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Query: UMLS:C0403608 (ureter)
 9,655 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Previous in vitro experiments demonstrated the reduced microhardness of calcium oxalate monohydrate (COM) calculi, relative to dry values, when saturated with an alkaline solution (pH = 9.5). Nineteen patients with a COM calculus in the distal ureter which had been resistant to prior extracorporeal shock wave lithotripsy in situ, were treated when the stone was surrounded by alkaline urine. The urine of 14 patients was alkalinized orally by administration of acetazolamine and citrate solution; in 5 other patients direct percutaneous irrigation of sodium bicarbonate via a nephrostomy tube was carried out. The urinary pH just before lithotripsy was greater than or equal to 9 in 17/19 patients. 4,000 shock waves, averaging 18.1 kV generated by the Siemens Lithostar, were delivered onto the calculus. No significant increase of comminution rate was apparent at radiographic control immediately after the treatment and only in half of the cases was evacuation obtained within 3 months.
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PMID:Effect of alkalinization on calcium oxalate monohydrate calculi during extracorporeal shock wave lithotripsy: in vivo experiments. 131 63

A 66-year-old female visited our university hospital with the chief complaint of right lower abdominal pain in July, 1984. Kidney-ureter-bladder roentgenograms disclosed the right ureter stone and several left renal stones. She passed the right ureter stone composed of calcium oxalate. Thereafter, she passed small stones twice and sand stones twice until September, 1985. The stone analysis revealed two of them as silica. Although most patients with silica stones reported in Japan had a history of long-term medication of magnesium trisilicate, this patient had not taken this drug. Silica stones are rare and fifteen cases including the present case have been reported in Japan.
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PMID:[Silica calculi: a case report]. 165 20

Blind ending bifid ureter is a rare anomaly in the urinary tract. This anomaly may result from failure of a premature branch of the ureteral bud to join with the metanephric blastema. A 21-year-old man was admitted with macroscopic hematuria and colic pain in the left flank region. Urinalysis demonstrated hematopyuria and excretory urography suggested bifid ending accessory ureter with a stone on the left side. Surgical exploration showed that the accessory ureter was bifurcated from the left ureter at about 5 mm from the bladder wall and ran parallel with the left ureter. Although dense adhesions to the surrounding tissue existed, the accessory ureter was resected at the site of the junction. It measured 3 cm in length and 1 cm in greatest diameter. The stone found at the tip of the accessory ureter was composed of calcium oxalate (24%) and calcium phosphate (76%). Histological examination revealed that the ureter had all layers of normal ureteral structure and no renal tissue was identified in the specimen resected. During a follow-up period of 22 months after the operation, he was free of urinary tract infection and abdominal pain. Of 77 cases with blind ending bifid ureter reported in the Japanese literature, a ureteral stone was found in the blind branch in only 5 cases.
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PMID:[Blind ending bifid ureter with stone in the blind branch: report of a case]. 185 88

A 3.3F electrohydraulic electrode (Wolf 2137.23) has been confined within a spring with a metal end cap, irrigated with water and covered with a 0.003-inch metal sheath (outside diameter 5F). The electrohydraulic lithotripsy discharge (Wolf Generator 2137.50) at E1 causes the metal cap to extend 3 mm. at 1,500 cm. per second and creates an impact pressure of 600 to 800 bar. Stone fragmentation efficiency of the electromechanical impactor was equivalent to unshielded electrohydraulic lithotripsy (gallstone 2.83 mg. per pulse, struvite/apatite 1.41 mg. per pulse, cystine 0.41 mg. per pulse, uric acid 1.48 mg. per pulse and 100% calcium oxalate monohydrate 0.10 mg. per pulse). Studies of the discharge of the electromechanical impactor within the pig ureter showed that minimal ureteral submucosal edema and hemorrhage occurred at 300 shocks discharged at a single point, and disruption of the mucosa and partial injury to the muscle layer occurred after 600 shocks given at the site of a pinched pig ureter. Pushing the electromechanical impactor perpendicular to the wall of the pig bladder will create a mechanical perforation within 35 shocks (electrohydraulic lithotripsy within 2 shocks). One patient had excellent fragmentation of a lower ureteral mixed monohydrate and dihydrate stone under direct vision performed with the electromechanical impactor passed via a 9.5F ureteroscope. There was no evidence of mucosal injury with 500 shocks. The electromechanical impactor has been developed to provide a safe and inexpensive method of ureteral stone fragmentation or disimpaction. These studies were performed to establish limits of safety that may allow use of the electromechanical impactor for stone fragmentation in the ureter without the need for ureteroscopy.
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PMID:Conversion of the electrohydraulic electrode to an electromechanical stone impactor: basic studies and a case report. 187 85

A series of 270 paediatric stone patients was studied retrospectively according to the clinical pattern of urolithiasis (age and sex, stone location, stone analysis, recurrence rate) and aetiology of stone disease (infection, anatomical, metabolic or idiopathic). Infection stones occurred earliest and more commonly in males and were usually upper tract struvite calculi related to Proteus infection. Anatomical stones were most commonly associated with pelviureteric junction (PUJ) obstruction and had a high recurrence rate, despite surgical correction of obstruction. Idiopathic stones most resembled those found in adult urolithiasis by virtue of occurring latest, being sited in the ureter more often and being more frequently composed of calcium oxalate. Metabolic stones were most frequently calcium phosphate or cystine and virtually all were renal. They comprised the smallest group but had the highest recurrence rate.
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PMID:Clinical patterns of paediatric urolithiasis. 188 49

The pulsed dye laser represents a new tool in the treatment of ureteral calculi. Laser energy channeled through a delicate optical fiber is used to disimpact and fragment calculi. Standard ureteroscopic instruments including graspers, baskets and dilatation balloons can be used with the laser system. Interchangeable optical fibers ranging from 200 to 400 micrometers deliver up to 120 mJ of energy to the stone's surface. For two weeks in 1989 an endourology clinic was held in upper Egypt. Eighty patients ranging in age from nine years to sixty-seven years old were evaluated and treated endoscopically. Endoscopes ranging from 6.9F to 12.5F were used to deliver the optical fiber. All stones visualized endoscopically were fragmented. Greater than 60 percent of the stones fragmented were composed of pure calcium oxalate monohydrate. Schistosoma hematobium was endemic among our study group. Bilharzial strictures of the distal ureter were noted in 30 percent of these patients. Treatment of these strictures using both balloon dilatation and graduated Teflon dilators is reviewed. Techniques in treating different types of ureteral calculi were explored. Large calcium oxalate dihydrate stones were treated most efficiently with the 3-point fragmentation technique. The shear off-center technique was used for the calcium oxalate monohydrate calculi. Variations in total energy delivered and frequency of pulsation allowed for prompt stone disimpaction as well as prevention of retrograde fragment migration. Concurrent use of stone baskets and graspers with the pulsed dye laser was explored.
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PMID:Techniques in endoscopic lithotripsy using pulsed dye laser. 199 81

To minimize urothelial tissue injuries by inadvertent laser irradiation during the laser stone fragmentation, we developed a novel fiber-optic analysis system which is able to distinguish the urothelial tissues from urinary stones. The reflection mode of the pulsed photo-thermal radiometry (PPTR) was employed for non-destructive tissue characterization. We developed the first fiber-optic PPTR system using chalcogenide infrared glass fibers as a transmission line. As excitation light sources for the samples, three different lasers were used in vitro and compared to select the proper excitation laser which is able to distinguish wet urinary stones from urothelial tissues. The e-folding decay time of the PPTR waveform, by which the samples are characterized, was measured as an index. The ultraviolet argon (UV Ar) laser had the best discriminative faculty. Using UV Ar laser, the e-folding decay time of calcium oxalate stones, uric acid stones and the ureter, was 239 +/- 57 ms, 33 +/- 4 ms, and 102 +/- 24 ms (p less than 0.001), respectively. The new analysis system which was composed of the fiber-optic PPTR analyzer using UV Ar laser excitation together with a thin-fiber endoscope was applied to measure the e-folding decay time of PPTR waveform of urinary stones and canine ureters in vivo general anesthesia. The e-folding decay time of calcium oxalate stones, uric acid stones and the ureter was 153 +/- 15 ms, 26 +/- 3 ms and 246 +/- 31 ms, respectively. The canine ureter was clearly differentiable from urinary stones by the measurement of the e-folding decay time of PPTR waveform.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:[The prevention method of inadvertent irradiation during laser stone fragmentation by the fiber-optic radiometry analysis]. 205

137 patients were treated by ESWL with a Sonolith 2000 lithotriptor using ultrasonography localization. 132 patients were eligible for review. Calculi were caliceal in 85 cases, pelvic in 51 cases, in the upper ureter in 1 case; 26 stones were treated by the "push and bang" technique with ureteric stent. Fragmentation rate was 83.9% and stone free rate at 3 months was 68.5%. Failure cases were reviewed: non fragmentation (16.1%) and insufficient fragmentation (15.6%): 14 calculi were analysed by infra red spectrophotometry and correlated with radiodensity on pre ESWL plain X-ray. Hardness and friability criteria were described. Calculi with different radiographic appearances respond differently to shock wave fragmentation. Some stone compositions such as calcium oxalate monohydrate pure or mixed with apatite and calcified uric acid are difficult to break by ESWL. These calculi represented almost 30% of the series. Another treatment should be proposed to improve the results of ESWL.
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PMID:[Effect of the chemical nature of urinary calculi on the results of extracorporeal shockwave lithotripsy]. 218 23

A pulsed dye laser (Candela) was used in our lithiasis treatment center during the period 02/88-09/89 to remove 325 calculi in 278 patients, requiring 285 endoscopic instrumentations. The pulsed laser allowed to obtain fragmentation of 318 calculi, 238 of which were reduced to thin sand and 80 to coarser fragments. The latter were either cleared using a Dormia probe or further disintegrated by electrohydrolytic shock wave treatment or extracorporeal shock wave lithotripsy (ESWL). No complication imputable to laser stone fragmentation was noted. Failure of stone clearance was chiefly due to the nature and shape of the stone (black, smooth monohydrated calcium oxalate calculi). The thinness of the laser fiber has made it possible to use small caliber ureteroscopes, thereby increasing the reliability of ureteroscopy. Coupled with ESWL (EDAP LT01), this technique has caused the rate of open surgical removal of ureter confined calculi to fall from 11% to 1%.
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PMID:[Rigid ureteroscopy and the pulsed laser. Apropos of 325 treated calculi]. 221 6

The rate of residual stones and that of recurrent lithiasis were investigated in 183 patients who had undergone extracorporeal shock wave lithotripsy (ESWL) between July, 1986 and December, 1988. The investigation was done by questionnaire survey at 22 institutions including our hospital on patients who were followed up after ESWL. The 183 patients included 126 male and 57 female patients between 9 and 77 years old (the mean 43.6 years). The greater part of patients had lithiasis of the lower renal calyx and upper ureter. The rate of residual stones 3 months after ESWL was 33.3% (61 patients) and the success rate was 72.2%. Chemical analysis of stones disclosed calcium oxalate-containing stones in 61% and calcium phosphate-containing ones in 10.8%. Recurrence of lithiasis was observed in 18 of the 131 patients (13.7%) who could be followed up for 6 months or more. These results were compared with those obtained after endoscopic treatment at Kinki University.
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PMID:[Follow-up study of residual and recurrent stone after extracorporeal shock wave lithotripsy]. 228 7


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