Urodynamic Study In Children With Voiding Dysfunction

Background and objective:Paediatric voiding dysfunctions possess multiple variations, which exert great influence on study, psychological and physical development of children, even threat their lives. Voiding dysfunctions are classified into neurogenic and non-neurogenic, mainly including primary monosymptomatic nocturnal enuresis (PMNE), valve bladder syndrome (VBS), prune belly syndrome (PBS) and neurogenic bladder-sphincter dysfunction (NBSD), etc. Nowadays, etiology of enuresis is not clear. However, there have been researches showing that bladder-urethral dysfunctions are related to it, which deserves further investigation because of its significance in the diagnosis and treatment of enuresis. Besides, whether the results of natural filling and artificial filling urodynamics are the same and which one is better in clinical work are in the controversy. Moreover, post-voiding contraction (PVC) has been described in 1933, but the mechanism and significance, especially in enuresis has not been known, which needs further research. Posterior urethral valve is the main cause of lower urinary tract obstruction in children, which results in severe consequences such as death. Even if the valve has been spotted and been operated in time, there are parts of patientsshowing unimproved bladder function leading to upper urinary tract dilation and incontinence. Some researches suggested the conception of "valve bladder syndrome". Because VBS also shows abnormal morpology and diverticulum, etc, it can be confused with neurogenic bladder. The prevalence of PBS is l/35000~50000, which possesses abnormality of abdomen muscle, urinary tract dilation and bilateral undescended testis. Children with PBS may have upper urinary tract dilation due to increasing post-voiding residual urine (PVR), which affects physical development tremendously, even death. Therefore urodynamic investigation has great significance in prevention of upper urinary tract dilation. But the manifestations of urodynamics which have not been reported within China need attention. NBSD having high prevalence can be caused by nerve diseases or injuries. Thirty to forty percent of NBSD children may show renal function deterioration, which is the main reason of death in NBSD children. There are many questions about mechanism of upper urinary tract deterioration. It is difficult for clinical symptoms, neural system examination and urinary system radiology to evaluate and prognosticate upper urinary tract deterioration efficiently and accurately. With the development and widespread of pediatric urodynamics, it has been the first choice of evaluation of NBSD, prognostication of upper urinary tract deterioration and reference of clinical management. Accurate evaluation and diagnoses of voiding dysfunction are the prerequisites of appropriate management. Urodynamic investigation can be utilized to evaluate the function of bladder, urethral and pelvic floor during both filling and voiding phrase. The exam is required to imitate the symptoms of daily activities in the controlled circumstances, through which urodynamic machine can determine the function status of bladder and urethral and find out the possible reasons. In brief, urodynamic investigation is a functional diagnostic method which can reflect the function of bladder and urethra directly and quantificationally. Due to the particularity and incertitude of etiology and development of pediatric diseases, the common methods to diagnose and evaluate voiding dysfunction and to prognosticate upper urinary tractdeterioration mainly focused on morphology, not on function. Urodynamic can make up for these drawbacks because of its characteristics of measuring bladder pressure, volume and relationship between pressure and urine flow. Objectives: The purposes of present studies are to investigate the clinical significance of urodynamic study in children with PMNE, VBS, PBS and NBSD, including in details:(1) To investigate the urodynamic changes and significance in the children with PMNE and the differences between by using natural filling and artificial filling cystometry in children with. Investigation of post-voiding contraction will be emphasized.(2) To investigate the urodynamic manifestations and significance in children with VBS.(3) To investigate the clinical significance of urodynamic study in children with PBS.(4) To investigate the reasons of upper urinary tract dilation in children with NBSD providing references to diagnose and treat it appropriately.Part one: Primary monosymptomatic nocturnal enuresis1. Urodynamic study with natural and artificial filling in children with PMNEand comparison1.1 Materials and methods:(1) PatientsA total of 50 children (30 boys and 20 girls, aged from 6 to 14 year-old) who suffered from PMNE were included in this study.(2) Urodynamic investigationThe uroflowmetry was carried out firstly to get maximum flow rate (Qmax). The catheterization was performed to measure bladder pressure. Saline at 25 °C was continuously filled into the bladder at less than lOml/min. The abdominal pressure was measured through a balloon 8Fr catheter placed in the rectum. Detrusor pressure was calculated by the subtraction the rectal pressure from the intravesicalpressure. Then fill the bladder. Children were asked to void when they could not delay it. Maximum bladder capacity (MBC) was measured. Immediately after voiding, post-voided residual urine (PVR) was extracted from bladder. Detrusor instability (DI), post-voiding contraction (PVC) and detrusor-sphicter dyssynergia (DSD) were observed. Bladder compliance (BC) was calculated. Normal MBC was calculated as 30+30xage (years). Normal BC was not less than 0.05xnormal MBC. A-G number was calculated as detrusor pressure at Qmax (Pdet at Qmax)-2Qmax, and the value of A-G more than 40 standed for obstruction. Other parameters are maximal detrusor pressure (Max. Pdet), the way of voiding, and detrusor leak point pressure (DLPP). The methods, definitions and units conform to the standards proposed by the International Children Continence Society (ICCS), excepted where specially noted. Natural and artificial filling cystometry were performed in present study, respectively. Natural filling was carried out, and then artificial filling cystometry was performed in present research. (3) Statistical analysisThe paired-samples T test was used to compare Max.PdeU Qmax, Pdet at Qmax, MBC> BC-. and PVR between two groups. Chi-square test was used to compare DI, PVC and DSD. Data are reported as range and mean plus or minus standard deviation, and <5% was considered statistically significant. All calculations were done by SPSS 10.0 statistical software. 1.2 ResultsIn children with PMNE, the difference of Max.Pdet, Pdet.at Qmax, PVR, BC, Qmax, DI, DSD and PVC were not significant during both natural and artificial filling cystometry (p>0.05). However, MBC showed great significance (p <0.05). 2. Post-voiding contraction in children with PMNE 1.1 Materials and methods: (1) PatientsA total of 70 children with PMNE (45 boys and 25 girls, aged from 5 to 14 years) were divided into two groups: group I with PVC and group II without PVC.(2) Urodynamic investigation Almost same to part one.(3) Statistical analysisThe two-samples t test for independent samples was used to compare MBC\ BCand PVR between two groups. Chi-square test was used to compare DI and DSD.Data are reported as range and mean plus or minus standard deviation, and <5%was considered statistically significant. All calculations were done by SPSS 10.0statistical software.1.2 ResultsIn 70 children with PMNE, PVC was observed in 42 children (26 boys and 16girls). MBC> BC% PVR> DI and DSD showed no significance between two groups(p>0.05). Three types of PVC were found, including Type I (single smooth wave)relating to a single detrusor-sphicter dyssynergia, Type II (single staccato wave)relating multiple dyssynergia and Type HI (multiple waves) in which 13 childrenwere observed dribbing after voiding and in 11 cases, the amplitude of PVC waveswas higher than that of voiding waves.Part two. Urodynamic investigation of valve bladder syndrome2.1 Materials and methods:(1) PatientsSixteen children with VBS were included, who were divided into two groups. The time between urethral valve fulguration and urodynamic study was less than one year in group one and more than one year in group two.(2) Urodynamic investigation Almost same to part one.(3) Statistical analysisThe two-samples t test for independent samples were used to compared MBC> B^ Max.Pdet and PVR between two groups. Fisher's exact test of probabilities was used to compare the frequecy of DI. Data are reported as range and mean plus or minus standard deviation, and <5% was considered statistically significant. Allcalculations were done by SPSS 10.0 statistical software.2.2 ResultsIn 16 cases with VBS, the Max. Pdet and BC were lower in group two than thosein group one, while the PVR and MBC were higher compared with group one.Difference in these four parameters between two groups was significant (p<0.05).There were 4 and 2 cases showing DI, but no difference of it was showed (p>0.05).In group two, intermittent detrusor contraction, a relatively special pattern wasfound in four cases, in which Max.Pdet and PVR were averagely 62.3±9.1cmH2Oand 87.5+41.9ml respectively.Part three. Urodynamic study in children with prune belly syndrome3.1 Materials and methods:(1) PatientsBoth cases with PBS showed lower urinary tract obstruction, increase in PVR and MBC and high urethral pressure. One case had unstable bladder. One accepted transurethral incision of cervix vesicae, which resulted in improvement of obstruction symptoms.(2) Urodynamic investigation Almost same to part one.3.2 ResultsBoth cases with PBS showed lower urinary tract obstruction, increase in PVR andMBC and high urethral pressure. One case had unstable bladder. One acceptedtransurethral incision of cervix vesicae, which resulted in improvement ofobstruction symptoms.Part four. The urodynamic study in children with neurogenicbladder-sphicnter dysfunction4.1 Materials and methods:(1) PatientsThirty-one NBSD children with hydronephrosis (18 boys and 13 girls, aged from 5to 18 years) and twenty-nine without it (16 boys and 13 girls, aged from 3 to 18years) were included in this study.(2) Urodynamic investigation Almost same to part one.(3) Statistical analysisThe two-samples t test for independent samples was used to compare MBC> BC>Max. PdeU DLPP and PVR between two groups. Chi-square test was used tocompare DI% DSD and frequency of detrusor acontractile. Data are reported asrange and mean plus or minus standard deviation, and <5% was consideredstatistically significant. All calculations were done by SPSS 10.0 statisticalsoftware.4.2 ResultsIn NBSD study, PVR> MBC> DLPP> BCU DSD and incidence of acontractileshowed great significance between two groups (p<0.05), while Max. Pdet and DIshowed no significance (p>0.05).Conclusions1. Children with PMNE, both natural and artificial filling cystmetry found DI> DSD^ lower urinary tract obstruction, decrease in MBC and BC. PVC was also a manifestation. There were no significant differences between two cystmetric studies indicating that artificial filling urodynamic study was acceptable as a routine evaluation of bladder function in children with PMNE because of its convenience; PVC had not been found to be related to DL DSD^ MB^ PVR and BC in PMNE. Type I and II of PVC were related to DSD, but Type HI was different and needed further investigation.2. VBS may present with multiple bladder dysfunctions. It is necessary to use Urodynamic study to evaluate the bladder function of VBS. With children growing, Max.Pdet and BC would decrease, while PVR and MBC would increase.3. The principal manifestations of children with PBS were lower urinary tract obstruction and increase in residual urine. These children should be routinely refened to urodynamic study in order to get more detail information of bladderdysfunction and carry out necessary management to prevent upper urinary tractdeterioration.4. Decreasing BC, increasing DLPP and evidence of detrusor acontractile and DSDwere main urodynamic risk factors in those children with NBSD. The urodynamicstudy showed great significances in the clinical treatment in NBSD children.