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Effective long-term management of urolithiasis depends on identification and manipulation of factors contributing to initial stone formation; identification of these factors depends on accurate identification of the mineral composition of the urolith involved. The purpose of this study was to determine the chemical composition of uroliths obtained from the low urinary tract of dogs in Mexico City. One hundred and five cases of urolithiasis were studied in which stones were surgically obtained from the low urinary tracts of dogs treated in different hospitals. The chemical composition of the uroliths was quantitatively and qualitatively determined by stereoscopic microscopy, IR-spectroscopy, scanning electron microscopy and X-ray microanalysis. Age of animals ranged from 4 months to 14 years, with a median of 5 years. Composition and distribution of the uroliths were struvite 38.1%, calcium oxalate 26.7%, silica 13.3%, urate 7.6%, mixed 11.4%, compounds 1.9%, and cystine 1%. Most uroliths were found in pure breed dogs (75.2%); 23 different breeds were identified, and more than half of the submissions were from breeds of small size. In our study, the frequency of struvite, calcium oxalate, cystine, urates, mixed and compounds stones are in agreement with papers that report on dog populations in America and Europe, but a higher frequency of silica uroliths was observed in Mexico City dogs. [ABSTRACT FROM AUTHOR]

Many studies have been done to determine the risk factors associated with urolithiasis so that preventive measures can be undertaken to prevent stone formation. However the exact aetiology of urinary stones still remains elusive. A prospective control study of epidemiological factors that influence urinary stone formation was done to determine the aetiology of urinary stones. Patients with stone disease had a significantly higher body mass index. 24-h urine excretion of uric acid and phosphate was found to be significantly higher in stone patients as compared to controls. The intake of non-vegetarian food was significantly higher amongst stone formers. Stone patients had a significantly higher consumption of curd and cheese as compared to controls. There was a significant correlation noted between stone formation and a positive family and past history of stone disease. The results indicate that obese patients, especially those with a family history of stone disease, should be counselled on weight loss. Individuals with a past history of stone disease should be advised to reduce their dietary intake of foods rich in uric acid (meat, liver and beans). [ABSTRACT FROM AUTHOR]

This paper attempts to assess the current status of the various modalities of available treatment for urinary stone disease in the Kerala scenario. A total of 300 patients who attended the stone clinic with urinary stone disease and had stones retrieved by different means were selected for the study. Their clinical symptoms, demographic profile, size, number and position of stones, metabolic profiles, retrieval modalities and end result of treatment in terms of stone clearance were assessed. Instances of failure, incomplete clearance and complication events were noted. Based on the experiences, a flowchart was created for appropriate decision-making in urinary stone management. The modalities of retrieval included nephrectomy, nephrolithotomy, pyelo-nephrolithotomy, extended pyelolithotomy, pyelolithotomy, ureterolithotomy, cystolithotomy, urethrolithotomy, ESWL, PCNL, URS, cystolithotripsy, urethrolithotripsy and spontaneous passage. The clearance rate of stone was maximum in open surgery. The extent of stone clearance by ESWL depended on various factors. PCNL was mostly limited by the difficulties in achieving puncture at the stone site. Availability of a variety of flexible nephroscopes also altered the success rate of the procedure. There were good success rates in pushing stones from the ureter to the pelvis followed by PCNL. In patients who had successful PCNL, postoperative morbidity was significantly reduced in terms of the number of days of hospitalization, time taken for return to work, absence of urinary leak, site infection, urinoma formation and urinary tract infection. URS was performed in many patients and stones retrieved. However, the indication for the procedure remains doubtful as the size of most of the stones thus retrieved was less than 6 mm. These would have passed out spontaneously or with chemotherapeutic support. URS, lithotripsy and basketting were confronted by upward migration of stones to the kidney, requiring further procedures for retrieval. Introduction of double J stents helped in relieving urinary obstruction, particularly in patients presenting with anuria, but retained stents, forgotten stents and failed stone retrieval were common following the procedure. The procedure of URS was simplified by the presence of dilated ureter in spontaneous stone passers or those with distal obstruction and proximal dilatation. It is concluded from the study that open surgery still remains the sheet anchor of treatment of urinary stones in many patients in Kerala. Newer lesser invasive procedures should be ethically selected. Decisions should be patient based, taking into consideration the economic feasibility for the procedure proposed. [ABSTRACT FROM AUTHOR]

This study was done to identify the value of the commonly performed investigations available for identifying urinary stone disease, namely X-ray of the kidney, ureter and bladder (KUB) regions and ultrasound scan (USS) to recognize stones in patients suspected to have the disease. Two hundred patients who attended the stone clinic with symptoms suggestive of urinary stone disease and had either stone retrieved or have been followed up for minimum of 6 months were interviewed. The final opinion on stone disease was made after follow-up to assess the efficacy of the initial opinion based on the plain X-ray KUB or USS. The patients were classified as proved stone patients only after retrieval of stones. The efficacy of the initial screening investigation was assessed to calculate the specificity and sensitivity of the two modalities of investigation. Of the 200 patients studied, all had plain X-ray KUB. Only 166 patients had USS for recognizing stones in the urinary tract; 74 patients showed positive evidence of stones either by X-ray or USS. The findings of the two modalities of investigation are given below. Number of X-rays done, 200; number positive, 24; proved positive, 24 (stone retrieved); proved negative, 0; number negative, 176; proved positive, 32 (stone retrieved); proved negative, 144; number of USS done, 166; number positive, 120; proved positive, 50 (stone retrieved); proved negative, 70; number negative, 46; proved positive, 14 (stone retrieved); proved negative, 32. USS showed back presence effects in 62 patients. Of these, 12% showed stones in the ureter, whereas the rest did not show evidence of stones. Those selected as positive stones finally had either passed stones or had PCNL, URS, cystolithotripsy or open surgery or were put on high-dose chemotherapy. Forty-six patients who had no ROS in KUB and no stones in USS passed stones subsequently. It is concluded that the plain both X-ray KUB and USS should be performed in patients with suspected stone disease for identifying stone disease and also to exclude other pathology which may produce similar urinary symptoms. [ABSTRACT FROM AUTHOR]

Genetic predisposition to urolithiasis is a much discussed topic. The objective of this paper is to identify the types of family members of proved urinary stone patients, who have a history of urinary stone formation. The study population consisted of 2,157 urinary stone patients interviewed in 2003–2007 in the urinary stone clinic. Family members with stone history were classified as group 1—first order single (one person in the immediate family—father, mother, siblings, or children), group 2—first order multiple (more than one member in the above group), group 3—second order single (one person in the blood relatives in family—grandparents, grandchildren, uncles, aunts, cousins, etc.) and group 4—second order multiple (more than one member in the above group). Of the 2,157 patients studied, 349 patients gave positive history of stone disease constituting 16.18%. Of these, 321 were males and 28 were females. Subdivision of the family members showed that 282 patients (80.80%) had single family member with stones and the rest 67 (19.20%) had multiple family members with history of stone disease. Group 1 which constituted one family member in the immediate family had 255 involvements (father: 88, mother: 16, brother: 135, sister: 2, son: 10, and daughter: 4); Group 2 with multiple members in the immediate family constituted 51 relatives; of these, father and brother combination was the most common with 35 occurrences. Group 3 with one person in the distant relatives in family namely grandparents, grand children, uncles, aunts, cousins, etc. constituted 27 occurrences and Group 4 with more than one member in the distant family constituted 16 occurrences. It is concluded that single family member involvement was more than multiple involvements. Males predominated. Stone occurrence was more in the immediate family members than distant relatives. Brothers formed the most common group to be involved with stone disease. Study of stone risk in the family members should be centred on brothers and sons of stone patients. [ABSTRACT FROM AUTHOR]

This paper has attempted to assess the changes noted in the trends in the incidence and biochemical pattern of female urolithiasis patients during the period 1971–2008. A prospective descriptive clinical study was done on 8,590 stone patients belonging to both sexes treated at the urinary stone clinic. The incidence of stone disease among the two sexes was plotted. The various metabolic parameters including 24-h urine volume, urine calcium, phosphorus, uric acid, oxalate, magnesium, creatinine and citrate, serum creatinine, calcium, phosphorus, uric acid and magnesium and calculated parameter calcium:magnesium ratio were studied. The possible causes for the change in incidence of stone disease in the female sex were elucidated. Of the patients studied, 12.7% (1,091) were females. There was a definite increase in the incidence of female urolithiasis over the past 37 years ( P < 0.001). There were significant variations in urine biochemical parameters. There was a definite increase in the excretion of urinary calcium over the years ( P < 0.001). The excretion rate of oxalate in urine of females also increased steadily over the years ( P < 0.001). The magnesium in urine of females reduced over the years ( P < 0.001). Urinary citric acid has however shown an increase over the years ( P < 0.001). Urinary excretion of phosphorus ( P < 0.001) and urinary uric acid ( P < 0.001) showed a decreasing trend. There was a considerable increase in the percentage of females with high calcium:magnesium ratio over the years ( P < 0.001). There was a definite decrease in female patients with hypercalcemia over the years. Serum phosphorus and magnesium also increased significantly with the passage of time. Serum uric acid did not vary significantly through the years. The decrease in the excretion rate of magnesium which is inhibitory to stone genesis, together with the increased excretion of calcium and oxalate may have contributed to the increasing incidence of stone disease in females. This might be due to changes in living standards and dietary habits. [ABSTRACT FROM AUTHOR]

Various risk indices have been propounded by various authors to assess the severity of stone formation in the human urinary tract. However, most of these indices are laboratory oriented and not feasible to be performed in a hospital setting. Most of these also do not take into consideration all the possible influences on stone formation. In this paper, the correlation of various clinically relevant risk indices has been assessed to understand the relevance of the prediction in the possibility of future stone formation. 500 stone patients were studied to find out the various possible risk factors. The total score of the index was fixed as 100. Forty three variables were used to calculate the index, and each variable was given a score ranging from one to eight. They included the following: age 20–40 (1), sex (2), family history (3), Gulf returned (1), external occupation (1), primary (1), recurrent (5), symptoms (2), RBC (1), PC (1), COD (1), COM (2), UA (2), crystal aggregation (2), urinary infection (1), pH below 6 (1), bilateralism (2), kidney/U/B/U (1), passer (2), multiple organs (2), multiple number (2), incomplete removal (5), serum calcium (3), serum phosphorus (1), serum magnesium (1), serum creatinine (1), serum uric acid (4), urine volume (1), urine specific gravity (1), urine calcium (1), urine phosphorus (1), urine uric acid (5), urine magnesium (2), urine oxalate (8), urine citrate (8), calcium magnesium ratio (2), creatinine clearance (1), tubular reabsorption of phosphate (4), urine calcium oxalate ratio (2), urine oxalate citrate ratio (5), urine oxalate uric acid ratio (2), urine calcium uric acid ratio (2), stone COM/COD (2) and stone UA/cystine (2). After calculating the index, it was correlated with the clinical severity index. The severity status of each patient was considered as +/++/+++/++++ (nil/low/moderate/severe) depending on the status of the disease in long term assessment. In 127 patients, the risk index was calculated after a period of over 1 year to see the change in index score. On calculating the risk index and correlating with the severity grade of the stone disease, the correlation coefficient r value was +0.67 which was significant at P < 0.001 level. The risk index could be altered by dietary habit changes, drugs, life style changes, and appropriate drug schedules. The second assessment after 1 year of the 127 patients showed that the mean risk index could be reduced from 43.08 to 36.56. This difference was statistically significant ( P < 0.01). It is concluded that by using the present clinical risk index assessment, it is possible to arrive at a prediction regarding future stone formation in any individual. It is also possible to reduce the risk of stone formation by dietetic and life style changes and appropriate chemotherapeutic drugs. [ABSTRACT FROM AUTHOR]

Cystine stones are produced by an inherited disorder of the transport of amino acid cystine that results in excess of cystine in the urine (cystinuria). Cystine calculi in urinary tract present a significant problem in patients. We have recorded that cystine calculi are very uncommon in our region. Cystine crystals are unusually identified in the urinary deposits. The problem of recognizing cystine by FTIR as a component in mixture of stones is significant. The problem is compounded by the similarity of wavelengths of cystine with that of whewellite and uric acid. The objective of this paper is to elucidate the problems of identifying cystine in stone analysis and identifying a solution to get over this deficiency. Out of 1,300 urinary stones analysed by ordinary wet chemical methods and infrared spectroscopy, 30 stone samples, which were reported to have cystine peaks in significant numbers, were selected. These samples were powdered, mixed with potassium bromide, pelletized and taken up for FTIR analysis. The wavelength patterns were scrutinized by comparing with the peaks obtained by the reference standards of cystine. Spectra were also obtained from pure cystine. Comparison of spectra with those of whewellite and uric acid was performed. Then the samples were taken for Scanning electron microscopy with elemental distribution analysis X-ray (SEM–EDAX). The samples were made conductive by gold sputtering and were fed into JEOL JSM 35 C SEM machine. Morphology was recorded by taking photographs. Further elemental distribution analysis (EDAX) was carried out to identify the elemental composition. Of the 30 samples taken up for FTIR analysis, all showed spectra identifiable with the reference peaks for cystine. However, when these peaks were compared with those of whewellite and uric acid, all the stone samples showed duplication of peaks for whewellite and uric acid and whewellite. The pure cystine spectra showed identifiable peaks are in the range of 3026, 1618.28, 1485, 846.75 cm−1, etc. (from the standard spectrum of pure cystine). All the analysis findings were correlated with EDAX findings. On doing EDAX, we could separately find out the components present in a mixture. Three stones contained elemental pattern to fit with those of cystine. Even though it is difficult to find out the presence of cystine molecule in FTIR, it is possible to recognize it through EDAX and will be possible to confirm the presence of cystine in mixed urinary stones. [ABSTRACT FROM AUTHOR]

Stone analysis is incompletely done in many clinical centers. Identification of the stone component is essential for deciding future prophylaxis. X-ray diffraction, Fourier transform infrared spectroscopy, and scanning electron microscopy (SEM) still remains a distant dream for routine hospital work. It is in this context that optical microscopy is suggested as an alternate procedure. The objective of this article was to assess the utility of an optical microscope which gives magnification of up to 40× and gives clear picture of the surface of the stones. In order to authenticate the morphological analysis of urinary stones, SEM and elemental distribution analysis were performed. A total of 250 urinary stones of different compositions were collected from stone clinic, photographed, observed under an optical microscope, and optical photographs were taken at different angles. Twenty-five representative samples among these were gold sputtered to make them conductive and were fed into the SEM machine. Photographs of the samples were taken at different angles at magnifications up to 4,000. Elemental distribution analysis (EDAX) was done to confirm the composition. The observations of the two studies were compared. The different appearances of the stones under optical illuminated microscopy were mostly standardized appearances, namely bosselations of pure whewellite, spiculations of weddellite, bright yellow colored appearance of uric acid, and dirty white amorphous appearance of phosphates. SEM and EDAX gave clearer pictures and gave added confirmation of the stone composition. From the references thus obtained, it was possible to confirm the composition by studying the optical microscopic pictures. Higher magnification capacity of the SEM and the EDAX patterns are useful to give reference support for performing optical microscopy work. After standardization, routine analysis can be performed with optical microscopy. The advantage of the optical microscope is that, it is easy to use and samples can be analyzed in natural color. [ABSTRACT FROM AUTHOR]

Several plant preparations are administered for treatment of stone disease without scientific basis. This paper presents the results of in vitro and animal experimental studies using scanning electron microscopy (SEM) in the identification of the therapeutic properties of trial drugs in medicine. In the first set of the study, urinary crystals namely calcium oxalate monohydrate and calcium oxalate dehydrate were grown in six sets of Hane’s tubes in silica gel medium. Trial drugs namely scoparia dulcis Lynn, musa sapiens and dolicos biflorus were incorporated in the gel medium to identify the dopant effect of the trial drugs on the size and extent of crystal column growth. The changes in morphology of crystals were studied using SEM. In the second set, six male Wistar rats each were calculogenised by administering sodium oxalate and ethylene glycol and diabetised using streptozotocin. The SEM changes of calculogenisation were studied. The rats were administered trial drugs before calculogenisation or after. The kidneys of the rats studied under the scanning electron microscope showed changes in tissue morphology and crystal deposition produced by calculogenisation and alterations produced by addition of trial drugs. The trial drugs produced changes in the pattern of crystal growth and in the crystal morphology of both calcium oxalate monohydrate and calcium oxalate dihydrate grown in vitro. Elemental distribution analysis showed that the crystal purity was not altered by the trial drugs. Scoparia dulcis Lynn was found to be the most effective anticalculogenic agent. Musa sapiens and dolicos biflorus were found to have no significant effect in inhibiting crystal growth. The kidneys of rats on calculogenisation showed different grades of crystals in the glomerulus and interstitial tissues, extrusion of the crystals into the tubular lumen, collodisation and tissue inflammatory cell infiltration. Scoparia dulcis Lynn exhibited maximum protector effect against the changes of calculogenisation. Musa sapiens and dolicos biflorus had only minimal effect in preventing crystal deposition, inflammatory cell infiltration and other changes of calculogenisation. SEM was found to be effective in assessing the effect of drugs on crystal growth morphology and tissue histology. [ABSTRACT FROM AUTHOR]

Mixed stones form a significant number of all urinary stones. Accurate analysis of individual areas of stones is fraught with uncertainties. Scanning electron microscopy with elemental distribution analysis (SEM-EDAX) is a very important tool in assessing stone composition. The objective of this paper is to project the role of the combination of Fourier transform infrared (FTIR) spectroscopy and SEM-EDAX combination in achieving a total understanding of mixed stone morphology. Ten mixed urinary stones were washed and dried and the composition recognized by analysis of FTIR spectra by comparing with the spectra of pure components. Spectra for different layers were obtained. Then the stone samples were further studied by SEM-EDAX analysis. The findings of FTIR were correlated with SEM-EDAX and detailed data generated. Using SEM-EDAX, the spatial distribution of major and trace elements were studied to understand their initiation and formation. As much as 80% of the stones studied were mixtures of calcium oxalate monohydrate (whewellite) and calcium phosphate (hydroxyapatite) in various proportions. Quantitative evaluation of components was achieved through FTIR and SEM-EDAX analysis. It was possible to get an idea about the spatial distribution of molecules using SEM analysis. The composition of different areas was identified using EDAX. Analyzing with EDAX, it was possible to obtain the percentage of different elements present in a single sample. The study concludes that the most common mixed stone encountered in the study is a mixture of calcium oxalate monohydrate and calcium phosphate in a definite proportion. The combination identified not only the molecular species present in the calculus, but also the crystalline forms within chemical constituents. Using EDAX, the amount of calcium, phosphorus, oxygen and carbon present in the stone sample could be well understood. [ABSTRACT FROM AUTHOR]

Several modalities of stone analysis are utilised in different laboratories. However, the treating clinician finds it hard to assess the initiation and progression of stone formation. The pathogenesis of calculogenesis still remains a mystery. The purpose of this paper is to assess the pathological mechanisms of stone nucleation and growth by observing the ultra microscopic morphology of the different layers of laminated stones; 130 fragments from 28 randomly selected laminated stones of more than 10-mm diameter were analysed. Wet chemical analysis of the stones was performed. Surface and cross-sectional morphology of the entire stones and the individual fragments was assessed using optical microscopy and images were recorded using ordinary camera. They were further analysed using FTIR for confirmation. By morphological analysis, whewellite, weddellite, uric acid, and phosphate were the main minerals identified. Mixtures of these minerals were also found. Concentric lamination, radial striation, frond formation, and amorphous pattern were the main cross-sectional morphologies obtained. The calculi analysed had differences in their outer and inner portions. This was more pronounced in stones containing predominantly whewellite and uric acid. Whewellite was the outer component in most mixed stones. Uric acid was more in the inner layers of mixed stones than the surface. [ABSTRACT FROM AUTHOR]

Struvite, one of the components of urinary stone grows rapidly forming “staghorn-calculi”, is a painful urological disorder. It is necessary to study the growth-inhibition of Struvite crystals. This in vitro study has been carried out in the presence of the juice of Citrus medica Linn. by using single diffusion gel growth technique. Sodium metasilicate solution of specific gravity 1.05 and an aqueous solution of ammonium dihydrogen phosphate of 0.5 M concentration were mixed so that the pH value 7.0 could be set. After the gelation, supernatant solutions comprising of pure 1.0 M Magnesium acetate (control solution) as well as mixed with the different concentrations of the juice were gently poured on the set gels. From the study of growth-inhibition behavior of Struvite crystals, it was found that Citrus medica Linn. inhibits the growth of the crystals. This study may be used for formulating the strategy for prevention or dissolution of Struvite. [ABSTRACT FROM AUTHOR]

We assessed the potential of dual-energy computed tomography (CT) for the differentiation between uric acid (UA)-containing and non-UA-containing urinary stones. Forty urinary stones of 16 different compositions in two sizes (< and ≥ 5 mm) were examined in an ex vivo model. Thirty stones consisted of pure calcium oxalate (whewellite or wheddellite), calcium phosphate (apatite, brushite, or vaterite), ammonium magnesium phosphate (struvite), UA, ammonium acid urate, ammonium phosphate, sodium hydrogen urate, or cystine, and ten stones were of mixed composition (UA-sodium hydrogen urate, whewellite-urate, wheddellite-urate, whewellite-brushite, or whewellite-brushite-struvite). Scans were performed using dual-source CT in a dual-energy mode with the tubes simultaneously operating at 80 and 140 kV. Two readers analysed the data with respect to stone attenuation at each energy level. The stones were classified as UA- or non-UA-containing using manual attenuation measurements and software analysis results. Sensitivity, specificity, PPV, and NPV were calculated using crystallographic stone analysis as the gold standard. Twenty-six out of 40 stones (65%) contained no UA; 14 stones (35%) contained UA. When compared with UA-containing stones, the differences in attenuation values at 80 and 140 kV were significantly ( P < 0.001) higher in stones containing no UA. The software automatically mapped 39/40 stones (98%). Only one (2%) 2 mm UA-stone was missed. The software correctly classified all detected stones as UA- or non-UA-containing. The attenuation values of the missed stone were manually plotted into the analysis sheet which allowed for the correct classification of the stone (containing UA). Therefore, the sensitivity, specificity, PPV, and NPV for the detection of UA-containing stones was 100%. Ex vivo experience indicates that differentiation between UA- and non-UA-containing stones can be accurately performed using dual-source dual-energy CT. [ABSTRACT FROM AUTHOR]

We investigated the effects of a traditional Chinese herbal formula, Wulingsan (WLS), on renal stone prevention using an ethylene glycol-induced nephrocalcinosis rat model. Forty-one male Sprague-Dawley (SD) rats were divided into four groups. Group 1 ( n = 8) was the normal control; group 2 ( n = 11) served as the placebo group, and received a gastric gavage of starch and 0.75% ethylene glycol (EG) as a stone inducer; group 3 received EG and a low dose of WLS (375 mg/kg); and group 4 received EG and a high dose of WLS (1,125 mg/kg). Baseline and final 24 h urine samples were collected individually; biochemical data of urine and serum were also obtained at the beginning and at the end of the experiment. After 4 weeks, animals were killed and kidneys were harvested. The kidney specimens were examined by polarized light microscopy and the crystal deposits were evaluated by a semi-quantitative scoring method using computer software ( ImageScoring). The results revealed that the rats of placebo group gained the least significant body weight; in contrast, the rats of WLS-fed groups could effectively reverse it. The placebo group exhibited lower levels of free calcium ( p = 0.059) and significantly lower serum phosphorus ( p = 0.015) in urine than WLS-fed rats. Histological findings of kidneys revealed tubular destruction, damage and inflammatory reactions in the EG-water rats. The crystal deposit scores dropped significantly in the WLS groups, from 1.40 to 0.46 in the low-dose group and from 1.40 to 0.45 in the high-dose group. Overall, WLS effectively inhibited the deposition of calcium oxalate (CaOx) crystal and lowered the incidence of stones in rats ( p = 0.035). In conclusion, WLS significantly reduced the severity of calcium oxalate crystal deposits in rat kidneys, indicating that Wulingsan may be an effective antilithic herbal formula. [ABSTRACT FROM AUTHOR]

Perforation of the upper ureter is a rare but serious complication of extracorporeal shock wave lithotripsy (SWL). Ureteral perforation can cause a series of problems including the retroperitoneal urinoma, urosepsis, abscess formation, infection, and subsequent renal function impairment. We reported here a rare case of SWL-induced upper ureteral rupture resulting in an expanding retroperitoneal urinoma that required percutaneous drainage. Ureteral perforation was treated successfully without major surgical intervention by employing temporary percutaneous drainage and antibiotics. The present case indicates that potential ureter rupture may form in rare cases; especially in patients having infected stones and exposed to a high number of shock waves. This complication further emphasizes the importance of adequate pre-and post-operative evaluation and the precise identification of the cause of the persistent pain after SWL. [ABSTRACT FROM AUTHOR]

Each of 92 patients in a Swedish district served by only one hospital had been treated for their first renal stone in 1977 and was evaluated 10 years later. Recurrent stone formation during the observation period was observed in 26% of the patients, with no difference between men and women. Of all the patients who had sought medical advice in 1977 because of urinary stone colic, 51% were experiencing their first stone episode. Ten years later 37% of the original patients were still classified as single stone formers. The recorded recurrence rate was lower than that prevously reported in the literature. [ABSTRACT FROM AUTHOR]