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Biomedical subjects

M L Ritchey

Publications and source records attributed to M L Ritchey.

At least 73 records · Page 4Linked to original sources
PubMed1993

Functional characteristics of enterocystoplasty after interruption of the mesenteric blood supply.

Previous studies have suggested that small (5 to 7 cm.) enteral patches used for bladder augmentation could remain viable following ligation of the mesenteric vascular pedicle. We performed subtotal cystectomy and ileocystoplasty in 5 female mongrel dogs using a 25 cm. segment of detubularized ileum. Functional bladder capacity, compliance and size of the bowel segment were measured 4 months later, and the mesenteric blood supply was interrupted. Immediately after pedicle ligation all patches appeared dusky and had diminished or absent Doppler pulsations with poor fluorescein uptake. However, all animals had an uneventful postoperative course without any signs of urine leak or peritonitis. Urodynamic studies were performed 2 months later and the animals were re-explored with removal of the augmented bladder for histological examination. All of the bowel segments were viable on exploration at that time but a decrease in patch size was noted ranging from 9 to 63%. Functional bladder capacity was also decreased in 4 animals. Although the integrity of augmentation was maintained in all animals, changes in bladder capacity and size of the enteral segment occurred in the majority after interruption of the mesenteric blood supply. These changes could possibly negate the clinical benefits that had been achieved by the bladder augmentation. This finding would suggest the need to consider revision of the enterocystoplasty in the event of inadvertent ligation of the vascular pedicle.

Animals↗
PubMed1993

Stress leak point pressure: a diagnostic tool for incontinent children.

The stress leak point pressure is the lowest bladder pressure at which leakage occurs during prompted increases in intra-abdominal pressure. The stress leak point pressure is distinct from the simple bladder leak point pressure and can be determined using simple urodynamic equipment without fluoroscopy. In 15 incontinent girls and boys 2.5 to 15 years old the mean stress leak point pressure was 54.7 cm. water (range 11 to 100), whereas the mean leak point pressure was 19.9 cm. water (range 5 to 50, paired t test p < 0.0001). The stress leak point pressure is a useful diagnostic tool that provides specific data on bladder neck and proximal urethral function.

Adolescent↗
PubMed1993

Enterocystoplasty in renal transplantation candidates: urodynamic evaluation and outcome.

In anticipation of renal transplantation 11 patients with end stage renal disease and small volume, poorly compliant bladders underwent enterocystoplasty. The etiology of bladder dysfunction included myelodysplasia in 4 patients, posterior urethral valves in 4 and vesicoureteral reflux in 3. Mean patient age at the time of bladder augmentation was 16.4 years (range 10 to 28). Detubularized bowel segments were used in all patients and included ileum in 7, ileocecal segment in 3 and sigmoid in 1. Urodynamic evaluation before and after enterocystoplasty demonstrated marked improvement in bladder capacity and compliance. These 11 patients have received 13 renal transplants with an 85% graft survival at a mean followup of 30.1 months. No bladder ruptures or other perioperative complications have occurred. All patients remain continent on clean intermittent catheterization. Our experience suggests that enterocystoplasty is a safe and effective method of restoring lower urinary tract function in the patient with end stage renal disease and a small, noncompliant bladder.

Adolescent↗
PubMed1993

Toilet habits and continence in children: an opportunity sampling in search of normal parameters.

An opportunity sampling of 1,192 children regarding parameters of toilet training and elimination status was obtained by interview and questionnaire. Toilet training ages ranged from 0.75 to 5 years, with a mean of 2.4 +/- 0.6 years (standard deviation). Voiding frequency was inversely related to age; most children between 3 and 12 years old urinated 5 to 6 times per day. Influences of gender, urinary infections and parental recall were investigated. Nocturnal and diurnal enuresis was reported in 18% and 10% of our sample, respectively. Bowel movements per week ranged from 1 to 21, with a mean of 6.8 +/- 2.5.

Age Factors↗
PubMed1993

Angiocentric myofibroblastic tumor of the penis in a child: case report and literature review.

A 6 1/2-year-old boy presented with a painless, white pearly nodule on the glans penis. Wedge excision was performed and pathological examination revealed a benign-appearing, well demarcated nodule confined to the corpus spongiosum. Histological examination revealed a peculiar multinodular myofibroblastic proliferation centered around the vessels within the penis. He has done well for 9 months without evidence of recurrence. To our knowledge this is a previously undescribed lesion arising from the male genitalia.

Child↗
PubMed1993

Transparenchymal suture fixation and testicular histology in a prepubertal rat model.

We evaluate the effect on testicular histology when fine suture materials are used for transparenchymal suture fixation of the testis during orchiopexy in immature Sprague-Dawley rats. Significant inflammatory reactions were observed in all groups of animals with suture fixation regardless of suture size and material. Only 5% of the animals in the dartos pouch control group had an inflammatory response and no inflammation was noted in the nonoperative controls. Although these findings have not been documented in humans, this evidence raises concerns about the impact of surgical technique on the future reproductive capabilities of these testes. Alternatives to transparenchymal suture fixation of the testis should be considered in patients with cryptorchidism and testicular torsion. Sutureless dartos pouch placement may provide adequate fixation during most orchiopexies without risking injury to testicular structure and function.

Age Factors↗
PubMed1993

Small bowel obstruction after nephrectomy for Wilms' tumor. A report of the National Wilms' Tumor Study-3.

OBJECTIVE: This study was undertaken to define the incidence and etiology of small bowel obstruction (SBO) after nephrectomy for Wilms' tumor. SUMMARY BACKGROUND DATA: Intestinal obstruction is one of the most common postoperative complications after nephrectomy for nephroblastoma. However, few reports have evaluated risk factors for SBO. Radiation therapy has been associated with increased intestinal complications in some adult cancer patients, but this has not been reported in children undergoing cancer surgery. METHODS: Postoperative SBO occurred in 131 of 1,910 children (6.9%) enrolled in the Third National Wilms' Tumor Study (NWTS). The etiology of the SBO was bowel adhesions in 104 cases, intussusception in 17, internal hernia in 2, and uncertain in the remaining 8 children. RESULTS: The factors found to be of potential importance in explaining the incidence of SBO were higher local tumor stage, extrarenal intravascular involvement, and en bloc resection of other organs at the time of nephrectomy. The incidence of postoperative SBO was not increased in children who received postoperative radiation therapy. CONCLUSIONS: Although the overall incidence of SBO after nephrectomy for Wilms' tumor is comparable to that after other major abdominal operations in children, it can be responsible for significant morbidity. There were 4 children among the 1,910 patients with infectious complications of SBO, which contributed to their death.

Child, Preschool↗
PubMed1993

Incidental vesicoureteral reflux in neonates with antenatally detected hydronephrosis and other renal abnormalities.

Postnatal imaging findings were reviewed in 130 neonates and young infants referred for imaging evaluation of antenatally detected renal abnormalities. All children underwent voiding cystourethrography and upper urinary tract imaging with sonography and/or renal scintigraphy. Vesicoureteral reflux was present in 49 patients (38%) and was bilateral in 24. All grades of reflux were observed. Reflux occurred in 41 of 98 neonates (42%) in whom postnatal imaging revealed persistent upper tract abnormalities (eg, hydronephrosis, cysts, renal agenesis) and in eight of 32 (25%) with normal findings at postnatal sonography and/or renal scintigraphy. Reflux was the single most common urologic diagnosis and was the only postnatal abnormality in 12 patients (9%). The authors conclude that neonates with antenatally detected hydronephrosis should be routinely screened for reflux with voiding cystography. Detection and aggressive management of reflux in the asymptomatic neonate in whom renal growth and function are unimpaired theoretically offer the best opportunity for preventing renal injury later in childhood.

Female↗
PubMed1993

Bladder capacity as measured at voiding cystourethrography in children: relationship to toilet training and frequency of micturition.

To assess the reliability of a frequently used formula for calculating bladder capacity in children, bladder capacity was measured prospectively at voiding cystourethrography in 274 consecutive healthy infants and children. Bladder volume index (BVI) was then calculated by dividing the measured capacity by the predicted capacity. Bladder capacity increased dramatically after 18 months and reached a plateau between 3 and 4 months of age, after which there was no further significant increase in capacity until approximately 9 years. BVI abruptly increased from 1.03 in children aged less than 18 months to 1.50-1.60 in children aged between 18 months and 4 years (P < or = .0001). Because bladder capacity increases sharply during infancy and early childhood and levels off once toilet training is complete, linear models used to predict bladder capacity on the basis of age alone significantly underestimate bladder capacity in infants and younger children.

Adolescent↗
PubMed1992

Prognosis of patients with unilateral renal agenesis.

The clinical course was reviewed in 157 patients with unilateral renal agenesis and a normal contralateral kidney for the purpose of establishing a prognosis. There were 85 males (54%) and 72 females (46%). The mean age at diagnosis of unilateral renal agenesis was 37 years. The mean years at risk was 56. Proteinuria (> 150 mg/24 h) was found in 19% of the 37 patients tested (P < 0.001), hypertension developed in 47% of the 47 patients tested (P = 0.010), and renal function (adjusted for age and sex) was decreased in 13% of the 32 patients tested (P = 0.001). An increased filtration fraction was found in 7 (54%) of 13 patients evaluated. At the completion of this study, 114 patients (73%) were alive, and the survival rate was similar to that of age-, sex-matched United States life tables. Forty-three patients (27%) died; 6 deaths (4%) were caused by renal failure. Our review indicates that patients with unilateral renal agenesis and a normal solitary kidney are at increased risk of proteinuria, hypertension, and renal insufficiency. Therefore, it is essential to have prolonged and careful follow-up and to employ strategies that maximize renal preservation.

Adolescent↗
PubMed1992

Single system ectopic ureters and ureteroceles associated with dysplastic kidney.

Eight children forming an uncommon subgroup of renal obstructive dysplasia are presented. Each child had a nonfunctioning dysplastic kidney with a single collecting system with ectopic ureteral insertion and/or ureterocele. Five of the children had classic multicystic dysplastic kidneys, one had the hydronephrotic type of multicystic dysplastic kidney and two had hypoplastic kidneys. Other significant medical problems in 5 of the 8 children (63%) included VACTERL association, congenital heart disease and other genitourinary malformations. Unlike some children with unilateral multicystic dysplastic kidney, this subgroup of children has an increased risk of infection. They must be correctly identified on imaging so that tailored clinical management decisions can be made and associated anomalies detected.

Abnormalities, Multiple↗
PubMed1992

Superior mesenteric artery injury during nephrectomy for Wilms' tumor.

Iatrogenic injury to the aorta or its major branches during nephrectomy for Wilms' tumor in children is rarely reported but may be more common than is currently acknowledged. We identified four patients with ligation of the superior mesenteric artery (SMA) that occurred during nephrectomy for nephroblastoma and another child in whom SMA thrombosis developed postoperatively. All of the tumors were on the left side. Interruption of the SMA was recognized intraoperatively in all four children, and primary repair was done. In three patients, appearance of the bowel remained normal before repair of the injury. Three of the arteries were repaired by primary reanastomosis, and one was joined with an interpositioned hypogastric artery graft. None of these patients had gastrointestinal complications postoperatively. In the fifth patient, SMA thrombosis developed after repair of an aortic tear during nephrectomy. This patient required subsequent small bowel resection for bowel infarction and died in the perioperative period. Every surgeon treating children with Wilms' tumor should be aware of the possibly distorted vascular anatomy and take precautions to avoid such a significant injury. Attempts at early ligation of the vessels may not be justified until the renal vasculature is clearly identified.

Child, Preschool↗
PubMed1992

The treatment of urinary incontinence in children using glutaraldehyde cross-linked collagen.

Periurethral injection of polytetrafluoroethylene (PolyTef) paste has been used to correct urinary incontinence for 2 decades. The controversy over distant migration of the paste has led to an interest in alternative materials particularly for the pediatric patient. Glutaraldehyde cross-linked collagen, derived from bovine dermal collagen, is effective in treating urinary incontinence in adults. Eight children with structural urinary incontinence underwent glutaraldehyde cross-linked collagen injection. Fluorourodynamic studies preceded and followed the injections. An average of 10.9 cc glutaraldehyde cross-linked collagen was injected per treatment (range 2.5 to 20). The number of injections per child ranged from 1 to 6 (mean 2.1) and followup averaged 13.75 months (range 6 to 33). Overall, 88% of the patients were cured or improved: 5 (63%) became continent, 2 were improved and 1 had no effect.

Adolescent↗
PubMed1992

Enterocystoplasty and reflux nephropathy in the canine model.

Correction of vesicoureteral reflux at enterocystoplasty is often recommended to prevent the development of reflux nephropathy. Children with enterocystoplasty who require intermittent self-catheterization invariably have asymptomatic bacteriuria. In patients with persistent vesicoureteral reflux after enterocystoplasty the risk of renal damage from this asymptomatic bacteriuria is unknown. Detubularized ileocystoplasty was performed in 17 dogs with either direct nontunneled reimplantation or unroofing of the intramural tunnel and incision of the ipsilateral hemitrigone to create vesicoureteral reflux. Fluoroscopic urodynamic studies were performed 1 month later and unilateral vesicoureteral reflux was present in 6 dogs. All animals had low intravesical pressure and excretory urograms were performed to exclude obstruction. The 6 dogs with reflux were euthanized 3 months postoperatively and the kidneys were examined for histological evidence of pyelonephritis. In 5 of 6 dogs bacterial bladder colonization and subsequent renal pelvic colonization developed on the side of the vesicoureteral reflux. All of these animals had histological evidence of pyelonephritis in the refluxing kidney, whereas only 1 of 6 nonrefluxing control kidneys had any evidence of pyelonephritis (p = 0.031). Our results suggest that vesicoureteral reflux in association with enterocystoplasty leads to chronic upper tract infection and pyelonephritis in a majority of animals, despite creation of a low pressure urinary reservoir. Correction of vesicoureteral reflux at enterocystoplasty should be considered to prevent upper tract damage.

Animals↗
PubMed1992

Prognosis of children with solitary kidney after unilateral nephrectomy.

The clinical course of 138 children who underwent unilateral nephrectomy and had a normal contralateral kidney at the time of nephrectomy was reviewed. The diagnosis leading to nephrectomy included obstructive uropathy in 46% of the cases, reflux or pyelonephritis in 30%, Wilms tumor in 15%, hypertension in 4%, dysplastic kidney in 2% and trauma in 2%. Mean age at nephrectomy was 7.3 years and median followup was 24.7 years. Of the 138 patients 121 (88%) are well and 17 died, including 14 secondary to metastatic Wilms tumor and 1 of renal failure. Survival of nonWilms tumor patients was similar to that of an age-matched control group. In 30 patients 24-hour creatinine clearance and 24-hour urinary protein excretion were measured. Proteinuria (greater than 150 mg./24 hours) was found in 8 of the 30 patients (27%) (p less than 0.001), renal insufficiency developed in 9 (30%) (p less than 0.0001) and hypertension occurred in 10% (p greater than 0.10). Children with an acquired solitary kidney are at increased risk for proteinuria and renal insufficiency.

Child↗
PubMed1992

Retroperitoneal neurogenous choristoma.

A 6-year-old girl with urinary complaints underwent ultrasonography, which revealed a retroperitoneal cystic mass adjacent to the left kidney. Computerized tomography did not demonstrate whether the mass was an adrenal cyst or a duplicated upper pole segment. Exploration revealed a neurogenous choristoma, which is a collection of histologically normal tissue that is ectopically situated. We believe that this is the first report of this rare entity occurring in the retroperitoneum.

Child↗