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Dive into the research topics where Ricardo Gonzalez is active.

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Featured researches published by Ricardo Gonzalez.


The Journal of Urology | 1984

Malignant Urachal Lesions

Curtis A. Sheldon; Ralph V. Clayman; Ricardo Gonzalez; Richard D. Williams; Elwin E. Fraley

Urachal cancers are uncommon malignancies with a location that often permits considerable local extension before they are discovered. The most common histological type is adenocarcinoma, which may produce mucus that is a valuable aid in diagnosis. The presence of stippled calcification in a midline abdominal wall mass is almost pathognomonic for urachal carcinoma. More commonly, however, the symptoms are less specific, such as hematuria and an abdominal mass. Many lesions are visible endoscopically and, thus, the diagnosis can be made preoperatively from a biopsy. Most treatment failures occur because the tumor is not controlled locally by the initial operation and, therefore, we recommend en bloc cystectomy with umbilectomy and pelvic lymphadenectomy unless the tumor is known to be a sarcoma or early stage (I) carcinoma. If these patients are undertreated and there is a local recurrence then the patient usually is not salvageable. Because of the difficulty in identifying the origin of a bladder adenocarcinoma, any tumor on the dome or anterior wall should be approached initially as if it were a urachal tumor.


The Lancet | 1999

Long-term outcome in children after antenatal intervention for obstructive uropathies.

Andrew L. Freedman; Mark P. Johnson; Craig A. Smith; Ricardo Gonzalez; Mark I. Evans

BACKGROUND Antenatal intervention has been done for fetal obstructive uropathy for over a decade, yet little is known about long-term outcomes. To assess the long-term implications of fetal intervention, we reviewed the outcomes of children who underwent vesicoamniotic shunt placement. METHODS We reviewed the clinical outcomes of 14 children who underwent vesicoamniotic shunt placement at our institution and who survived beyond 2 years of age. FINDINGS In 1987-96, 34 patients underwent vesicoamniotic shunt placement. 13 died and 21 survived, of whom 17 are now more than 2 years old. Three survivors were lost to follow-up. Mean age at follow-up was 54.3 months (range 25-114). Final diagnoses included prune belly syndrome (seven cases), posterior urethral valves (four), urethral atresia (one), vesicoureteral reflux (one), and megacystis (one). Height was below the 25th percentile in 12 (86%) with seven (50%) below the 5th percentile. Five (36%) had renal failure and had successful transplantation, three (21%) have renal insufficiency, and six (43%) have normal renal function. Seven (50%) are acceptably continent, five (36%) have not yet begun toilet-training, and two (14%) are incontinent. Three of four children with valves needed bladder augmentation. INTERPRETATION Antenatal intervention may help those fetuses with the most severe forms of obstructive uropathy, usually associated with a fatal neonatal course. Intervention achieves outcomes similar to less severe cases that are usually diagnosed postnatally.


Urology | 2000

Surgical complications of bladder augmentation: comparison between various enterocystoplasties in 133 patients.

Bijan Shekarriz; Jyoti Upadhyay; Savas Demirbilek; Julia Spencer Barthold; Ricardo Gonzalez

OBJECTIVES Ileal and sigmoid augmentation are equally effective at increasing bladder capacity and compliance. Therefore, knowledge of the incidence of major complications, including perforation, small bowel obstruction (SBO), anastomotic complications, calculus formation, and indications for revision may be useful in choosing the ideal segment. We compared the complications of ileocystoplasty and two types of sigmoidocystoplasty that required reoperative surgery. METHODS Between 1981 and 1997, 158 patients with a mean age of 11 years (range 2 to 25) underwent augmentation cystoplasty. Ileum or sigmoid colon was used in 133 patients, who were the subjects of this study. The mean follow-up was 64 months (range 6 to 185). Indications included neurogenic bladder (n = 100), bladder exstrophy (n = 12), cloacal exstrophy (n = 6), posterior urethral valves (n = 3), and miscellaneous (n = 12). Ileum was used in 65 patients and sigmoid colon in 68. Of these, 48 underwent conventional colocystoplasty and 20 seromuscular colocystoplasty lined with urothelium (SCLU). Seventy-nine percent required additional procedures to achieve continence or facilitate catheterization, which included bladder neck procedures in 56% or continent stomas alone in 23%. RESULTS There were no deaths or complications of bowel anastomosis. Overall, continence was achieved in 95%. Spontaneous bladder perforation was highest in patients with neurogenic bladder. Calculi developed more frequently in patients with continent stomas (P = 0.04) and in patients with bladder/cloacal exstrophy (32%) than in patients with neurogenic bladder (P = 0.01). Additional procedures and route of catheterization did not increase the risk of perforation. One patient with SCLU with known hypercalciuria developed bladder calculi. CONCLUSIONS Sigmoid colon showed a trend of a lower rate of SBO with no difference in perforation or stone formation compared with ileum. Primary diagnoses of bladder or cloacal exstrophy and continent stomas are risk factors for the development of calculi. SCLU has a low rate of surgical complications and no incidence of perforation or SBO thus far; therefore, we advocate the use of SCLU when feasible, and sigmoid as the preferred bowel segment for augmentation cystoplasty.


The Journal of Urology | 1980

Renal Cell Cancer Invading the Inferior Vena Cava: Clinical Review and Anatomical Approach

Ralph V. Clayman; Ricardo Gonzalez; Elwin E. Fraley

Renal cell carcinoma invades the inferior vena cava in approximately 5 per cent of the patients. The only effective therapy for intravascular renal cell carcinoma is radical nephrectomy and complete removal of the tumor thrombus. To formulate a reasonable operative approach to intracaval renal cell carcinoma we have reviewed our experience with 6 cases as well as the experience of other investigators. In addition, we studied the collateral circulation of the renal veins as described by various anatomists, and to this information we have added our experience with inferior venacavography and with intraoperative and autopsy dissections. Herein we describe a new preoperative staging system for intravascular renal cell carcinoma. The operative approach to each stage is discussed in detail beneficial intraoperative maneuvers are described and illustrated.


The Journal of Urology | 1998

ALTERNATIVE TECHNIQUES FOR AUGMENTATION CYSTOPLASTY

Barry P. Duel; Ricardo Gonzalez; Julia Spencer Barthold

PURPOSE We discuss conventional intestinal cystoplasty and show how concern about potential complications has led to an interest in alternative methods for cystoplasty. Techniques such as gastrocystoplasty, ureterocystoplasty, vesicomyomectomy (autoaugmentation), seromuscular augmentation, alloplastic replacement and bioprosthetic materials are reviewed. Laboratory and clinical results of these techniques are examined critically to compare advantages, disadvantages and potential applications. MATERIALS AND METHODS Computer searches of available medical data bases were used to generate a list of relevant publications, including original contributions and review articles, which were then reviewed, compared and summarized. RESULTS Augmentation cystoplasty is used routinely for treatment of reduced bladder compliance and capacity secondary to infectious, inflammatory, neurogenic and congenital disorders. Sigmoidocystoplasty and ileocystoplasty have become standard techniques but there is renewed interest in alternative techniques due to the relatively high morbidity of intestinal cystoplasty. Alternative techniques have been described to avoid inclusion of intestinal mucosa in the urinary tract while creating a compliant bladder of adequate capacity. These techniques include gastrocystoplasty, vesicomyotomy, seromuscular augmentation, various alloplastic or biodegradable scaffolds and in vitro culture with subsequent grafting of autologous urothelium. Although encouraging animal and human results have been reported, each technique is associated with its own limitations and disadvantages. CONCLUSIONS While intestinal cystoplasty remains the standard, several alternative techniques show promise. At present only gastrocystoplasty, ureterocystoplasty and seromuscular augmentation should be considered clinically useful.


The Journal of Urology | 1986

The Value of Urodynamic Testing in the Management of Neonates with Myelodysplasia: A Prospective Study

Abraham Ami Sidi; Dennis D. Dykstra; Ricardo Gonzalez

We report the results of a prospective study conducted to identify neonates with myelomeningocele at risk for changes in the upper urinary tract. Thirty newborns underwent full urological evaluation and were followed for a mean period of 18.2 months. The initial studies included voiding cystourethrography, excretory urography and urodynamic tests. Followup consisted of periodic radiographic studies and repeat urodynamic testing if any changes were observed. According to urodynamic findings the patients were divided into 2 groups: group 1 consisted of 9 neonates (30 per cent) with detrusor-sphincter dyssynergia and high pressure, decreased-compliance bladders, and group 2 consisted of 21 children (70 per cent) with atonic bladders and low pressure, reduced-compliance bladders without dyssynergia. In group 1, 55 per cent of the patients had initially abnormal radiographic findings in contrast with 28.5 per cent in group 2. Anticholinergic drugs and clean intermittent catheterization or vesicostomy reversed the changes in 40 per cent of the children in group 1, 40 per cent remained stable and 20 per cent showed signs of deterioration. Four children in group 1 with normal neonatal radiographs were treated expectantly and at followup they all showed signs of deterioration. The neonates in group 2 with normal radiographic findings remained normal at followup. Of those who initially had changes 67 per cent reversed to normal without treatment, 17 per cent remained stable and 17 per cent had deterioration. Newborns with detrusor-sphincter dyssynergia or high pressure, reduced-compliance bladders are at high risk of having upper urinary tract changes and require preventive decompressive treatment. Children with atonic or low pressure, reduced-compliance bladders and those with a coordinated bladder and sphincter are at low risk and need only close followup.


The Journal of Urology | 1992

Prognosis for Patients with Prenatally Diagnosed Posterior Urethral Valves

Yuri Reinberg; Iris de Castano; Ricardo Gonzalez

Children in whom posterior urethral valves are diagnosed shortly after birth are at higher risk for renal failure than children in whom posterior urethral valves are diagnosed later in life. The influence of prenatal diagnosis of posterior urethral valves on clinical outcome has not been established. We collected data on children with posterior urethral valves treated since birth at our hospital between 1975 and 1990. The clinical outcomes for 8 patients diagnosed prenatally and 15 diagnosed neonatally were compared. Of the 8 patients in the prenatal group 5 (64%) had renal failure compared to 5 of 15 (33%) in the neonatal group (p greater than 0.05). Nadir creatinine of more than 1.2 mg./dl. correlated with the development of renal failure in all patients in the neonatal and prenatal groups. There was 1 death in the prenatal group. In our experience prenatal diagnosis of posterior urethral valves has grave implications, including a 64% incidence of progressive renal failure and a 64% incidence of transient pulmonary failure. Oligohydramnios and postnatal pulmonary insufficiency are predictive of progressive renal failure. Earlier diagnosis and treatment of children with posterior urethral valves did not improve the clinical prognosis.


Urology | 1995

Seromuscular colocystoplasty lined with urothelium : experience with 16 patients

Ricardo Gonzalez; Hélio Buson; Churphena Reid; Yuri Reinberg

OBJECTIVES Report of initial clinical experience with seromuscular colocystoplasty lined with urothelium (SCLU), a new operation to increase bladder capacity and compliance without incorporating intestinal mucosa into the urinary tract. We have previously reported the technique and results of this procedure in a canine model. METHODS Sixteen patients underwent SCLU at two institutions. Their charts were reviewed retrospectively. The patients have been observed for a mean of 12 months. RESULTS Postoperatively, the bladder capacity increased an average of 2.4-fold from a mean of 139 mL (+/- 23.7 SEM) to 335 mL (+/- 38.9 SEM) in 14 patients (P < 0.001). Two patients required reaugmentation. Preoperative and postoperative bladder end filling pressures were available in 13 patients and decreased from a mean of 51.6 cm H2O (+/- 4.2 SEM) to 27.7 cm H2O (+/- 2.4 SEM) (P < 0.001). Of the 16 patients, 13 were incontinent preoperatively; 5 had renal insufficiency. Three patients have undergone renal transplantation following SCLU. After SCLU, 13 patients were dry day and night, 1 incontinent at night only, and 2 remained incontinent. Ten patients have undergone postoperative bladder biopsy. Seven demonstrate urothelium covering the augmented portion of the bladder, 2 have regrowth of colonic mucosa, and 1 shows a mixture of colonic mucosa and urothelium. CONCLUSIONS The results presented suggest that SCLU is a viable alternative to the more conventional forms of bladder augmentation in selected patients.


The Journal of Urology | 1988

The Outcome of Renal Transplantation in Children with Posterior Urethral Valves

Yuri Reinberg; Ricardo Gonzalez; David S. Fryd; S. Michael Mauer; John S. Najarian

The effect of vesical dysfunction on the survival and function of renal transplants was evaluated by a retrospective study in which 18 children with posterior urethral valves and 18 children with vesicoureteral reflux were randomly matched with 36 children used as controls. There was no statistically significant difference in patient survival among the 3 groups. Five years after transplantation 50 per cent of the grafts in children with posterior urethral valves were functioning, while 73 and 75 per cent, respectively, of the grafts were functioning in children with vesicoureteral reflux and in the control group. Renal function during the 5 years was significantly better in children in the control group and in those with vesicoureteral reflux than in children with posterior urethral valves. We believe that the presence of an abnormal bladder may alter graft survival and adversely affect the function of the transplanted kidney.


The Journal of Urology | 1996

Fetal Therapy for Obstructive Uropathy: Specific Outcomes Diagnosis

Andrew L. Freedman; Timothy P. Bukowski; Craig Smith; Mark I. Evans; Mark P. Johnson; Ricardo Gonzalez

AbstractPurpose: Attempts to evaluate prenatal vesico-amniotic shunt therapy have been hampered by inconsistencies in patient selection, treatment and termination criteria, and outcomes measurement. Outcomes have generally been measured against those of patients with postnatally detected posterior urethral valves. The purpose of this report was to evaluate the influence of the underlying diagnosis on the clinical outcomes of fetuses undergoing evaluation for prenatal intervention for suspected obstructive uropathy. Furthermore, specific outcomes diagnosis was compared to the published natural history of these disorders to begin to establish a basis for measuring the efficacy of prenatal intervention.Materials and Methods: We retrospectively reviewed the outcomes of 55 consecutive patients undergoing prenatal evaluation using structured outcome measures stratified by specific diagnoses to provide a comparison to the reported natural history for each underlying disorder.Results: All fetuses had early onset ...

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Julia Spencer Barthold

Alfred I. duPont Hospital for Children

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Lisandro Piaggio

Alfred I. duPont Hospital for Children

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Craig Smith

Wayne State University

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