.91; p<0.00001) and final stone-free rate (OR = 6.41; 95%CI 2.24-18.32; p=0.0005) than URS. There was a significantly higher need for auxiliary procedures in URS cases (OR = 6.58; 95%CI 3.42-12.68; p<0.00001). Conclusions: Outcomes with LU for larger proximal ureteral calculi are favorable compared to semi-rigid URS and should be considered as a first-line alternative if flexible ureteroscopy is not available. Utilization of flexible ureteroscopy in conjunction with semi-rigid ureteroscopy may impact these outcomes, and deserves further systematic evaluation.

Corrigendum re: “Percutaneous Nephrolithotomy Versus Retrograde Intrarenal Surgery: A Systematic Review and Meta-analysis” [Eur Urol 2015;67:125–37]

Wewrite to informyou of an error in the analytic presentation of this paper.Wewould like to apologize for this inaccuracy and correct the resultingconclusion. Specifically, the x-axis legend in the forestplotdetailingstone-free rates forminimally invasive percutaneous nephrolithotomy (PCNL) and retrograde intrarenal surgery (RIRS) in Figure 4b was inadvertently reversed. The stone-free rate was actually higher for minimally invasive percutaneous procedures (MIPPs) compared with RIRS (odds ratio: 1.70; 95% confidence interval, 1.07–2.70; p = 0.03). A corrected forest plot is provided (revised Fig. 4b). Basedonthis correction, the conclusionsof thepaper shouldbemodifiedas follows: ‘‘Meta-analysisof availablecomparative studies suggests that overall PCNL provides significantly higher stone-free rates than RIRS, at the expense of higher complication rates, blood loss, and longer length of stay, with no differences in surgical time and secondary procedures. RIRS also provides lower stone-free rates when specifically compared with MIPPs but offers less morbidity. Consequently, both techniques canbeoffered, and advantages anddisadvantages of each one should bediscussedwith the patient to tailor the best treatment.MIPPs canplaya rolewhenever instrumentationor expertise inRIRS is lacking. Strongconsideration shouldbegiven to standard PCNL in this situation due to the inferior efficacy of MIPPs.’’

Hydroureteronephrosis secondary to juxta-uretrovesical junction bladder diverticula.

Bladder diverticulum is rarely associated to hydroureteronephrosis. We present clinical images of an adult patient with a bladder diverticulum near the ureterovesical junction (UVJ) with secondary obstruction. An 84-year-old man presented with left hydroureteronephrosis and a presumed 25-mm left ureteral stone at UVJ on computed tomography. Cystoscopy revealed a stone located in a bladder diverticulum just cephalad and medial to left ureteral orifice; the patient successfully underwent endoscopic laser cystolithotripsy with resolution of his hydronephrosis. Juxta-UVJ bladder diverticula may cause obstruction of the ipsilateral upper urinary tract.

Irreversible Renal Function Impairment Due to Silent Ureteral Stones

OBJECTIVE To evaluate if renal function loss and hydronephrosis due to a silent ureteral stone might be reversed. MATERIALS AND METHODS We prospectively selected patients with silent ureteral stones between January 2006 and January 2014. A silent case was considered if there were no specific or subjective symptoms related to the ureteral stone. Patient, stone, and kidney characteristics were evaluated preoperatively, 3 and 12 months postoperatively. Renal function was accessed in the same intervals with serum creatinine (SCr), glomerular filtration rate (GFR), and (99m)Tc-dimercaptosuccinic acid. Patients without complete pre- and postoperative evaluation were excluded. Primary end point was midterm progress of global and ipsilateral renal function. Secondary end points included the evaluation of renal and collecting system anatomy from diagnosis to 12 months after treatment. Analysis of variance with repeated measures and marginal homogeneity test were used to evaluate renal function and hydronephrosis progression. RESULTS Twenty-six patients met our inclusion criteria. Mean preoperative SCr and GFR were 1.24 mg/dL and 72.5 mL/min, respectively. At initial scintigraphy, mean renal function was 33.4%. Laser ureterolithotripsy was performed in 84.6% of cases and all patients were rendered stone free. Two patients (8%) developed ureteral stenosis. There was no difference regarding SCr (P = .89), GFR (P = .48), and renal function at scintigraphy (P = .19) during follow-up. Hydronephrosis significantly improved from preoperatively to 3 months postoperatively (P < .0001), but not from 3 to 12 months (P = .065). CONCLUSION Patients with silent ureteral stones present with significant impairment of ipsilateral renal function and hydronephrosis at diagnosis. On midterm follow-up evaluation, renal function of the affected unit remains stable whereas hydronephrosis improves after treatment.