Medical therapy for urinary stone passage.
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Adrenergic alpha-Antagonists↗
Biomedical subjects
Margaret S Pearle
Publications and source records attributed to Margaret S Pearle.
Assessment of basic human performance resources predicts performance of ureteroscopy.
BACKGROUND: Our objective was to predict endoscopic performance in a cadaver model using basic performance resources (BPRs) measurements. METHODS: Medical students (n = 16) underwent intense ureteroscopic training on a virtual reality ureteroscopy trainer and were rated on performing ureteroscopy on a cadaver. The medical students also underwent 13 validated BPR measurements. Urology residents also performed cadaveric ureteroscopy and BPRs. A predictive model built from urology residents' (n = 16) BPRs and performance assessment was used to predict medical student cadaveric ureteroscopy performance based on their BPRs alone. RESULTS: The predictive model built with urology residents predicted the ureteroscopic performance of 10 of 16 medical students within 15% of their rated ureteroscopic performance on the cadaver. CONCLUSIONS: A predictive model built with urology residents can moderately predict the ureteroscopic performance of medical students from BPRs. Additional in vivo evaluation is required.
Adult↗
A randomized, controlled, prospective study validating the acquisition of percutaneous renal collecting system access skills using a computer based hybrid virtual reality surgical simulator: phase I.
PURPOSE: The need to develop new methods of surgical training combined with advances in computing has led to the development of sophisticated virtual reality surgical simulators. The PERC Mentortrade mark is designed to train the user in percutaneous renal collecting system access puncture. We evaluated and established face, content and construct validation of the simulator in this task. MATERIALS AND METHODS: A total of 63 trainees underwent baseline testing on the simulator, consisting of percutaneous renal puncture followed by the introduction of a guidewire into the collecting system. Subjects were then randomized to an intervention arm, in which they underwent 2, 30-minute training sessions on the simulator, and a control arm, in which no further training was given, followed by repeat testing. Performance was assessed using a global rating scale and by virtual reality derived parameters. RESULTS: There were no significant differences between the 2 groups with respect to baseline measures. Subjects who underwent training with the simulator demonstrated significant improvement in objective and subjective parameters compared to their baseline performance and compared to the untrained control group. Spearman rank correlations demonstrated a significant relationship between multiple parameters of the objective and subjective data. CONCLUSIONS: Training on the simulator improves virtual reality skills. It may allow trainees to develop the basic skills necessary to perform percutaneous renal collecting system access. Face and content validity were demonstrated and construct validity was supported by establishing convergent validity.
Computer Simulation↗
Shock wave lithotripsy for upper tract stones: refining the algorithm.
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Humans↗
Imaging for percutaneous renal access and management of renal calculi.
Percutaneous renal stone surgery requires detailed imaging to define stone burden and delineate the anatomy of the kidney and nearby organs. It is also essential to carry out safe percutaneous access and to assess postoperative outcomes. The emergence of CT as the imaging modality of choice for detecting renal calculi and the ability of CT urography with or without three-dimensional reconstruction to delineate the collecting system makes this the most versatile and sensitive imaging modality for pre- and postoperative evaluation. At present, intravenous urogram continues to play an important role in the evaluation of patients considered for percutaneous nephrostolithotomy. Fluoroscopy re-mains the mainstay of intraoperative imaging, although ultrasound is a useful alternative. Selection and application of appropriate imaging modalities for patients undergoing per-cutaneous nephrostolithotomy enhances the safety and success of the procedure.
Humans↗
Resorbable clip migration in the collecting system after laparoscopic partial nephrectomy.
A complication is reported in which Lapra-Ty absorbable suture clips (Ethicon EndoSurgery) migrated from a laparoscopic partial nephrectomy bed into the collecting system, causing renal colic. During surgery performed with hilar occlusion, visual inspection did not reveal collecting system entry. Transected vessels were oversewn with absorbable suture secured with Lapra-Tys. Absorbable bolsters were placed in the parenchymal bed, and compression sutures secured with Lapra-Tys were placed through the renal capsule. Six weeks postoperatively, the patient developed ipsilateral renal colic, and computed tomography demonstrated several 3-mm opacities within the ureter. After 2 weeks of conservative management, he spontaneously passed several Lapra-Ty clips.
Foreign-Body Migration↗
Effect of high and low calcium diets on stone forming risk during liberal oxalate intake.
PURPOSE: Recent studies suggest that a high calcium diet protects against calcium oxalate stone formation. We compared the effect of high and low calcium diets on urinary saturation of calcium oxalate during liberal oxalate intake. MATERIALS AND METHODS: A total of 10 healthy subjects (5 male, 5 female) participated in a 2-phase, randomized, crossover study comparing high (1,000 mg daily) and low (400 mg daily) calcium intake on a liberal oxalate diet (200 mg daily). During each phase subjects adhered to an instructed diet for 3 days followed by a controlled, metabolic diet for 4 days. Blood and 24-hour urine specimens collected on the last 2 days of each phase were analyzed for serum biochemistry studies and stone risk factors, respectively. RESULTS: Urinary calcium was higher (mean +/- SD 171 +/- 64 vs 124 +/- 49 mg daily, p = 0.002) and oxalate was lower (25 +/- 4.8 vs 27 +/- 4 mg daily, p = 0.02) on the high vs low calcium diet. Overall, the urinary relative saturation ratio of calcium oxalate was higher on the high compared with the low calcium diet (3.3 vs 2.5, p <0.0001) even after adjusting for confounding variables. CONCLUSIONS: In normal subjects urinary saturation of calcium oxalate was higher on a high calcium diet than a low calcium diet during liberal oxalate intake because the decrease in urinary oxalate did not overcome the effect of increased calcium. A high calcium diet during liberal oxalate intake may pose an increased risk of calcium oxalate stone formation.
Adult↗
Comparison of basic elements of human performance scores between urologists with various extents of experience.
BACKGROUND AND PURPOSE: An objective evaluation of innate ability and its ability to predict potential success as a surgical trainee is an appealing concept for the selection process of residency applications. The objective of this study was to evaluate whether basic elements of performance (BEP) could discriminate among resident applicants and urologists with various extents of surgical experience. SUBJECTS AND METHODS: One hundred forty-five participants were divided into four study groups: group A, 57 urology residency applicants to the 2002 and 2003 interview process; group B, 8 post-internship urology residents; group C, 19 urologists tested with BEP within 10 years of graduation from their residency training program; and group D, 61 urologists who had graduated from their residency training program more than 10 years prior to testing. The BEP measures consisted of 13 basic performance resources (BPR) including visual-information processing speed, visual-spatial immediate-recall capacity, and neuromotor channel capacity. RESULTS: The four study groups differed significantly in their mean age: group A=27.6 years, group B=29.1 years, group C=37.1 years, and group D=48.9 years (P<0.0005). There was essentially no significant difference between the groups with regard to immediate-recall memory, reaction time simple, or reaction time complicated. The younger participants (groups A and B) were faster than the older surgeons (groups C and D) (P<0.02). However, the older surgeons (groups C and D) were significantly more accurate than the younger groups (A and B) (P<0.0005). The only sex differences noted were in hand-grip strength and shoulder-strength scores, which were all higher in the men. CONCLUSIONS: There generally appears to be a lack of direct correlation between innate abilities and surgical experience. Urology resident applicants with no surgical experience and urology residents with limited surgical experience are faster but less accurate in innate skills testing than experienced practicing urologists.
Adult↗
Endoscopically guided percutaneous renal access: "seeing is believing".
Image-guided percutaneous nephrostomy tube placement can be a challenging procedure, particularly in a nondilated system or in the morbidly obese patient. Herein, we report the routine use of ureteroscopy-guided percutaneous renal access. With this method, rapid, accurate creation and dilation of the nephrostomy tract is assured in all patients regardless of body habitus or stone burden.
Endoscopes↗
The contemporary management of renal and ureteric calculi.
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Female↗
International comparison of cost effectiveness of medical management strategies for nephrolithiasis.
Although medical therapy is known to reduce the risk of kidney stone recurrence, the cost effectiveness of medical prophylaxis is controversial. We evaluated medical treatment strategies including dietary measures (conservative), empiric medical therapy (empiric) or directed medical therapy (directed) based on comprehensive metabolic evaluation (CME) for patients with recurrent kidney stones, and compared the costs of these strategies using cost data from ten different countries. We previously established rates of stone formation in recurrent stone-formers, risk reduction of medical therapy, sensitivity of CME and rates of spontaneous stone passage from a comprehensive literature search (Lotan et al. 2004 J Urol 172: 2275). The costs of medication, surgical therapy, emergency room visits and CME for ten different countries were obtained from a published report of an international cost survey (Chandhoke 2002 J Urol 168: 937) as well as from our own county hospital in the US. Medication costs in the US were obtained from two national pharmacy chains. A decision tree model was created to compare the costs of different treatment strategies assuming cost accrual for metabolic evaluation, medical therapy and surgery or emergency room visits. For medical therapy, we assumed the distribution of medication use described in the published report, consisting of potassium citrate (60%), thiazide (30%) and allopurinol (10%). A nearly 20-fold difference in the costs of shock-wave lithotripsy, ureteroscopy and medication was found among different countries. From the model (US dollars/patient/year), conservative therapy alone was the most cost effective approach followed by empiric and directed medical therapy in all countries except in the UK. In the UK, the cost of drug therapy (estimated at dollar 29/patient/year) resulted in empiric therapy being the most cost effective strategy for recurrent stone formers. The low likelihood of surgical intervention, as well as the low relative cost of surgery to medication, contributed to the higher cost of empiric and directed medical therapy strategies. Of note, despite the higher cost, drug treatment strategies were associated with significantly lower stone recurrence rates. We found that drug treatment strategies are more costly than conservative treatment but produce good control of stone formation. In all but one country (UK), dietary therapy was the most cost effective approach due to the relatively low cost of surgery compared with medication. The differential resource allocation to different components of a healthcare system (i.e. subsidized medication versus surgical treatment) in different countries determines the cost effectiveness of various treatment strategies.
Cost-Benefit Analysis↗
Cytokine response to surgical stress: comparison of pure laparoscopic, hand-assisted laparoscopic, and open nephrectomy.
BACKGROUND AND PURPOSE: Laparoscopic surgery has been shown to induce less immune suppression than open surgery, presumably because there is less tissue trauma, a factor that may impact oncologic-disease control. The objective of this study was to compare the cytokine and stress response associated with pure laparoscopic, hand-assisted laparoscopic (HAL), and open nephrectomy. MATERIAL AND METHODS: Fifteen female farm pigs (45-50 kg) underwent transperitoneal laparoscopic, handassisted (HAL), or open nephrectomy (N = 5 in each group). At 1, 4, 24, and 48 hours post-nephrectomy, blood and peritoneal fluid samples were collected for measurement of tumor necrosis factor (TNF) alpha, interleukin (IL)-1beta, and IL-6 using enzyme-linked immunosorbent assay (ELISA) techniques. Body temperature and serum glucose and cortisol were also measured. RESULTS: No evidence of perioperative infection was detected in any animal through temperature and glucose monitoring. Operating time and blood loss were comparable among the three groups. Peak serum cortisol concentrations were significantly higher in the HAL group than in the pure laparoscopic group at 24 hours (P = 0.02). Serum TFNalpha concentrations were significantly lower in the pure laparoscopy group (40 +/- 6 pg/mL) than in the HAL and open-nephrectomy groups (81 +/- 6 pg/mL and 83 +/- 17 pg/mL, respectively; P < 0.05), although no differences between groups were found in the serum IL-1beta and IL-6 concentrations. Peritoneal IL-1beta was significantly higher in the HAL than in the open-nephrectomy group (2993 +/- 507 pg/mL and 733 +/- 185 pg/mL, respectively; P = 0.05). Peritoneal IL-6 was significantly lower in the pure laparoscopy group (694 +/- 234 pg/mL) than in the open-surgery group (1668 +/- 312 pg/mL) (P = 0.04). CONCLUSION: Pure laparoscopic surgery in pigs elicits a less-robust cytokine response than HAL or open nephrectomy with respect to serum TNFalpha and peritoneal IL-6 concentrations, perhaps reflecting less impairment of the immune system. Clinical confirmation is required, and the implications with regard to oncologic tumor surveillance in humans require further study.
Animals↗
Contrast-enhanced ultrasound evaluation of radiofrequency ablation of the kidney: reliable imaging of the thermolesion.
BACKGROUND AND PURPOSE: Radiofrequency ablation (RFA) is limited by the inability to monitor progression of the thermal lesion. Contrast-enhanced ultrasonography (CEUS) imaging has considerable potential as a monitoring modality for RFA. We report our experience using CEUS to evaluate the lesion produced by RFA in a porcine model. MATERIALS AND METHODS: Five pigs underwent laparoscopic RFA twice, spaced by a 1-week interval. Post- RFA ultrasound imaging was performed transcutaneously immediately after ablation. The kidneys were assessed for a contrast void corresponding to the ablated tissue. The kidneys were then harvested and the gross RFA lesions measured to compare lesion size with that measured using CEUS. RESULTS: A clear lesion was identified at the site of each RFA application. As measured by CEUS, the acute lesions averaged 1.8 +/- 0.4, 1.7 +/- 0.4, and 1.8 +/- 0.3 cm in length, height, and width, respectively, compared with 2.0 +/- 0.5, 1.8 +/- 0.4, and 1.9 +/- 0.3 cm, respectively, by measurement in the gross specimen (P = 0.33, 0.13, and 0.44, respectively). At 1 week, the CEUS-measured dimensions of the lesions were 2.7 +/- 0.5, 2.6 +/- 0.6, and 2.6 +/- 0.6 cm, and the gross measurements of the lesion were 2.7 +/- 0.4, 2.7 +/- 0.9, and 2.6 +/- 0.4 cm (P = 0.75, 0.92, and 0.40, respectively). CONCLUSIONS: Contrast-enhanced ultrasonography appears to be an accurate modality for immediate monitoring of RFA defects. Further study is necessary to assess the clinical utility of CEUS for monitoring RFA of small renal lesions.
Animals↗
Urologic diseases in America project: urolithiasis.
PURPOSE: We quantified the burden of urolithiasis in the United States by identifying trends in the use of health care resources and estimating the economic impact of the disease. MATERIALS AND METHODS: The analytical methods used to generate these results have been described previously. RESULTS: The rate of national inpatient hospitalizations for a diagnosis of urolithiasis decreased by 15% and hospital length of stay decreased from 2.6 to 2.2 days between 1994 and 2000. Rates of hospitalization were 2.5 to 3-fold higher for Medicare beneficiaries with little change between 1992 and 1998. Almost 2 million outpatient visits for a primary diagnosis of urolithiasis were recorded in 2000. Hospital outpatient visits increased by 40% between 1994 and 2000 and physician office visits increased by 43% between 1992 and 2000. In the Medicare population hospital outpatient and office visits increased by 29% and 41%, respectively, between 1992 and 1998. The distribution of surgical procedures remained relatively stable through the 1990s. Shock wave lithotripsy was the most commonly performed procedure, followed closely by ureteroscopy. Overall the total estimated annual expenditure for individuals with claims for a diagnosis of urolithiasis was almost $2.1 billion in 2000, representing a 50% increase since 1994. CONCLUSIONS: The cost of urolithiasis is estimated at almost $2 billion annually and it appears to be increasing with time despite a shift in inpatient to outpatient treatment and the emergence of minimally invasive treatment modalities, perhaps because the prevalence of stone disease is increasing.
Adolescent↗
Prospective, randomized trial comparing shock wave lithotripsy and ureteroscopy for lower pole caliceal calculi 1 cm or less.
PURPOSE: The optimal management of lower pole renal calculi is controversial. We compared shock wave lithotripsy (SWL) and ureteroscopy (URS) for the treatment of patients with small lower pole stones in a prospective, randomized, multicenter trial. MATERIALS AND METHODS: A total of 78 patients with 1 cm or less isolated lower pole stones were randomized to SWL or URS. The primary outcome measure was stone-free rate on noncontrast computerized tomography at 3 months. Secondary outcome parameters were length of stay, complication rates, need for secondary procedures and patient derived quality of life measures. RESULTS: A total of 67 patients randomized to SWL (32) or URS (35) completed treatment. The 2 groups were comparable with respect to age, sex, body mass index, side treated and stone surface area. Operative time was significantly shorter for SWL than URS (66 vs 90 minutes). At 3 months of followup 26 and 32 patients who underwent SWL and URS had radiographic followup that demonstrated a stone-free rate of 35% and 50%, respectively (p not significant). Intraoperative complications occurred in 1 SWL case (unable to target stone) and in 7 URS cases (failed access in 5 and perforation in 2), while postoperative complications occurred in 7 SWL and 7 URS cases. Patient derived quality of life measures favored SWL. CONCLUSIONS: This study failed to demonstrate a statistically significant difference in stone-free rates between SWL and URS for the treatment of small lower pole renal calculi. However, SWL was associated with greater patient acceptance and shorter convalescence.
Adult↗
Chapter 1: AUA guideline on management of staghorn calculi: diagnosis and treatment recommendations.
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Adult↗
Effect of cranberry juice consumption on urinary stone risk factors.
PURPOSE: We evaluated the effect of cranberry juice on urinary stone risk factors. MATERIALS AND METHODS: A total of 12 normal subjects and 12 calcium oxalate stone formers underwent 2, 7-day phases of study in random order while on a controlled metabolic diet. Subjects ingested 1 l of cranberry juice (CBJ) daily in 1 phase and 1 l of deionized water in the other phase. On the last 2 days of each phase 2, 24-hour urine collections and blood samples were obtained for stone risk factors and serum chemistries. RESULTS: No significant differences were found between normal subjects and stone formers in response to CBJ and, therefore, the groups were combined. CBJ significantly increased urinary calcium (from 154 to 177 mg per day, p =0.0008) and urinary oxalate (from 26.4 to 29.2 mg per day, p =0.04), thereby increasing urinary saturation of calcium oxalate by 18%. Urinary citrate was unchanged and urinary magnesium increased slightly. Urinary pH decreased (from 5.97 to 5.67, p =0.0005), and urinary ammonium, titratable acidity and net acid excretion increased during CBJ ingestion. Urinary uric acid decreased (from 544 to 442 mg per day, p <0.0001) as did serum uric acid. Thus, the urinary saturation of brushite and monosodium urate was reduced by CBJ but the amount of undissociated uric acid increased. CONCLUSIONS: CBJ exerts a mixed effect on urinary stone forming propensity. It reduces urinary pH likely by providing an acid load and decreases urinary uric acid perhaps by retarding urate synthesis. Overall CBJ increases the risk of calcium oxalate and uric acid stone formation but decreases the risk of brushite stones.
Acid-Base Equilibrium↗
Effect of dietary modification on urinary stone risk factors.
BACKGROUND: This study was undertaken to ascertain the effect of dietary modification on urinary stone risks, and to determine whether the response depends on the prevailing urinary calcium. METHODS: A retrospective data analysis was conducted from our stone registry involving 951 patients with calcareous stones undergoing ambulatory evaluation, whereby 24-hour urine samples were collected during random diet and after dietary modification composed of restriction of calcium, oxalate, sodium, and meat products. Samples were analyzed for stone risk factors. Urinary calcium was also obtained after overnight fast and following a 1 g-calcium load. Changes produced by dietary modification from the random diet were evaluated in 356 patients with moderate-severe hypercalciuria (>6.88 mmol/day, group I), 243 patients with mild hypercalciuria (5.00-6.88 mmol/day, group II), and 352 with normocalciuria (<5.00 mmol/day, group III). RESULTS: Urinary calcium postcalcium load and the percentage of patients with absorptive hypercalciuria type I were highest in group I, intermediate in group II, and lowest in group III. During dietary modification, urinary calcium declined by 29% in group I, 19% in group II, and 10% in group III. Urinary oxalate did not change. Urinary saturation of calcium oxalate declined by only 12% in group I, 6% in group II, and nonsignificantly in group III, owing to various physicochemical changes in urinary biochemistry, which attenuated the effect of the decline in urinary calcium. Urinary saturation of brushite declined in all 3 groups due to the fall in urinary calcium, phosphorus, and pH. This reduction was more marked in the hypercalciuric groups than in the normocalciuric group. Urinary saturation of monosodium urate also decreased from a decline in urinary sodium and uric acid. CONCLUSION: Secondary rise in urinary oxalate occurring from calcium restriction can be avoided by concurrent dietary oxalate restriction. Dietary modification (restriction of dietary calcium, oxalate, sodium, and meat products) is more useful in reducing urinary saturation of calcium oxalate among patients with hypercalciuria than among those with normocalciuria.
Adult↗