In utero myelomeningocele (MMC) repair has shown benefits with reduced need for ventriculoperitoneal shunt and improved motor status (MOMS study).¹ The potential improvement in the bladder function is controversial, as the different studies published in the post-MOMS era are conflicting: the American groups involved in MOMS^2,3 and the Zurich group^4,5 suggest benefits, while our studies in São Paulo, Brazil go in the opposite direction and show no difference in the urological status, regardless of whether it is fetal or postnatal surgery.^6–12

In 2011 we started a prospective urological followup protocol of patients with MMC operated in utero. After clinical evaluation and radiological examinations (urinary tract ultrasound, voiding cystourethrography and urodynamic evaluation [UE]) patients were categorized⁷ and treated as follows (fig. 1): 1) High Risk Pattern (overactive bladder with detrusor leak point pressure higher than 40 cmH₂O and higher filling pressures also above 40 cmH₂O)–anticholinergics (0.2 mg/kg) 2 or 3 times daily in association with clean intermittent catheterization (CIC), 2) Incontinent Pattern (overactive bladder with detrusor leak point pressure lower than 40 cmH₂O or stable bladder but leaking below 40 cmH₂O), 3) Underactivity Pattern (underactive bladder with post-void residual urine)–only CIC and 4) Normal Pattern (stable bladder cystometry with/without leak page–only clinical surveillance.⁷ Our protocol suggests assessments at 6-month intervals until stability of the urodynamic pattern and then yearly controls with further ultrasound and UE. All urodynamic evaluations were performed using the same device and by the same investigators.

Incidence of Abnormal Bladder Patterns

Our first 100 cases evaluated at mean age of 5.8 months (median 4 months) were classified as high risk in 52.6%, incontinent in 27.4%, underactive bladder in 4.2%, and only 14.7% had a normal bladder profile (fig. 2).⁹ CIC was initiated in 57.3% of cases and anticholinergics in 52.6%. Antibiotic prophylaxis was started in 19.1% patients presenting with vesicoureteral reflux.⁹ This paper outlined the high incidence of abnormal bladder patterns and suggests poor benefit of in utero MMC surgery towards the urinary tract. Very importantly, papers from the U.S. and Europe do not record patients with low sphincteric function and simply classify them as nonrisk. I consider this wrong. These patients will need major bladder reconstruction to be continent and therefore their bladder pattern should be counted as abnormal, too.

Figure 1. Bladder patterns in MMC.⁷

Figure 2. Bladder categorization after in utero MMC surgery: first 100 cases.⁹

Figure 3. Detrusor Pmax of high-risk pattern after treatment in active followup.¹³

Urinary Continence

In a previous paper we looked for patients aged 5 years or older for evaluation of urinary and fecal continence.¹¹ We identified 14 patients; 3 patients had undergone surgery (2 augmentations, ie 1 in association with a left colon antegrade colonic enema Macedo-Malone procedure and 1 mini-sling urethroplasty). Twelve patients underwent CIC (85.7%). Only 3 (21.4%) patients had no urinary leakage. Eleven patients (78.6%) used diapers. Eight patients (57.2%) underwent retrograde rectal irrigation and 11 (78.6%) complained of fecal loss. Despite the use of CIC in 85.7% of the cases, the continence rate in MMC patients operated on in utero was low and 78.6% of the patients used diapers.¹¹

We have recently reported on our experience in patients operated in utero and presenting with sphincter insufficiency patterns.¹² From a total of 117 patients we found 30 patients (25.64%) classified as incontinent when leaking at low pressure (<40 cmH₂O). We noticed a change of bladder pattern with time as follows: 6 patients became of high-risk pattern, 5 normal and 2 with underactive bladder pattern. The average interval between the first and last UE was 25.5 months (median: 15 months). We concluded that 43.47% of patients with low detrusor leak point pressure have kept the incontinent pattern. If the initial leak point pressure was below 30 cm H₂O, 70% remained with the incontinent pattern.¹²

Response to Treatment in High-Risk Patterns and Incidence of Surgery

Between 2011 and 2020, we have studied 121 patients and 60 (49.6%) of them were initially categorized as high-risk and included in this study.¹³ The initial UE was performed at a mean age of 7.9 months and hyperactivity was found in 83.3% (mean maximum pressure of 76.5 cmH₂O). When evaluating patients with 2 or more UEs, we identified 44 patients (followup: 36.8 months). The recategorization of the bladder pattern confirmed maintenance of high-risk in 61.4% and low-risk in 38.6% in the second examination. Patients who underwent 3, 4 and 5 UEs had a response close to 60% of change in the bladder pattern to low-risk. The incidence of surgery was 13.3% (3 vesicostomy, 2 vesicoureteral reflux surgeries and 3 bladder augmentation). Early urological treatment of high-risk bladder patterns was effective at approximately 60% and the incidence of surgery was 13.3%.¹³

Comparison of in Utero and Postnatal Repair Objectively Assessed by Urodynamic Evaluation

We compared the bladder status in patients who underwent fetal MMC surgery and postnatal repair. Group 1 consisted of in utero surgery and Group 2 consisted of postnatal repair. Group 3 was a subgroup of Group 2, including patients presenting initially with age below 12 months.¹⁰ We identified 88 patients in Group 1, 86 in Group 2 and 38 patients in Group 3. The incidence of urinary tract infection was higher in the postnatal period (45% vs 20%). Hydronephrosis occurred in 20.7%, 22.6% and 28.9% in Groups 1, 2 and 3, respectively. Vesicoureteral reflux was diagnosed in 15% in all groups. Urodynamic data showed a higher prevalence of detrusor overactivity in Group 1 and no difference in other urodynamic parameters. The high-risk bladder pattern at initial evaluation occurred in 56%, 50% and 46% of groups 1, 2 and 3, respectively. There was a trend to decrease the percentages of the high-risk bladder pattern and to increase the normal pattern after the treatment in all groups.¹⁰ We were able to conclude that in utero repair did not improve urological parameters when compared to patients operated in the postnatal period.