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J C Pope

Publications and source records attributed to J C Pope.

At least 19 recordsLinked to original sources
PubMed2006

Continent catheterizable channels and the timing of their complications.

PURPOSE: We reviewed our experience with continent catheterizable channels with interest in the timing of conduit related complications. MATERIALS AND METHODS: A retrospective review was performed of the outcome of continent catheterizable channels in all patients between 1998 and 2003 who had undergone construction of an antegrade continence enema and/or a Mitrofanoff procedure using appendix, small bowel or continent cutaneous vesicostomy. We performed a total of 117 such stomas in 37 male and 41 female patients 2.5 to 20 years old (mean age 8.9). For the antegrade continence enema we used appendix in 92% of cases, an ileal Yang-Monti tube in 6% and a cecal tube in 2%. For the continent catheterizable channel we used appendix in 43% of cases, a Yang-Monti tube in 38% and continent cutaneous vesicostomy in 19%. RESULTS: Continence was achieved in 98% of patients. Followup was 6 to 71 months (mean 28.4). There were 27 channel related complications (23%). Stomal stenosis occurred in 7 antegrade continence enema procedures (14%) within 1 to 10 months (mean 6.2) and in 9 continent bladder channels (13%), including 5 continent cutaneous vesicostomies, within 1 to 24 months (mean 9.4) after surgery. False passages occurred in 5 antegrade continence enema procedures (10%) within 1 to 13 months (mean 3.6) and in 4 continent catheterizable channels (6%) within 1 to 13 months (mean 6.5) after surgery. Of patients with stomal stenosis 50% were treated with surgical revision, while the remainder was successfully treated with dilation. Most false passages were managed by catheter drainage alone. Reasons for revision were contained perforation, colovesical fistula and inability to catheterize. Patient noncompliance appeared to have a role in stomal stenosis. CONCLUSIONS: Continent catheterizable stomas help patients achieve bowel and bladder continence. Stomal incontinence after reconstruction is rare. In our experience most stoma related complications occurred in the first year after reconstruction. Experience with more patients and longer followup will help determine whether such problems continue to accumulate with time or whether continent stomas function well with time, particularly after the initial period of healing.

Adolescent↗
PubMed2005

Management of the failed pyeloplasty: a contemporary review.

PURPOSE: We reviewed our experience with open dismembered pyeloplasty, with specific focus on the presentation and management of failed pyeloplasty in the pediatric population. MATERIALS AND METHODS: We performed a retrospective review of patients who had undergone open dismembered pyeloplasty between 1998 and 2003. All patients with less than 6 months of followup were excluded from analysis. The patients were followed postoperatively with serial ultrasounds, with renograms reserved for those patients with prolonged, persistent or worsening hydronephrosis, or recurrent symptoms during followup. RESULTS: A total of 105 pyeloplasties were performed in 103 patients (71 males and 32 females) 1 to 204 months old (mean 60), with an overall success rate of 93.3%. Followup ranged from 6 to 69 months (mean 23). The 7 patients with treatment failure were males 1 to 204 months old (mean 125), who presented most commonly with pain within 3 to 38 months (mean 13.1) after initial surgery. Subsequent ultrasound revealed worsening hydronephrosis, and renography in these patients showed a pattern consistent with obstruction. Five patients underwent initial balloon dilation, in which 1 was successful. In addition, 1 of these patients underwent an unsuccessful antegrade laser endopyelotomy. Six patients (86%) underwent open surgery, consisting of ureterocalicostomy in 3 and reoperative dismembered pyeloplasty in 3. Dense scarring was seen in all patients, 2 patients had a redundant pelvis causing kinking and 2 patients had unrecognized crossing vessels. Overall salvage rate was 100% with continued followup of 3 to 50 months (mean 18). CONCLUSIONS: Dismembered pyeloplasty was successful in the vast majority of patients. In our series failures occurred as late as 3 years postoperatively, although most presented within 12 months of followup. Excluding routine postoperative nuclear renography did not seem to affect our ability to identify these cases. Although anatomical features such as renal pelvic size may have a role, failure is most likely secondary to technical issues, including missed crossing vessels and dependency of the anastomosis. In this series failed pyeloplasties did not respond well to balloon dilation, likely due to scar formation. Our current practice is to manage failures by open surgery, although endoscopic management by an incision may be an option.

Adolescent↗
PubMed2001

Early evolution of bladder emptying after myelomeningocele closure.

OBJECTIVES: To analyze bladder emptying in newborns with spina bifida after closure of the myelomeningocele defect. Manipulation of the spinal cord and nerve roots results in temporary changes in bladder function in many settings. METHODS: We reviewed 62 consecutive newborn patients who underwent closure of a myelomeningocele defect at our institution from January 1990 to December 1997. We examined the catheterized urine volumes obtained before and after closure, radiographic and urodynamic studies, and the subsequent need for intermittent catheterization. Poor bladder emptying was defined as most catheterized urine volumes greater than 10 mL (20% of expected bladder capacity). Adequate follow-up was available for 54 patients for a period of 4 to 96 months (mean 42). One patient with posterior urethral valves was excluded from the study, leaving 53 for evaluation. RESULTS: Of the 53 patients, 4 with high outflow resistance and dyssynergy never emptied the bladder adequately before or after closure. Of the remaining 49 patients, 6 (12%) emptied well immediately after the myelomeningocele repair. In the other 43 (88%), the bladder did not empty as well after closure. The mean volume obtained with catheterization after closure was 20 mL, significantly higher (P <0.001) than the mean volume obtained before repair (6.5 mL) or after resumption of better spontaneous emptying (4 mL). Intermittent catheterization done for poor emptying was required for an average duration of 11 days (range 2 to 42). Of the 43 patients with poor emptying immediately after closure, 32 (74%) required catheterization for 2 weeks or less; the remaining 11 (26%) required catheterization for 2 to 6 weeks. Despite the relatively early resumption of good emptying, numerous patients (19 of 49) required additional intervention (clean intermittent catheterization or vesicostomy) before attempts to toilet train. CONCLUSIONS: A clinical pattern similar to spinal shock does occur in most newborns after closure of a myelomeningocele defect. Resumption of near-complete emptying usually occurs less than 2 weeks after repair but may require up to 6 weeks.

Female↗
PubMed2001

Is postoperative cystography necessary after ureteral reimplantation?

OBJECTIVES: To evaluate the patients in our practice to determine whether postoperative cystography was useful in monitoring the outcome after ureteroneocystostomy. Surgical repair of vesicoureteral reflux is the treatment of choice after medical therapy failure. Radiographic evaluation by ultrasonography or voiding cystourethrography (VCUG) is commonly used postoperatively to evaluate for urinary tract obstruction or persistent reflux. However, imaging modalities are not without cost, both in monetary terms and in terms of radiation exposure and trauma to the child. METHODS: We reviewed the records of all patients who underwent ureteroneocystostomy without ureteral tapering at our institution between January 1, 1996 and December 31, 1999 for primary vesicoureteral reflux. These records were evaluated with respect to the type of surgical procedure, preoperative and postoperative clinical course, and radiographic studies performed. RESULTS: We performed reimplantation on 267 renal units in 153 patients. The surgical technique was the Cohen cross-trigonal in 120 renal units (45%), Glenn-Anderson ureteral advancement in 92 (35%), and modified Leadbetter-Politano ureteral advancement in 55 (20%). All patients underwent imaging with ultrasonography within 6 weeks of surgery. The follow-up ranged from 4 to 42 months (average 14.2). Between 3 and 8 months postoperatively, 61 patients underwent imaging with VCUG. We identified persistent reflux in six renal units. Four of six had marked improvement in their reflux. All the patients with persistent reflux were asymptomatic, including 2 patients who were no longer receiving antibiotics. Four patients developed febrile urinary tract infections postoperatively. Three of the four underwent imaging with VCUG after treatment; all three had no evidence of reflux. CONCLUSIONS: In our population, the addition of VCUG to the postoperative evaluation did not allow us to identify those patients at risk of febrile urinary tract infections. Patients in whom persistent reflux was identified were all asymptomatic. We continue to monitor patients with ultrasonography, but believe that VCUG often provides little benefit to these children.

Adolescent↗
PubMed2001

Congenital anomalies of the kidney and urinary tract--role of the loss of function mutation in the pluripotent angiotensin type 2 receptor gene.

PURPOSE: Recent studies of the human genome and genetic engineering experiments in mice revealed that congenital anomalies of the kidney and urinary tract commonly seen in newborns in various anatomical forms are polygenic disease, that is a disease caused by simultaneous defects in multiple genes. We discuss some possible genetic explanations of the classic theories of the formation of congenital kidney and urinary tract anomalies. MATERIALS AND METHODS: We reviewed classic and current theories regarding urinary tract development. Included in our review are recent results from our laboratory evaluating the genetic role of normal and abnormal urinary tract development. RESULTS: We observed a genetic abnormality that may explain many classic anatomical theories of congenital kidney and urinary tract anomalies. One of the genes involved in urinary tract ontogenesis is the angiotensin type 2 receptor gene, which is the "other" angiotensin receptor. While the type 1 receptor mediates essentially all known actions of angiotensin, including its hypertensive effect, relatively little is known about the angiotensin type 2 receptor. Careful dissection studies in mutant mouse embryos selectively lacking the angiotensin type 2 receptor gene revealed that this gene is pleiotropic, that is its defect causes not only ectopic ureteral budding from the wolffian duct, but also disturbance in other subsequent ontogenic events that are critical for the normal growth of the kidney and urinary tract. CONCLUSIONS: Many congenital anomalies of the kidney and urinary tract appear to share a common genetic cause. While these anomalies are caused by various genetic hits, abnormalities in the angiotensin type 2 receptor gene are often involved in this anomalous development. This review article offers a better understanding of the genetics involved in urinary tract development and ties some of the newly emerging genetic theories with classic anatomical theories.

Angiotensin II↗
PubMed2001

The use of radiography, urodynamic studies and cystoscopy in the evaluation of voiding dysfunction.

PURPOSE: Children with dysfunctional voiding disorder often undergo radiological, cystoscopic or urodynamic evaluation to identify an anatomical or organic cause. We determined the role of these studies in the evaluation, management and ultimate outcome of a large patient population with voiding dysfunction at a single institution. MATERIALS AND METHODS: We retrospectively evaluated the records of 1, 153 children with dysfunctional voiding disorder treated from 1990 to 1999. A thorough history and physical examination with specific emphasis on voiding patterns were done and urinalysis was performed in all cases. Ultrasound of the urinary system and excretory urography were done in 1,050 (91%) and 24 (2%) patients, respectively, while voiding cystourethrography was performed in 672 (58%), including 564 with a history of nonfebrile urinary tract infection. Cystoscopy and a formal urodynamic study were performed in 61 (5%) and 40 (3.5%) cases, respectively. RESULTS: Mean patient age at referral was 6 years (range 3 to 14). Of the children 74% were girls and 26% were boys. Physical examination of the abdomen, back, genitalia and neurological system was unremarkable in all cases. Ultrasound of the upper urinary system was normal in 1,018 patients (97%) and showed insignificant pyelectasis in 32 (3%). All 24 excretory urography studies were normal and voiding cystourethrography was normal in 470 of 672 cases (70%). Unilateral and bilateral low grade, and unilateral high grade reflux was present in 108, 19 and 3 patients, respectively. Urodynamic studies were performed in 40 children who did not respond to standard treatment. We noted detrusor instability in 16 patients, detrusor-sphincter dyssynergia in 6 and sensory abnormality in 3, while the study was completely normal in 10. Cystoscopy revealed normal findings in 17 cases, trabeculations in 21, inflammation in 20 and type 1 posterior urethral valves in 2. CONCLUSIONS: The incidence of upper tract changes and positive anatomical findings in children with voiding dysfunction is too low to justify routine radiological evaluation and cystoscopy. However, in those who present with a nonfebrile urinary tract infection there remains an important role for voiding cystourethrography. We do not recommend routine urodynamics in children with voiding disorder because this study does not change therapy or influence the final outcome. Thorough history and physical examination lead to the correct diagnosis and treatment in the majority of children. A focus on correcting faulty voiding behavior with the judicious administration of antibiotics and anticholinergic therapy leads to a favorable outcome in most cases.

Algorithms↗
PubMed2001

Small intestinal submucosa as a urethral coverage layer.

PURPOSE: Urethrocutaneous fistula is the most common complication of hypospadias surgery. Numerous techniques have been used to decrease the incidence of this complication and the use of biocompatible materials in surgery has expanded the options in difficult situations. We hypothesized that porcine small intestinal submucosa may be used as a coverage layer after urethral surgery. We evaluated the histological changes associated with small intestinal submucosa when used as a coverage layer over the urethra in a rabbit model. METHODS AND METHODS: We performed urethral surgery in 16 New Zealand White rabbits divided into 4 animals each in groups 1-sham operation with penile degloving only, 2-penile degloving and small intestinal submucosa patch placement, 3-urethrotomy without a patch and 4-urethrotomy with a small intestinal submucosa patch. The graft edges were marked with permanent suture at surgery for later identification. All rabbits were maintained for 6 weeks before sacrifice. The urethra of each animal was then serially sectioned and examined histologically. RESULTS: Histological examination of animals with an small intestinal submucosa patch revealed a foreign body tissue reaction with an infiltrate of histiocytes, giant cells and lymphocytes in the area of graft placement. There was no histological evidence of remaining small intestinal submucosa patch in any sections. The urethral mucosa healed normally in all cases in which it was disrupted. There was no evidence of acute or chronic inflammation in any group 1 or 2 nonsmall intestinal submucosa animals and none in the animals with a small intestinal submucosa graft in areas other than the former graft site. There were also no urethrocutaneous fistulas in any of the 8 rabbits that underwent urethrotomy. CONCLUSIONS: Small intestine submucosa provides an adequate coverage layer in the rabbit penis after urethrotomy. Histologically the foreign material did not alter normal healing of the urethral mucosa, although it did appear to cause an infiltration of histiocytes, giant cells and lymphocytes. Small intestinal submucosa has previously been studied as a scaffold on which tissue may be remodeled or may regenerate. Our study shows that small intestinal submucosa did not interfere with normal tissue healing in this animal model. When used as a urethral coverage layer, it appears to provide extra tissue between the urethra and skin. Small intestinal submucosa may potentially decrease the incidence of urethrocutaneous fistula after urethral surgery.

Animals↗
PubMed2001

Angiotensin type II receptor expression and ureteral budding.

PURPOSE: Deletion of the angiotensin type II receptor gene (Agtr2) in mice results in a spectrum of urinary tract anomalies similar to that in humans. The mechanism behind this anomalous development is poorly understood. We evaluated Agtr2 expression as it relates to normal and abnormal ureteral budding. MATERIALS AND METHODS: A total of 400 wild type mice were inspected at birth for gross evidence of a urinary tract anomaly. In addition, the urinary tracts of 30 wild type embryos were evaluated at 11.0/11.5 and 13.5 weeks of gestation. These embryos were examined for ureteral budding site via section and whole mount in situ hybridization with c-ret probe and Agtr2 expression via in situ hybridization with Agtr2 riboprobe. There were 740 newborn mice homozygous for the null mutation of Agtr2 also evaluated along with 55 angiotensin type II knockout embryos at the aforementioned gestational ages. RESULTS: All wild type newborn animals were grossly normal. Of the angiotensin type II knockout newborns 23 (3.1%) had gross abnormalities of the urinary tract at birth. The predominant finding was a duplicated collecting system associated with a hydronephrotic upper pole moiety. These duplicated collecting systems fulfilled the Meyer-Weigert law. Interestingly, 25 (59.5%) of the knockout embryos showed abnormal ureteral budding. However, in wild type embryos Agtr2 was expressed at this "ectopic" cranial site between the wolffian duct and metanephric mesenchyme. CONCLUSIONS: Although not the sole regulator, angiotensin type II receptor expression may have a role in the embryological development of the urinary tract by inhibiting aberrant ureteral budding. A defect in this inhibitory process appears to cause ectopic ureteral budding, and may subsequently lead to renal dysplasia and other congenital anomalies of the kidney and urinary tract.

Animals↗
PubMed2000

Y-to-I wrap: use of the distal spongiosum for hypospadias repair.

PURPOSE: Rather than resecting the distal spongiosum lateral to the open urethra for hypospadias, we mobilized this tissue with the urethral plate away from the corpora cavernosa, subsequently wrapping it around various types of urethroplasty to prevent fistula formation. MATERIALS AND METHODS: The distal spongiosum was preserved and used for coverage in 25 hypospadias repairs in 1 year. We initially applied it in this manner when the distal spongiosum persisted as a pillar of healthy erectile tissue but later when the distal tissue appeared more fibrous in nature. The wrap was used to cover various types of urethroplasty, including advancement in 6 cases, tubularization in 10, flip-flap repair in 6 and an island onlay pedicle graft in 3. RESULTS: All patients have at least 1 year of followup. There has been no fistula formation or residual chordee. In 1 patient minor meatal retraction did not require a secondary procedure. Cosmetic results have been good. CONCLUSIONS: A distal wrap of corpus spongiosum may be used to avoid fistula formation without causing residual or recurrent curvature. It re-creates a nearly normal urethra in some cases.

Adolescent↗
PubMed1999

Does every patient with prenatal hydronephrosis need voiding cystourethrography?

PURPOSE: Prenatal ultrasound has allowed early identification of urinary tract abnormalities that may require urological followup or early intervention. While all children with prenatal hydronephrosis should undergo ultrasound within the first few weeks of life, we believe that there is a subset of postnatal hydronephrosis for which voiding cystourethrography can be avoided if careful observation is continued. MATERIALS AND METHODS: For 5 years 175 infants with a history of prenatal hydronephrosis were evaluated by ultrasound. Of 60 infants with less than Society for Fetal Urology grade II unilateral or bilateral hydronephrosis 44 underwent voiding cystourethrography as part of the early evaluation and 16 were observed without voiding cystourethrography. Four infants for whom we would routinely obtain voiding cystourethrography were excluded from study due to severe prenatal hydronephrosis, renal duplication, hydroureter, ipsilateral small or echogenic kidney and grade II or higher hydronephrosis. RESULTS: Voiding cystourethrography was positive in 6 of the 40 infants (15%) with less than grade II hydronephrosis. Of these cases 3 had grade III or higher vesicoureteral reflux and 1 with high grade reflux required reimplantation. None of the 16 patients followed without voiding cystourethrography has required further evaluation or intervention. In all patients with negative or no voiding cystourethrography parenchyma was preserved and hydronephrosis stabilized or resolved. CONCLUSIONS: Prenatal and postnatal ultrasound in infants should be used to guide further urological evaluation. Among infants with less than grade II hydronephrosis postnatally 15% had reflux on voiding cystourethrography, which is significantly higher than that reported among normal children (approximately 1%). However, none of the 16 infants observed without voiding cystourethrography on short-term antibiotic prophylaxis had deleterious renal events with 6 months to 4.5 years of followup. Therefore, we question the actual significance of the reflux detected in the first cohort of infants. Voiding cystourethrography can provide a definitive answer. However, we also believe that it is not absolutely mandatory based on the outcome in the observed group. With careful counseling and followup most patients with less than grade II hydronephrosis can be observed without urological sequela.

Female↗
PubMed1999

How they begin and how they end: classic and new theories for the development and deterioration of congenital anomalies of the kidney and urinary tract, CAKUT.

CAKUT are problems that often require surgical intervention or, in the worst case, lead to renal failure and the need for dialysis and/or renal transplantation. It is believed that these anomalies share a common genetic cause and to date there has been no good animal model with which to study these abnormalities. Although the abnormal interaction between the ureteral bud and metanephric blastema leads to renal hypodysplasia, vesicoureteral reflux, and ectopic ureters to name a few, the genetic and biochemical modulation of urinary tract development is not understood. Studies using the mouse strain mutant for angiotensin type 2 (AT2) receptors have given new insight into this mystery. The animals show defective apoptosis of undifferentiated mesenchymal cells in the area surrounding the developing kidney and urinary tract. This abnormal apoptosis may well interfere with the normal interaction between the ureteral bud and metanephric blastema resulting in CAKUT. This abnormal interaction would theoretically lead to preexisting intrinsic abnormalities of the kidney, which are programmed and take effect early in embryonic development. In the worst cases, the renal abnormalities would lead to progressive deterioration of renal function. Undoubtedly, there are more genes and biochemical modulators involved in this process other than the RAS and AT2 receptors. Our current animal model gives new and unique possibilities with which to study development of the kidney and urinary tract and ultimately seek ways of preventing an often debilitating disease process.

Animals↗
PubMed1998

Angiotensin induces the urinary peristaltic machinery during the perinatal period.

The embryonic development of mammalian kidneys is completed during the perinatal period with a dramatic increase in urine production, as the burden of eliminating nitrogenous metabolic waste shifts from the placenta to the kidney. This urine is normally removed by peristaltic contraction of the renal pelvis, a smooth muscle structure unique to placental mammals. Mutant mice completely lacking angiotensin type 1 receptor genes do not develop a renal pelvis, resulting in the buildup of urine and progressive kidney damage. In mutants the ureteral smooth muscle layer is hypoplastic and lacks peristaltic movements. We show that angiotensin can induce the ureteral smooth muscles in organ cultures of wild-type, but not mutant, ureteral tissues and that, in wild-type mice, expression of both renal angiotensin and the receptor are transiently upregulated at the renal outlet at birth. These results reveal a new role for angiotensin in the unique cellular adaptations of the mammalian kidney to the physiological stresses of postnatal life.

Angiotensin II↗
PubMed1998

Ureterocystoplasty: is it necessary to detubularize the distal ureter?

PURPOSE: The conventional technique for ureterocystoplasty includes complete mobilization and incision of the ureter. We describe a modified procedure in which the distal 3 cm. of ureter are left in place and intact. MATERIALS AND METHODS: This modification has been used in our last 13 cases of ureterocystoplasty. The first 7 patients with followup of more than a year (mean 28 months) are included in this series, and 6 have undergone video urodynamic evaluation before and after reconstruction. RESULTS: Clinical results have been good. Four patients who have been toilet trained are continent. There have been no problems from stagnant urine in the intact ureter with only 1 case of pyelonephritis and no bladder calculi. Mean bladder capacity on cystometrogram has increased from 103 to 236 ml. after reconstruction and reached 137% of expected capacity for age and size (range 110 to 155%). No uninhibited contractions or problems with compliance have been noted. CONCLUSIONS: The distal ureter may be left intact for ureterocystoplasty to protect ureteral blood supply. This modified technique is sound from a physiological standpoint, technically easier and associated with good results.

Adolescent↗
PubMed1998

Augmenting the augmented bladder: treatment of the contractile bowel segment.

PURPOSE: Bowel used for bladder reconstruction regardless of detubularization occasionally retains its contractile properties. Of 323 patients who underwent primary enterocystoplasty we identified 19 who continue to have high pressure bladder contractions and required augmentation of the previously augmented bladder. MATERIALS AND METHODS: Reason for repeat augmentation, upper tract changes, original and secondary bowel segments used, and urodynamic findings were evaluated in all patients. Current status and followup also were noted. RESULTS: After initial augmentation 8 patients had persistent incontinence, 5 bladder perforation, 3 isolated upper tract changes, 2 incontinence and bladder perforation, and 1 incontinence plus intractable pain. Preoperative urodynamics revealed detrusor pressures from 30 to 100 cm. water. All patients had adequate bladder outlet resistance. The original bowel segments used were sigmoid in 12 cases, stomach in 4, ileum in 2 and cecum in 1. Bowel segments for re-augmentation were ileum in 16 cases and sigmoid in 3. Of the 11 patients with incontinence 10 are now dry. All cases of upper tract changes resolved. Mean followup since re-augmentation is 52 months. CONCLUSIONS: If the outcome of bladder augmentation is less than optimal, it is important to reevaluate the bladder dynamics. In rare instances these patients may continue to have high pressure contractions with a functionally small bladder capacity. In such situations reaugmentation with an additional bowel segment is an excellent alternative to a difficult clinical problem and provides good results in the vast majority of cases. This treatment may not totally alleviate the contractions but it does decrease them and increase the volumes at which the contractions occur, making them no longer clinically or functionally significant.

Adolescent↗
PubMed1998

Natural history of refluxing distal ureteral stumps after nephrectomy and partial ureterectomy for vesicoureteral reflux.

PURPOSE: We evaluated the natural history of refluxing distal ureteral stumps after nephrectomy and partial ureterectomy. MATERIALS AND METHODS: Between 1985 to 1996, 38 patients a mean age of 37 months underwent nephrectomy and partial ureterectomy for reflux into a nonfunctioning kidney. The diagnosis included primary reflux in 23 patients, reflux associated with posterior urethral valves in 10 and ipsilateral ureterocele in 5. Mean followup was 45 months. RESULTS: Only 1 patient with an ipsilateral ureterocele and 1 with contralateral reflux (5%) had symptomatic infections during postoperative followup, and each underwent a secondary procedure to remove the ureteral stump. No patient with only primary unilateral reflux required surgery for the refluxing stump. CONCLUSIONS: Because of the low risk of morbidity associated with a refluxing ureteral stump, we recommend nephrectomy and proximal ureterectomy in patients with reflux into a nonfunctioning kidney.

Adolescent↗
PubMed1998

Etiology, management and surgical complications of congenital chordee without hypospadias.

PURPOSE: We comprehensively evaluated the etiology, management and surgical complications of chordee without hypospadias. MATERIALS AND METHODS: We reviewed the records of patients who underwent chordee correction between January 1985 and December 1996. A total of 87 patients with a median age of 14 months were treated for chordee without hypospadias. Mean followup was 10 months. Patients were treated in the standard fashion and a straight phallus was confirmed in all postoperatively. We grouped cases according to the etiology of chordee, including skin tethering, fibrotic dartos and Buck's fasciae, corporeal disproportion and urethral tethering. RESULTS: Of the 87 patients 28 (32%) were successfully treated with release of the skin and superficial fascia. In 29 cases (33%) extensive resection of the fibrotic dartos and Buck's fasciae was necessary to straighten the phallus, including 2 (7%) in which chordee recurred. Corporeal disproportion was identified in 24 patients (28%), of whom 2 (8%) also had complications (urethrocutaneous fistula and recurrent chordee in 1 each). In 6 cases (7%) urethral tethering was the etiology of chordee, of which 3 (50%) had complications (urethrocutaneous fistula and recurrent chordee in 2 and 1, respectively). Overall 80 of the 87 patients (92%) were successfully treated with 1 operation. CONCLUSIONS: In our series the etiology of chordee without hypospadias was evenly divided among skin tethering, fibrotic dartos and Buck's fasciae, and corporeal disproportion. A congenitally short urethra was a rare cause of isolated chordee. Surgical correction is highly successful with a low 8% complication rate.

Adolescent↗
PubMed1998

Role of angiotensin in the development of the kidney and urinary tract.

When perfusion pressure to the kidney falls, e.g., as a result of dehydration or mechanical hindrance to the renal arterial blood flow, the release of renin, hence angiotensin (Ang), surges. This feedback regulation is geared to preservation of renal hemodynamic environment by raising systemic blood pressure. We are aware that a surge of renin-angiotensin release also occurs when there is a mechanical hindrance to urine outflow. This phenomenon of ureteral pressure-sensitive activation of renin-angiotensin has been heretofore viewed as an error of nature. We have obtained evidence which challenges this traditional view when we examined strains of mutant mice which are completely devoid of either angiotensin type 1 (AT1) receptor gene (Agtr1-) or angiotensin type 2 (AT2) receptor gene (Agtr2-) as a result of genetic manipulation of these animals. These strains of mice display varying degrees of urinary tract obstruction. In Agtr2- mice obstructions develop during early kidney ontogenesis in ureto, and, in Agtr1- mice, during late ontogenesis ex utero. One may recall that, throughout its normal ontogenesis, the kidney is twice at risk for obstruction of urine outflow. Thus, in utero the ureter is transiently obliterated. This transient obliteration is believed to protect the kidney from the high pressure from the cloaca when urine is not yet formed. During this period, the ureter is surrounded by dense layers of undifferentiated mesenchymal cells. Subsequent expansive growth that the ureter must achieve, therefore, in concert with a timely disappearance of the surrounding mesenchymal cells. The study in Agtr2- embryos indicated that Ang, through the Agtr2 receptor, promotes disappearance of these mesenchymal cells, and that inactivation of this receptor results in congenital obstructive nephropathy. Our additional studies in human specimens indeed indicate that many infants with congenital anomalies of the kidney and urinary tract have a significant mutation within the AT2 gene. Once animals are born, the kidney comes to be of primary importance for preservation of body fluid homeostasis, and urinary output increases dramatically. The large volume of urine predisposes the kidney to obstructive nephropathy due to the high resistance offered to the urine by the downstream ureter. Normally, a special device develops within the urinary tract in a timely fashion, which enables the kidney to collect a bulk of urine, and then to expel it downward periodically without imposing positive pressure upon the renal parenchyma. This special device is the renal pelvis. In the studies on Agtr1 null mutant mice, we learned that Ang, through the AT1 receptor, promotes development of the pelvis shortly after birth, so that inactivation of this receptor in Agtr1- mice leads to absence of development of the pelvis, hence to obstructive nephropathy. Collectively, Agtr1 or Agtr2 null mutant mice suffer from urinary tract obstruction. Given that urinary tract obstruction per se is a potent stimulus for Ang generation, Ang is essential for the kidney to escape from obstructive injury.

Angiotensin II↗