Changes in the incidence of lower urinary tract stones in Japan from 1965 to 1995

BACKGROUND: The changes over time of the annual incidence of lower urinary tract stones in Japan from 1965 to 1995 were analyzed. METHODS: Data on lower urinary tract calculi were abstracted from the past three nationwide surveys of urolithiasis, which covered nearly all major hospitals and urologists in Japan and enumerated all outpatient visits diagnosed as urolithiasis in the years 1965, 1975, 1985 and 1995. Chronological changes in the sex- and age-related annual incidences of lower urinary tract stones and stone composition were estimated. RESULTS: Lower urinary tract stones were predominant in men 60 years of age or older. Between 1965 and 1995, the annual incidence has significantly decreased in men > or = 60 years of age from 37.2 to 27.0 per 100000 and significantly increased in women > or = 60 years of age from 2.4 to 4.8 per 100000. In men, an increased proportion of uric acid and calcium stones as well as a decreased frequency of infection stones is a phenomenon common to upper urinary tract stones. However, infection and calcium stones have been two major stone types in women. CONCLUSIONS: In contrast to upper urinary tract calculi, the incidence of lower urinary tract stones has decreased over the last 30 years in men > or = 60 years of age predisposed to this disease.     

Characteristics of pediatric urolithiasis in south-east Anatolia

BACKGROUND: Urolithiasis is endemic in Turkey and characteristics of urolithiasis vary in different regions of the world. The aim of the present study was to evaluate the etiological and clinical characteristics and course of pediatric urolithiasis in south-east Turkey. METHODS: The study population consisted of 81 children (52 girls) with urolithiasis at a mean age of 6.2 +/- 4.2 years who were followed up for 1-32 months. RESULTS: Metabolic disorders, anatomical defects and infection stones were found to be the etiological factor in 34.6, 29.6 and 22.2% of patients, respectively, while 13.6% of patients were considered idiopathic. Of all patients, 28.4% were admitted with acute renal failure (ARF) and 72.8% had urinary tract infection. Recurrence was seen in 19.8% of patients at presentation. The localization of the stone was found to be in the upper urinary tract, the lower urinary tract or both in 65.4, 14.8% and 17.3% of patients, respectively. Patients with multiple and bilateral stones had a higher risk for ARF than the others. The risk for chronic renal failure was significantly higher in children with multiple, bilateral or recurrent stones and with ARF at presentation. CONCLUSIONS: Early diagnosis and management of renal stones and urinary tract infections is necessary to prevent the development of ARF or chronic renal failure and to improve the quality of a patient's life.     

Clinical analysis of urolithiasis in Poh Ai Hospital of I-Lan, Taiwan, R.O.C.--a comparative study with urolithiasis in Japan]

Between August 1987 and December 1990, 546 patients were admitted to the department of Urology at the Poh Ai Hospital of I-Lan, Taiwan, R.O.C. for the treatment of urinary stones. These urinary stone cases accounted for 50 to 60% of all urology patients admitted. The incidence of urolithiasis in I-Lan was estimated at 147/100,000 population in 1990. There were 402 male patients and 144 female patients, The male to female ratio was 2.8: 1. There were 450 upper urinary tract stones (kidney, ureter) in 314 males and 136 females, and 79 lower urinary tract stones (bladder, urethra) in 72 males and 7 females. The ratio of upper to lower urinary tract stones was 6:1. Endourological treatments such as percutaneous nephrolithotripsy and transurethral ureterolithotripsy have increased rapidly in recent years. A summary of the present analysis for composition of 365 stones follows. The most frequent type was calcium-containing stone (92.3%), followed by infection stone (4.7%), then uric acid (UA) stone (3.0%). There were no UA stones found in the female patients. According to urinalysis criteria of more than 10 WBC/HPF (x 400), pyuria was found in 67 cases of 334 metabolic stones (20.1%), and 11 cases of 17 infection stones (67.7%). There were neither pediatric case of stone formation nor cystine stones.     

Epidemiological characteristics of urolithiasis in Okhotsk coast area in Hokkaido

An epidemiological study of 422 stone-formers who visited our hospital from 1997 to 2001 was conducted. The mean annual prevalence and incidence of both upper and lower urinary tract stones were higher than what was found in a nationwide urolithiasis survey carried out in Japan in 1995. The incidence of upper and lower urinary tract stones was 90.8% and 9.2%, respectively. The frequency of lower urinary tract stones was higher than that found in the previously mentioned nationwide study. The male-to-female ratio of upper and lower urinary tract stones was 1.68:1 and 2.25:1, respectively. The frequency in females was higher in this study than that found in the nationwide survey. The peak age for incidence of upper urinary tract stones is 50s in males and females. In the treatment of upper urinary tract stones, ureteroscopic lithotripsy was carried out more often than shock wave lithotripsy (SWL), because our hospital had no SWL device. Many endoscopic lithotripsy procedures were performed to treat stones located in the lower urinary tract. Of the upper urinary tract stones 83.7% were composed of calcium, the incidence of uric acid stones was high (6.6%), whereas the incidence of infectious stones was low (1.9%). For lower urinary tract stones, the frequency of infectious stones was high (52.6%). In the present study, the epidemiological features were as follows: high annual prevalence and incidence, high frequency of lower urinary tract stones, high frequency in females, many endoscopic treatment procedures and high frequency of uric acid stones in the upper urinary tract.     

Urolithiasis in Northeast Bombay: Seasonal prevalence and chemical composition of stones

The seasonal prevalence of urinary calculus disease from the records of L. T. Municipal General Hospital, Sion, Bombay, which primarily caters services to poor people of Northeast Bombay, especially Dharavi slum area, is reported. The qualitative and quantitative compositions of stones collected from the patients of Dharavi slum area are also described. Interestingly, the prevalence of bladder stones (BSF) was lower than that of upper urinary tract stones (UUTSF) which suggests the possibility of involvement of environmental pollution. As regards total number of stone patients, a sharp fall in male BSF in March and increase in male UUTSF in November were evident. In females the number was maximum in April in both BSF and UUTSF. However, no recognizable pattern of seasonal variation was seen in operated stone patients indicating that metabolically active disease is unrelated to season. Prevalence of bladder stones in children was high and male/female ratio was about 5. All stones were of the mixed type. Infection was not a major contributor of stone growth. Calcium oxalate was the major constituent and ammonium acid urate was present in the majority of stones.     

Composition chimique des calculs urinaires et caractéristiques épidémiologiques associées en République Démocratique du Congo

To compare the chemical composition of the upper and lower urinary tract stones in Congolese patients, and to identify factors associated with the different types of stones. Stones from 119 patients originating from the upper tract and 75 from the lower tract were analyzed by infrared spectrophotometry. Among 119 patients with upper tract stones, age ranged from 10 to 81 years with a mean (SD) of 45.8 (13.6) years; males were the majority (55.5%). The main types of stones identified were whewellite (79%). For the 75 patients with lower apparatus stones, age ranged from 4 to 87 years with a mean (SD) of 51.6 (21.6) years; the majority were males (89.3%). The main types of stones were whewellite (44%) and anhydrous uric acid (22.7%). Overall, the factors associated with calcium oxalate included: site [4.95 (95% CI 2.35-10.44)] and diameter [3.03 (95% CI 1.45–6.25)]; patient's place of residence [0.05 (95% CI 0.01–0.29)] was associated with calcium phosphate. Infection stones were associated with; site [0.19 (95% CI 0.06–0.63)] and diameter [0.10 (95% CI 0.03–0.38)]. Finally, age 0.26 (95% CI 0.09–0.71) and stone site [0.23 (95% CI 0.07–0.68)] were associated with uric stones. The epidemiological and chemical profile of upper and lower tract stones were different. Several factors were associated with the chemical and crystalline composition of stones in the Democratic Republic of Congo.     

Clinical studies on childhood urolithiasis during the past 22 years

We have studied retrospectively 68 children who presented with urolithiasis between 1965 and 1986. Male to female ratio was 1.83 to 1 and the mean age was 9.5 years. Fifty four children (79%) had calculi in the upper urinary tract, 9 (13%) had in the lower, and 4 (6%) had calculi both in the upper and lower urinary tract. The most common presenting symptoms were gross hematuria (53%) and abdominal or flank pain (38%). Predisposing factors could be found only in 21 children (31%). Twenty four of the 68 patients (35%) had open surgery and 16 patients (24%) passed their stones spontaneously. Twenty one stones were analyzed by infrared spectroscopy. Infectious stone was more frequent than in adult cases. Among children five years old and younger, infectious stone was the most frequent. Among children over five years old, the number of idiopathic calcium stone has been on the increase with the years.     

Urolithiasis in adult spina bifida patients: study in 260 patients and discussion of the literature

Purpose

To describe incidence and risk factors of urinary tract stones in adult spina bifida (SB) patients. Although spina bifida patients have an allegedly higher risk of urinary tract stones, only two small non-English case series are available and do not provide adequate epidemiological data and analyses on risk factors.

Methods

A total of 260 adult SB patients followed in our centre for 10 years were retrospectively analysed for stone disease. Both a univariate analysis (Fisher’s exact, two-sided Student’s t test) and a binary logistic regression analysis were performed to identify independent risk factors for stone disease.

Results

Of the 260 patients, 24 (9.2 %) were identified with a history of urolithiasis. Fourteen patients (5.4 %) had bladder stones in 26 episodes. Sixteen patients (6.2 %) had upper urinary tract stones: 14 kidney stones and two ureteral stones. Lifetime incidence of both bladder stones and upper tract stones was 2.25 per 1,000 patient-years. Recurrent urinary tract infections (OR 4.34, p = 0.013) and incorporation of bowel tissue into a continent reservoir (including enterocystoplasty) (OR 4.80, p = 0.012) were independent risk factors for bladder stone disease in a multivariate model. An indwelling catheter was an independent predictor for upper tract stones (OR 5.89, p = 0.02).

Conclusions

Urolithiasis, especially in the bladder, is a frequent finding in patients with SB. Bladder stones occur about 10 times more often in SB patients than in the population. In patients without risk factors, frequent ultrasound of the urinary tract is not necessary for the sole detection of stones.     

Incidence of urolithiasis in cystectomy patients after intestinal conduit or continent urinary diversion

The purpose of this study was to determine the incidence of nephrolithiasis in radical cystectomy patients treated with either intestinal conduit or continent urinary diversion. The charts from 94 patients who had undergone radical cystectomy with urinary diversion at our institution from 1988 to 1998 were reviewed retrospectively for this study. Charts and radiographs from all patients were examined for renal function and evidence or urinary tract calculi. Two groups were compared: group I patients had undergone diversion with an intestinal conduit, and group II patients had received a continent diversion (primarily involving an Indiana pouch). Conduit diversions were typically done with a freely refluxing anastomosis (Bricker), whereas continent diversions were done with a nonrefluxing ureteral-intestinal anastomosis. Group I consisted of 54 patients who had undergone ileal conduit (50) or colon conduit (4) diversion with a mean follow-up of 2.5 years (range 0.6–7.0 years). Group II consisted of 40 patients who had undergone continent diversion (33 Indiana pouches, 7 orthotopic diversions) with a mean follow-up of 3.1 years (range 0.5–10.5 years). Laboratory studies of serum blood urea nitrogen, creatinine, and CO₂ were similar between the two groups. Six patients in group I developed urolithiasis, all in the upper tract. Stones developed at a mean of 3.1 years after urinary diversion. Three patients required operative intervention, whereas the others were managed expectantly. One patient in group II had an upper tract stone at the time of presentation for his bladder cancer, but no patient developed new upper tract stones during the present study period. Two patients in group II developed pouch calculi at a mean of 5 years after diversion; both required surgical intervention. In our study the risk for upper tract urolithiasis seemed higher in the intestinal conduit group (group I), with 11% of the patients developing stones. In the continent diversion group, no patient developed upper tract stones, although two patients (5%) developed pouch stones. Refluxing urine may contribute to an increased risk for stone formation after urinary diversion, whereas pouch stasis may contribute to stone formation in the continent diversion group.     

The relation between urinary tract infections and stone composition in renal stone formers

During a seven-year period (1975-1981) a total of 1325 patients hospitalized for stone disease were studied as to the occurrence of positive urine cultures. Urinary stones from 535 surgically treated patients were analyzed with infrared spectrophotometry and the relationships between stone composition, level of surgery and bacteriological strains were studied. Positive urinary cultures were found in 34% of the surgically treated patients and in 21% of those not operated upon. Among the surgically treated patients with urinary tract infection (UTI) E. coli was the most frequent microorganism (35%), followed by Proteus (28%). Patients with Proteus infection had the highest frequency of UTI episodes, most of which occurred before hospitalization. There was a higher frequency of magnesium ammonium phosphate (MAP) calculi among patients with Proteus infection than among those with non-Proteus infection, in whom no difference in stone composition was found. Patients infected with E. coli had more phosphate-containing stones (CaP+MAP) than non-infected patients. The highest frequency of oxalate calculi (CaOx+CaOx/CaP) was found among patients without infection. No E. coli infections were seen in male patients with CaP and MAP calculi. MAP stones were most often found in the kidney and oxalate stones in the ureter.     

Evaluation of a synchronous twin-pulse technique for shock wave lithotripsy: the first prospective clinical study

OBJECTIVE: To present the results of the first clinical study of a synchronous twin-pulse technique for extracorporeal shock-wave lithotripsy (ESWL), which is effective for in vitro stone fragmentation and safe when assessed in vivo on animal tissue. PATIENTS AND METHODS: Fifty patients with urinary stones (35 men and 15 women) were enrolled and treated with the TWINHEADS lithotripter. The entry criteria were: age > or = 18 years, with a radio-opaque single stone in the kidney or upper ureter, a normal laboratory profile (serum creatinine, liver function, blood, bleeding and clotting times, and prothrombin concentration). The exclusion criteria included lower ureteric stones, patients with urinary tract infection, obstructed urinary tract distal to the stones, or congenital abnormalities. All patients received one session and were evaluated by ultrasonography (US), urinary tract plain X-ray, and complete laboratory investigations before and immediately after treatment, and after 2, 14 and 30 days. Patients requiring re-treatment at the 14-day visit received a second session and were re-evaluated after 7 and 14 days. RESULTS: The mean (sd, range) stone size (longest diameter) was 12.3 (2.6, 9-18) mm. Intravenous sedation was used in 30 patients. There was mild haematuria in 25 patients on the day of treatment. During the follow-up there was no evidence of haematoma, gross renal injury, upper urinary tract obstruction or significant changes in the laboratory investigations. After 14 days, 17 patients (34%) were free of stones, with residual stones of < or = 5 mm in 20 (40%); they were free of stones at the 1-month follow-up. Thirteen patients (26%) had residual stones of 6-9 mm, but the stones were half or less of the original size. Patients with residual stones of > 5 mm had another ESWL session and were free of stones within 14 days. Thus all patients were rendered stone-free within 1 month. CONCLUSIONS: Synchronous twin-pulse ESWL is promising, seems safe and effective for treating patients with renal and upper ureteric lithiasis.     

Surgical treatmnt for urolithiasis (in view of medical economics)

Surgical treatment for upper urinary stones has dramatically changed since extracorporeal shock wave lithotripsy (ESWL) was introduced in 1985 in Japan. Since then, the number of ESWL apparatus is increasing year by year, and there were about 800 ESWL apparatus available in Japan in 2001. On the other hand, the number of patients with upper urinary stones are also increasing in Japan, and the age-adjusted annual incidence of first-episode upper urinary tract stones in 1995 was estimated at 68.9 per 100,000 (100.1 in men and 55.4 in women), a steady increase from 54.2 in 1965. Under these circumstances, it would be very important to treat stone patients surgically even from an economical point of view, because the cost of ESWL is very expensive and more than 90% of the patients with urolithiasis are now treated by ESWL. In this paper, the medical economics of urolithiasis in Japan is discussed especially in the surgical treatment.     

Flexible ureterorenoscopy for the treatment of refractory upper urinary tract stones.

OBJECTIVE: To report our experience of using flexible ureterorenoscopy for upper urinary tract stones. PATIENTS AND METHODS: Thirty-seven patients (13 females, 24 males, mean age 48 years, range 10-76) with upper urinary tract stones not responding to other treatments had their residual symptomatic stones treated through a 9.3 F flexible ureterorenoscope. Electrohydraulic lithotripsy (EHL) was used to fragment the stones and a basket or a grasper used to retrieve the fragments. RESULTS: Twenty-three patients were completely freed of stone and a further five had asymptomatic residual fragments of < 5 mm. Of 15 patients with ureteric stones, 14 were rendered stone-free at the end of the procedure and 14 of the 22 patients with kidney stones were treated successfully; 80% of the lower calyceal stones were treated successfully and a firm decision was possible on the further management of the remaining stones. There were no major complications. CONCLUSION: Flexible ureterorenoscopy should be considered in patients with symptomatic upper ureteric or renal stones refractory to other treatments, but the instrumentation is expensive and delicate, and its use should be reserved for such cases.     

National trend of the incidence of urolithiasis in Japan from 1965 to 1995

BACKGROUND: A nationwide survey of urolithiasis in Japan was made in order to evaluate the chronological trend of upper urinary tract stones in the Japanese. It succeeded previous studies done in 1955, 1966, 1979, and 1990. METHODS: All outpatient visits to urologists that resulted in a diagnosis of first-episode upper urinary tract stones in the years 1990 and 1995 were enumerated, irrespective of admission and treatment. The study enrolled all of the Japanese Board of Urology-approved hospitals, thereby covering nearly all urologists practicing in Japan. The annual incidence by sex and age was estimated and compared with the incidences in the previous nationwide surveys. RESULTS: The age-adjusted annual incidence of first-episode upper urinary tract stones in 1995 was estimated as 68.9 per 100,000 (100.1 in men and 55.4 in women), a steady increase from 54.2 in 1965. The annual incidence has increased in all age groups, except in those of the first three decades. The peak age for both sexes has shifted in toward the older population's direction. Estimations of longitudinal changes between 1965 and 1995 showed that the annual incidence has more than doubled for the cohort of the 1965 census population (from 43.7 in 1965 to 110.9 in 1995) and that younger generations have had progressively higher annual incidences. CONCLUSIONS: The annual incidence of upper urinary tract stones in Japan has increased steadily over the past 30 years and will continue to do so in the near future, but it still is lower than in the United States.     

The bacteriology of operated renal stones

In a group of patients consecutively operated on for renal stones, more than half of the patients had urinary tract infection. In a significant number of the patients with infection stones containing magnesium ammonium phosphate, no urease-producing microorganism could be cultured. Escherichia coli was on the other hand rather frequently cultured from the stone in these patients. This suggests the possibility that E. coli might be involved in stone formation. The correlation between stone and voided urine cultures was incomplete. It is thus important to perform stone cultures. This could be done without loss of accuracy by culturing crushed stones.     

Bacteriology of upper urinary tract stones

Extensive cultures of stones and urine were performed in 215 patients who underwent an operation for upper urinary tract calculi. Microorganisms could be cultured from the stone in 1 of every 3 patients. Despite the extended culture technique urease-producing microorganisms could be cultured from the stone in only 48% of the patients with calculi that contained magnesium ammonium phosphate. This finding suggests that an infection with urease-producing microorganisms is not obligatory for the formation of this type of stone. Of the patients with calcium oxalate phosphate stones 32% had positive stone cultures, which distinguished them from patients with pure calcium oxalate stones, only 8% of whom had a positive stone culture (p less than 0.001).     

Extracorporeal shock wave lithotripsy: the evolution of a revolution

Extracorporeal shockwave lithotripsy has now been in clinical use for 8 years, and it has replaced other treatment techniques for the majority of surgical calculi in the upper urinary tract. For the first time it provides a completely noninvasive method for the treatment of renal and ureteral calculi. The current range of indications means that approximately 70% of nonselected urinary stone patients can be treated by this method, while 25% of the patients with more complex stones in the upper urinary tract can receive treatment with the lithotripter combined with endourological procedures. The clinical role of this method is determined by a high success rate and minimal complications. This has led to a rapid worldwide acceptance in the urological community, and up to now more than 1.5 million patients with urinary stone disease have been treated.     

Recurrence of upper urinary tract calculi

Treatment of upper urinary tract stones has changed greatly. The recurrence of calculi after the discharge was studied in the 634 patients with urolithiasis admitted to our department during the 9 years up to the end of 1984. The recurrence rate in the 325 cases followed for more than 3 months after the disappearance of the original stones, was 15.6% after 2 years, 27.6% after 5 year and 51.4% after 8 years. In recurrent stone formers, the rate of recurrence thereafter was greater than that of primary stone formers. The growth of calculi was rapid in the renal stone former concomitant with urinary tract infection together with a past history of renal surgery. In relation to the composition of the stone, uric acid calculi tended to recur more often than calculi composed of other substances. In view of recurrence, pyelolithotomy is preferred to renal parenchymal incision.     

Urinary tract stone disease in modern Japan. Stone incidence, composition and possible causes in Osaka district

2,969 stones, obtained from affiliated hospitals as well as the Osaka University Urologic Clinic were analyzed by infrared spectrophotometry. 2,724 of the 2,969 stones were obvious upper urinary tract stones, and the composition of these 2,724 stones is reported. The incidence and possible cause of stones in 750 patients with upper urinary tract calculi, managed in Osaka University Urologic Clinic, are discussed, as well as the recent figures on urinary tract stone disease in Osaka district. These figures are representative of stone disease in Japan.