Why is desmopressin sometimes ineffective at curing bedwetting?
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Central Nervous System↗
Biomedical subjects
S A Koff
Publications and source records attributed to S A Koff.
Complications of intestinal augmentation and substitution cystoplasty.
The content of these papers has been heavily weighted towards reconstructions performed utilizing segments of stomach. This was not done to place a value judgment on this type of reconstruction, rather it helps establish an awareness of: (1) potentially serious metabolic and gastrointestinal complications not previously reported in children and (2) particularly frequent symptomatic disturbances collectively included in the hematuria-dysuria syndrome. Recognition of problems specifically associated with a certain type of intestinal segment, as well as complications generally accompanying any form of intestinal reconstruction, will hopefully provide pediatric urologists and nephrologists with a better understanding of the issues that must be addressed in using these newer surgical techniques and focus attention on the specific indications and contraindications for incorporating intestinal segments into the urinary tract. Although long-term follow-up information still remains sparse, it appears that regular surveillance programs are required and both pediatric nephrologists and urologists need to be part of these programs.
Child↗
The nonoperative management of unilateral neonatal hydronephrosis: natural history of poorly functioning kidneys.
During the last 5 years we have followed nonoperatively all neonates with unilateral hydronephrosis and suspected ureteropelvic junction obstruction, regardless of the degree of hydronephrosis, shape of the diuretic renogram washout curve or initial degree of functional impairment. Of 104 patients 7 (7%) ultimately required pyeloplasty for obstruction, which was defined as a greater than 10% reduction in differential glomerular filtration rate and/or progression of hydronephrosis. Pyeloplasty returned renal function to pre-deterioration levels in all kidneys. In 16 patients with profound hydronephrosis and initial differential renal function less than or equal to 40% all traditional diagnostic tests for assessing obstruction, including diuretic renography washout pattern, were inaccurate in diagnosing obstruction and predicting which kidney would deteriorate. In 15 of 16 poorly functioning hydronephrotic kidneys rapid improvement in absolute and per cent differential renal function was observed, and the level of initial differential renal function served as a useful guide for timing of further diagnostic studies. Unilateral neonatal hydronephrosis appears to be a relatively benign condition and the risk of developing renal obstruction appears relatively slight. Because of diagnostic inaccuracy, the low risk of developing obstructive injury and the fact that many newborn kidneys with hydronephrosis rapidly improve function and dilation, it appears safe to follow neonatal unilateral hydronephrosis closely and nonoperatively.
Follow-Up Studies↗
The assessment of obstruction in the newborn with unilateral hydronephrosis by measuring the size of the opposite kidney.
We measured the size of the normal kidney opposite a unilateral hydronephrotic kidney in infants to determine if compensatory changes occurred and could be used as a diagnostic test for defining or excluding obstruction. Comparison of subgroups of neonates with unilateral hydronephrosis or multicystic renal dysplasia to normal controls demonstrated that compensatory changes do occur in the normal kidney. Normal kidneys opposite obstructed hydronephrotic kidneys requiring surgery became larger than normal for age. Normal kidneys opposite nonobstructed poorly functioning hydronephrotic kidneys whose function rapidly improved were smaller than normal for age. These changes in renal growth by the normal newborn kidney reflect renal counterbalance, which is exaggerated in this age group and which may be used to corroborate rapid changes in renal function caused by the presence or absence of obstruction. By plotting serial measurements of normal renal length on a renal growth chart, the diagnosis of obstruction in newborn hydronephrosis can be facilitated and the clinical management of the patient improved.
Humans↗
Extensive mobilization of the urethral plate and urethra for repair of hypospadias: the modified Barcat technique.
The modified Barcat technique was used to treat 168 patients with hypospadias during the last 5 years. The technique, which is applicable for distal hypospadias, uses apposing fully mobilized meatal based skin flaps. Cosmetic and functional results are excellent, with only 3.5% of the patients requiring reoperation. Because the surgical technique does not depend on the configuration of the glans, depth of the urethral groove, caliber of the urethral meatus or even whether the patient has been circumcised, it is particularly suitable for training residents who can perform a single operation to correct a wide variety of cosmetic deformities.
Child↗
Nonoperative management of unilateral neonatal hydronephrosis.
We followed nonoperatively 45 neonates with unilateral hydronephrosis and suspected ureteropelvic junction obstruction for 30 months, regardless of the degree of hydronephrosis, shape of diuretic renogram washout curve or initial degree of functional impairment. Of the patients 30 had mild hydronephrosis and no renal deterioration, while 15 had severe hydronephrosis, an obstructed diuretic renogram and markedly decreased hydronephrotic kidney function. During followup percentage and absolute renal function rapidly increased in all patients, hydronephrosis improved in 7 and contralateral compensatory hypertrophy did not develop in any. These findings help to define the natural history of untreated hydronephrosis, suggest that many newborn kidneys with severe hydronephrosis are not obstructed despite even profound initial decreases in renal function and demonstrate that traditional tests for diagnosing obstruction are inaccurate in this age group. Therefore, the methods for assessing obstruction and the indications for surgical intervention in these patients require reexamination.
Follow-Up Studies↗
Relationship between dysfunctional voiding and reflux.
Bladder instability and the nonneurogenic neurogenic bladder are 2 urodynamically different dysfunctional voiding patterns. However, they share a common urodynamic mechanism in that they both produce functional urinary obstruction, which by changing the anatomy and function of the bladder, and ureterovesical junction produces and perpetuates vesicoureteral reflux. Urodynamic studies show that bladder decompensation with high end filling pressures, rather than high voiding pressures, is the mechanism for reflux and help to explain the seemingly paradoxical relationship among obstruction, reflux and high bladder pressures, namely that reflux does not usually occur when bladder pressures are high. This urodynamic analysis and review of the literature strongly support the belief that functional urinary tract obstruction caused by dysfunctional voiding can initiate and perpetuate vesicoureteral reflux, and provide an understanding of the mechanisms involved.
Child↗
Continent urinary diversion using an ileal servomechanism sphincter.
A continent, catheterizable, physiologically responsive urinary sphincter servomechanism can be created from a short segment of ileum for use in a continent urinary diversion. Because it is easily constructed and provides dynamic continence control, this new sphincter appears to have applications in reconstructive urologic surgery.
Humans↗
A practical approach to evaluating urinary tract infection in children.
After a first urinary tract infection (UTI), all children require an evaluation with imaging studies to screen the urinary tract for anatomic abnormalities and for reflux. Ultrasonography and voiding cystography readily accomplish this and are recommended, knowing that such a recommendation is controversial. While the likelihood for reflux-induced renal damage is age related, the presence of reflux in any child with infection is clinically important for management. Abnormal screening results or recurrence of infection warrant further radiographic testing. However, imaging studies are necessary but do not constitute sufficient evaluation for UTI because the etiology of infection is only rarely identified with these tests. Sorely neglected in most recommended protocols for evaluating urinary infection is an investigation for micturitional disturbances which may be responsible for the infections. Treatment of these conditions may actually prevent recurrence of infection. Controversy surrounding the proper imaging evaluation for UTI appears to be mis-directed. Instead of arguing about which imaging study should be performed or which child with a first UTI should have a cystogram, our patients might be better served if we wondered why traditional protocols for evaluating UTI deal only with imaging studies.
Child↗
Does compensatory testicular enlargement predict monorchism?
In 37 boys 3 years old or younger with an impalpable testis the length and volume of the normally descended testis were measured. In 12 boys who had surgically proved monorchism the descended testis length and volume exceeded 2 cm. (mean 2.22) and 2 cc, respectively. This represented significant compensatory enlargement of the descended testis compared to the descended testis in 19 boys with normal sized (mean 1.51) or 6 boys with atrophic (mean 1.78) impalpable undescended testes. Histological examinations revealed that in no case in which the descended testis was greater than 2 cm. long was there histological evidence contralaterally of normal, recognizably abnormal or dysgenetic testicular tissue. In these patients compensatory descended testis enlargement with testis length exceeding 2 cm. (2 cc volume) defined monorchism.
Child, Preschool↗
A technique for bladder neck reconstruction in exstrophy: the cinch.
A surgical modification of the Young-Dees-Leadbetter procedure for bladder neck reconstruction is presented. The procedure uses a bladder muscle flap devoid of mucosa as a cinch to encircle and compress the reconstructed neourethra, increasing urethral resistance and helping to achieve continence in patients with bladder exstrophy. The operation combines the continence enhancing features of bladder neck narrowing, urethral elongation, cuff compression, sling suspension of the urethra and urethropexy. Of 10 patients who underwent an operation 6 are dry during the day and night, and they achieved continence relatively soon postoperatively.
Bladder Exstrophy↗
Pathophysiology of ureteropelvic junction obstruction. Clinical and experimental observations.
The preceding discussion has identified many of the frustrating difficulties in the definition, diagnosis, and determination of the significance of obstruction in hydronephrosis. Unfortunately, doubts have been raised about the indications for surgical intervention, which is so often needed to prevent renal deterioration. Are the newer diagnostic tests seriously flawed; should we be relying more heavily on anatomic studies such as intravenous and retrograde pyelography and operating purely for pelvic enlargement and characteristic radiographic appearances? Absolutely not. All upper urinary tract (ureteropelvic) obstructions are not the same. Obstruction is not a single disease process, and its outcome cannot be predicted purely by anatomic appearance. Most cases of suspected obstruction are straightforward, and the correct diagnosis can be arrived at easily, but the difficult cases remain a diagnostic challenge. In these, we must use newer diagnostic tests freely but not merely as triggers for surgical intervention; they are not that accurate. Instead, they should be used to obtain as much physiologic information as possible to help categorize the suspected obstruction and predict its potential for obstructive injury. Only in this way can we hope to prevent progressive renal deterioration and to ensure that surgical reconstruction is both necessary and effective.
Child↗
Clinical and urodynamic features of a new intestinal urinary sphincter for continent urinary diversion.
We describe a new sphincter mechanism and its clinical application in 11 patients requiring continent diversion. The sphincter, composed of 2 short segments of ileum, is urodynamically responsive and actually increases its resistance to leakage when reservoir pressure or volume increases. Because of this dynamic continence control and its ease of construction, it appears to be a useful addition to the reconstructive urological armamentarium.
Colon↗
Guidelines to determine the size and shape of intestinal segments used for reconstruction.
The geometry of intact and detubularized intestinal segments was examined to establish guidelines in estimating the length of bowel required for urinary reconstruction and for the preferential use of bowel in its detubularized form.
Humans↗
Diuretic radionuclide assessment of obstruction in the infant: guidelines for successful interpretation.
Diuretic renography frequently is used to assess obstruction in hydronephrosis of infancy but it is invalidated by poor renal function, which occurs frequently in this age group. In an attempt to establish a guideline to determine when renal function is too poor in infancy to rely on diuretic renography for an accurate diagnosis we analyzed the slope of the diuretic renographic washout curve of the normal, nonaffected kidney in 33 infants with unilateral hydronephrosis. When the T 1/2 time in the normal, nonaffected kidney was greater than 9 minutes, as occurred in 68 per cent of the infants less than 1 month old, it defined a significant renal functional impairment in both kidneys that interfered with diuretic renographic test interpretation. With time renal function improved and after 4 months of age the T 1/2 time in all nonaffected kidneys became normal and the diuretic renographic diagnosis of obstruction became accurate. Our study indicates that nonaffected kidney T 1/2 time provides a qualitative assessment of global renal function in infancy and defines a level of renal functional maturity that must be achieved to ensure diuretic renographic test accuracy.
Diuretics↗
The daytime urinary frequency syndrome of childhood.
We reviewed retrospectively 43 completely toilet trained children who suddenly developed isolated daytime urinary frequency. Patient age ranged from 2 to 12 years. The condition lasted 2 days to 16 months and resolved spontaneously in all patients. The recurrence rate was 3 per cent unless nocturnal symptoms of nocturia or enuresis coexisted, whereupon it increased to 40 per cent. Anticholinergic medication characteristically produced no improvement in symptoms. Noninvasive investigation included a history and physical examination, urinalysis and renal ultrasonography, and appeared to be sufficient for diagnosis. The etiology is unknown but it may be predominantly behavioral. The daytime urinary frequency syndrome of childhood appears to be a benign self-limited condition that does not require extensive urological evaluation.
Child↗
The prophylactic use of clean intermittent catheterization in the treatment of infants and young children with myelomeningocele and neurogenic bladder dysfunction.
To examine the hypothesis that the prophylactic use of clean intermittent catheterization can prevent urinary tract deterioration in infants and young children with myelomeningocele a prospective controlled study was performed on 24 patients. Preliminary results indicate that more than 50 per cent of the patients with bladder sphincter incoordination managed by self-voiding had urinary tract deterioration. In contrast, in only 10 per cent of the patients treated prophylactically with clean intermittent catheterization did deterioration occur. We conclude that when bladder sphincter incoordination is diagnosed in children with myelomeningocele they are at a high risk for the development of future urinary tract injury. The prophylactic use of clean intermittent catheterization can actually prevent this deterioration and its use in this manner is recommended.
Age Factors↗
Evaluation and management of voiding disorders in children.
The author examines the non-neuropathic voiding disturbances of childhood in an attempt to develop a practical approach to their evaluation and management. Analysis of each child's presenting symptoms permits a classification into voiding pattern disturbances that are benign and those that are potentially harmful. Such an approach helps to define the indication for and scope of urologic investigation and aids in treatment selection.
Child↗