Single Renal Stone Research Articles

Urolithiasis: The Most Risk for Nephrectomy in Nonrenal Tumor Patients

The existence of upper urinary tract calculus may cause complete loss of renal function, which eventually results in nephrectomy. Our purpose was to describe the prevalence and clinical characteristics of upper urinary tract calculus cases among a series of patients undergoing nephrectomy during a 10-year period. The data of 1059 patients undergoing nephrectomy between January 2001 and December 2010 in our center were reviewed. The prevalence and clinical characteristics of upper urinary tract calculi-derived nonfunctioning kidney were analyzed. Among 1059 patients, 177 (16.7%) had nonfunctioning kidneys, which were second in number to renal tumor cases (801, 75.6%). Upper urinary tract calculi accounted for the greatest cause (101, 57.1%) in these nonfunctioning kidney cases. These patients were mainly screened by ultrasonography and the diagnosis confirmed by CT, intravenous urography, and nuclear renography. There were 44 (43.6%) patients with a single renal stone in the ureteropelvic junction, 36 (35.6%) with a single ureteral stone, and 21 (20.8%) with multiple unilateral renal and ureteral stones. The average size of the renal stones and ureteral stones were 15.6±8.8 mm (4-50 mm) and 13.4±4.0 mm (4-21mm) in diameter, respectively. Prevalence of urolithiasis derived nonfunctioning kidney had not changed significantly over 10 years and even showed a slight increase. Most of the stones were more than 10 mm in diameter. A nonfunctioning kidney was more likely to develop in females or patients with a low living standard. Upper urinary tract calculus (>10 mm) and loss to follow-up are the greatest risk factors for a nonfunctioning kidney. A nonfunctioning kidney develops more easily in females or patients with a low living standard. A regular urinary system health examination is recommended. Routine follow-up of urolithiasis is also recommended for patients with a stone history to prevent renal dysfunction.

Outcomes of Retrograde Intrarenal Surgery Compared with Percutaneous Nephrolithotomy in Elderly Patients with Moderate-Size Kidney Stones: A Matched-Pair Analysis

The aim of our study was to evaluate the outcomes of retrograde intrarenal surgery (RIRS) in elderly patients with stones of moderate size. Between September 2008 and June 2011, a total of 28 patients over 65 years of age with single renal stones that measured 1.5 to 3 cm were treated with RIRS. The outcomes of these patients were compared with those of the patients who underwent percutaneous nephrolithotomy (PCNL) using matched-pair analysis (1:1 scenario). The matching parameters were the size and location of the stone as well as age, sex, body mass index, degree of hydronephrosis, presence of previous shockwave lithotripsy, and open surgery. SPSS version 16 was used for statistical analysis. Stone-free rates after a single procedure were achieved in 82.1% of patients for the RIRS and 92.8% of patients for the PCNL group. The second flexible ureterorenoscopy procedure was performed for five patients in the RIRS group. Finally, stone-free rates during the third month of the follow-up period were 92.8% in the RIRS group and 96.4% in the PCNL group. The mean operative time per patient was 64.5 ± 20.9 minutes in the RIRS group after a total of 33 procedures, while it was 40.7 ± 10.7 minutes in the PCNL groups (P<0.0001). The overall complication rates for the RIRS and PCNL groups were 7.1% and 10.7%, respectively. Blood transfusions were needed in two patients in the PCNL group. Hospitalization time was significantly shorter in the RIRS group (26.5 ± 10.6 h per patient vs 60.0 ± 28.8 h; P<0.0001). In both groups, stones were most frequently composed of calcium oxalate (68.4% in the RIRS group and 77.7% in the PCNL group). RIRS has a low complication rate and represents a safe and effective treatment alternative in selected geriatric patients with kidney stones of moderate size.

Predicting the fragility of renal calculi in response to shock wave lithotripsy through their radiographic appearance

To evaluate the radiological characteristics of renal stones on plain X-ray film of the kidneys, ureters and bladder (KUB) area as predictors of stone fragility during shock wave lithotripsy (SWL). This prospective study included 336 patients who had a single renal pelvic stone ≤20 mm and were managed by SWL at 3 different centers. The patients were classified according to the radiological appearance of the stone on KUB film in terms of homogeneity, smoothness of the outline, and radiodensity in comparison to the last rib. The primary endpoint was the stone-free rate (SFR) within 3 months post-SWL. Multivariate regression analysis was used to compare the results. The overall SFR was 71.43%. SFR was significantly higher in heterogeneous compared with homogenous stones (86% vs. 53%; p<0.01) and in rough compared with smooth surface calculi (77% vs. 61%, p<0.01). SFRs for stones with density less than, similar to or higher than that of the last rib were 82%, 69% and 56%, respectively (p<0.01). Multivariate analysis showed a positive proportional relationship between stone fragility (SWL outcome) and one or more favorable radiological criteria. The radiological characteristics of renal calculi could predict their fragility after SWL. Stones which were heterogeneous, rough, or less dense than the last rib on KUB film were more likely to disintegrate during SWL.

Management of Solitary Renal Pelvic Stone: Laparoscopic Retroperitoneal Pyelolithotomy Versus Percutaneous Nephrolithotomy

Percutaneous nephrolithotomy (PCNL) is considered the main management option for large single renal pelvic stones; however, laparoscopic retroperitoneal pyelolithotomy (LRP) can be used as an alternative management procedure. We compare both procedures in the management of solitary large renal pelvic stones. Between June 2002 and July 2010, 105 patients with solitary large renal pelvic stones were selected and randomly divided into two groups; group 1 included 55 patients who were treated by LRP and group 2 included 50 patients who were treated by PCNL. The differences between the two procedures were compared and analyzed. There was no difference between the two groups regarding patient demographics and stone size. There was no statistically significant difference between LRP and PCNL regarding mean estimated blood loss (166.4±98.3 mL vs 178±102.4 mL), mean hospital stay (4.5±1.9 d, vs 4.4±1.4 d), mean time of postoperative analgesia (2.2±0.9 d vs 2.4±0.9 d), rate of postoperative blood transfusion (5.5% vs 6%), and stone-free rate (100% vs 96%). The mean operative time was significantly longer in the LRP group (130.6±38.7 min vs 108.5±18.7 min), respectively. There was only one (1.8%) case from the laparoscopy group converted to open surgery because of uncontrolled bleeding. RLP is a suitable surgical technique for patients with large renal pelvic stones but with good selection of cases; however, PCNL remains the standard treatment in most cases.

Totally tubeless percutaneous nephrolithotomy: a prospective randomized controlled study

The purpose of this study was to perform a randomized controlled trial to evaluate the role, safety, and effectiveness of totally tubeless PCNL and whether this procedure is less morbid in terms of analgesia requirement, related complications and convalescence. A total of 131 patients, with impacted ureteropelvic junction stone or single renal pelvic stone larger than 20 mm, were prospectively randomized (using random numbers table) into two groups, and underwent conventional (63 patients) or totally tubeless (68 patients) PCNL. Preoperative data included urinalysis, urine culture, complete blood count, biochemistry study, renal ultrasonography, intravenous urography and Tc 99m DTPA clearance for determination of selective glomerular filtration rate. Intraoperative findings, operative time, and outcome were also recorded. All patients were followed regularly at clinic every 3 months during year 1 and every 6 months, thereafter, and Tc 99m DTPA clearance for the determination of selective glomerular filtration rate, renal ultrasonography and intravenous urography was performed to assess the kidney function 6 months later. There was no difference between the groups with regard to serum creatinine change, hemoglobin decrease, morphology improvement, resumption of normal activity and complication grading. The length of stay, pain visual analog scale and analgesic requirements favored the tubeless group with statistical significance. There was significant statistical difference in relative perfusion rate between preoperative and postoperative in both groups. This trial demonstrates that totally tubeless PCNL is safe and well tolerated in selected patients and associated with decreases in length of stay, postoperative pain and analgesia requirement. Most importantly, patients undergoing uncomplicated PCNL are not mandated to have a nephrostomy or ureteral stent placed for specific indications.

Comparison of the Analgesic Effects of Dexketoprofen and Diclofenac During Shockwave Lithotripsy: A Randomized, Double-Blind Clinical Trial

This prospective, randomized, and double-blind clinical study aimed to assess the analgesic efficacy of single-dose intramuscular (IM) injection of dexketoprofen (group DE) compared with single-dose IM injection of diclofenac (group DI) in patients who were undergoing shockwave lithotripsy (SWL). A total of 70 men with single renal or ureteral stones were randomly separated into two groups. The 40 men in group DI received 75 mg IM diclofenac sodium and 30 men in Group DE received 50 mg IM dexketoprofen trometamol 30 minutes before SWL. A 10-point visual analog scale was used to evaluate pain. The age, body mass index, and mean stone burden were comparable between the two groups (P > 0.05). The mean visual analog scale score for group DE was statistically lower compared with the score for group DI (P = 0.02). In 34 (85%) of the 40 men in group DI, the SWL procedure was performed with no, minor, or tolerable pain. In group DE, however, 28 (93.3%) of 30 patients evaluated the pain severity as no, minor, or tolerable (p = 0.01). No major/minor adverse effects were observed in group DI, whereas in one patient in group DE, dyspepsia after injection was noticed (P = 0.423). The severity of SWL-related pain was significantly better tolerated with dexketoprofen trometamol. During an SWL procedure, the analgesic efficacy of dexketoprofen was greater than that of diclofenac sodium. Although statistically insignificant, a little increased risk for gastric irritation was noticed with dexketoprofen.

1460 PREDICITION OF RENAL STONE FRAGILITY IN RESPONSE TO SHOCK WAVE LITHOTRIPSY BY THEIR RADIOLOGIC APPEARANCE

You have accessJournal of UrologyStone Disease: SWL, Ureteroscopic or Percutaneous Stone Removal I1 Apr 20101460 PREDICITION OF RENAL STONE FRAGILITY IN RESPONSE TO SHOCK WAVE LITHOTRIPSY BY THEIR RADIOLOGIC APPEARANCE Mohamed Nady, Alaa AbdelHafez, Mohamed ElKoushy, and Emadeldeen Ali Salah Mohamed NadyMohamed Nady Assiut, Egypt More articles by this author , Alaa AbdelHafezAlaa AbdelHafez Sohag, Egypt More articles by this author , Mohamed ElKoushyMohamed ElKoushy Ismailia, Egypt More articles by this author , and Emadeldeen Ali SalahEmadeldeen Ali Salah Assiut, Egypt More articles by this author View All Author Informationhttps://doi.org/10.1016/j.juro.2010.02.1174AboutPDF ToolsAdd to favoritesDownload CitationsTrack CitationsPermissionsReprints ShareFacebookTwitterLinked InEmail INTRODUCTION AND OBJECTIVES Extracorporeal shock wave lithotripsy (ESWL) provides a non invasive method for treatment of renal and ureteral calculi. Currently, fluoroscopic stone targeting remains a major component of ESWL. A plain (KUB) film is often required to plan lithotripsy treatment. The appearance of a stone on KUB (size, shape and radiodensity) might give a clue for the success of ESWL. The aim of this work was to evaluate the efficacy of ESWL in treatment of different types of upper urinary tract stones regarding their radiological characteristics like texture homogeneity, surface smoothness and radiodensity degree in relation to last rib. METHODS About 336 patients with single renal pelvic stone less than 2cm were treated by ESWL at 3 centers. The patients were classified based on stone imaging characters. Type I classification was done according to how homogeneous were the stones while type II classification was based on the surface outline of the calculi. Finally, type III classification according to radiodensity degree of stones in relation to last rib as landmark comprised three subclasses with less, equal and more density than last rib. The percentage of stone free rate (SFR) within 3 months post ESWL was calculated. The results were classified based on imaging studies. RESULTS Homogenous stones were 53% clear after ESWL, while the majority (86%) of nonhomogenous stone patients became stone free (p> 0.01). On the other hand, smooth and rough calculi showed 61% and 77% SFR (p> 0.05). Lastly, the SFRs of less, same and more dense stone than the last rib were 82%, 69% and 56% respectively. CONCLUSIONS The efficacy of ESWL in treatment of different types of upper urinary stones is related to the radiological characteristics of the stone. Stones which are heterogonous, rough or less dense in KUB film are more likely to disintegrate by ESWL © 2010 by American Urological Association Education and Research, Inc.FiguresReferencesRelatedDetails Volume 183Issue 4SApril 2010Page: e562 Advertisement Copyright & Permissions© 2010 by American Urological Association Education and Research, Inc.MetricsAuthor Information Mohamed Nady Assiut, Egypt More articles by this author Alaa AbdelHafez Sohag, Egypt More articles by this author Mohamed ElKoushy Ismailia, Egypt More articles by this author Emadeldeen Ali Salah Assiut, Egypt More articles by this author Expand All Advertisement Advertisement PDF downloadLoading ...

Clinical Experience with Ultrasound-Based Real-Time Tracking Lithotripsy in the Single Renal Stone Treatment

An ultrasound-based real-time tracking system has been shown to improve the efficacy of lithotripsy in animal studies. This system has been implemented into an electromagnetic shockwave lithotripter (LM-9200 ELMA), and the treatment outcomes were prospectively evaluated. A total of 1332 patients with one renal stone were treated with LM-9200 ELMA lithotripter between December 2004 and November 2007. Fluoroscopy and ultrasound were alternately used for calculus localization and focusing first. After the calculus was focused and displayed clearly by ultrasound, the ultrasound-based real-time tracking system was applied for calculus monitoring and shockwave trigger control. All patients were followed for up to 3 months. Data regarding stone location, stone size, shockwave number, treatment time, stone free rate, and possible complications were obtained. Of the 865 males and 467 females treated (mean stone size = 12.3 mm), the stone-free rate in 3 months was 80.0%. For all patients, neither anesthetics nor analgesics were necessary. The incidence of blood pressure and microscopic hematuria grading increment at 2 weeks after treatment was 6.8% and 13.8%, respectively. There were no subcapsular hematoma or prolonged hematuria observed. Stone size was an important factor predicting stone-free rate (9.1 +/- 2.1 mm in the successful group vs. 22.0 +/- 3.1 mm in the failed group, p < 0.001). The calculated efficiency quotient of this machine was 0.67. An electromagnetic shockwave lithotripter using ultrasound-based real-time tracking system showed efficient crushing of renal calculi in vivo. Our experience has shown that patients treated by this lithotripter are safe with slight microscopic hematuria and having 80% chance of stone clearance.

Novel Electromagnetic Lithotriptor for Upper Tract Stones With and Without a Ureteral Stent

We compared the treatment efficacy and safety of the novel Lithoskop electromagnetic extracorporeal shock wave lithotriptor for upper urinary tract stones with and without prior ureteral stent placement. A total of 665 consecutive patients harboring single renal or ureteral stones underwent shock wave lithotripsy between August 2006 and July 2008. In 75 and 46 patients with renal and ureteral stones, respectively, stents were placed before the first shock wave lithotripsy session. Treatment outcome was assessed in relation to stent placement. All data were derived from a prospectively maintained database. The mean size of nonstented vs stented renal and ureteral stones was 8.6 vs 12.5 mm (p <0.0001) and 7.1 vs 7.3 mm (p = 0.6), respectively. The stone-free rate in nonstented vs stented renal and ureteral stone cases was 76.3% vs 77.3% and 91.4% vs 93.5%, respectively (each p >0.99). The total energy applied per stone was 110 +/- 83 vs 150 +/- 89 J (p <0.0001) and 183 +/- 131 vs 209 +/- 125 J (p = 0.1), respectively. Auxiliary measures were required after shock wave lithotripsy for renal and ureteral stones in 5.4% and 10.8% of nonstented, and in 1.3% and 4.3% of stented cases, respectively. No complications were detected in stented renal and ureteral stone cases compared to 2.9% and 6.9% in nonstented cases, respectively. A high success rate and a low complication rate were achieved in renal and ureteral stone cases with and without prior ureteral stent placement. Total energy needed to achieve a stone-free state did not differ between stented and nonstented ureteral cases, suggesting the absence of a significant influence of the stent. Overall stents decreased complications necessitating hospitalization and auxiliary invasive measures.

Calculations of Electrets Property of Single Human Renal Stones at Regular Interval of Removing Minerals Compositions

In the modern science and technology the electrical and thermal conductivity studies of renal stone plays an impotent role to understand the natural formation. The free electrons act as carriers to carry their energy. In the present investigations, three renal stones are collected poor hard working male who was affected with mineral deposition in the urinary tracts in a periodic collection within three years. The stones are collected from the hospital by Lithotropic treatment process. Electrical, thermal conductivities are measured at different temperatures and calculated temperature coefficients of the renal stones.

Evaluation of a synchronous twin‐pulse technique for shock wave lithotripsy: a prospective randomized study of effectiveness and safety in comparison to standard single‐pulse technique

To asses the efficacy and safety of bidirectional synchronous twin-pulse extracorporeal shock wave lithotripsy (ESWL) compared with standard ESWL. Between March 2003 and December 2006, 240 patients with a radio-opaque single renal stone of <or=25 mm were randomized to treatment either by the Twinheads (TH) lithotripter (FMD, Lorton, Virginia, USA) or the Dornier Lithotripter S (DLS, Dornier MedTech Europe GmbH, Germering, Germany). Before and after ESWL, urinary N-acetyl-B-glucosaminidase (NAG) levels were assessed and patients were evaluated with dynamic MRI. The efficacy and complications were compared, with success defined as no residual fragments. For stones of >10 mm the rate for the failure of disintegration was 13.3% for the DLS vs 1.4% for the TH (P = 0.009). For stones of <or=10 mm the stone-free rate was 74.4% for the TH vs 67.7% for the DLS (P = 0.6), while for stones of >10 mm it was 78.1% and 66.7%, respectively (P = 0.14). The median (range) number of sessions in both groups was 2 (1-5). After ESWL urinary NAG levels were increased significantly in both groups; in the TH group it declined below the level before ESWL after 2 days, while in the DLS group it remained high after 7 days. In the DLS group four patients developed subcapsular or parenchymal haematoma after ESWL, vs none in the TH group. There was loss of corticomedullary differentiation after ESWL in three patients in the DLS group and only one in the TH group. In the DLS group there was a statistically significantly decrease in bilateral renal perfusion after ESWL, but no changes in the TH group. Synchronous twin-pulse ESWL has clinical advantages over standard ESWL in terms of safety and efficacy.

Efficacy and Safety of a New-Generation Shockwave Lithotripsy Machine in the Treatment of Single Renal or Ureteral Stones: Experience with 2670 Patients

To review the treatment efficacy and to assess the complications encountered in patients with single renal or ureteral calculi managed with a new-generation SWL machine, the Siemens Lithostar Modularis Uro-Plus. The stone location, size, minimum and maximum energy used, localization technique, number of shockwaves, fluoroscopy time, and number of sessions were reviewed for 2670 patients. The medical records were consulted to identify post-SWL secondary treatments in order to calculate the efficacy quotient (EQ). The stone-free rate was 79%. Calculi in the renal pelvis and upper, middle, and lower ureter had success rates of 86%, 86%, 86%, and 85%, respectively (P < 0.05). Higher re-treatment rates were encountered for midureteral stones (P < 0.05). The major complications were renal hematoma, acute pyelonephritis, perirenal abscess, and acute pancreatitis. The overall EQ was 0.67. The EQ was higher for the renal pelvis (0.73) and upper ureter (0.71). Our experience has shown that this new lithotripter is safe and provides a 68% to 86% chance of stone clearance.

Comparison of Intravenous Sedation Versus General Anesthesia on the Efficacy of the Doli 50 Lithotriptor

We compared the impact of intravenous sedation versus general anesthesia on the efficacy of extracorporeal shock wave lithotripsy. From November 1997 to May 1998, 295 patients with a single renal or upper ureteral radioopaque stone of less than 2 cm. were treated with the Doli 50 lithotriptor (Dornier Medical Systems, Marietta, Georgia). The treating anesthesiologist and patient together elected intravenous sedation or general anesthesia. Of the 92 patients 60 (65%) treated under intravenous sedation and 126 of the 203 (62%) treated under general anesthesia had 3-month followup records available for review. Extracorporeal shockwave lithotripsy was considered a failure if residual stone fragments remained after 3 months, or an auxiliary procedure or re-treatment was required. At 3 months the stone-free rate in patients treated under intravenous sedation was 55% compared with 87% in those treated under general anesthesia (p <0.001). There was no statistically significant difference in treatment time or the power index in the 2 groups. Stone size (1 to 10 versus 11 to 20 mm.) did not significantly affect the anesthesia specific stone-free rate. For single renal or upper ureteral stones less than 2 cm. a significantly better 3-month stone-free rate is achieved with the Doli 50 lithotriptor when general anesthesia is used instead of intravenous sedation.

The incidence of lower-pole nephrolithiasis--increasing or not?

To determine if the incidence of lower-pole nephrolithiasis is increasing. A previously published meta-analysis of trends in the location of stones in the kidney, using data from 1984 to 1992, determined the percentage of lower pole stones in 26,722 kidney stones treated by extracorporeal shockwave lithotripsy (ESWL). We performed prospective studies on all patients treated by ESWL for a single renal stone (not manipulated from the ureter) in two organizations: at Lithotripters Inc., 47,303 stones were treated with ESWL by 1000 urologists in private practice from 1989 to 1995. At the Midwest Urologic Stone Unit, 9357 stones were treated with ESWL by 200 urologists in private practice from 1987 to 1995. The distribution of stones in both samples was compared with that reported earlier. The meta-analysis for stone location trends from the previously published article suggested that the percentage of kidney stones in the lower pole at ESWL increased erratically from 1984 to 1989 but was then stable for 3 years. The Lithotripters Inc. sample showed an essentially constant incidence from 28% in 1990 to 30% in 1995, and the Midwest Urologic Stone Unit sample showed an essentially constant incidence from 35% in 1988 to 36% in 1995. The incidence of lower pole nephrolithiasis has remained stable from 1990.

Radiation awareness program for extracorporeal shockwave lithotripsy using Medstone lithotripters.

To determine the effectiveness of a radiation awareness program in reducing the radiation exposure to patients treated by a Medstone lithotripter, the exposure was calculated at the end of each extracorporeal shockwave (SWL) treatment using a table of measurements of the estimated entrance exposure rates 70 cm from the X-ray tube port. The results, related to stone size and patient weight, were distributed every month to each radiologic technologist, and a summary was sent regularly to the treating urologists. The doses before and after the introduction of the radiation awareness program were compared to determine the effectiveness of the program, and the chi-square test was used to determine statistical significance. The average calculated radiation exposure before and after introduction of the radiation awareness program was 16.39 rad and 8.26 rad, respectively, for patients with single renal stones; 17.31 rad and 9.02 rad, respectively, with single ureteral stones; 18.45 rad and 9.39 rad, respectively, with multiple renal stones; and 20.59 rad and 11.28 rad, respectively with multiple ureteral stones. These reductions in calculated radiation exposure were statistically significant only with multiple ureteral stones (P = 0.03). The only statistically significant differences in the stone-free rates, retreatment rates, and post-SWL secondary procedure rates before and after the introduction of the radiation awareness program were seen in the stone-free rates with single renal stones: 70% v 65%, respectively (P = 0.02); in the retreatment rates with single ureteral stones: 10% v 6%, respectively ( P < .01); and in the post-SWL secondary procedure rates with single renal stones: 4% v 2%, respectively (P = 0.01), and single ureteral stones: 7% v 4%, respectively (P = 0.05). The radiation awareness program resulted in a 51% reduction in the estimated radiation exposure to patients during SWL using Medstone lithotripters.

Comparison of First Generation (Dornier HM3) and Second Generation (Medstone STS) Lithotriptors: Treatment Results With 13,864 Renal and Ureteral Calculi

Some reports have shown a decreased effectiveness of extracorporeal shock wave lithotripsy (ESWL*) with newer lithotriptors. We used a first generation unmodified Dornier HM3 lithotriptor to treat 5,698 patients with renal and ureteral calculi and a second generation Medstone STS device to treat 8,166 patients with renal and ureteral calculi. The treatment results were compared using the chi-square test to determine statistical significance. The stone-free rate, retreatment rate and post-ESWL secondary procedure rate were 69.5%, 4.4% and 3.1%, respectively, with the Dornier HM3 device and 72.1%, 4.9% and 2.3%, respectively, with the Medstone lithotriptor for single renal stones, and 81.5%, 5.2% and 5.5%, respectively, with the Dornier HM3 and 83.2%, 5.2% and 5.0%, respectively, with the Medstone device for single ureteral stones. There were no statistically significant different results between a second generation tubless Medstone STS lithotriptor and the gold standard unmodified Dornier HM3 instrument.

体外衝撃波腎・尿管結石破砕術 (ESWL) 時における尿管留置カテーテルの効用と副作用

We retrospectively studied the effects and side effects of placing indwelling ureteral stents in 196 cases who underwent extracorporeal shock wave lithotripsy with a ureteral stent. The average period of ureteral stenting was approximately 22 days. Placing ureteral stents was mainly for large renal stones (79.3%), single kidney etc. There were no significant differences between the stunted and non-stunted patients with approximately 2 cm sized single renal stone with respect to the stone free rate, stone free period, and symptoms during stenting, which suggested that ureteral stenting might be unnecessary in those patients. High fever was highest in incidence of the symptoms and complications during stenting (17.2%). It occurred frequently in patients with infected stones or cystine stones. The percentages of pyrexia and stone street in patients using Towers type's stents were higher than those using the others. It was also shown that the bladder portions of the stents in patients using Towers peripheral ureteral stents were densely encased in calculous material and were very brittle. Fortunately the ureteral portions were removed intact. This study suggests that use of an indwelling ureteral stent may not contribute to the higher rate of being free of stones after the treatment of small to medium sized renal calculi, and that stents should be removed or changed early.

Should Patients with Single Renal Stone Occurrence Undergo Diagnostic Evaluation?

AbstractDiagnostic evaluation was conducted on 34 patients with a single episode of renal stone formation. Absorptive hypercalciuria was disclosed in 55.9 per cent (23.5 per cent type 1 and 32.4 per cent type II), renal hypercalciuria in 11.8 per cent, primary hyperparathyroidism in 2.9 per cent, hyperaricosuric calcium oxalate nephrolithiasis in 8.8 per cent and no metabolic abnormality in 20.6 per cent. Compared to the group with recurrent stone formation the group with a single stone episode had just as severe biochemical abnormalities or laboratory results, such as hypercalciuria and exaggerated calciuric response to oral calcium load in absorptive hypercalciuria, high fasting urinary calcium and cyclic adenosine monophosphate in renal hypercalciuria, hyperuricosuria in hyperuricosuric calcium oxalate nephrolithiasis and low urine volume in no metabolic abnormality. The results suggest that the same physiological and environmental disturbances characterize stone formation in patients with a single stone episode as in those with recurrent stone formation and indicate the need for diagnostic evaluation.