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Biomedical subjects

S A Koff

Publications and source records attributed to S A Koff.

At least 19 recordsLinked to original sources
PubMed1992

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↗
PubMed1992

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↗
PubMed1992

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↗
PubMed1991

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↗
PubMed1991

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↗
PubMed1990

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↗
PubMed1990

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↗
PubMed1989

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↗
PubMed1979

Association of urinary tract infection and reflux with uninhibited bladder contractions and voluntary sphincteric obstruction.

We studied 53 neurologically normal children with recurrent urinary tract infection who were found to have bladder-sphincter incoordination characterized by voluntary sphincteric constriction during involuntary uninhibited bladder contraction. Increased intravesical pressure was documented during these events and was associated with vesicoureteral reflux in nearly 50 per cent of the children and with abnormalities of the ureteral orifice in 30 per cent of those without reflux. We hypothesize that increased intravesical pressure causes urinary infection in these children and produces a spectrum of intravesical anatomic distortion that predisposes to vesicoureteral reflux. In a prospective uncontrolled study treatment of the uninhibited bladder contractions allowed 58 per cent of the patients to maintain sterile urine without subsequent antimicrobial therapy after cure of the initial infection.

Adolescent↗
PubMed1979

Neurogenic bladder dysfunction.

The combined use of cystometry and perineal electromyography permits the physician to detect abnormalities in the synchronization of bladder contraction and urinary sphincter relaxation. With each pattern of neurogenic bladder disease, the coordination between bladder and sphincter determines whether urinary tract problems will develop. Treatment is tailored to specific bladder and sphincter defects.

Humans↗
PubMed1978

The pseudo-obstructed bladder in enuretic children.

In a minority of enuretic children with severe day symptoms, and especially when there is urinary infection, there a bladder diverticula and trabeculation and possbily also harmful vesicoureteric reflux which suggest the presence of an infravesical obstruction. However, in 11 children with this syndrome who underwent urodynamic studies, no anatomical or functional obstruction was demonstrable. It is contended that the obstructive signs are the result of uninhibited detrusor contractions being voluntarily resisted by contraction of the external urethral sphincter so that abnormallay high intravesical pressures result. Management involves the use of detrusor-inhibitory drugs. Ureteric reimplantation may be needed for reflux. In the majority of cases symptoms improve with time but the bladder diverticula persist.

Child↗
PubMed1978

Experimental assessment of graded ureteral obstruction utilizing liquid and gaseous perfusion techniques.

Ureteral perfusion studies (Whitaker's test) utilizing both saline and carbon dioxide were performed in nonobstructed canine ureters and in ureters subjected to a standardized partial and high grade obstruction to characterize the pattern of pressure response. Three separate ranges of pressure elevation were identified with each perfusate and a high degree of correlation between saline and CO2 pressures was observed. However, a significant overlap between the pressure range for nonobstructed and partially obstructed ureters was noted. This overlap must be carefully considered in human studies before defining clinically significant obstruction on the basis of an absolute perfusion pressure value.

Animals↗
PubMed1977

Patterns of neurogenic bladder dysfunction in sacral agenesis.

Patterns of neurogenic bladder disease were defined in 13 patients with sacral agenesis. Each patient demonstrated an individualized mixture of upper and/or lower motor neuronal deficits. The paucity of clinical parameters capable of identifying and assessing bladder dysfunction in these patients mandates complete neurourological evaluation and careful followup.

Adolescent↗
PubMed1977

Covered cloacal exstrophy: another variation on the theme.

Two cases showing many of the visceral features of exstrophy of the cloaca are described. In addition, there were the typical pelvic skeletal deformity and lumbosacral spina bifida but the abdominal wall was intact, although thin and weak. The embryogenesis is discussed. It is considered that the condition resulted from the breakdown of an infra-umbilical membrane at the 5 mm. stage. Later, mesodermal infiltration led to secondary closure of the membrane but visceral development was halted.

Abdominal Muscles↗
PubMed1977

Intermittent catheterization in the treatment of acute purulent urethritis: case report.

Acute purulent urethritis is a complication associated with an indwelling. Foley catheter in male patients. A refractory purulent urethral discharge, fever and the sequelae of urethral stricture, periurethral abscess and epididymitis are familiar problems to the urologist. The usual therapy is removal of the catheter, antibiosis and provision for another type of vesical drainage. Our recent successful experience using clean intermittent catheterization to treat an acute urethritis is presented.

Acute Disease↗