Minimally invasive percutaneous nephrolithotomy: an alternative to retrograde intrarenal surgery and shockwave lithotripsy

Purpose

There is a lack of studies comparing shock wave lithotripsy (SWL), retrograde intrarenal surgery (RIRS) and minimally invasive percutaneous nephrolithotomy (MIP) in renal stone treatment. This study compared treatment outcome, stone-free rate (SFR) and stone-free survival (SFS) with regard to stone size and localization.

Methods

This analysis included 482 first-time-treated patients in the period 2001–2007. Detailed clinical information, stone analysis and metabolic evaluation were evaluated retrospectively. Outcome, SFR and SFS were analyzed with regard to size (<1 vs. ≥1 cm) and localization (lower vs. non-lower pole).

Results

Higher SFRs in lower and non-lower pole stones ≥1 cm were confirmed for RIRS and MIP (p < 0.0001). A regression model confirmed a higher risk of non-lower pole stone persistence for SWL versus RIRS (OR: 2.27, p = 0.034, SWL vs. MIP (OR: 3.23, p = 0.009) and larger stone burden ≥1 versus <1 cm (OR: 2.43, p = 0.006). In accordance, a higher risk of residual stones was found in the lower pole for SWL versus RIRS (OR: 2.67, p = 0.009), SWL versus MIP (OR: 4.75, p < 0.0001) and stones ≥1 cm versus <1 cm (OR: 3.02, p = 0.0006). In RIRS and MIP patients, more complications, stenting, prolonged disability, need/duration of hospitalization and analgesia were noticed (p < 0.05). Overall SFS increased from SWL, RIRS, to MIP (p < 0.001). SWL showed lower SFS for non-lower pole (p = 0.006) and lower pole stones (p = 0.007).

Conclusions

RIRS and MIP were shown to have higher stone-free rates and SFS compared to SWL. The price for better outcome was higher, considering tolerable complication rates. Despite larger preoperative stone burden, MIP achieved high and long-term treatment success.     

逆行肾内手术治疗不同大小肾结石的疗效分析

目的探讨逆行肾内手术（RIRS）治疗肾结石的临床疗效、安全性及适应证。方法回顾性分析2008年3月至2013年5月采用RIRS治疗432例肾结石患者的临床资料,对患者手术时间、术后结石清除率、并发症发生率进行评估。结果本组RIRS术432例,其中≤2cm结石患者272例,平均手术时间为（81．6±23．7）min,一期结石清除率为87．8％;2cm至3cm肾结石133例,平均手术时间为（163．3±71．5）min,一期结石清除率为72．2％;〉3cm结石27例,平均手术时间为（163．3±58．3）min,一期结石清除率为40．7％。术中发生输尿管穿孔性损伤17例（3．9％）,术后22（5．1％）例体温超过38．5℃,7例（1．6％）出现尿脓毒血症,经抗感染及支持治疗等治疗缓解。比较结石直径≤2cm组和2cm〈直径≤3cm的一期清石率,无显著性差异（P〉0．05）;比较结石直径≤2cm组和结石直径〉3cm的一期清石率,有显著性差异（P〈0．05）。结论对于≤3cm的肾结石,RIRS具有创伤小,恢复快,结石清除率高等优点,值得推广。     

A practical formula to predict the stone-free rate of patients undergoing extracorporeal shock wave lithotripsy

ObjectivesWe studied patients who underwent extracorporeal shock wave lithotripsy (SWL) to investigate the factors influencing the outcome, and built a logistic regression model to estimate the stone-free rate (SFR) after SWL.Material and methodsFrom January 2013 to December 2013, we retrospectively reviewed the clinical status of 641 patients with a solitary urinary calculus who underwent SWL in our hospital. Univariate logistic regression was used to identify the factors leading to a high SFR, and significant factors were further analyzed by multivariate logistic regression. After the optimal model had been developed, we placed it on the website so others could calculate the SFR at their institutions.ResultsThe overall SFR for all patients, patients with ureteral stones, and patients with renal stones were 54.8%, 67.8%, and 46.7%, respectively. Multivariate logistic regression showed that body mass index (BMI), stone length, stone width, and stone location were the independent factors that affected the overall successful rate. Stone length was the only significant factor to predict SFR for ureteral stones. BMI, stone length, and stone width were significant SFR predictors for renal stones. A logistic regression model was designed to estimate SFR, which has a sensitivity of 77.8% and specificity of 75.5%.ConclusionBMI, stone length, stone width, and kidney and ureteral stones were all prognostic factors influencing the outcome of SWL. We built a logistic regression formula to predict the SFR, which helps urologists to select patients for SWL.     

Outcome of retrograde flexible ureterorenoscopy and laser lithotripsy for treatment of multiple renal stones

Objective

To evaluate the efficacy and safety of retrograde intrarenal surgery (RIRS) using flexible ureterorenoscopy (F-URS) and laser lithotripsy as a treatment option for multiple renal stones greater than 1 cm.

Development of a high-precision bladder hyperthermic intracavitary chemotherapy device for bladder cancer and pharmacokinetic study

Background

Although the indications of minimally invasive treatments for pediatric urolithiasis are similar to those in adults, it is still crucial to make the right treatment decision due to the special considerations of children. This review aims to evaluate the efficacy and safety of extracorporeal shockwave lithotripsy (SWL), percutaneous nephrolithotomy (PCNL), and retrograde intrarenal surgery (RIRS) in the management of pediatric upper urinary tract stones.

Methods

EMBASE, PubMed, and the Cochrane Library were searched from their first available date to March 2018. The studies that meet the inclusive criteria were included. The efficacy and safety of the treatments were assessed by means of meta-analysis of the stone free rate (SFR), complication rate, effectiveness quotient (EQ) and secondary outcome indicators.

Results

A total of 13 comparative studies were identified for data analysis. PCNL presented a significantly higher SFR compared with SWL. Similarly, the single-session SFR of RIRS was significantly higher than SWL. However, no significant difference was found between RIRS and SWL in the overall SFR. There was no significant difference between PCNL and RIRS in the SFR. Furthermore, no significant differences in complication rates were found among the three therapies. Compared with the other two treatments, PCNL had a longer operative time, fluoroscopy time and hospital stay. SWL had a shorter hospital stay, higher retreatment rate and auxiliary rate in comparison with the other two treatments. The present data also showed that PCNL presented a higher EQ than the other two treatments, and RIRS had a lower efficiency than SWL and PCNL. In the subgroup analysis of pediatric patients with stone ≤20 mm, the comparative results were similar to those described above, except for the higher complication rate of PCNL than SWL.

Conclusions

Although SWL as an outpatient procedure provides shorter hospital stay and reduces operative time, it has a lower SFR and higher retreatment rate than the other two treatments. PCNL exhibits a higher SFR and EQ than SWL; nevertheless, it has a longer operative time and fluoroscopy time than the other two procedures. RIRS offers a similar SFR as PCNL but a lower efficiency than PCNL.

     

Comparison of retrograde intrarenal surgery, shockwave lithotripsy, and percutaneous nephrolithotomy for treatment of medium-sized radiolucent renal stones

Objectives

To compare the outcomes of shock wave lithotripsy (SWL), percutaneous nephrolithotomy (PNL), and retrograde intrarenal surgery (RIRS) for 10–20 mm radiolucent renal calculi by evaluating stone-free rates and associated complications.

Patients and methods

A total of 437 patients at 7 institutions who underwent SWL (n = 251), PNL (n = 140), or RIRS (n = 46) were enrolled in our study. Clinical success was defined as stone-free status or asymptomatic insignificant residual fragments <3 mm. The success rates, auxiliary procedures, and complications were compared in each group.

Results

Success rates were 66.5, 91.4, and 87 % for SWL, PNL, and RIRS (p < 0.001). The need for auxiliary procedures was more common after SWL than PNL and RIRS (21.9 vs 5.7 vs 8.7 %, respectively; p < 0.001). The overall complication rates for the SWL, PNL, and RIRS were 7.6, 22.1, and 10.9 %, respectively (p < 0.001). Thirteen patients in PNL group received blood transfusions, while none of the patients in RIRS and SWL groups transfused. Hospitalization time per patient was 1.3 ± 0.5 days in the RIRS group, while it was 2.6 ± 0.9 days in the PNL group (p < 0.001). Fluoroscopy and operation time were significantly longer in the PNL group compared to RIRS (145.7 ± 101.7 vs 28.7 ± 18.7 s, and 57.5 ± 22.1 vs 43.1 ± 17 min, respectively).

Conclusions

For treatment of moderate-sized radiolucent renal stones, RIRS and PNL provide significantly higher success and lower retreatment rate compared with SWL. Although PNL is effective, its biggest drawback is its invasiveness. Blood loss, radiation exposure, hospital stay, and morbidities of PNL can be significantly reduced with RIRS technique.     

Changes of renal function after retrograde intrarenal surgery using flexible ureteroscope in renal stone patients

BackgroundRetrograde intrarenal surgery (RIRS) is widely performed for renal stones. Theoretically, removing renal stones could prevent the deterioration of renal function. However, two studies reported that not all patients would see an increase in renal function after RIRS. The aim of our study was to evaluate the change of renal function of the operative site, and to identify predictors of improvement or deterioration of renal function after RIRS.MethodsWe retrospectively reviewed renal stones patients who received RIRS and single-photon emission computed tomography (SPECT) before and after surgery. Improved renal function was defined as the change of glomerular filtration rate (GFR) >10% postoperatively, and that <−10% was regarded as deteriorated renal function. Logistic and least absolute shrinkage and selection operator regression analyses were used to identify predictors for the improvement or deterioration of renal function, and predictive nomogram models were built.ResultsA total of 120 renal stone patients were included. Twenty-one (17.5%), 79 (65.8%) and 20 (16.7%) patients had improved, stable and deteriorated renal function of operative site after surgery, respectively. Lower alkaline phosphatase, lower low-density lipoprotein, lower GFR of the operative site, thicker renal parenchyma, higher serum creatinine, and extracorporeal shock wave lithotripsy (SWL) history were associated with the improved renal function. The predictive accuracy of the model for the improved renal function was 0.800. Additionally, older age, longer flexible ureteroscopic time, thinner renal parenchyma and existence of ureteral stones were risk factors for deteriorated renal function. The predictive accuracy of the model for the deteriorated renal function was 0.725.ConclusionsThe renal function of most renal stone patients did not decrease after RIRS. For patients with potential deterioration of renal function postoperatively, urologists could shorten flexible ureteroscopic time to prevent the occurrence of this outcome.     

Comparison of pneumatic and Holmium laser ureteroscopic lithotripsy for upper third ureteral stones

ObjectiveTo evaluate the outcomes of ureteroscopic lithotripsy with pneumatic lithotripter and Holium:Yttrium-Aluminum-Garnet (Ho:YAG) laser in the management of upper third ureteral stones.Materials and methodsPatients who underwent ureteroscopic lithotripsy with pneumatic lithotripter or Ho:YAG laser for upper third ureteral stones were retrospectively reviewed. Patients with urinary tract infection, radiolucent stones, loss of follow-up, concurrent middle or lower third ureteral stones or acute renal failure were excluded. Patient age, stone size and burden (based on KUB or computerized tomography), stone upward migration, double J stent insertion rate, stone free rate and secondary intervention rate for residual stones were compared in both groups.ResultsThere were 158 patients with 178 upper third ureteral stones (135 in pneumatic lithotripsy group and 43 in Ho:YAG laser lithotripsy group) meeting the study criteria. Patients' age, gender, stone laterality, stone size and burden were similar in both groups. The Ho:YAG laser lithotripsy group had better stone free rate, less double J stent insertion rate and less secondary intervention rate as compared with pneumatic lithotripsy (53.4% vs. 40.1%; 72.1% vs. 91.9%; 25% vs. 48.5% respectively, all p < 0.05). In patients with stones larger than 10 mm, Ho:YAG laser lithotripsy had significantly lower upward migration rate, lower double J stent insertion rate, higher stone free rate and less secondary intervention rate.ConclusionsHo:YAG laser lithotripsy is superior to pneumatic lithotripsy in the management of upper third ureteral stones in terms of double J stent insertion rate, stone free rate and secondary intervention rate for stones of all sizes. For stones larger than 10 mm, laser lithotripsy results in less stone upward migration.     

Successful retrograde intrarenal surgery (RIRS) for a 2-centimeter stone in a chronic renal failure (CRF) patient

Introduction and importanceRetrograde intrarenal surgery (RIRS) is the best complementary method to Flexible Ureterorenoscopy (URF). In the case of renal insufficiency in patients with urolithiasis, the stone treatment strategy can be different because it should have the least injury to the kidney and be minimally invasive. There was no previous evidence of RIRS in stone-breaking in a chronic renal failure (CRF) patient. For the first time, we presented a successful RIRS in the monokidney CRF case with >2 cm stone.Case presentationWe have done the RIRS over a 55-year-old monokidney woman. She already has lymphoma, chemotherapy, lithotripsy, right renal nephrostomy, and a left kidney stone removal. She had hydronephrosis with a >2 cm stone in her left kidney. The patient underwent RIRS surgery and Holmium lithotripsy (strength 8 and impact strength 13,000) on pinking layers of stone.Clinical discussionDuring the RIRS surgery, we put a ureteric stent (the patient already had a double J before), and we fixed the ureteral catheter with the Foley catheter and removed the ureteral catheter 4 days after the surgery. The result of the surgery was satisfying and after three days the patient goes into a stable condition.ConclusionRegarding the least injury to the kidney during RIRS surgery, it can be the best treatment option for urolithiasis in CRF patients.     

Intrarenal Surgery vs Percutaneous Nephrolithotomy in the Management of Lower Pole Stones Greater than 2 cm

Purpose

To compare the efficacy of RIRS and PNL in lower pole stones ≥2 cm. Materials and and Methods: A total of 109 patients who underwent PNL or RIRS for solitary lower pole stone between April 2009 and December 2012, were retrospectively analyzed. Lower pole stone was diagnosed with CT scan. Stone size was assessed as the longest axis of the stone. All patients were informed about the advantages, disadvantages and probable complications of both PNL and RIRS before the selection of the procedure. Patients decided the surgery type by themselves without being under any influences and written informed consent was obtained from all patients prior to the surgery. Patients were divided into two groups according to the patients’ preference of surgery type. Group 1 consisted of 77 patients who underwent PNL and Group 2 consisted of 32 patients treated with RIRS. Stone free statuses, postoperative complications, operative time and hospitalization time were compared in both groups.

Results

There was no statistical significance between the two groups in mean age, stone size, stone laterality, mean follow-up periods and mean operative times. In PNL group, stone-free rate was 96.1% at first session and 100% after the additional procedure. In Group 2, stone-free rate was 90.6% at the first procedure and 100% after the additional procedure. The final stone-free rates and operative times were similar in both groups.

Conclusions

RIRS should be an effective treatment alternative to PNL in lower pole stones larger than 2 cm, especially in selected patients.     

Cystinuria in childhood and adolescence: recommendations for diagnosis, treatment, and follow-up

Cystinuria, an autosomal-recessive disorder of a renal tubular amino acid transporter, is the cause of about 10% of all kidney stones observed in children. Different genetic characteristics are not represented by different phenotypes. The stones are formed of cystine, which is relatively insoluble at the physiological pH of urine. Without any preventive measures, the patients will suffer from recurrent stone formation throughout their life. Even with medical management, long-term outcome is poor due to insufficient efficacy and low patient compliance. Many patients suffer from renal insufficiency as a result of recurrent stone formation and repeated interventions. However, regular follow-up and optimal pharmacotherapy significantly increase stone-free intervals. Medical management is mainly based on hyperhydration and urine alkalinization. Sulfhydryl agents such as tiopronin can be added. Recurrent stone formation necessitates repeated urological interventions. These mostly minimally invasive procedures carry the risk of impairment of renal function. In adults, extracorporeal shockwave lithotripsy (SWL) as well as intracorporeal lithotripsy is often unsuccessful. However, in children SWL shows excellent results for cystine stones. In cases with large stone burden, percutaneous nephrolithotripsy (PNL) or even open surgical nephrolithotomy are preferred. This review discusses the underlying pathogenetic mechanisms and provides guidance for the diagnosis, therapy, and management of cystinuria following the recommendations of the International Cystinuria Consortium and the European Association of Urology.     

Retrograde Intrarenal Lithotripsy Outcome After Failure of Shock Wave Lithotripsy

PurposeWe report our experience with retrograde intrarenal lithotripsy (RIRL) for renal stones not alleviated by shock wave lithotripsy (SWL).Materials and MethodsA total of 28 females and 53 males with a mean age of 53 years (range 18 to 86) were studied. They had been treated with a mean of 3.2 previous SWLs. Mean stone size was 9.2 mm (range 4 to 22) and the mean number of stones per patient was 1.27 (range 1 to 5) for a total of 103 stones overall. In 70 patients there was 1 stone. Rigid and flexible ureteroscopes were used in 8 and 67 cases, respectively, while a combined approach was used in 6. A holmium:YAG laser was used for fragmentation in 52 patients. Success was defined as stone-free status or residual fragments less than 3 mm.ResultsThe overall success rate was 67%. RIRL yielded a 46% stone-free rate. Of the 44 patients 17 (39%) had residual stones less than 3 mm, while 13 required ancillary procedures. There were no residual ureteral stones. Original stone size correlated inversely with the success rate. Most failures involved lower pole stones, in that laser fiber deflection prevented reaching them in 9 cases. The procedure was interrupted due to extravasation or bleeding in 5 patients and 6 had postoperative urinary tract infections (16% overall complication rate).ConclusionsRIRL effectively and safely alleviated upper tract stones unresponsive to earlier SWL. It can be considered salvage therapy in such cases. RIRL is well suited for treating stones less than 2 cm with better stone-free rates than SWL in the same circumstances. Residual stones were more likely in lower pole cases.     

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.     

Stone Disease

ObjectivesThe purpose of this review is to discuss the major findings presented at the “New Horizons in Urology” closed expert meeting, held October 2006 in Marbella, Spain, on improving the management of stone disease (renal and ureteral stones), and to summarise the consequences of these findings on improving current practice in managing stone disease.MethodsApproximately 135 European urologists attended the meeting. Data and papers discussed in recent congress meetings in 2006 were considered. Experts in the field of stone disease selected and discussed the most relevant new findings. Furthermore, the delegate's opinion on representative clinical case studies was assessed by interactive voting. An expert panel commented on voting results.ResultsAt the meeting, it was highlighted that stones that fail to pass spontaneously in a reasonable time can be treated by minimally invasive surgical procedures including extracorporeal shock wave lithotripsy (SWL), ureteroscopy (URS), and percutaneous nephrolithotomy (PNL). The choice of treatment largely depends on the size and location of stones. However, treatment with URS is more frequently used for managing stone disease, and the number of SWL therapies is decreasing. Furthermore, the use of α₁-adrenoceptor antagonists as medical expulsive therapy has been shown to increase the expulsion rate and decrease the time until the stone is passed.ConclusionsMinimally invasive surgical procedures such as SWL, URS, and PNL have been widely adopted for stone removal, with each approach having its own advantages and disadvantages.     

Tubeless percutaneous nephrolithotomy in selected patients: a prospective randomized comparison

Objectives To prospectively compare the outcome of standard and tubeless percutaneous nephrolithotomy (PNL) in a selected group of patients with renal stones. Methods Patients with simple, isolated renal pelvis or lower pole caliceal stones and no significant hydronephrosis were randomly enrolled to undergo either standard PNL, in which routine nephrostomy tube was placed at the end of operation, or tubeless PNL. Occurrence of intraoperative complications, total operative time exceeding 2 h, indication for additional access or second-look PNL due to residual stones were exclusion criteria. Results There were 11 isolated lower pole caliceal stones (mean stone burden: 3.1 cm²) and 6 isolated renal pelvis stones (mean stone burden: 2.8 cm²) in the tubeless PNL group (n: 17), and 9 isolated lower pole caliceal stones (mean stone burden: 3.4 cm²) and 9 isolated renal pelvis stones (mean stone burden: 3.1 cm²) in the standard PNL group (n: 18). Mean operation time was 59.6 ± 9.1 (range: 50–90) min in the tubeless group, and 67.3 ± 10.1 (range: 60–115) min in the standard PNL group (P > 0.05). Successful stone removal was achieved in all patients, and no significant complication was observed in any case. The mean postoperative analgesic requirement was significantly less in the tubeless group (P < 0.05). Mean hospital stay was 1.6 ± 0.4 (range: 1–3) days in the tubeless group, and 2.8 ± 0.9 (range: 2–4) days in the former group (P < 0.05). Conclusion Our results indicate that tubeless PNL is safe in the management of selected patients and that mean analgesic requirement as well as hospitalization time is diminished with this modification. Presented at the 23rd World Congress on Endourology and SWL, August 23–26, 2005, Amsterdam, The Netherlands     

The “old” 15 mm renal stone size limit for RIRS remains a clinically significant threshold size

Purpose

To investigate the performance of retrograde intrarenal surgery (RIRS) for the 1–2 cm renal stone size range in comparison to smaller stones.

Materials and methods

From a data base of 3000 ureteroscopies between 2004 and 2014, 635 consecutive patients underwent RIRS for renal stones. Patients were divided to three groups according to their renal stone size (<10, 10–15, 15–20 mm). Preoperative, operative, stone free rate (SFR) and follow-up data were analyzed and compared.

Results

The SFR for the three groups was 94.1, 90.1 and 85%, respectively. Patients with renal stone size above 15 mm had a statistically significantly lower SFR. The efficiency quotient calculated for stones larger and smaller than 15 mm was 83.9 vs. 91.8%, respectively (p < 0.01). The mean operative time and hospital stay were longer for patients with renal stones larger than 15 mm (73.6 ± 29.9 vs. 53 ± 19.4 min, p < 0.01 and 2.2 ± 2 vs. 1.8 ± 1.8 days, p = 0.031, respectively). Moreover, the complication rate was almost two times higher (10 vs 5.4%, p = 0.08). Concomitant ureteral stones and older age were independent predictors of failure in the large stone group.

Conclusions

While the overall SFR following RIRS for renal stones up to 2 cm is generally high, the SFR for 15–20 mm stones is significantly lower, with a longer operating time and hospital stay, and a higher complication rate.

     

Retrograde renoscopic fragmentation of moderate-size (1.5-3.0-cm) renal cystine stones

PURPOSE: We present a series of cystinuric patients with renal cystine calculi between 1.5 and 3.0 cm treated with retrograde renoscopy and intracorporeal lithotripsy and report our results, complications, and inpatient utilization with this approach. PATIENTS AND METHODS: The hospital and office charts of five consecutive patients with six treated renal units who underwent retrograde renoscopy and electrohydraulic lithotripsy for renal cystine stones between 1.5 and 3.0 cm were reviewed. Data on stone size and location, procedures performed, results, complications, and inpatient hospital days were compiled. RESULTS: Five of the six renal units were either rendered stone free or had fragments totalling 3 mm or less. Three renal units required only a single procedure, one required repeat ureteroscopy for Steinstrasse, and one required SWL and repeat ureteroscopy for Steinstrasse. One renal unit was left with a 6-mm fragment for which the patient refused further treatment. There were no major complications. The mean hospital stay was 1 day, and the mean number of procedures per patient was 1.3. CONCLUSION: Retrograde renoscopy and intracorporeal lithotripsy for renal cystine stones 1.5 to 3.0 cm is safe and effective and should be considered as an alternative to percutaneous nephrolithotomy in these patients.     

Retrograde intrarenal surgery as second-line therapy yields a lower success rate

BACKGROUND AND PURPOSE: Retrograde intrarenal surgery (RIRS) is a recent addition to the treatment options for renal calculi. Therefore, the indications, as well as the predictors of success, are still being studied. Herein, we report a retrospective comparison of RIRS performed as the primary treatment and as second-line therapy, mostly after shockwave lithotripsy (SWL) failure. PATIENTS AND METHODS: Between October 2001 and August 2004, 93 patients underwent RIRS (11% of all ureteroscopies), all by the same surgeon. Patients were divided into two groups: group 1 (n = 42) consisted of patients undergoing RIRS as a first-line modality and group 2 (n = 51) of those having RIRS as secondline therapy. The indications for RIRS in group 1 were renal calculi with prior placement of a double-J stent (30%), renal + ureteral stone (25%), pushback of ureteral stone during ureteroscopy (22%), a radiolucent stone (8%), coagulopathy, and abnormal renal anatomy. In group 2, the patients were initially treated by SWL (92%) or percutaneous nephrolithotomy. The groups did not differ significantly in demographic characteristics, mean stone size (9.5 and 8.7 mm, respectively), or stone location (in both 60% in the lower pole). The variables analyzed were operating time, complications, length of hospitalization, and stone-free rate. RESULTS: The overall stone-free rate was 73%. However, the stone-free rate was significantly higher in group 1 than in group 2: 80% v 67%, respectively. A higher complication rate and longer hospitalization were noted in group 2, although the difference was not statistically significant. CONCLUSIONS: When RIRS is performed after failed SWL, it has a lower success rate and may be associated with a higher morbidity rate than if it is performed as first-line therapy. These results suggest that the success rate of RIRS may be influenced by the same negative factors that reduce SWL success. Therefore, if a patient fails SWL, careful consideration should be given to the best second-line therapy comparing RIRS with percutaneous stone removal.     

The concentration of Zn,Mg and Mn in calcium oxalate monohydrate stones appears to interfere with their fragility in ESWL therapy

Extracorporeal shockwave lithotripsy (SWL) has remained the preferred method of treatment of urinary stones since its introduction in 1980. Although SWL is classified as a potential first-line treatment for renal stones smaller than 2 cm and its overall success rate is higher than 85% for stone clearance, not all renal calculi are successfully fragmented after SWL. Among the urinary stones, calcium oxalate monohydrate (COM) stone is one of the hardest stones to fragment. Several factors interfering with stone fragility are known to exist. In addition to technical properties for SWL to increase the quality and rate of stone disintegration, the composition of stones such as trace element levels may also interfere with the efficacy of SWL. Therefore, in the present study, we aimed to elucidate the correlation, if it exists, between fragmentation of renal stones and their trace element (Cu, Zn, Mg, Fe, Pb, Mn, Cr) concentrations. For this purpose, the patients admitted to our department who were identified with urinary stones (740 patients) and underwent SWL sessions were evaluated prospectively. Patients having 5–20 mm of solitary COM stone in the renal pelvis were included in this study. The trace element concentrations of renal stones that were successfully fragmented with SWL (SWL-S) were compared with those that were unsuccessfully fragmented after three SWL sessions (SWL-US) and removed surgically. Our measurements showed that the concentrations of Cu, Fe, Pb, and Cr were similar in both groups; by contrast, the concentration of Zn, Mg and Mn was significantly lower in SWL-US renal stones. The present results suggest that low concentrations of Zn, Mg and Mn in COM stones appear to make them resistant to SWL fragmentation and may offer a critical distinction for the choice of a treatment program.