Clinical impact of fetal sac size on closed neural tube defects.

PURPOSE

To evaluate the association between lesion volume and postnatal outcomes in patients with closed spina bifida (SB).

METHODS

Single-center retrospective review of all patients diagnosed with a closed SB evaluated between 2013 and 2023. Prenatal lesion volume < 3 mL was categorized as "no sac," and volume ≥ 3 mL was categorized as "sac."

RESULTS

Of eligible patients, 22 had a sac, and 33 did not. Myelocystocele patients more commonly had an associated saccular lesion than lipomyelomeningoceles (80% vs. 28%, p = 0.02). Lipomyelomeningocele patients demonstrated less prenatal lesion growth compared to myelocystocele patients (6.26 vs. 58.0 mL) over a median of 12.7 and 10.5 weeks, respectively. Patients with a sac had a higher proportion of talipes (40.9% vs. 9.1%; p = 0.007) compared to those without. At 5 years old, a higher proportion of patients with no sac was able to ambulate independently and required less CIC than patients with a sac (80% vs. 42%; 0% vs. 41.7%). VUDS showed a greater frequency of detrusor overactivity (60.0% vs. 45.0%) and abnormal bladder compliance (60.0% vs. 5.0%) in those with a sac compared to those without. Repeat tethered cord release was also more common (30.0% vs. 3.4%) among patients with a sac-associated defect.

CONCLUSIONS

Patients with a sac had an increased risk of prenatal talipes, decreased ability to ambulate independently, increased use of CIC, and increased need for repeat tethered cord release compared to patients without a sac. Given numerous associated morbidities reported in this study, longitudinal multidisciplinary follow-up is critical in the care of these patients.