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Purpose: We develop a "consilient" (unified) view of pressure as a physical phenomenon and "clinimetric" tool, making a connection between barometers and bladders., Materials and Methods: The philosophy, physics and clinical applications of pressure during the last 2 millennia were examined from Lucretius to the modern medical subspecialties., Results: A variety of units and systems of pressure quantification developed as the physics of pressure became understood. Applications of pressure in clinical medicine with distinct physiological relevance have been created for organ systems across the subspecialties. Some measurements have become useful for management of urinary tract and other diseases., Conclusions: Despite a broad range of units, systems and applications, a consilient view of pressure in medicine can be approached. This perspective is fundamental to understanding the significance of pressures in the expanding clinimetric arena and should mitigate against misplaced concreteness that is tempting in modern medical practice, whereby laboratory tests become virtual realities and are mistaken for patients.

Purpose: The origin and the development of the cystometrogram are described., Materials and Methods: We reviewed and analyzed the published literature on cystometrography., Results: The cystometrogram originated in the latter half of the nineteenth century, an age of intense clinimetric investigation. Early investigators studied fundamental aspects of bladder function with meticulous techniques using relatively crude equipment. The first clinical cystometer was designed by Dalton K. Rose in 1927. He was followed by Nesbit, McLellan, Muschat and Munro, who brought the cystometrogram to its current key role in modern urology., Conclusions: Numerous investigators have advanced the knowledge of bladder function using the cystometrogram, a key urological tool.

Purpose: We have observed a difference in the radiographic appearance of the body of the bladder (trabeculated) and its base (smooth) in boys with severely obstructing posterior urethral valves. We wanted to determine if (1) this was a reproducible finding and (2) there was an anatomic and/or physiologic explanation for it., Materials and Methods: We reviewed the initial voiding cystourethrogram in 47 boys with severe posterior urethral valves. The interureteric ridge was used as the division between the body and base of the bladder. The presence of trabeculation for each region was recorded., Results: Ages ranged from 1 day to 6 years at the time of initial cystographic evaluation (median 14 days). The body of the bladder was trabeculated and the base smooth in 72 % (34 patients). In the remaining patients, both the body and base were smooth. In no patient was the base trabeculated., Conclusions: The cystographic morphology of the urinary bladder in boys with posterior urethral valves can be explained by its neuroanatomy. The body of the bladder, which contracts during voiding because of parasympathetic (cholinergic) stimulation, becomes trabeculated. The bladder base relaxes during voiding due to sympathetic (alpha adrenergic) stimulation and remains smooth. Thus, this difference in the cystographic appearance of the two parts of the urinary bladder reflects the normal innervation and the mechanics of micturition in boys with urethral obstruction.

One hundred and twenty-two augmentation cystoplasties performed over an 8-year period were reviewed. Mean age at surgery was 37 years (range 2-82 years). There were 82 female patients. The primary urodynamic diagnosis was reduced compliance in 92 (77%) patients and detrusor hyperreflexia/instability in the remainder. The clinical diagnostic groups were: spinal cord injury/disease in 32 (27%), myelodysplasia in 27 (22%), interstitial cystitis in 21 (17%), idiopathic detrusor instability in 13 (11%), radiation cystitis in 8 (7%), Hinman-Allen syndrome in 5 (4%), and miscellaneous in 11 (9%). A detubularized ileal augmentation was used in 82 (67%) patients. In 36 (30%) a detubularized ileocecocystoplasty was fashioned and in the remainder detubularized sigmoid was used. In 19 patients augmentation accompanied undiversion. Sixteen patients had a simultaneous fascial sling for urethral incompetence. Mean follow-up was 37 months (range 6-96 months). There was no postoperative mortality. During follow-up 4 patients died from unrelated causes, 11 have been lost to follow-up, and 5 patients await planned transplantation. Bladder capacity was increased from a preoperative mean of 108 ml (range 15-500 ml) to 438 ml (200-1,200 ml) postoperatively. Of the 106 assessable patients, 80 (75%) had an excellent result, 21 (20%) were improved, and 5 (5%) had major ongoing problems. During the period of follow-up, 17 (16%) patients underwent revision of their augmentation. Twenty-four (21%) patients developed bladder stones and 30% of these did so more than once. Urinary incontinence became manifest in 15 (13%) patients but required surgical treatment in only half of these. Pyelonephritis occurred in 13 (11%) patients. Five patients developed small bowel obstruction following discharge from hospital. There were 7 instances of reservoir rupture in 5 (4%) patients. Augmentation cystoplasty has a pivotal role in the treatment of a broad range of lower and upper urinary tract problems. Careful patient selection and close follow-up are essential.

From June 1984 to December 1992 voiding cystourethrography performed on 209 patients with myelodysplasia revealed vesicoureteral reflux in 57 (27%). High grade reflux (3 to 5/5) occurred in 33 patients (58%). Bladder pressure at typical capacity, defined as the pressure at average catheterization volume or bladder leak point pressure, was determined urodynamically. After a mean of 56 months vesicoureteral reflux resolved or improved in 55% of patients and remained unchanged in 28%. There was no correlation between the grade of reflux and the rate of spontaneous resolution. Pressure at typical capacity of 40 cm. water or more was significantly more common in patients with reflux (44%) than in those with no reflux (20%) (p < 0.001). There was a strong association between pressure at typical capacity of 40 cm. water or more and upper tract deterioration (p < 0.0001). However, there was no correlation between pressure at typical capacity and grade of reflux (p = 0.18). Treatment of pressure at typical capacity of 40 cm. water or more led to resolution or improvement of vesicoureteral reflux in 8 of 10 reevaluated patients. Hydronephrosis resolved (7) or improved (1) in 8 of 9 cases. Measurement of intravesical pressure is of paramount importance in the management of spina bifida patients with vesicoureteral reflux. Maintaining the pressure at typical capacity at less than 40 cm. water is associated with increased spontaneous resolution of vesicoureteral reflux and a lower incidence of upper tract deterioration.

The sonographic findings in the bladder are presented in four children with myelomeningocele and neurogenic dysfunction of the bladder, who were treated with intermittent self-catheterization and intravesical oxybutinin chloride. All were referred for routine sonography of the urinary tract. Each had infused a crushed tablet of oxybutinin chloride intravesically 30-120 min before the examination. In two children, brightly echogenic, non-shadowing particles were suspended in the bladder urine. In one of these, the particles swirled giving the impression of a "snowstorm"; in the other, most of the particles gradually settled forming an irregular clump on the bladder base. In the remaining two children, the urine appeared diffusely hazy with innumerable tiny particles giving the impression of a fine mist filling the bladder. The sonographic appearance of the urine in the bladder after intravesical instillation of crushed tablets can be dramatic and can simulate pus, blood, fungus, or other debris in the bladder lumen. In the absence of clinical symptoms or hematuria, a history of recent infusion of medication into the bladder should be sought.

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.

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.

Pre- and postoperative sonograms were reviewed in 59 children who underwent ureteral reimplantation to assess the frequency, location, extent, and evolution over time of focal thickening of the posterior bladder wall and bladder base after reimplantation. The interval between reimplantation and follow-up sonography ranged from 2 weeks to 12.36 years (mean, 1.29 years). Thirty-two patients (54.2%) had focal thickening of the posterior bladder wall and trigone after reimplantation. The earlier after reimplantation the children were first evaluated with sonography, the much more frequently was thickening observed. Thirteen had fusiform thickening along the submucosal tunnel and twenty-four had a hyperechoic nodule at the trigone. The thickening resolved in one third of the children and is presumed to have represented postoperative edema in these cases. However, on the sonographic appearance alone it was not possible to differentiate transient changes resulting from postoperative edema from those representing developing fibrosis or granuloma formation.

Among 350 children with myelomeningocele 18 with elevated leak point pressures were managed by urethral dilation and followed for 1 to 5 years. Longitudinal measurements of bladder compliances revealed durable improvement in the pressure-volume relationships after dilation. These data suggest that noncompliant bladders are acquired because of high outlet resistance, and early intervention may improve long-term bladder storage characteristics.

The 2 components of detrusor compliance were analyzed in 32 children with myelomeningocele and compared to compliance in 15 age-matched controls with nonneuropathic enuresis. In myelomeningocele initial compliance was variable, whereas terminal compliance was relatively constant. Low terminal compliance corresponded with vesicoureteral reflux, deterioration of upper tract morphology and diminished renal function.

A program for the management of neurogenic bladder in patients with myelodysplasia was instituted in July 1983. Of the 114 patients entered into the program who have been followed for a minimum of 18 months 42 per cent required treatment for high intravesical pressures. None of this group or the larger group with low bladder pressures showed progressive upper urinary tract deterioration. In 8 children (17 per cent of those with high pressure bladder dysfunction) high intravesical pressure persisted despite anticholinergic medication and intermittent catheterization, and they required an operation to achieve a low pressure bladder. These results confirm the findings in other studies that about 40 per cent of myelodysplastic children are at high risk for the development of upper tract changes, and that approximately 6 to 8 per cent will not respond sufficiently to anticholinergic agents and intermittent catheterization.