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Biomedical subjects

P López Pereira

Publications and source records attributed to P López Pereira.

At least 19 recordsLinked to original sources
PubMed2004

Initial and long-term management of posterior urethral valves.

Posterior urethral valves are the most common cause of congenital obstructive uropathy, resulting in renal failure in childhood. Nowadays, in most cases, diagnosis is suggested by antenatal ultrasound. However, antenatal intervention has not resulted in a significantly improved outcome. Endoscopic valve ablation is the initial treatment in most of these neonates, but others procedures, like vesicostomy or ureterostomy, can also be justified in some particular cases in order to improve renal function prognosis. Different factors like bladder dysfunction, VUR, polyuria and proteinuria, can be responsible for the slow and progressive deterioration in renal function that some of these patients show over the years. By treating them all, we may prevent or delay the onset of end stage renal disease.

Algorithms↗
PubMed2003

[Results of kidney transplantation in children weighing less than 11 kilograms].

Weigh and age are risk factors of graft failure. The aim of the study is to review the characteristics and the outcome of cadaver renal transplant in children weighing less than 11 Kg. From 1985 to 1999 10 cadaver renal transplant were performed in 10 children (7 boys and 3 girls). Primary renal disease were renal dysplasia(3), posterior urethral valves(5) and congenital nephrotic syndrome(2). All except two suffered end stage disease from birth. The cadaver donor age ranged from 4 to 45 years (mean 12.3). Cold ischaemia time was 14 to 30 hours (median 22.8 h). Grafts were placed extraperitoneally in the iliac fossa in all patients and special care was taken in aggressive intravascular volume expansion. In the first 5 children initial immunosuppression consisted of CyA, Pd and Aza. After 1991, the other five received sequential induction therapy with polyclonal antibodies and triple therapy (CyA, Pd, Aza). Renal function was evaluated as GFR yearly by Swartz formula and the actuarial and graft survival rates were obtained by Kaplan-Meier analysis. Patient survival was 90% at 1 and 10 years. Graft survival was 80% at 1 and 5 years; it decreased to 64% at 7 years. Seven continue with their first graft and the mean follow-up time is 6.6 years. Their renal function measured by the mean of GFR yearly decreased lightly from 102 ml/min/1.73 m2 at 1 year to 87.6 ml/min/1.73 m2 at 5 years. A successful patient and graft survival can be achieved in young receiving kidneys and small reciepients can improve their physical and mental development after transplantation.

Body Weight↗
PubMed2001

Should we treat vesicoureteral reflux in patients who simultaneously undergo bladder augmentation for neuropathic bladder?

PURPOSE: If high pressure is responsible for vesicoureteral reflux in neurogenic bladders, eliminating the high pressure should resolve reflux in noncompliant bladders. Nevertheless, the need for simultaneous ureteral reimplantation and bladder augmentation remains controversial in patients with a noncompliant bladder and vesicoureteral reflux. MATERIALS AND METHODS: Bladder augmentation was performed in 8 boys and 8 girls with a noncompliant bladder and vesicoureteral reflux at a mean age of 10 years (range 2 to 17) because they had not responded satisfactorily to clean intermittent catheterization and anticholinergic therapy alone. No effort had been made to correct reflux surgically in these patients. Before bladder augmentation reflux was grade II to III in 4 ureters (3 patients) and IV to V in 18 (13). The bladder was augmented with intestine in 14 patients and with ureter in 2. Mean followup was 5.2 years (range 2.8 to 7.5). RESULTS: After bladder augmentation bladder compliance improved in all patients. Of the 18 ureters with high grade reflux 2 were used for bladder augmentation, and reflux resolved in 13, was downgraded in 1 and persisted in 2. Of the 4 ureters with low grade reflux, reflux disappeared in 2 and was down graded in 2. The rate of high and low grade vesicoureteral reflux resolution or improvement was 87.5% and 100%, respectively. At the end of the study only 3 patients had persistent reflux, which was downgraded in 2. No urinary tract infections developed in any patient and none was receiving chemoprophylaxis 6 months postoperatively. CONCLUSIONS: Our experience indicates that antireflux procedures are not routinely needed in patients with a noncompliant bladder and associated vesicoureteral reflux who undergo bladder augmentation.

Child↗
PubMed2001

[Pediatric renal transplantation from related living donor].

Living related donor (LRD) provides significant advantages when compared with cadaveric donor (CAD) in term of improved patient and graft survival and shorten waiting time. From 1985, 176 kidney transplants were performed at our Center. Of these, 156 (89%) were from CAD and 20 (11%) were from LRD, first degree. The purpose of this paper is to show our experience at 5 years with use of LRD. All donors underwent standardized metabolic workup, angiography assessed and renal function test. Twelve children received their first transplant and 8 were retransplant (6-second, 1-third and 1-fourth). Immunosuppressive therapy consisted of globulin antithymocyte, azathioprine, cyclosporine and prednisolone, using FK506 and mycophenolate mofetil in some of them. Four kidneys with multiple renal arteries were reconstructed ex vivo with microsurgical technique before transplantation. The most significant morbidity was due to FK506-associated thrombotic microangiopathy (TMA) with graft lost. All patients (donor and recipient) survived. Five years graft survival rate is 95% and mean glomerular filtration rate is 81.33 ml/min/1.73 m2.

Adolescent↗
PubMed1999

[Bladder augmentation in reconstruction of the urinary tract (1985-1997)].

Bladder augmentation with intestinal or urinary segments has virtually replaced other treatments in the management of both neuropathic and no neuropathic bladder dysfunction that has not responded to pharmacotherapy nor other intervention. We present herein our experience in 55 patients who underwent augmentation cystoplasty. Their mean age were 12.2 years (range 2.5-22.8) and the mean follow-up time was 4 years (1-13.1). They were divided in three groups according to the diagnosis: vesical or cloacal exstrophy (14 patients), neuropathic bladder (36) and posterior urethral valves (5 patients). Indications were: 1) to get a low pressure, high volume reservoir and avoid upper urinary tract damage in low-compliance bladders (41 patients); 2) as an undiversion (8 patients), and 3) prior to renal transplantation. Cystoplasty was performed with bowel segments in 47 cases and ureter in 8, adding some other urological procedures in 22 patients. Mean bladder capacity after 1 year was 400 ml versus 112 as previous value. 52 out of the 55 patients are continent after augmentation. There was no impairment of the renal function in the 5 patients with prior renal failure who underwent cystoplasty. Vesicoureteral reflux disappeared in 78.6% of the patients after cystoplasty. The complications were urinary stones in 5 cases, upper urinary tract infections in 3, and spontaneous bladder perforation in 1 patient. Augmentation cystoplasty is the best choice to achieve a low pressure reservoir, to assure contingency and to avoid progressive damage of the upper urinary tract in neuropathic or no neuropathic pediatric bladder dysfunctions.

Adolescent↗
PubMed1997

[The Mitrofanoff principle in the lower urinary tract reconstruction].

Since its description in 1980, the Mitrofanoff principle has become a widely utilized and successful technique for the management of patients with a variety of urological disorders. We report our experience with this procedure in 12 patients (8 M, 4F). The age range was 3.5 years to 17 years (average 13y) and follow-up was from 6 months to 3 years (average 1.7y). Patients were classified in 2 groups: I. When this procedure was done because of the patient was unable to perform urethral catheterization (6p). II. Concomitant bladder neck transection and Mitrofanoff diversion (6p). The appendice was used in 8 p and ureter in 4. Bladder augmentation was performed with ureter in 2 p and colon sigmoid in 3. In 1p, ileocecal segment and in other colon + ileum, were used to replace the bladder. All patients catheterize the Mitrofanoff channel easily, there were no cases of stomal stenosis and the conduit was continent in all. We consider that Mitrofanoff principle is a very successful technique and it can be used as the primary continence mechanism or as an adjunct of major urinary tract reconstruction, to ensure complete bladder emptying, in patients unable to perform urethral catheterization.

Adolescent↗
PubMed1997

[The effectiveness of the trigonoplasty in the treatment of the primary vesicoureteral reflux].

Trigonoplasty is a minor surgical procedure to treat vesicoureteral reflux that preserves the integrity of the vesicoureteral junction. This technique was introduced in 1984 by Gil Vernet. Between 1989 and 1995 we performed trigonoplasty in 20 children from 6 to 15 years old with primary vesicoureteral reflux. In our study 15 patients had bilateral vesicoureteral reflux and five were unilateral, they had 35 refluxing units. Gil Vernet's trigonoplasty was performed after a five year observational treatment and it was always indicated in children with special wide trigone (1 grade I, 14 grade II, 17 grade III and 3 grade IV). Surgery was successful in 94% of the patients controlled one year after. Unilateral reflux recurrence in two patients. We consider that trigonoplasty is a good procedure with indication in patients with vesicoureteral reflux with wide trigone. The procedure shorten the postoperative hospital stay and offers a similar percentage of good results as other techniques.

Adolescent↗
PubMed1997

[The use of a continent urinary stoma in complex reconstructions of the lower urinary tract in children].

Since its description in 1980, the Mitrofanoff principle has become a widely utilized and successful technique for the management of patients with a variety of urological disorders. We report our experience with this procedure in 14 patients (10 M, 4 F). The age range was 3.5 years to 17 years (average 12 y) and follow-up was from 6 months to 3 years (average 1.7 y). Patients were classified in 2 groups: I) When this procedure was done because of the patient was unable to perform urethral catheterization (8p). II) Concomitant bladder neck transection and Mitrofanoff diversion (6p). The appendice was used in 9p, ileum in 1 and ureter in 4. Bladder augmentation was performed with ureter in 2p and colon sigmoid in 4. In 1p, ileo-cecal segment and in other colon+ileum, were used to replace the bladder. All patients catheterize the Mitrofanoff channel easily, there were no case of stomal stenosis and the conduit was continent in all. We consider that Mitrofanoff principle is a very successful technique and it can be used as the primary continence mechanism or as an adjunct of major urinary tract reconstruction, to ensure complete bladder emptying, in patients unable to perform urethral catheterization.

Adolescent↗
PubMed1996

[A new method for assessing sphincter resistance, in patients with low compliant bladder].

Since 1990, in our department we have planned out a test to find out the grade of sphincteric resistance in patients with low compliant bladders. In order to know which patients will have a sufficient sphincteric resistance to achieve satisfactory continence after bladder augmentation and which patients will not have sufficient sphincteric resistance, needing procedures to increase outlet resistance along with bladder augmentation. This test consisted in: to determine what volume the bladder can admit at a detrusor pressure of 10 cm H2 O, we fill the bladder at that volume and then, we check if the patient had leaks with abdominal pressure increases. The study was carried out in 15 patients with low compliant bladders and suffering from incontinence, who had not responded to I.C. and anticholinergic therapy, who was to undergo bladder augmentation. In 12 patients the test was negative and in 3 was positive. After bladder augmentation, all patients with negative tests, are completely dry, and the three patients whose test was positive, in spite of having urodynamically normal neobladder they remain incontinent. In our opinion, this test is simple to perform and very useful diagnostic tool to known which patients beside bladder augmentation, may need procedures to increase outlet resistance.

Adolescent↗
PubMed1996

[Are there a neuro-urological symptomatology improvement after spinal cord untethering?].

Changes in bladder behaviour and neurological symptoms were evaluated in 47 patients underwent untethered spinal cord because of tethered cord syndrome secondary to myeloneningocele closure. Patients were located in 3 categories (A < or = 5 years, B = 6-10 years and C > 10 years) in relation to age of treatment. After untethering 77% improved neurologically and the best results were evident in children whose condition was repaired promptly (90%). Urodynamic studies were performed in 33 patients before and after surgery. Fifteen had hyperreflexic bladders, six low complicance and 12 hyperreflexia plus low compliance. After treatment in 6 patients bladder dysfunction improved (18%), hyperreflexia disappeared in 4 and sphinteric resistance increased in 2. In patients with tethered cord syndrome, untethering is recommended treatment in preventing further, sometimes rapid neurologic dysfunction and better results are got in childs whose condition is repaired at an early ages.

Child↗
PubMed1996

[Multicystic renal dysplasia and Wilms tumor].

We review a case of multicystic right dysplasia containing nodular renal blastema in a 3-year-old girl with left Wilms tumor. In relation to this finding the management of the asymptomatic multicystic dysplastic kidney in discussed.

Child, Preschool↗
PubMed1995

[Neuro-urologic impact of spinal cord untethering in patients with myelomeningocele and tethered cord].

Changes in bladder behaviour and neurological symptoms were evaluated in 47 patients underwent untethered spinal cord because of tethered cord syndrome secondary to myeloneningocele closure. Patients were located in 3 categories (A < or = 5 years, B 6-10 years and C > 10 years) in relation to age of treatment. After untethering 77% improved neurologically and the best results were evident in children whose condition was repaired promptly (90%). Urodynamic studies were performed in 33 patients before and after surgery. Fifteen had hyperreflexic bladders, six low compliance and 12 hyperreflexia disappeared in 4 and sphinteric resistance increased in 2. In patients with tethered cord syndrome, untethering is recommended treatment in preventing further, sometimes rapid neurologic dysfunction and better results are got in childs whose condition is repaired at an early ages.

Child↗
PubMed1995

[Problems associated with nephrectomy of transplanted kidneys].

Graft survival is not indefinite and a proportion of the failures must be removed. This study pretend to know the fate of failed renal transplant (RT) in the child, indication for transplant nephrectomy (TN) and morbidity involved. 96 RT were performed between 1985 and september 1994, during this time 31 grafts were lost: 71% immunologic causes, 13% relapse of original disease and 16% other reasons. Mean patient age and weight were 9 years and 27.3 kg, respectively. TN was performed in 28 (29%) and the most common indication was symptomatic rejection after withdrawal of immunosuppression (35.7%). Postoperative complications were diverse, including wound hematoma (13.6%), major hemorrhage (7%), fluid and electrolyte disorders (45.5) and 1 patient died (4.5%). Re-surgical approach was necessary in the 2 patients with major hemorrhage and 50% of the patients were in need of dialysis in the early postoperative. In this paper we appreciated that child with failed renal allograft could need TX in 90% of the cases, mainly because of symptomatic rejection. Furthermore, this procedure is more risky than simple native nephrectomy.

Adolescent↗
PubMed1994

[The prognosis of patients with posterior urethral valves according to the initial treatment and their urodynamic behavior].

Long-term outcome of 35 boys with severe posterior urethral valves is reviewed, with intention to know if the course of renal function depended on initial treatment and bladder dysfunction. Diagnosis was established during the first month in 15 patients, before one year in 16 and later in 4. Surgical management was initially, upper urinary tract diversion (pyeloureterostomy) in 19 patients (group A) and valve ablation in 15 (group B). The average age for closure of temporary urinary diversion was 17 months. Follow-up ranged from 4-19 years (mean 8.3 years). Twenty one patients had a urodynamic study years after initial treatment and this study showed 8 normal bladder, 7 unstable and 6 non-compliant. In group A, at the end of study, 13 patients (70%) have a glomerular filtration of more than 80 ml/min/1.72 m2 while in group B only 6 (37.5%) and average height after treatment was higher in patients of group A. Noncompliant bladders had worst prognosis (66% renal failure) than unstable bladders (25%) and the prognosis was improved in these types of bladders when initial treatment was upper tract diversion. The results of our study suggest that in patients with severe posterior urethral valves, the renal function improved with early diversion (pyeloureterostomy) and irreversible bladder dysfunction worsen the prognosis in these patients.

Follow-Up Studies↗
PubMed1993

[Enterocystoplasty: the results with our first 21 patients].

The use of intestinal segments for bladder replacement or augmentation is an alternative in the management of urologic patients. Twenty-one patients (13 M, 8 F) underwent enterocystoplasty by different reason, neurogenic bladder (NB) (10 p), bladder exstrophy (7 p), cloaca exstrophy (3 p) and posterior urethral valves (PUV) (1 p) are presented. Mean age at operation was 12 years (range: 6-19) and the average followed was 3 years. Five patients undergone external urinary diversion. All patients had reflux and 3 chronic renal failure. Bowel segments employed were ileum (11 p), sigma (7 p) and ileocaecal (3 p). Average bladder capacity has been of 354 ml. (range: 200-510). The reflux disappeared in 14 patients and none of them had impaired renal function. In all patients has improved continence and 71% are dry.

Adolescent↗
PubMed1993

[The pediatric kidney transplant in recipients under 2 years old].

We report our experience with renal transplantation in 7 infants less than 2 years of age. The mean duration of follow-up was 32.4 m. except one who died in the immediate postoperative period. Immunosuppressive therapy consisted of methyl prednisolone, azathioprine, cyclosporin. No patient showed either vascular or lymphatic complications however the infections were frequent. All except one, have their graft functioning well. Graft and patient survival rates were 85% at 36 m. We conclude that renal transplantation in this age group is technically feasible although it needs a team with wide experience in the management of pediatric renal transplantation.

Combined Modality Therapy↗