Ureteropelvic Junction Stones Research Articles

A robust localization approach for Percutaneous Nephrolithotomy (PCNL): A single-center retrospective study.

Percutaneous Nephrolithotomy (PCNL) represents the gold standard treatment method for cases with large kidney stones. As a critical step in performing PCNL, the procedure of establishing a safe and accurate nephrostomy tract will dramatically impact the treatment quality of patients with large-sized kidney stones. This work attempts to describe a new and improved process of establishing an accurate nephrostomy tract and clinically evaluate the effectiveness and safeness of this proposed methodology. This work represents a retrospective single-center study carried out between August 2013 and November 2019. The collected samples consist of 937 patients who were operated on using PCNL coupled with our proposed procedure. Briefly, a preoperative B-ultrasonography was firstly performed to decide the puncture point in a simulated surgical position where was marked with ureteral catheter segments (2-3 cm). A computed tomography (CT) scan was followed to correct the anchor points in the simulated surgical position. After this, an accurate puncture operation was performed under the real-time guidance of intraoperative B ultrasound. Examining this study, 851 subjects with renal stones and 86 subjects with ureteropelvic junction stones were included for the PCNL operation project. All samples were grouped with Guy's grading system: grade I, II, III, and IV patients there were 0.00%, 42.69%, 51.01%, and 6.30%, respectively. Among these patients, the average age was 48.49 ± 10.80 years old, with a male to female ratio of around 1.73:1. This study showed that our developed method warrants an accurate and safe PCNL operation that involves the process of establishing the nephrostomy tract. Other advantageous attributes of this new PCNL process include negligible radiation exposure, lesser complications, and low failure rates. More importantly, this new localization approach is particularly attractive for hospitals that are new to the field of adopting PCNL considering its safeness, effectiveness, and learnability.

PERCUTANEOUS DRAINAGE AS AN ALTERNATIVE OF SURGICAL MANAGEMENT IN PARARENAL ABSCESS: A CASE REPORT

Objective: This case report will discuss the experience of using percutaneous drainage as an alternative of open surgery in pararenal abscess therapy. Case(s) Presentation: 61 years old woman complained of left flank pain 6 months before with septic condition. Physical examination revealed tenderness and mass in the left flank region with leukocytosis. Abdominal Computed Tomography (CT) Scan results showed a left lower pole pararenal abscess, severe hydropyonephrosis and ureteropelvic junction stones. Percutaneous abscess drainage and percutaneous nephrostomy was performed with an 18Fr troicart using ultrasound guidance. Discussion: The pus culture showed Escherichia coli bacteria. After three days of operation and intravenous antibiotics, the patient experienced clinical improvement. Outpatient follow-up showed decreased drain production from percutaneous abscess drainage and clear yellow liquid production from percutaneous. Percutaneous nephrolithotomy was performed for the management of stone evacuation. After going through the whole procedure, there is clinical improvement of patient. Conclusion: Percutaneous drainage is an alternative option in the management of perirenal abscesses. Compared to open surgical drainage, the percutaneous technique provides a minimally invasive process, shorter length of stay and more effective costs. This procedure has also shown good clinical improvement in patients.
 Keywords: Minimal invasive, pararenal abscess, percutaneous drainage.

The impact of Hounsfield unit-related variables on percutaneous nephrolithotomy outcomes

We aimed to identify the association between Hounsfield Unit(HU)-related variables and percutaneous nephrolithotomy (PCNL) outcomes. We enrolled patients with single renal stones (1–3 cm) who underwent single-tract PCNL between January 2014 and October 2019. Demographics and stone characteristics were retrospectively reviewed. Preoperative computerized tomography (CT) and follow-up CT within at least 3 months after PCNL were included in this analysis. Stone-free status was defined as residual stone measuring ≤ 2 mm within 3 months postoperatively. HU and cross-sectional area (CSA) were measured using the free-draw technique. We analyzed HU-related variables using logistic regression model for outcomes. Altogether, 188 out of 683 patients met the inclusion criteria. The stone-free rate (SFR) was 79.2%. There were no significant differences in age, sex, BMI, ASA class, laterality, pre-op shockwave lithotripsy, stone size, stone burden, skin-to-stone distance, and HU between the stone-free and remnant groups. CSA and HU/CSA in the stone-free and remnant groups were 94.5 ± 46.1 and 128.3 ± 98.5 (p = 0.043) and 10.1 ± 5.6 and 7.3 ± 3.4 (p = 0.001), respectively. Multivariate logistic regression analysis revealed that pelvis, ureteropelvic junction stones, and HU/CSA were independent predictors of SFR. HU did not affect PCNL outcomes. We believe that HU/CSA could be used for determining stone treatment plans and predicting outcomes.

INCIDENTAL SOLE CONTRALATERAL PLEURAL METASTASIS FROM RENAL CELL CARCINOMA SEVEN YEARS POST NEPHRECTOMY

TOPIC: Disorders of the Pleura TYPE: Medical Student/Resident Case Reports INTRODUCTION: Renal cell carcinoma (RCC) accounts for 3% of all adult male cancers, and half of them are incidental findings on imaging [1]. 18% of patients have synchronous metastasis at RCC diagnosis, and 85% have metachronous metastasis within five years after surgery. A better prognosis is seen with a metachronous metastasis occurring after a long disease-free interval [2] CASE PRESENTATION: A 68-year-old male presented to an outside emergency department with generalized weakness, fatigue, and loss of appetite for a week's duration with no respiratory complaints. He was a former smoker who quit 40 years back. He had significant asbestos exposure as a sandblaster and changing railroad brake shoes. His initial blood work revealed an acute kidney injury with a serum creatinine of 14.8 mg/dL with no leukocytosis. Computed tomography (CT) abdomen revealed an obstructive right ureteropelvic junction stone (1.4 x 1 cm) with moderate hydronephrosis. Chest x-ray and CT revealed multiple right pleural soft tissue masses (largest measuring 7.7 x 3.1 x 3.5 cm) with no effusion concerning for malignancy (Figure A). Past medical history was significant for left clear cell RCC grade 3/4 with no invasion (T1bNxMx) treated by left radical nephrectomy seven years ago. His obstruction was relieved by urological intervention. A nuclear positron emission tomography showed hypermetabolic right pleural masses and a right paratracheal lymph node (Figure B). A CT-guided biopsy returned positive for metastatic RCC (Figure C1-C2). His creatinine improved, and he was discharged with an oncology follow-up DISCUSSION: The risk of RCC metastasis via hematogenous or lymphatic spread increases if it is locally advanced (stage 3-4), higher nuclear grade, and clear cell histology [2]. The lung is the frequent site of metastasis (45%), and pleural lesions occur in 12% along with lung spread [3]. Isolated pleural spread without an effusion is rare. Dormant metastasis uses Batson's venous plexus draining into thoracic veins (bronchial and intercostal) and reaches the pleura rather than by lung parenchyma direct extension [2]. Most reported cases of solitary pleural spread are symptomatic with effusion. Our patient was asymptomatic with incidental contralateral pleural metastasis without pleural effusion seven years postresection with a rare combination of pleural and paratracheal lymph node spread. 5-15% of patients recur with a distant spread questioning the current five-year surveillance strategy [4] CONCLUSIONS: Metastatic RCC to the pleura is a rare finding. This diagnosis should be considered in patients with RCC history, even if the presentation is many years after initial diagnosis and treatment. Postnephrectomy, the surveillance should be based on an individual's RCC risk factors REFERENCE #1: Ohnishi H, Abe M, Hamada H, et al. Metastatic renal cell carcinoma presenting as multiple pleural tumours. Respirology. 2005;10(1):128-31 REFERENCE #2: Brufau BP, Cerqueda CS, Villalba LB, Izquierdo RS, González BM, Molina CN. Metastatic renal cell carcinoma: radiologic findings and assessment of response to targeted antiangiogenic therapy by using multidetector CT. Radiographics. 2013;33(6):1691-716 REFERENCE #3: Saitoh H. Distant metastasis of renal adenocarcinoma. Cancer. 1981;48(6):1487-91 DISCLOSURES: No relevant relationships by Mohammed Alnijoumi, source=Web Response No relevant relationships by Cliff Chen, source=Web Response No relevant relationships by Tarang Patel, source=Web Response No relevant relationships by SACHIN PATIL, source=Web Response

Integrated retrograde and antegrade contact electro-impulse lithotripsy in the treatment of kidneys and ureteropelvic junction stones

Introduction. Nowadays, the tactics of removing stones from the kidneys and the ureteropelvic junction are widely covered and described in detail in modern guidelines. Determination of one or another treatment way depends on stone specific features and patient`s constitutional peculiarities. However, usage of percutaneous or retrograde access only does not always allow achieving a good result. In sophisticated cases, such as a large-size branchy renal stone, a “penetrated” stone in the ureter’s upper third, or some patient`s anatomic peculiarities, search for new ways to remove such stones with integrating accesses. Purpose of the study. To evaluate the removal efficiency of kidney stones and ureteropelvic junction by a combination of retrograde and percutaneous lithotripsy using electrical impulse energy. Materials and methods. In 2014-2019 in Siberian State Medical University Clinics (Tomsk, Russia), the integrated retrograde and percutaneous lithotripsy was applied in 26 cases to patients that had differently positioned kidneys’ and ureteropelvic junction stones. The treatment was based on the usage of the electro-impulse lithotriptor Urolith-105M (Lithotech Medical, Israel, MedLine LLP, Russia). In some cases, the laser lithotriptor Calculase II (Karl Storz, Germany) was also engaged. Result. The patients were aged from 25 to 76 (women - 69.2%). The calculus average size was 19.5 mm (varying from 5 to 51 mm). The calculus average density was 1229 HU (from 510 to 1720 HU). The operation average duration was 131 minutes (from 40 to 280 minutes). The incidence of complications was 3.84%. The complete calculus destruction occurred in 92.3% of cases. The overall response rate in re-operations reached up 100%. Conclusion. Integration of antegrade and retrograde accesses with use of the electro-impulse energy in removing complex stones from ureteropelvic junctions and kidneys proved to be an efficient method of treatment and demonstrated great results. Furthermore, this option of the single-step access to the stones is the only one possible in some cases when the extracorporeal lithotripsy is contraindicated, application of upfront surgery is quite risky, or endoscopic methods as an antegrade/retrograde mono-access are not effective .

Pearl-unjammed: the Seattle stone maneuver for ureteropelvic junction urolithiasis.

Renal colic encounters are common; in the United States alone, they represent greater than one million annual emergency department (ED) visits. Most of these stones are managed conservatively with a trial of passage. However, some lead to repeat colic episodes, secondary ED visits, increased anxiety, and increased cost. Of the 5%–10% of symptomatic stones that become lodged at the ureteropelvic junction and are larger than 5 mm, most require operative intervention. In the process of executing a NASA‐funded study of ultrasonic repositioning of kidney stones, the subject was administered fluid to dilate the collecting system, placed in Trendelenburg bed positioning, and rolled to both sides. During this process a symptomatic, obstructing 9‐mm ureteropelvic junction stone moved back into the kidney's lower pole/infundibulum and symptoms were immediately resolved. The patient remained asymptomatic for a period of 5 weeks at which point elective intervention was scheduled. This case demonstrates that ureteropelvic junction stones may be repositioned in a non‐invasive manner, turning a stone that requires urgent intervention into one that can be managed electively.

Emergency percutaneous nephrostomy versus emergency percutaneous nephrolithotomy in patients with sepsis associated with large uretero-pelvic junction stone impaction: a randomized controlled trial.

ABSTRACTIntroduction A randomized trial was conducted prospectively to evaluate the efficacy, related complications, and convalescence of emergency percutaneous nephrolithotomy compared to percutaneous nephrostomy for decompression of the collecting system in cases of sepsis associated with large uretero-pelvic junction stone impaction.Materials and Methods The inclusion criteria included a WBC count of 10.000/mm3 or more and/or a temperature of 38°C or higher. Besides, all enrolled patients should maintain stable hemodynamic status and proper organ perfusions. A total of 113 patients with large, obstructive uretero-pelvic junction stones and clinical signs of sepsis completed the study protocol. Of those, 56 patients were placed in the emergency percutaneous nephrostomy group, while the other 57 patients were part of the percutaneous nephrolithotomy group. The primary end point was the time until normalization of white blood cells (WBC) at a count of 10.000/mm3 or less, and a temperature of 37.4°C or lower. The secondary end points included the comparison of analgesic consumption, length of stay, and related complications. Statistical analysis was performed using SPSS® version 14.0.1. The Mann-Whitney U test, chi-square test, and Fisher’s exact test were used as appropriate.Results The length of hospital stays (in days) was 10.09±3.43 for the emergency percutaneous nephrostomy group and 8.18±2.72 for the percutaneous nephrolithotomy group. This set of data noted a significant difference between groups. There was no difference between groups in regard to white blood cell count (in mm3), time to normalization of white blood cell count (in days), body temperature (in ºC), time to normalization of body temperature (in days), C-reactive proteins (in mg/dL), time taken for C-reactive proteins to decrease over 25% (in days), procalcitonin (in ng/mL), or complication rates.Conclusions This study confirms that emergency percutaneous nephrolithotomy may be as safe as early percutaneous nephrolithotomy in a selected low risk patients with sepsis-associated large, obstructive stone.

Ultrasonic propulsion of kidney stones.

Ultrasonic propulsion is a novel technique that uses short bursts of focused ultrasonic pulses to reposition stones transcutaneously within the renal collecting system and ureter. The purpose of this review is to discuss the initial testing of effectiveness and safety, directions for refinement of technique and technology, and opinions on clinical application. Preclinical studies with a range of probes, interfaces, and outputs have demonstrated feasibility and consistent safety of ultrasonic propulsion with room for increased outputs and refinement toward specific applications. Ultrasonic propulsion was used painlessly and without adverse events to reposition stones in 14 of 15 human study participants without restrictions on patient size, stone size, or stone location. The initial feasibility study showed applicability in a range of clinically relevant situations, including facilitating passage of residual fragments following ureteroscopy or shock wave lithotripsy, moving a large stone at the ureteropelvic junction with relief of pain, and differentiating large stones from a collection of small fragments. Ultrasonic propulsion shows promise as an office-based system for transcutaneously repositioning kidney stones. Potential applications include facilitating expulsion of residual fragments following ureteroscopy or shock wave lithotripsy, repositioning stones prior to treatment, and repositioning obstructing ureteropelvic junction stones into the kidney to alleviate acute renal colic.

The relationship between ureteral stone characteristics and secondary signs in renal colic

PurposeTo assess correlations between stone size/location and severity of secondary signs for ureteral obstruction. MethodsUnenhanced multi-detector computed tomography examinations of 150 patients with acute renal colic were reviewed. Stone size, location in the ureter, kidney size and Hounsfield unit values, perinephric edema, and degree of hydronephrosis were assessed. ResultsPale kidney sign was detected in 36%. Hydronephrosis was mild in 63% and severe in 21%; severe hydronephrosis was associated with larger stones. Mid-ureter and ureteropelvic junction stones were more likely to cause hydronephrosis. Perinephric edema (56%) was not correlated with stone size/location. ConclusionOnly severe hydronephrosis was significantly associated with larger stone size.

Totally tubeless percutaneous nephrolithotomy: a prospective randomized controlled study

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

Is a Safety Wire Necessary During Routine Flexible Ureteroscopy?

The use of flexible ureteroscopy (URS) for nephrolithiasis has been rapidly expanding. Initially, safety guidewires were maintained alongside the ureteroscope during stone manipulation to prevent loss of access and allow stent insertion in the event of perforation. We intend to determine the safety of flexible URS without a separate safety guidewire in a large series of patients. A retrospective chart review was performed on all cases of flexible URS with laser lithotripsy performed by a single surgeon from August 2003 to May 2008. Preoperative patient characteristics, radiographic stone sizes, operative findings, and postoperative outcomes were recorded. Patients with renal or ureteropelvic junction (UPJ) stones were isolated for a qualitative data analysis. Flexible URS was performed on 305 kidneys in 246 consecutive patients, of which 59 cases were bilateral. Cases were subdivided into complicated and uncomplicated. Two hundred seventy cases were uncomplicated and performed without a safety guidewire. No intraoperative complications resulted from the lack of a safety guidewire, including no cases of lost access, ureteral perforation/avulsion, or need for percutaneous nephrostomy tube. Thirty-five cases were complicated, necessitating a safety guidewire. Of these, 16 had concomitant obstructing ureteral stones, 5 had encrusted ureteral stents, and 14 had difficult access because of large stone burden or aberrant anatomy. This study demonstrates that, in a large series of patients, a safety guidewire was not necessary for routine cases of flexible URS with laser lithotripsy on renal or UPJ stones. Particular cases with complicated anatomy, difficult access, concomitant ureteral stones, simultaneous stone basketing, or bulky stone burden still necessitate use of a safety guidewire because of increased risk of adverse outcomes.

Effect of output voltage distribution on stone comminution efficiency during shockwave lithotripsy in renal or ureteropelvic junction stones: A preliminary study

This study evaluated stone comminution efficiency according to the distribution of the lithotripter output voltage during extracorporeal shockwave lithotripsy (SWL) of renal or ureteropelvic junction (UPJ) stones. Sixty-two patients with a single radiopaque renal or UPJ stone of surface area about 50-400 mm(2) were prospectively randomized to receive a total of 2400 shocks per session according to one of three shock protocols: group A, output voltage was increased from 25% to 35% to 45% with 800 shocks per voltage; group B, constant output voltage of 35%; group C, decreasing output voltage from 45% to 35% to 25%. SWLs were carried out using a fourth generation electroconductive lithotripter, the Sonolith Vision, without anesthesia. The stone-free (SF) and success (SF + clinically insignificant residual fragment) rates were assessed. Patient demographics, body mass index, stone burden, laterality and stone locations were comparable among the three groups. There were no differences in the cumulative success rates (30%, 32% and 35% after the first session for groups A, B and C, respectively; 65%, 50% and 65% after the second session; and 80%, 68% and 75% after the third session). The cumulative SF rates and complications showed no differences among the three groups. In this preliminary study, manipulation of the lithotripter output voltage distribution did not affect stone comminution efficiency for renal or UPJ stones. This finding should be confirmed by larger studies including more patients.

2107 FOCUSED ULTRASOUND APPLICATION TO REPOSITION KIDNEY STONES AND FACILITATE PASSAGE OF RESIDUAL FRAGMENTS

You have accessJournal of UrologyStone Disease: New Technology1 Apr 20102107 FOCUSED ULTRASOUND APPLICATION TO REPOSITION KIDNEY STONES AND FACILITATE PASSAGE OF RESIDUAL FRAGMENTS Anup Shah, Mathew Sorensen, Jonathan Harper, Bryan Cunitz, Wei Lu, and Michael Bailey Anup ShahAnup Shah More articles by this author , Mathew SorensenMathew Sorensen More articles by this author , Jonathan HarperJonathan Harper More articles by this author , Bryan CunitzBryan Cunitz More articles by this author , Wei LuWei Lu More articles by this author , and Michael BaileyMichael Bailey More articles by this author View All Author Informationhttps://doi.org/10.1016/j.juro.2010.02.2194AboutPDF ToolsAdd to favoritesDownload CitationsTrack CitationsPermissionsReprints ShareFacebookTwitterLinked InEmail INTRODUCTION AND OBJECTIVES Lower pole kidney stones have lower rates of stone clearance after shock wave lithotripsy (SWL) and ureteroscopic treatment compared to other stone locations because of dependant positioning and difficult access. Residual stone fragments often lead to additional morbidity and need for secondary surgery. We describe the use of acoustic force and streaming created by transcutaneous focused ultrasound to manipulate the location of stone fragments within the collecting system in order to facilitate stone clearance. METHODS A newly developed focused ultrasound therapy probe consists of an 8-element annular array with a nominal frequency of 2.0 MHz, acoustic power output of 5-20W, and programmable focal depth of 4.5-8.5 cm. There is an opening in the center of the therapy probe for an HDI P4-2 imaging probe to provide ultrasound image guidance in a 2D plane. Artificial and human stones were placed into the lower pole of transparent kidney phantoms and live porcine kidneys using retrograde ureteroscopy. Focused ultrasound was applied. Stone motion was observed visually in the kidney phantom and using both diagnostic ultrasound and fluoroscopy in the porcine kidneys. Any tissue effects caused by focused ultrasound were assessed. RESULTS All stones placed in the kidney phantoms and live porcine kidneys were seen to move. Stone size ranged from 2 mm to 6 mm in maximal dimension. Stone velocities were on the order of 1 cm/s. Stone displacement distance was up to 3 cm and operators could generally control the direction of stone movement. No evidence of thermal necrosis or mechanical damage of renal tissue was observed on gross and microscopic examination. CONCLUSIONS Focused ultrasound can be used to move stones within the collecting system and may be able to improve rates of lower pole stone fragment clearance. Other applications for this new technology may include adjunctive use with medical expulsive therapy, repositioning of obstructing ureteropelvic junction stones, and ensuring complete clearance of infectious stones. Seattle, WA© 2010 by American Urological Association Education and Research, Inc.FiguresReferencesRelatedDetails Volume 183Issue 4SApril 2010Page: e819 Advertisement Copyright & Permissions© 2010 by American Urological Association Education and Research, Inc.MetricsAuthor Information Anup Shah More articles by this author Mathew Sorensen More articles by this author Jonathan Harper More articles by this author Bryan Cunitz More articles by this author Wei Lu More articles by this author Michael Bailey More articles by this author Expand All Advertisement Advertisement PDF downloadLoading ...

Shock Wave Lithotripsy for Renal Stones Is Not Associated with Hypertension and Diabetes Mellitus

To clarify the influences of shock wave lithotripsy (SWL) treatments for renal and ureteropelvic junction stones on new onsets of hypertension and diabetes mellitus (DM). We compared the new onsets of hypertension and DM after SWL in renal and ureteral stone groups. The renal stone group consisted of 772 patients treated with SWL, who had a possibility of renal and pancreatic shock wave damage. The ureteral stone group consisted of 505 patients treated with SWL, who were unlikely to have suffered SWL damage in the kidney and pancreas areas. Both treatment groups received SWL between 1984 and 1994. The rates of new onset of hypertension in the renal stone and ureteral stone groups were 22.8% and 20.0% in men and 23.1% and 20.5% in women, respectively. The rates of new onset of DM in the renal stone and ureteral stone groups were 7.4% and 11.0% in men and 8.7% and 8.7% in women, respectively. There was no significant difference in the new onsets of hypertension and DM between renal and ureteral stone groups depending on each age decade or sex. Treatment for renal stone was not a significant risk factor for new onsets of hypertension and DM by logistic regression analysis. Our findings suggest that SWL treatment for renal and UPJ stones might not be associated with new onset of hypertension or DM.

Color Doppler sonography examination of partially obstructed kidneys associated with ureteropelvic junction stone before and after percutaneous nephrolithotripsy: Preliminary report

To evaluate resistive index (RI) changes before and after unilateral percutaneous nephrolithotripsy in chronic partially obstructed kidneys due to ureteropelvic junction (UPJ) stones. Intrarenal RI of obstructed and contralateral normal kidneys of 18 patients were recorded immediately before the operations and at postoperative days 1, 7 and 30. Postoperative RI measurements were compared with baseline values for all patients without grouping and separately for different groups according to the preoperative RI value of the obstructed kidney. Mean age and symptom duration were 27.5 years and 43.8 weeks, respectively. Preoperatively and at all postoperative controls, kidney diameters and renal parenchyma thicknesses were normal in all patients. Mean RI of obstructed kidneys decreased from 0.68 to 0.63 for all patients (P=0.032), from 0.64 to 0.63 for those with preoperative RI<0.70 (P=0.850) and from 0.73 to 0.62 for those with preoperative RI>or=0.70 (P=0.001). In patients with preoperative RI>or=0.70 in obstructed kidney, significant RI decreases were recorded at postoperative day 7 and RI differences between obstructed and contralateral kidneys disappeared after then. No difference was present pre- and postoperatively between the mean RI of obstructed and contralateral kidneys of the patients with RI<0.70. Mean RI of contralateral kidneys were normal preoperatively and showed no significant change postoperatively. Preoperative RI levels may indirectly reflect the presence of functionally significant obstruction in chronic obstructed kidneys related to UPJ stones. Patients with RI>or=0.70 may have a good indication for a surgical approach. Normalization of high RI occurs rapidly after percutaneous nephrolithotripsy.

ACUTE RENAL FAILURE ASSOCIATED WITH SULFUR CALCULI

An 85-year-old Japanese man presented with abdominal discomfort and general fatigue. History included (stage A1) prostate cancer, G1T1a transitional cell carcinoma of the bladder for 4 years and ulcerative colitis, which had been treated with 4.5 gm. sulfasalazine daily for 14 years. Laboratory examination showed renal failure (serum blood urea nitrogen was 26 mg./dl. and creatinine was 1.71 mg./dl.). Ultrasonography, computerized tomography and x-ray revealed bilateral hydronephrosis, right multiple renal stones, a ureteropelvic junction stone and a left ureterovesical junction stone (see figure). The left ureteral stone was spontaneously discharged 5 days after the initial consult. The patient underwent 4 sessions of shock wave lithotripsy and percutaneous nephrolithotomy to remove stones in the right renal pelvis and ureteropelvic junction, after ureteral stenting. After stenting, renal function returned to normal (blood urea nitrogen 10 mg./dl. and serum creatinine 0.89 mg./dl.). Stone analysis revealed acetylsulfapyridine, which is a metabolite of sulfasalazine. After the final diagnosis, sulfasalazine was replaced with mesalamine (5-aminosalicylic acid) to treat the ulcerative colitis, and at 6-month followup no recurrence of stone disease was observed.

Xanthogranulomatous pyelonephritis, the gatekeeper's dilemma: A contemporary look at an old problem

Objectives To review 12 patients with a clinicopathogenic diagnosis of xanthogranulomatous pyelonephritis (XGP) and to determine if a computed tomography (CT) scan is the imaging procedure of choice for diagnosis. Methods A retrospective review, over the last 12 years, of patients with XGP at our institution. Results Nine of 10 patients (90%) who were evaluated by CT scan had the correct diagnosis made prior to nephrectomy. The most common presenting symptoms and signs were flank pain (64%), leukocytosis (73%), and anemia (82%). Seventy-five percent of the patients had a ureteropelvic junction stone or a staghorn stone in the affected kidney at the time of clinical presentation. Proteus was the most common organism cultured. Conclusions After reviewing the clinical features of these 12 patients, we recommended CT scan to evaluate the patient in whom clinical suspicion of XGP is entertained. CT has proven to be the most accurate imaging study to evaluate this disease.

Extracorporeal Shock Wave Lithotripsy in the Prone Position: Treatment of Stones in the Distal Ureter or Anomalous Kidney

A total of 15 patients underwent ESWL using the Dornier HM3 lithotriptor with the patient in the prone position. The stones were in the distal ureter over the sacroiliac joint in 10 patients, 8 of whom had undergone unsuccessful ureteroscopic manipulation. Two patients had horseshoe kidneys with stones that were too anterior to permit accurate targeting with the patient in the standard supine position. One patient had a solitary stone in a pelvic kidney and 1 had an obstructing ureteropelvic junction stone in a crossed ectopic kidney. The final patient had a reconstructed lower urinary tract with a stone at 1 of the ureterointestinal anastomoses.Excellent pulverization was achieved in all patients after only 1 prone ESWL treatment. One patient required temporary percutaneous nephrostomy after ESWL and 1 may require retrograde manipulation of fragments at the ureterovesical junction. No patient had melena, and other than temporary ileus in 1 patient who had concurrent supine ESWL of renal calculi, no gastrointestinal complications were seen. All but 1 patient were free of stones 1 month after prone ESWL.Prone ESWL prevents blockage of shock wave energy by the bony pelvis, because the shock waves enter anteriorly and exit posteriorly. ESWL with the patient in the prone position is a safe and effective treatment of calculi in the distal ureter or anomalous kidney.