Introduction: Around 80% of children with bladder dysfunction respond to the first proactive approach with anticholinergics and clean intermittent catheterization (CIC). A number of them will need other second-line treatments and finally some are refractory to all pharmacological therapies, leading to enlargement cystoplasty. The objective of the study is to present this pre-reconstruction subgroup of the lower urinary tract, characteristics and consequences.Material and methods: Retrospective analytical study of children with neurogenic bladder was performed at a tertiary pediatric center from 2003 to 2017. We will define "Refractory phenotype" as the set of neurogenic bladder characteristics that is divided into a subgroup of individuals with insufficient clinical and urodynamic response to high-dose pharmacological therapy and/or with side effects, with relevant consequences such as hydronephrosis. Patients with follow-up <5 years and those with an adequate response to pharmacological treatment were excluded. Variables were considered: bladder emptying diary, urodynamics/video urodynamics, renovesical ultrasound, and renal function laboratory. Recurrent UTIs were defined: 4/year and constipation by Rome IV criteria. For quantitative variables, measures of centralization and dispersion (mean and SD) were calculated, and for categorical variables, absolute and percentage distributions were calculated. Student's t test was applied for the comparison of means (after Shapiro-Wilks Normality test) and chi2 test in the correlation of categorical variables. In all cases, a significance level equal to 0.05 was used. The STATA 18 statistical package was used.Results: 128 children were studied and 54% were boys and the average age was 11 years (4-18). The average follow-up time was 52 months. The most frequent etiologies were: myelomeningocele, anorectal malformation and lipomeningocele (63%, 15% and 6%, respectively). All of them were refractory to medical treatment: oral oxybutynin and/or mirabegron and/or botulinum toxin. 30% were dry, 56% had urinary incontinence and 13% had continent catheterizable channels through ostomies. 44% presented recurrent UTIs, 45% presented ureterohydronephrosis and 31% presented VUR. Bladder capacity was reduced on average by up to 81%. Mean Pdetmax was 47 cmH2O (SD:14) and 71% had DLPP>40. Only 14% persisted with overactivity. Cases with DLPP >40 were associated with greater incontinence (p=0.001) and recurrent UTIs (p= 0.0001). Cases with VUR and recurrent UTIs were associated with kidney disease (n:24) (p=0.043 and p=0.011 respectively). There was no association between Pdetmax/DLPP and hydronephrosis, VUR and impaired renal function.Conclusions: Preadolescent patients refractory to bladder pharmacological therapy show the phenotype characterized by urine incontinence, symptomatic/recurrent urinary infections and ureterohydronephrosis in almost half of the cases. Almost all of them presented reduced bladder capacity and hypertonia associated with urine leaks.
