Análise comparativa das intervenções cirúrgicas pré-natal e pós-natal na Mielomeningocele: desfechos urodinâmicos precoces avaliados por meio do ultrassom dinâmico de rins e vias urinárias

Abstract

Introduction and objectives: Myelomeningocele (MMC) is the leading cause of neurogenic bladder (NB) in childhood and is frequently associated with lower urinary tract dysfunction, recurrent urinary tract infections, vesicoureteral reflux, and a high risk of early renal deterioration. Although urodynamic studies (UDS) are widely used for functional assessment, their technical limitations and invasive nature reduce their applicability in neonates and young infants. Dynamic ultrasound (DUS) of the kidneys and urinary tract has emerged as a promising non-invasive alternative, enabling simultaneous morphological and functional evaluation of the urinary system under physiological conditions. This study aimed to: (1) characterize DUS-based urodynamic findings in neonates with MMC compared to healthy controls; (2) systematically review the literature on DUS in pediatric NB; and (3) compare early urodynamic outcomes between neonates with MMC who underwent prenatal versus postnatal surgical repair. Methods: This thesis included two original studies and a systematic review. Both studies were conducted at a quaternary referral center between 2021 and 2025. The first study had a cross-sectional design that compared neonates with MMC and age-matched healthy controls, all assessed with a standardized DUS protocol. A systematic review was also included in the first study and conducted following PRISMA and Cochrane Handbook guidelines, registered in the PROSPERO platform (CRD42023556854). The second study was a prospective cohort comparing DUS findings between patients who underwent prenatal MMC repair and those submitted to postnatal correction. In both studies, DUS was performed between 10 and 90 days of life and assessed bladder wall thickness, maximum bladder capacity (MBC), residual urine volume (RUV), detrusor activity, sphincter competence, and intravesical pressure. Statistical analyses included group comparisons, post hoc power analysis, and interobserver agreement using Kappa and ICC coefficients. Results: In the first study, 41 MMC patients and 45 healthy controls were included. The MMC group showed significantly reduced MBC and increased RUV compared to controls (p < 0.001). Involuntary detrusor contractions were present in over 75% of MMC patients. A systematic review was also performed and identified only three studies evaluating DUS in children with neurogenic bladder, highlighting the scarcity of data but showing promising accuracy and clinical applicability. The second study compared neonates with MMC who underwent pre- (n=15) and postnatal (n=26) surgery with each other and with healthy controls (n=52). Among MMC neonates, those undergoing prenatal surgery had significantly lower MBC (p = 0.006), lower RUV (p = 0.001), and a reduced RUV/MBC ratio (p = 0.003), suggesting more effective bladder emptying. No significant differences were observed in detrusor or sphincter function between surgical groups. Conclusions: Prenatal MMC repair may enhance bladder emptying efficiency in neonates and infants. DUS presented capacity of detecting morphological and functional abnormalities in the early evaluation of NB, aligning well with UDS findings and supporting individualized management following fetal surgery. The technique was safe, well-tolerated, and technically feasible in the neonatal period. Despite the limited number of publications, the findings of this thesis suggest that DUS may serve as a valuable tool for screening, diagnosis, and follow-up of neurogenic bladder dysfunction in MMC patients, as well as for assessing the urological impact of surgical timing. Further studies with larger cohorts and longer follow-up are essential to validate these findings.