Urodynamic Patterns Research Articles

Urodynamic pattern changes in multiple sclerosis

Objectives. Multiple sclerosis (MS) causes neurologic symptoms to change over time. Voiding dysfunction is common in patients with MS, and few studies have examined the changes in urodynamic patterns in these patients over time. The purpose of this study was to examine the frequency and nature of urodynamic pattern changes in patients with MS who underwent two or more urodynamic studies. Methods. Twenty-two patients (7 men and 15 women) with well-documented MS were referred to one urologist (T.B.B.) for evaluation of lower urinary tract symptoms. All patients had undergone two or more urodynamic evaluations during a 14-year period for persistent or new symptoms, and a retrospective comparison was made among the urodynamic test results. Results. Overall, 12 (55%) of 22 patients experienced a change in their urodynamic patterns and/or compliance during a mean follow-up interval of 42 ± 45 months between the urodynamic studies. Most patients initially had urodynamic patterns showing detrusor hyperreflexia, detrusor external sphincter dyssynergia, or detrusor hypocontractility. Fourteen (64%) of the 22 patients studied had the same or worsening of the same symptoms and 8 (36%) of 22 had new urologic symptoms. Six (43%) of 14 patients with no new symptoms and 6 (75%) of 8 with new symptoms had significant changes found with follow-up urodynamic testing. Conclusions. A significant proportion of patients with MS with and without new urinary symptoms will develop changes in their underlying urodynamic patterns and detrusor compliance. Therefore, urodynamic evaluations should be repeated at regular intervals in symptomatic patients to optimize clinical management, reduce complications, and better enable these patients to manage their neurogenic bladder dysfunction.

Editorial comment

In my opinion, the conclusions the authors have reached are exactly correct. The clinical implication is that patients with MS do experience changes in their voiding pattern, and thus the dictum has been (and remains) that one should avoid invasive or irreversible procedures designed to affect the voiding dysfunction in these patients unless absolutely necessary. Doubtless, all who treat such patients would agree with this. The authors have collected a good deal of data in the process of putting together this report. There are at least two caveats with respect to the data themselves: 1.If medication was instituted at the time of the first evaluation and not discontinued before the second evaluation (not mentioned in the article), it may be that any difference in urodynamic pattern has resulted from the treatment and not the disease.2.One of the golden rules of urodynamic evaluations is that if the study does not reproduce the clinical symptoms, it is not an optimal study. Thus, in someone who complains of urge incontinence or frequency and urgency, if the urodynamic study shows only “hypocontractility,” it may well be that under other circumstances (eg, ambulatory urodynamic assessment) the urodynamic study would have revealed quite different findings.

Urodynamic follow-up of experimental urethral obstruction in individual guinea pigs.

It is unknown whether changes in bladder function due to urethral obstruction follow a specific sequence. To answer this, we adapted a small animal model to allow repeated complete pressure-flow studies, enabling individual follow-up of changes in bladder function on urethral obstruction. Obstruction was induced in guinea pigs by placing a silver ring around the urethra. Urodynamic studies were repeated under anesthesia with ketamine/xylazine. Bladders were filled and bladder pressure measured through a single suprapubic catheter. Urine flow rate was measured using an ultrasound probe around the penis. Accurate measurements of bladder pressure and urine flow rates were obtained at 1-week intervals for 11 weeks in individual guinea pigs. In the control animals, the urodynamic parameters did not show significant changes. In the obstructed group, urethral resistance (P(low,ave)) increased from 20 to 35 cm H(2)O after 4 weeks and remained at that level. The maximum flow rate (Q(max)) increased from 0.17 to 0.24 mL/s after 2 to 3 weeks. After this peak, it gradually decreased to lower than the starting value after 10 to 11 weeks. The pressure at maximum flow rate (p(Qmax)) increased from 24 to 47 cm H(2)O after 6 to 7 weeks and thereafter declined. During weeks 1 through 4 of obstruction, unstable contractions were seen. All animals followed a similar sequence of patterns but at variable rates. Our animal model allows complete urodynamic follow-up of individual animals with urethral obstruction. We observed a specific sequence of changes in urodynamic patterns and parameters of bladder function.

The changing urodynamic pattern from infancy to adolescence in boys with posterior urethral valves: M. De Gennaro, M.L. Capitanucci, P. Mosiello, et al. Br J Urol Int 85:1104–1108, (June), 2000.

The changing urodynamic pattern from infancy to adolescence in boys with posterior urethral valves: M. De Gennaro, M.L. Capitanucci, P. Mosiello, et al. Br J Urol Int 85:1104–1108, (June), 2000.

VOIDING PATTERN IN HEALTHY CHILDREN 0 TO 3 YEARS OLD: : A LONGITUDINAL STUDY

We describe the development of voiding patterns and bladder control in healthy children during the first 3 years of life. We determined voiding patterns, bladder capacity and post-void residual urine volume per 4 hours individually and noninvasively every 3 months in 36 female and 23 male healthy infants using the 4-hour voiding observation. Voiding frequency decreased slowly from 5 to 2 voiding episodes per 4 hours from ages 3 months to 3 years. We noted interrupted voiding in 33% of subjects at age 3 months but this condition was rare after age 2 years. Voiding during sleep occurred mainly during the first 7 months of life and did not continue after age 18 months. Bladder capacity increased from a median of 52 to 67, 68 and 123 ml. during years 1 to 3, respectively. As measured by post-void residual urine volume, bladder emptying was unchanged during years 1 and 2 but it decreased during year 3 (median 6 versus 0 and mean 4 versus 3 ml. per 4 hours). During the first 3 years of life the number of voiding episodes, including interrupted voiding, post-void residual urine and voiding during sleep, decreased while bladder capacity increased.

The changing urodynamic pattern from infancy to adolescence in boys with posterior urethral valves.

To determine whether bladder dysfunction in boys with posterior urethral valves (PUV) changes from a uniform pattern of hypercontractility during infancy to the hypocontractility found in adolescence, by reviewing serial urodynamic studies. Thirty boys with PUV and no voiding symptoms underwent a total of 86 urodynamic tests (mean 2.8 each). The first urodynamic study was undertaken at 1-4 years of age in 15 boys and at 5-13 years in 15. They were re-evaluated at least 3 years later; 15 patients underwent the first and last urodynamic study, respectively, at a mean age of 2.8 and 7.7 years (group A), 10 boys at 6.2 and 8. 8 years (group B) and five at 9.4 and 15.2 years (group C). In 10 boys aged > 5 years the first and last pressure-flow studies (PFS) were analysed using an advanced analysis (PFA) to better identify hypocontractility. Bladder dysfunction was found in 21 of 30 (70%) boys at the first evaluation and in 18 (60%) at the last. In 25 boys the urodynamic pattern changed. Of the 15 boys in group A, 10 of 12 who had hypercontractility changed to normal (seven), low compliance (one) or hypocontractility (two), and two remained stable; two of the remaining three with normal urodynamic studies changed to hypocontractility, while one was unchanged. Among the 10 boys in group B, six with hypercontractility changed to normal (three) or hypocontractility (three); two with normal urodynamic findings and one with low compliance changed to hypocontractility. Of the five boys in group C who showed severe hypocontractility after puberty, three had a normal pattern, one low compliance and one hypercontractility before puberty. The PFA showed a 'weak' detrusor in four of the seven boys who were considered normal on standard PFS. At the urodynamic follow-up, the PFA pattern changed to a 'weak' detrusor in four boys who had a normal (two) or strong (two) detrusor at the first evaluation. Bladder dysfunction in boys with PUV changes during childhood and through adolescence. The urodynamic pattern of hypercontractility generally found soon after valve ablation gradually changes to hypocontractility in many boys and this pattern seems to be the rule after puberty. The evidence from this series supports the hypothesis that long-term detrusor hyperactivity in boys with PUV leads to detrusor failure, but a longitudinal 15-year follow-up from birth to puberty is needed to validate this concept.

URODYNAMIC FINDINGS IN BOYS WITH POSTERIOR URETHRAL VALVES AFTER TREATMENT WITH PRIMARY VALVE ABLATION OR VESICOSTOMY AND DELAYED ABLATION

Primary valve ablation and temporary vesicostomy with delayed valve ablation are alternative initial management procedures in neonates and infants with posterior urethral valves. To investigate whether initial vesicostomy followed by delayed valve ablation and simultaneous vesicostomy closure may lead to more alterations in bladder function than primary valve ablation only we retrospectively compared postoperative urodynamic findings in 2 small groups of patients. From 1980 to 1990, 15 male infants 19 days to 34 months old with posterior urethral valves were treated with 1 of 2 initial surgical approaches, including valve ablation only in 8 (group 1), and primary vesicostomy and delayed valve ablation associated with concomitant vesicostomy closure in 7 (group 2). Mean age at valve ablation and vesicostomy in groups 1 and 2 was 10.8 +/- 11.2 months (range 1 to 35) and 55.4 +/- 43.3 days (range 19 to 151), respectively. Average duration of vesicostomy diversion was 33.6 +/- 18.8 months (range 14 to 70). All patients underwent conventional urodynamics postoperatively using normal saline at room temperature. In groups 1 and 2 mean age at followup was 11.5 +/- 6.6 (range 5 to 16.2) and 9. 4 +/- 3.1 (range 4.10 to 14) years, respectively. Controls comprised 46 age matched males who underwent urodynamics using similar methodology. Postoperative urodynamic assessment of maximum cystometric bladder capacity and the incidence of detrusor instability in each treatment group were not statistically different. In group 1 bladder capacity was significantly higher than that in controls (p <0.0001). In group 2 mean end filling detrusor pressure was increased compared with that in group 1 (29 cm. water, range 15 to 60 versus 8, range 4 to 21). Compliance was significantly lower in group 2 than in group 1 (p <0.0005). Analysis of detrusor voiding pressure at maximum flow was not significantly different in the 2 groups. We noted detrusor under activity in 1 group 1 and 2 group 2 cases. In these patients post-void residual urine volume was 8% to 66% of cystometric bladder capacity. However, only 1 of these 3 patients who required augmentation cystoplasty needed intermittent catheterization. Urodynamic patterns of outflow obstruction developed in 1 patient in each group, including urethral stricture and bladder neck obstruction. At followup we observed no difference in renal function impairment in the 2 groups. Our retrospective study of rapid filling cystometry suggests that primary valve ablation for posterior urethral valves is associated with a better bladder function outcome than that in patients treated with vesicostomy and delayed valve ablation. Therefore, although cutaneous vesicostomy may be performed as initial management of posterior urethral valves, primary valve ablation is the most effective surgical option in these cases.

URODYNAMIC PATTERN IN ASYMPTOMATIC INFANTS: SIBLINGS OF CHILDREN WITH VESICOURETERAL REFLUX

We studied the urodynamic pattern in asymptomatic infants who are siblings of children with vesicoureteral reflux. Cystometry and perineal electromyography were performed with voiding cystourethrography in 16 male and 21 female infant siblings screened for reflux at age 0.2 to 7.3 months (median 1.1). Vesicoureteral reflux was present in 25% of the male and 10% of the female infants. In those without vesicoureteral reflux unstable bladder contractions were noted in 8% of the male and 16% of the female subjects. In these infants median maximum voiding detrusor pressure was 127 (range 84 to 211) and 72 cm. water (range 42 to 240), respectively, and median bladder capacity was 20 ml. (range 10 to 49 and 10 to 120, respectively). Maximum voiding detrusor pressure was significantly higher in male than in female infants (p <0.01). Perineal electromyography was interpretable in 13 of the 16 male and 16 of the 21 female infants overall. All but 1 female subject had increased activity during voiding, which was also present intermittently in all subjects. Our study of asymptomatic siblings of children with vesicoureteral reflux has provided results that may be used as reference data for normal urodynamics in early infancy. Instability was rare. Bladder capacity was lower than expected with a predicted capacity at birth of approximately 20 ml. Maximum voiding pressure was high, especially in male subjects. The urodynamic voiding pattern suggests physiological dyscoordination, probably due to immature detrusor-sphincter function.

The urodynamic profile of prostatodynia.

To evaluate urodynamically patients with prostatodynia, and thus define a specific urodynamic pattern that might add to the pathophysiology of the syndrome and possibly aid definitive treatment. Forty-three patients (mean age 38.1 years, sd 9.25, range 24-59) with symptoms suggestive of chronic prostatitis, e.g. dysuria, frequency of micturition and a burning sensation in the perineum, were classified as having prostatodynia after excluding prostatic infection by standard bacteriological methods. Thereafter, the patients were evaluated urodynamically, including the measurement of free flow-rate, filling (water) cystometry, a pressure/flow study of micturition, with fluoroscopy and electromyography of the external urethral sphincter. Twenty-eight patients (65%) had a low maximum free flow rate (Qmax ), with a mean (sd) of 10.91 (1.26) mL/s. Of the 42 patients who underwent filling cystometry, 26 (62%) had a first sensation of filling, and 28 (67%) a first desire to void, at low volumes (<150 mL and <300 mL, respectively). Of the 25 patients who underwent a pressure/flow study, 16 (64%) had an obstructive pattern of micturition, as defined by a low Qmax of 10.04 (1.38) mL/s and a high intravesical pressure at Qmax of 83.3 (5.3) cmH2O. The site of obstruction was at the level of the bladder neck, as confirmed by fluoroscopy. A significant proportion of these patients had a particular urodynamic pattern of functional infravesical obstruction at the level of the bladder neck and sensory disturbances.

Urodynamic findings in children with isolated epispadias.

The exstrophy-epispadias complex represents a spectrum of anomalies with variable implications for upper and lower urinary tract function. Successful treatment of incontinence in this population is challenging and often elusive. To date few studies have focused on urodynamic findings specific to primary epispadias. We retrospectively reviewed the records of patients presenting with primary epispadias in the absence of bladder exstrophy. We identified 18 boys and 12 girls, of whom 16 underwent formal urodynamic evaluation before (5), after (6) or before and after (5) surgical narrowing of the bladder neck. Bladder capacity was recorded as percent of expected capacity for age. Bladders were considered hypertonic when end filling pressure was greater than 20 cm. water. End filling pressure was defined as the pressure at which urinary leakage was noted or the patient had discomfort. Uninhibited contractions were considered significant when the amplitude was greater than 15 cm water. The ability of the detrusor to generate a voiding contraction at the end of the filling phase was also recorded. Urodynamic studies were performed with a balloon catheter occluding the incompetent bladder neck or with a standard urodynamic catheter after formal bladder neck repair. Before bladder neck repair average bladder capacity was 157 ml (range 55 to 450), corresponding to 52% (range 22 to 100) of expected capacity. Significant uninhibited contractions were noted in 2 patients. In 7 of the 9 evaluable patients (78%) a voiding contraction was generated. In children in whom urodynamic studies were done after surgery mean bladder capacity was 260 ml (range 77 to 660), corresponding to 76% (range 36 to 147) of expected capacity. Hypertonicity and hyperreflexia were noted in 3 and 2 patients, respectively. In 5 of the 11 cases (46%) a voiding bladder contraction was generated. Of the 5 patients who underwent urodynamic evaluation before and after bladder neck repair the percent increase in bladder capacity was significantly greater in the 2 boys (67 and 110%, respectively) than in the 3 girls (-20, 10 and 20, respectively). The most frequently noted urodynamic pattern before surgical correction of the bladder neck in patients with isolated epispadias is a low capacity, highly compliant bladder with minimal detrusor dysfunction. Postoperatively capacity increases, albeit to a greater extent in boys than in girls, and the incidence of detrusor dysfunction increases as well. In some patients classic bladder neck repair may result in detrimental bladder dynamics due to as yet poorly elucidated mechanisms.

URODYNAMIC FINDINGS IN CHILDREN WITH ISOLATED EPISPADIAS

Purpose The exstrophy-epispadias complex represents a spectrum of anomalies with variable implications for upper and lower urinary tract function. Successful treatment of incontinence in this population is challenging and often elusive. To date few studies have focused on urodynamic findings specific to primary epispadias. Materials and Methods We retrospectively reviewed the records of patients presenting with primary epispadias in the absence of bladder exstrophy. We identified 18 boys and 12 girls, of whom 16 underwent formal urodynamic evaluation before (5), after (6) or before and after (5) surgical narrowing of the bladder neck. Bladder capacity was recorded as percent of expected capacity for age. Bladders were considered hypertonic when end filling pressure was greater than 20 cm. water. End filling pressure was defined as the pressure at which urinary leakage was noted or the patient had discomfort. Uninhibited contractions were considered significant when the amplitude was greater than 15 cm. water. The ability of the detrusor to generate a voiding contraction at the end of the filling phase was also recorded. Urodynamic studies were performed with a balloon catheter occluding the incompetent bladder neck or with a standard urodynamic catheter after formal bladder neck repair. Results Before bladder neck repair average bladder capacity was 157 ml. (range 55 to 450), corresponding to 52% (range 22 to 100) of expected capacity. Significant uninhibited contractions were noted in 2 patients. In 7 of the 9 evaluable patients (78%) a voiding contraction was generated. In children in whom urodynamic studies were done after surgery mean bladder capacity was 260 ml. (range 77 to 660), corresponding to 76% (range 36 to 147) of expected capacity. Hypertonicity and hyperreflexia were noted in 3 and 2 patients, respectively. In 5 of the 11 cases (46%) a voiding bladder contraction was generated. Of the 5 patients who underwent urodynamic evaluation before and after bladder neck repair the percent increase in bladder capacity was significantly greater in the 2 boys (67 and 110%, respectively) than in the 3 girls (-20, 10 and 20, respectively). Conclusions The most frequently noted urodynamic pattern before surgical correction of the bladder neck in patients with isolated epispadias is a low capacity, highly compliant bladder with minimal detrusor dysfunction. Postoperatively capacity increases, albeit to a greater extent in boys than in girls, and the incidence of detrusor dysfunction increases as well. In some patients classic bladder neck repair may result in detrimental bladder dynamics due to as yet poorly elucidated mechanisms.

Vesicourethral Dysfunction and Urodynamic Findings in Multiple Sclerosis: A Study of 149 Cases

Vesicourethral Dysfunction and Urodynamic Findings in Multiple Sclerosis: A Study of 149 Cases

COMPARISON OF URODYNAMIC AND FREE VOIDING PATTERN IN INFANTS WITH DILATING REFLUX

Purpose We compared simultaneous investigations of free voiding pattern and urodynamic assessment in infants with dilating reflux to obtain further information on previously suspected bladder dysfunction based on abnormal urodynamic findings. Material and Methods A total of 33 male and 8 female infants with dilating reflux were included in the study. Free voiding pattern was determined by 4-hour voiding observation compared to previously described voiding pattern studies of healthy infants. Simultaneous invasive urodynamic assessments were performed. Results The patients were grouped according to urodynamic bladder capacity. Half of the male patients had low bladder capacity with high voiding pressure levels (hypercontractile) and the other half had either normal or high capacity bladder. The low capacity group had frequent small voids and a high rate of interrupted voiding, the high capacity group had infrequent voids of high volumes with high residual urine, and the pattern of the normal capacity group differed only from that of healthy infants by an increase in residual urine. All female infants had the typical characteristics of high capacity bladder on free voiding and urodynamic assessments. Conclusions Infants with abnormal invasive urodynamic investigations, including those with a small capacity hypercontractile bladder and those with a high capacity bladder, could be identified on free voiding studies, indicating that an abnormal urodynamic pattern represents bladder dysfunction.

Vesicoureteral reflux in infants.

Grade 5 vesicoureteral reflux (VUR) is almost exclusively seen in male infants, and in one-third of cases occurring with a generalized small kidney with decreased renal function without a previous history of urinary tract infection. In females, however, high-grade reflux is rare and kidney damage almost always less severe and of the focal type, as in older children. Assessment of the bladder function with urodynamic and free voiding studies also indicates a difference between male and female reflux during infancy. Half of the males with dilating reflux initially have a hypercontractile urodynamic pattern indicating small functional capacity with high voiding pressures and often instability during filling. This pattern changes during the first couple of years to high-capacity overdistended bladders, often with incomplete emptying. In females, hypercontractility is seldom seen, but bladder function is characterized by high capacity and there is an increase in residual urine from presentation. The pathogenesis of VUR has also been suggested to differ between the sexes. Transient anatomical obstruction during fetal life has been proposed as the cause of gross VUR in males. The spontaneous resolution rate of dilating infant VUR seems to be significantly higher than in older children. A resolution of 40% of grades 4 and 5 has been reported during the first couple of years in prenatally diagnosed cases, suggesting that antireflux surgery should be postponed until after the infant year.

DIAGNOSING BLADDER OUTLET OBSTRUCTION IN WOMEN

There are no universally accepted urodynamic criteria for diagnosing female bladder outlet obstruction. When accepted criteria for men are applied to women, the diagnosis of obstruction may often be missed, which is most likely due to differences in voiding dynamics. We propose video urodynamic criteria for diagnosing obstruction in women, and describe the urodynamic findings in those with and without obstruction. We reviewed the charts of 331 women who underwent multichannel video urodynamics for nonneurogenic voiding dysfunction. Of these women 261 (mean age 55.8 years) had evaluable voiding pressure flow studies with simultaneous video fluoroscopy of the bladder outlet during voiding. At video urodynamics cases were classified as obstructed if there was radiographic evidence of obstruction between the bladder neck and distal urethra in the presence of a sustained detrusor contraction. Strict pressure flow criteria were not used. Maximum flow rate, detrusor pressure at maximum flow rate, post-void residual, bladder capacity and the incidence of detrusor instability were compared between obstructed and unobstructed cases. A total of 76 women met the criteria for obstruction (mean age 57.5 years), while 184 (mean age 55) did not. Causes of obstruction were dysfunctional voiding in 25 cases, cystocele in 21, primary bladder neck obstruction in 12, iatrogenic from incontinence surgery in 11, urethral stricture in 3, uterine prolapse in 2, urethral diverticulum in 1 and rectocele in 1. Obstructed cases had lower mean maximum flow rate (9 versus 20.2 ml. per second, p <0.0001), higher mean detrusor pressure at maximum flow rate (42.8 versus 22.1 cm. water, p <0.0001) and higher mean post-void residual (157 versus 33 ml., p <0.0001). There was no difference in bladder capacity (381 versus 347 ml.) or incidence of detrusor instability (45 versus 41%). Using the proposed video urodynamic criteria obstructed cases had significantly higher voiding pressures, lower flow rates and higher post-void residual than unobstructed cases, as expected. However, absolute values, especially for voiding pressure, are not as dramatic in women as in men. Pressure flow studies alone may fail to diagnose obstruction but simultaneous imaging of the bladder outlet during voiding greatly facilitates diagnosis.

Urodynamic patterns in infants with normal lower urinary tracts or primary vesico-ureteric reflux: C.K. Yeung, M.L. Godley, H.K. Dhillon, et al. Br J Urol 81:461–467, (March), 1998

Urodynamic patterns in infants with normal lower urinary tracts or primary vesico-ureteric reflux: C.K. Yeung, M.L. Godley, H.K. Dhillon, et al. Br J Urol 81:461–467, (March), 1998

Endoscopic treatment for urinary incontinence in children with a congenital neuropathic bladder.

To verify, in a retrospective analysis, the effectiveness of endoscopic treatment (collagen injection) in children with neurogenic bladder and neurogenic urinary incontinence. From January 1992 to March 1997, 36 endoscopic collagen injections were performed to treat neurogenic urinary incontinence in 23 patients (mean age 10.9 years, range 6-17 at the time of the first procedure) selected on the basis of clinical status and the patient's motivation. Nineteen patients were affected by myelomeningocele and four had an occult spinal dysraphism. All patients underwent a preoperative cystometric urodynamic evaluation (without urethral pressure measurement) which showed detrusor areflexia in 12, normal reflexia in one and hyper-reflexia in 10 patients. Bladder compliance was considered good (> or =20 cmH2O) in 13 patients and low (10-20 cmH2O) in 10, four of whom had detrusor areflexia. Twenty-one children emptied their bladder by intermittent clean catheterization. The mean (range) follow-up was 19.2 (6-54) months. Twenty (group A) and 16 (group B) procedures, performed early and late in the series, were analysed separately to determine any increase in effectiveness with surgical experience. The evaluation criteria were; the increase in the 'dry' interval (between catheterizations) before and after treatment/s (delta dry); the patient's and parent's satisfaction; the number of endoscopic procedures and quantity of injected materials. There was an improvement (dryness of at least 2 h: delta dry of 1 h) in 13 of 23 patients after 1-3 (mean 1.5) procedures; 10 patients had a 0.2 h increase in delta dry after 1-3 injections and none was satisfied. There was no difference in the delta dry (0.9 vs. 0.7 h) between groups A and B, and/or the patient's/parent's satisfaction. Success rates differed with urodynamic patterns; seven of 10 patients showing no improvement had hyper-reflexia and three of the remaining 12 with areflexia had hypocompliant bladders, while nine of the 13 showing improvement had an areflexic detrusor and low-pressure bladders. The efficacy of the treatment depends largely on the urodynamic selection of patients (mainly those with detrusor areflexia and good compliance). The outcome may be improved further by increasing the quantity of injected material and with a longer follow-up, performing the procedure again if advisable. A close postoperative clinical (pad test) and personal observation is necessary to evaluate the outcome and thus optimize the strategy of treatment.

URODYNAMIC PATTERN IN INFANTS WITH URINARY TRACT INFECTION

Purpose We studied the urodynamic pattern in infants with urinary tract infection and evaluated the influence of the infection. Materials and Methods Cystometry was combined with voiding cystourethrography (video cystometry) and 90 male and 68 female infants admitted to the hospital with first time urinary tract infection. Evaluation was performed 1 to 30 days (mean 11) and 32 to 78 days (mean 46) after diagnosis in 93 and 65 infants, respectively. Results Bladder instability was found in two-thirds of male and female infants. Compared to older children male infants had high voiding detrusor pressure and low bladder capacity (hypercontractility). Female infants also had increased voiding pressure levels but they were significantly lower than those in male infants. The voiding detrusor pressure was even higher in both sexes when evaluation was delayed after the infection. Conclusions Infants with urinary tract infection have bladder instability and hypercontractility compared to older children. Bladder hypercontractility was less pronounced early after infection, suggesting that the infectious agents inhibit detrusor muscle contractility. Whether hypercontractility is a normal urodynamic pattern in infancy or represents bladder dysfunction can only be addressed by urodynamic studies of healthy infants.

Detrusor hypocontractility in children with posterior urethral valves arises before puberty.

To assess prepubertal boys with posterior urethral valves (PUV) using an analysis of pressure-flow studies to evaluate the voiding phase and thus determine if myogenic failure (hypocontractility) arises before puberty and if it can be detected early. Eleven boys (8-13 years old) with PUV underwent urodynamics and the results were analysed using pressure-flow mathematical analysis (PFA) of the following variables of detrusor activity: contraction velocity (Vdet), detrusor contractile power expressed as power factor (WF) and Schafer's diagram, which differentiates a 'strong', 'normal' and 'weak' detrusor. Vdet and WF were compared with normal values previously determined in boys of similar age and considered 'low' if more than 2 SDs below the mean. The results of PFA were compared with standard pressure-flow studies and the three classical urodynamic patterns in boys with PUV, as determined by voiding symptoms. The subsequent PFA of seven of the 11 boys were also assessed as they had undergone previous urodynamics when < 8 years old. As assessed by the three patterns of dysfunction, two boys had bladder instability, two had low compliance and three had hypocontractility, with four boys being normal. From the PFA, the Vdet and WF were lower than normal, respectively, in seven and nine of the 11 boys; Schafer's nomogram showed a 'weak' detrusor in seven boys. The PFA suggested a pathology in four of five boys with symptoms and in three of six with no symptoms (two of the six showing a 'low' WF). Moreover, in older (11-13 years) boys, all five had a 'weak' detrusor, a 'low' WF and four a 'low' Vdet. Of the seven patients who underwent repeat PFA, three had a stable WF 3 years later, one (normal) worsened slightly and two were clearly worse, while one, who underwent late (at 3 years old) valve ablation, had an increased WF. The PFA showed hypocontractility in two-thirds of prepubertal boys with PUV, including asymptomatic patients. These findings confirm the hypothesis that bladder dysfunction in boys with PUV eventually causes detrusor myogenic failure and finally a postpubertal overdistended bladder.

Urodynamic patterns in infants with normal lower urinary tracts or primary vesico-ureteric reflux.

To compare bladder function in infants with primary vesico-ureteric reflux (VUR) and those with normal lower urinary tracts. The study comprised 42 patients (36 males) with VUR (grades III to V) and 21 (16 males) without VUR (mean age in both groups, 6 months). Intravesical catheters were placed suprapubically under general anaesthesia and, after at least 24 h, natural-tilling urodynamics were monitored for three or more filling and voiding cycles. Various urodynamics patterns were defined: for infants without VUR these were either normal or normal-immature (discoordinated micturition) and none showed features indicating abnormal bladder function. By comparison, 24 of 42 infants with VUR showed abnormal urodynamic patterns (57%, 95% confidence interval 41% to 72%, P < 0.001). Seven (17%) were defined as unstable with small voided volumes, five (12%) had inadequate voiding dynamics, 10 (24%) showed a markedly dyssynergic pattern and two (5%) had obstructive patterns. The unstable, inadequate and obstructive patterns occurred only in boys. Detrusor activity during the filling phase occurred in 14 infants (13 boys) with VUR and in only one without VUR, when it was trivial. Post-void residual volumes of > 30% capacity were seen only in the VUR group (in 24 patients). There were 18 infants with VUR that showed the normal or immature urodynamics patterns, but for the 14 males the voiding pressures were higher than for those without VUR (mean maximum detrusor pressure, 161 and 117 cmH2O, respectively: P < 0.02). There is an association between abnormal urodynamic variables and a diagnosis of primary VUR in young infants (notably males) that may have important implications for concepts about the genesis and persistence of VUR.