Comparison of radiographic methods for detecting radiolucent uroliths in dogs.

The purpose of this study was to evaluate and compare positive cystography techniques at 5%, 10%, and 20%, as well as three different double-contrast protocols for detecting radiolucent uroliths with a diameter of less than 3.0 mm in dogs. Six cadavers were used, one was selected at random to represent the negative control, and the others were submitted to urolith implantation in the bladder by urethral catheter. Three radiology professionals blindly accessed ventrodorsal and -lateral projections of each test. Contrast at 20% showed greater diagnostic sensitivity, but with greater difficulty identifying the number and size of the uroliths. Consequently, double-contrast techniques are better and should be used for diagnostic and therapeutic planning. Sensitivity and specificity tests demonstrated that positive 5% cystography and different concentrations of double contrast obtained better results in terms of sensitivity and specificity. However, due to the presence of a greater amount of artifacts in the 5% cystography, it is suggested that double contrast is used for this purpose, especially with the removal of contrast excess (protocol 2).

Minimally invasive percutaneous nephrolithotomy guided by ultrasonography to treat upper urinary tract calculi complicated with severe spinal deformity

ABSTRACT Objective: To report our experience of minimally invasive percutaneous nephrolithotomy(MPCNL) in managing upper urinary tract calculi complicated with severe spinal deformity. Materials and Methods: Between August 2001 to December 2012, 16 upper urinary calculi in 13 patients with severe spinal deformity were treated by MPCNL. Preoperative investigation of the respiratory function, evaluation of anatomy by intravenous urography (IVU) and CT scan, and preoperative kidney ultrasonagraphy with simulation of the percutaneous puncture were performed in all patients. The percutaneous puncture was guided by ultrasonography. Results: A total of 19 MPCNL procedures were performed in 16 kidneys, with an average 1.2 procedures in each kidney. Three kidneys needed two sessions of MPCNL, and 2 kidneys needed combined treatment with retrograde flexible ureterscopic lithotripsy. All procedures were successfully completed with no major complications during or after surgery. The mean (range) operative duration was 67 (20-150) min and the mean postoperative haemoglobin drop was 1.0 (0.2-3.1) g/dL. Complete stone-free status was achieved in 14 kidneys. At a mean follow-up of 48(3-86) months, recurrence of small lower calyx stone was detected in one patient. Recurrent UTI was documented by urine culture in two patients and managed with sensitive antibiotics. Conclusion: PCNL for patients with severe spinal deformities is challenging. Ultrasonography-assisted puncture can allow safe and successfully establishment of PCN tract through a narrow safety margin of puncture and avoid the injury to the adjacent organs. However, the operation should be performed in tertiary centers with significant expertise in managing complex urolithiasis.

Minimally invasive percutaneous nephrolithotomy guided by ultrasonography to treat upper urinary tract calculi complicated with severe spinal deformity.

OBJECTIVE: To report our experience of minimally invasive percutaneous nephrolithotomy(MPCNL) in managing upper urinary tract calculi complicated with severe spinal deformity. MATERIALS AND METHODS: Between August 2001 to December 2012, 16 upper urinary calculi in 13 patients with severe spinal deformity were treated by MPCNL. Preoperative investigation of the respiratory function, evaluation of anatomy by intravenous uro¬graphy (IVU) and CT scan, and preoperative kidney ultrasonagraphy with simulation of the percutaneous puncture were performed in all patients. The percutaneous puncture was guided by ultrasonography. RESULTS: A total of 19 MPCNL procedures were performed in 16 kidneys, with an ave¬rage 1.2 procedures in each kidney. Three kidneys needed two sessions of MPCNL, and 2 kidneys needed combined treatment with retrograde flexible ureterscopic lithotripsy. All procedures were successfully completed with no major complications during or after surgery. The mean (range) operative duration was 67 (20-150) min and the mean postoperative haemoglobin drop was 1.0 (0.2-3.1) g/dL. Complete stone-free status was achieved in 14 kidneys. At a mean follow-up of 48(3-86) months, recurrence of small lower calyx stone was detected in one patient. Recurrent UTI was documented by urine culture in two patients and managed with sensitive antibiotics. CONCLUSION: PCNL for patients with severe spinal deformities is challenging. Ultra¬sonography-assisted puncture can allow safe and successfully establishment of PCN tract through a narrow safety margin of puncture and avoid the injury to the adjacent organs. However, the operation should be performed in tertiary centers with significant expertise in managing complex urolithiasis.

Predicting calyceal access for percutaneous nephrolithotomy with computed tomography multiplanar reconstruction.

OBJECTIVES: Objective parameters in computed tomography (CT) scans that could predict calyceal access during percutaneous nephrolithotomy have not been evaluated. These parameters could improve access planning for percutaneous nephrolithotomy. We aimed to determine which parameters extracted from a preoperative multiplanar reconstructed CT could predict renal calyceal access during a percutaneous nephrolithotomy. METHODS: From January 2009 through April 2011, 230 patients underwent 284 percutaneous nephrolithotomies at our institution. Sixteen patients presented with complete staghorn calculi, and 11 patients (13 renal units) were analyzed. Five parameters were extracted from a preoperative reconstructed CT and compared with the surgical results of percutaneous nephrolithotomy. RESULTS: Fifty-eight calyces were studied, with an average of 4.4 calyces per procedure. A rigid nephroscope was used to access a particular calyx, and a univariate analysis showed that the entrance calyx had a smaller length (2.7 vs. 3.98 cm, p=0.018). The particular calyx to be accessed should have a smaller length (2.22 vs. 3.19 cm, p=0.012), larger angles (117.6 vs. 67.96, p<0.001) and larger infundibula (0.86 vs. 0.61 cm, p=0.002). In the multivariate analysis, the only independent predictive factor for accessing a particular calyx was the angle between the entrance calyx and the calyx to be reached (OR 1.15, 95% confidence interval [CI], 1.053-1.256, p=0.002). CONCLUSION: The angle between calyces obtained by multiplanar CT reconstruction is the only predictor of calyx access.

[CT SCAN as a predictor of composition and fragility of urinary lithiasis treated with extracorporeal shock wave lithotripsy in vitro]. / Tomografía computada como predictor de composición y fragilidad de la litiasis urinaria al tratamiento con litotricia extracorporea por ondas de choque in vitro.

OBJECTIVES: To evaluate the ability of non contrast computed tomography (NCCT) to predict stone composition and fragility for treatment with extracorporeal shock wave lithotripsy (ESWL). METHODS: 27 stones of about 10 mm from patients who had undergone different endourological procedures were collected. All patients had been evaluated with NCCT. To perform in vitro ESWL an experimental device was designed. Three thousand pulses were applied with 17.2 Kv intensity using an electromagnetic generator (Lithostar) to all stones. Composition of each fragment was studied with crystallographic study. Results were statistically analyzed with Student Test, Chi2 Test and multivariate study. RESULTS: In vitro ESWL had a success rate of 59.26%. Average stone HU, grouped by composition: cistine 1015 HU, Calcium monohydrate oxalate 1193 HU, uric acid 419 HU, dihydrate calcium oxalate 2122 HU, struvite 1543 HU and basic phosphate magnesium 1517 HU. A statistically significant relationship was found between values which were lower than 500 HU and uric acid composition (p=0.0006), as well as values higher than 2000 HU and composition of dihydrated calcium acid (p=0.0244). In the group of stones with less than 1000 HU (n=11) efficacy was 81.1%, whereas it was 43.75% in the others (p=0.0479). We found a statistically significant relationship between uric acid and effectiveness (p=0.021). There was not statistically significant relationship between size and treatment effectiveness. CONCLUSIONS: The use of NCCT will allow predicting stone composition and fragility.

Giant intravesical calculus during pregnancy.

Urolithiasis is commonly found during pregnancy; but the presence of a giant vesical calculus during pregnancy is a very rare entity, associated with several potential obstetric complications. A 25-year-old primigravida at 25 weeks of gestational age was referred to our tertiary care unit because she presented a giant hyperechoic intravesical mass and inability to pass urine with suprapubic pain since 2 days. An open cystolithotomy revealed a huge intravesical calculus. The patient continued with her pregnancy until full term without adverse perinatal outcomes.

Prevalence and risk factors for urolithiasis in primary gout: is a reappraisal needed?

OBJECTIVE: To assess the prevalence and risk factors for urolithiasis in primary gout. METHODS: One hundred forty patients with primary gout were studied. Urolithiasis was defined as a history of urolithiasis, or nephrolithiasis detected via ultrasonography in patients with no previous record of urolithiasis. Patient age, duration of gout, presence of tophi, obesity, alcoholism, high blood pressure, diabetes, hyperlipidemia, family history of urolithiasis, daily urine output, uricemia, urine pH, FeNa, FeUrate, urine pH/FeUrate index, and daily urine excretion of urate, sodium, calcium and potassium were compared between lithiasic and non-lithiasic subjects. RESULTS: Fifty-five (39%; 95% CI 31-47) patients had urolithiasis, of which 37 (26%) were diagnosed by clinical history and 18 (13%) by ultrasonography. Patients with a silent kidney stone diagnosed by ultrasound tended to have shorter evolution of gout. Aside from urinary H+ ion concentration (lithiasic subjects 5.17 +/- 3.9 microM/l; non-lithiasic subjects 3.80 +/- 3.01 microM/l; p = 0.02), no difference was found between lithiasic and non-lithiasic subjects for the other variables studied. CONCLUSION: Ultrasonography increased the probability of diagnosing urolithiasis by 50%, meaning the prevalence of urolithiasis in gout is likely higher than previously reported. A higher urinary H+ ion concentration was the only variable associated with urolithiasis. Due to advances in diagnosis of gout and urolithiasis, as well as biochemical assays, the prevalence and risk factors for urolithiasis in gout require reassessment.

Is stone radiodensity a useful parameter for predicting outcome of extracorporeal shockwave lithotripsy for stones < or = 2 cm?

PURPOSE: Several factors determine the success of extracorporeal shockwave lithotripsy (SWL) for kidney stones: stone size, stone location within the collecting system, stone type, and the SWL machine used. It has been suggested that stone radiodensity, as determined either by plain radiography or computed tomography attenuation values, may be an independent predictor of SWL success. We examined the outcome of SWL for solitary stones less than or equal to 2 cm located within the renal pelvis, based on their radiodensity. MATERIAL AND METHODS: 211 patients with solitary renal pelvic stones measuring less than or equal to 2 cm were treated on a Dornier Doli 50 lithotriptor under general anesthesia. The radiodensity of the stone was determined to be either less than, equal to, or greater than the radiodensity of the ipsilateral 12th rib. Stone-free rates (SFR) were determined at 3 months by kidney, ureters and bladder (KUB) plain X-rays. Patients requiring re-treatment or auxiliary procedures were considered failures of SWL. RESULTS: Follow-up SFR information was available in all 211 patients. Stone composition was available in 158 (75%) treated patients, but no correlation was found between stone radiodensity and stone composition. For stones < or = 10 mm within the renal pelvis, the SFRs were similar (71 to 74% regardless of stone radiodensity). For stones between 11 and 20 mm, the SFR was 60% if the stone had a radiodensity > 12th rib compared to a SFR of 71% if the stone radiodensity was < or = 12th rib. However, these differences in SFRs were not statistically significant. CONCLUSIONS: On the Doli machine, stone radiodensity alone does not predict lithotripsy treatment outcome for stones < or = 1 cm within the renal pelvis. This parameter is probably only useful as the stone size becomes larger than 1 cm, and should be used in conjunction with other stone parameters to select appropriate therapy.

Valor de la tomografía computada en los pacientes con posible sospecha clínica de urolitiasis / Diagnostic value of unenhanced helical CT in patients with urolithiasis

El objetivo del presente trabajo es evaluar la efectividad de la tomografía computada helicoidal (TC) sin contraste oral ni endovenoso para la detección y el manejo de los pacientes con sospecha clínica de urolitiasis. Se estudiaron 60 pacientes con presunción diagnóstica de cólico renoureteral. A todos se les efectuó tomografía computada helicoidal sin contraste oral ni endovenoso. La tomografía computada fue leída para la presencia o ausencia de litiasis. El diagnóstico definitivo fue efectuado mediante seguimiento en todos los casos. Con los resultados obtenidos el valor predictivo positivo de una tomografía computada es del 98 por ciento y la certeza global un 93 por ciento. En los pacientes con sospecha de litiasis, debido a que la TC de árbol urinario es sencilla, eficaz y sin contraindicaciones, debe formar parte del protocolo de estudio de éstos pacientes (AU)

Scintigraphy and Doppler ultrasonography for the evaluation of obstructive urinary calculi.

Forty-seven patients with unilateral obstructive calculi (12 males and 35 females) were submitted to 99mTc-diethylene triamine pentaacetic acid (DTPA) or 99mTc-dimercaptosuccinic acid (DMSA) scans for assessment of renal function. The scans revealed unilateral functional deficit in 68 and 66% of the patients, respectively. A calculus size of 1.1 to 2.0 cm was significantly associated with deficit detected by DTPA, but duration of obstruction and calculus localization were not. After relief of the obstruction, the mean percent renal function of the affected kidney was found to be significantly increased from 25 +/- 12% to 29 +/- 12% in DTPA and from 21 +/- 15% to 24 +/- 12% in DMSA. Initial Doppler ultrasonography performed in 35 patients detected an increased resistive index in 10 (29%). In the remaining patients with a normal resistive index, ureteral urinary jet was observed, indicating partial obstruction. The high frequency of renal function impairment detected by DTPA and of tubulointerstitial damage detected by DMSA as well as the slight amelioration of unilateral renal function after relief of obstruction suggest that scintigraphy assessment may help evaluate the unilateral percentage of renal function and monitor renal function recovery when it occurs. The presence of a urinary jet detected by Doppler ultrasonography further indicates the severity of obstruction and the recovery prognosis.

A model of suture-induced urolithiasis with urographic control in the bladder of the rat.

The characteristics of a model of urolithiasis in the bladder of male Wistar rats were evaluated. Two techniques were compared: one knot of suture material through the bladder wall, or 15-throw knots inside the bladder. Rats were randomly assigned to one of six groups, according to the technique and suture material used (polyester, silk, or chromic catgut). An excretory urogram was performed at days 30, 60, and 90. At the moment of positive radiographic diagnosis, animals were sacrificed and stones were obtained. All rats were sacrificed at day 90 regardless of the x-ray results. Variables evaluated were average days to a positive urogram, average weight of all uroliths, and percentage of animals developing urolithiasis throughout the study. There were no statistical differences between groups for the average weight of stones, which ranged from 0.008 to 1.502 g for individual cases. All three materials were more lithogenic with the 15-throw knot inside technique. No significant differences were detected for lithogenesis criteria between suture materials. X-ray dispersion spectroscopy evidenced calcium phosphate composition of two stones from chromic catgut, and magnesium phosphate composition of two stones from chromic catgut, two from silk, and two from polyester. Neo-epithelization over the suture was confirmed microscopically in bladders with the one-throw technique. We conclude that (1) this is an effective model of urolithiasis, with predictability in time, composition, and amount of stone formation; (2) the presence of more suture material inside the bladder is more lithogenic; and (3) excretory urograms are highly sensitive and specific for the noninvasive diagnosis of bladder urolithiasis.

Urethral stones: US for identification in boys with hematuria and dysuria.

There are multiple causes for hematuria in infants and children. When hematuria is accompanied by dysuria, however, one should focus attention on the lower urinary tract. Although ultrasound (US) is a well-established method for assessing the kidneys and bladder, little attention has been focused on its use for evaluating urethral abnormalities, since voiding cystourethrography or retrograde urethrography usually is used. In the cases of two young boys, sonography aided in the identification of clinically unsuspected urethral stones. US evaluation of the urethra is now included as an integral part of urinary tract sonography in male patients with hematuria accompanied by dysuria.

Extracorporeal shock wave lithotripsy of radiolucent urinary calculi using the Siemens Lithostar Plus.

Between October 1989 and June 1991, 1,250 patients with urinary calculi were treated at our institution using the Siemens Lithostar. A total of 17 patients (1.37%) with radiolucent or slightly opaque calculi underwent lithotripsy with the Lithostar Plus, which has an overhead electromagnetic generator module and a localization system composed of a real-time on-line 3.5 mHz. ultrasound transducer. The stones were located in the calices in 52.9% of the cases, renal pelvis in 17.7%, ureter in 23.5% and bladder in 5.9%. Followup consisted of a nephrotomogram or ultrasound 1 day and 1 to 3 months postoperatively. Complete removal of all stone fragments was achieved in 76.4% of the cases after 3 months. Retreatment was necessary in 23.5% of the cases. All treatments were performed without anesthesia and hospitalization. Complications were present in 11.8%; perirenal hematoma was noted in 1 patient but this resolved spontaneously within a few days and the same occurred in 1 patient with renal pain. Extracorporeal shock wave lithotripsy using the Lithostar Plus proved to be an effective noninvasive procedure to treat radiolucent and slightly opaque urinary calculi. However, since the Lithostar Plus has a higher power setting, care must be taken to avoid damage with the use of high energy.

[Extracorporeal lithotripsy of urinary calculi: experience with Modulith SL-20 (Storz Medical)]. / Litotricia extracorporea de calculos urinarios: experiencia con el Modulith SL-20 (Storz Medical).

The results of extracorporeal lithotripsy on 250 patients with renal and ureteral stones are reported. Stone size varied from less than 1 cm (64%), 1 to 2 cm (31%) to over 2 cm (4%). 51% of patients were treated on an ambulatory basis. Complete fragmentation was obtained in 97% of patients and 78% were free of any demonstrable stone after 90 days. lithotripsy is an effective procedure allowing ambulatory non surgical treatment of urinary stones in many patients.

Endoluminal sonography of the urinary tract: preliminary observations.

Endoluminal sonography of the urinary tract was performed by using endoluminal ultrasound transducers contained within 2-mm-diameter catheters. The catheters were inserted into the urinary bladder via the urethra and advanced into the ureters and renal pelvis under cystoscopic control; then, cross-sectional images of the bladder, ureters, and renal pelvis were obtained. Two dogs and seven human patients were studied. In one dog, a 4.5-mm pseudopolyp, which was surgically created in the bladder wall, was successfully imaged; in the other, stones 2 mm or larger inserted into the bladder were identified. Of the seven patients, sonography showed stones embedded in the renal parenchyma (one patient) and the mucosa of the distal ureter (one patient). These were ultimately confirmed by their eventual removal. In a third, sonography showed a tumor of the distal ureter and identified the depth of the tumor. This was confirmed by biopsy. In a fourth, sonography clearly showed a crossing vessel as the cause for narrowing of the proximal ureter. In a fifth, sonography showed that the cause of a ureteral stricture was idiopathic. In the last two cases, sonography did not reveal a cause for hematuria. In these last three cases, negative sonographic results were confirmed by direct ureteroscopic examinations and follow-up studies. Our observations based on this limited study suggest that endoluminal sonography is a useful procedure for diagnosing diseases of the urinary tract. Further study is warranted.