Duncan E. Govan

Spatial Distribution and Timing of Transmitted and Reflexly Generated Urethral Pressures in Healthy Women

We localized the temporal and spatial distribution of pressures in the urethra to identify their contribution to continence. With the data obtained we resolved the timing between the passively transmitted and actively generated urethral pressures. Data were obtained from 11 healthy female volunteers, with a mean age of 22 years. Simultaneous measurements of bladder and urethral pressures were taken from subjects during the Valsalva maneuver and coughing, and then holding with the subject in the supine, standing and sitting positions. The ratio of urethral to bladder pressure increase and the latency between these pressure increases were analyzed. A biphasic pressure distribution results from coughing with subjects in all positions. The first phase occurs at the normalized distance of 10 to 15 per cent from the bladder neck, where the ratio of urethral to bladder pressure increase is 0.8. The second phase occurs at 60 to 70 per cent of the urethral length and has a 1.5 to 1.7 ratio of urethral to bladder pressure increase, indicating the presence of pressure magnification. Simultaneous latency measurements indicate that the pressure increase in the urethra precedes that of the bladder by 240 plus or minus 30 msec. in the region that exhibits maximum pressure magnification. These results indicate that a fast-acting contraction occurs in the distal third of the urethra, which contributes reflexly to the compressive forces of the proximal urethra, thereby preventing urine loss during stress.

Development and Progression of Clubbing and Scarring in Children with Recurrent Urinary Tract Infections

Recent publications state that development and progression of clubbing and scarring do not occur in children with recurrent urinary tract infections. To test this assertion, we reviewed the excretory urograms of 106 children (208 renal units) with carefully documented recurrent bacterial urinary infections which commenced before the age of 10 years. We followed 93 of these renal units radio-logically for at least two years. In 31 kidneys, scarring and clubbing progressed; 4 previously normal kidneys developed scarring and clubbing. Two factors, infection and reflux, appeared important in the development of these changes. This study demonstrates that clubbing and scarring can develop and that existing lesions can progress in children with recurrent bacterial urinary infections.

Extracorporeal Shock Wave Lithotripsy: Multicenter Study of Kidney and Upper Ureter Versus Middle and Lower Ureter Treatments

Six institutions throughout the United States participated in this study. Each center used a multifunctional flat table lithotriptor (Dornier MFL-5000) to treat 658 patients with kidney and upper ureteral stones (766 treatments) and 323 with middle and lower ureteral stones (391 treatments), for a total of 925 patients (1,157 treatments). Some patients received more than 1 treatment (that is the kidney and ureter), for a total of 981 patient events. Complete followup was available for 81% of the patients. The overall stone-free rate at followup of approximately 90 days was greater in the middle and lower ureter group (83%) than in the kidney and upper ureter group (67%). The proportion of single stones treated was greater for the former group (89.5%) than for the latter group (72%). A larger proportion (18%) of the middle and lower ureter group required 2 or more treatments to the targeted stone than did the kidney and upper ureter group (13%). Anesthesia was required or selected in only 26.7% of the kidney and upper ureteral stone patients and in 18.5% of those with middle and lower ureteral calculi, usually at the request of the patient or physician, or for performance of an adjunctive procedure. The relative safety of this treatment is demonstrated by a low overall rate of complications reported during and after treatment, including a ureteral obstruction rate of 2.1% for kidney and upper ureteral stones and 2.5% for middle and lower ureteral stones. There were no demonstrated trends in a review of laboratory data to suggest significant treatment side effects. The diastolic blood pressure increased to more than 95 mm. Hg after extracorporeal shock wave lithotripsy (ESWL*) in 6% of the kidney and upper ureteral and 4% of the middle and lower ureteral stone patients, while pretreatment hypertension resolved after ESWL in 11% of both groups. The results of this clinical evaluation indicate somewhat greater effectiveness for the specified indications of ESWL of stones in the ureter below the upper rim of the bony pelvis, as opposed to those in the kidney and upper ureter, with a low incidence of complications and side effects.

The Impact of Bladder Neck Suspension on the Resting and Stress Urethral Pressure Profile: A Prospective Study Comparing Controls with Incontinent Patients Preoperatively and Postoperatively

Abstract For further understanding of the urodynamics of urinary stress incontinence 20 female patients with this condition were evaluated using resting and stress urethral pressure profiles before and after endoscopic suspension of the bladder neck. The results were compared to those in 13 normal volunteers who were evaluated similarly. In addition, the effect of posture on the urethral pressure profile was studied with the patients in the supine, standing and sitting positions. The results show that the mean maximum urethral closure pressure and functional profile length were significantly lower (p equals 0.005) in patients with stress urinary incontinence when compared to the normal volunteers. Posture did not significantly affect the maximum urethral closure pressure and functional profile length in either group (p greater than 0.1). Successful endoscopic suspension of the bladder neck did not significantly alter the maximum urethral closure pressure, while it significantly increased the functional profile length with the patient in the standing position only (p less than 0.05). The stress urethral pressure profile separated objectively the stress urinary incontinent patients and the continent volunteers. In continent women the transmitted abdominal pressure in the urethra during a cough or Valsalva’s maneuver was significantly higher than that in the bladder over most of the urethral length in all 3 positions. In the group with stress urinary incontinence the transmitted abdominal pressure in the urethra during the same maneuvers was less than that in the bladder. The data also showed that the stress urethral pressure profile curves in patients with stress urinary incontinence who were cured surgically reverted to the normal control pattern with higher abdominal pressure transmission in the urethra than in the bladder during a cough or Valsalva’s maneuver. The anatomical and physiological implications of these findings with their clinical application in the understanding of the mechanisms of continence in normal and stress incontinent women are discussed.

Management of children with urinary tract infections The Stanford experience

Two hundred seventy-eight female children with urinary tract infections have been evaluated at Stanford division of urology. All children were followed up for a period of not less than twelve months. Age of onset of infection, clinical presentation, and nature of infecting organisms were observed. The group consisted of 144 children without ureteral reflux and 134 children with ureteral reflux. Sixty-one of the female children with ureteral reflux had ureteral reimplantation, while 73 received medical treatment alone. A study of infection rates in each of the three groups of children indicated a similar infection rate, although those children with reflux experienced a higher incidence of clinical pyelonephritis. Correction of ureteral reflux did not alter the infection rate; however, infections after surgical correction were generally of a type usually associated with children without reflux. Twenty-nine children had urethral dilatation, and the infection rate prior to and following urethral dilatation indicated a similar rate of infection pre- and posturethral dilatation. One hundred nonrefluxing kidneys were observed radiologically: 97 were normal and 3 showed clubbing and scarring. Of 110 refluxing renal units observed, 62 were clubbed and scarred and 48 were normal. Following surgical correction of reflux, renal clubbing and scarring were not observed in previously normal renal units. Of those renal units found to be abnormal at time of surgery, 66 per cent showed progression of clubbing and scarring after surgical correction of reflux. It was observed that the greater the degree of reflux present, the higher the incidence of renal damage. This study suggests that children who experience recurrent urinary tract infections who do not have ureteral reflux are seldom at renal risk; similar children who do have ureteral reflux are at risk unless the infections are controlled or the reflux either disappears or is corrected surgically.

Isometric Detrusor Pressure during Bladder Filling and its Dependency on Bladder Volume and Interruption to Flow in Control Subjects

We characterized the isometric pressures generated by the bladder during voluntary detrusor contraction and interruption of flow. Urodynamic studies were done in 34 healthy female volunteers, with a mean age of 29.6 plus or minus 9.3 years. Control urodynamics were done first to characterize bladder and urethral parameters to filling and voiding. Subsequently, isometric detrusor pressures were elicited during bladder filling at increments of 100 ml. by asking subjects to attempt to void against a urethral obstruction produced by an inflated Foley balloon. Isometric pressures also were obtained by interruption of flow through the lumen of the 22F Foley catheter. The results showed that the maximum isometric pressure increase generated remained relatively constant during bladder filling at 39.6 plus or minus 13.1 cm. water. This pressure is not significantly different from voiding pressures developed with a 10F urethral catheter. On the other hand, isometric pressure increases during voiding showed that the increase in bladder pressure following interruption of flow was volume sensitive. The possibility that this volume dependency may result in errors in the interpretation of bladder contractility is discussed.

Dynamics of the Upper Urinary Tract

The characteristics of ureteral peristaltic rate response and bolus volume are investigated with electrophysiological methods during water and osmotic load diuresis. It is shown that the maximum rate of peristalsis during sustained diuresis is limited by the lowest detected mode in the interperistaltic interval distribution and is accompanied with a reduction in the speed of transmission and ureteral dilation. Comparative data on the symmetry of urine flow between the two kidneys and ureteral peristalsis at constant and transient diuresis are also presented in terms of bolus volume per interval.

Conservative Management of Testicular Endodermal Sinus Tumor in Childhood

Endodermal sinus tumor is the most common testicular neoplasm in childhood. The management of children with this neoplasm remains controversial. We have treated prospectively 5 children with stage I endodermal sinus tumor with limited surgery and no adjuvant therapy. The median patient age at diagnosis was 21 months (range 5 to 24 months). All children underwent an inguinal orchiectomy with high ligation of the spermatic cord. Retroperitoneal node dissection was not performed in any case and no child received adjuvant chemotherapy or radiation therapy. All patients were well without evidence of recurrent disease at a median followup of 46 months (range 19 to 72 months). Because these tumors usually are localized at the time of diagnosis, rarely spread to the retroperitoneal nodes and have a biological marker in most cases, and because good salvage chemotherapy is available for patients with relapse, we believe that nonmetastatic testicular endodermal sinus tumors in children can be managed with radical orchiectomy alone. Retroperitoneal node dissection is not necessary and adjuvant therapy is not indicated if markers return to normal. Further treatment should be reserved for the rare child with relapse.

Simulated Vesicoureteral Reflux

The effects of diuresis on the function of the ureterovesical junction have been comparatively examined in the normal and hydrostatically bypassed ureters. Electromyography of the ureter and renal pelvic pressures were simultaneously monitored with elevations of bladder pressure. It is shown that under oliguric conditions the bypassed ureter reflects bladder pressures to the renal pelvis, while the control ureter and the renal pelvis is hydrostatically isolated from the bladder. Under polyuric conditions the control and bypassed ureters respond identically.

Urodynamic Analysis of Urethral, Vesical and Perivesical Pressure Distribution in the Healthy Female

The transmission of intra-abdominal pressures to the urethra of the healthy female is examined with respect to cough, Valsalva and holding stimuli. A new method of recording urethral pressures using a four-channel, perfused gap catheter specifically constructed for this investigation is used. The results show that the increase of urethral pressure to stimuli is magnified at the distal urethra to a significant degree. This magnification is significantly higher than that expected by direct intra-abdominal transmission. Anatomically, the focus of urethral magnification of pressures is located 2-3 mm distal to the external urethral sphincter. The data provided from this study indicate that the mechanism of action of urethral closure to stress is active and does not directly correspond to the transmission properties of the lower urinary tract to stresses. Evidence supporting this mechanism is drawn also from the differential behavior of the proximal and distal regions of the urethra to the initiation and cessation of voiding.