Is Ventriculomegaly and Hindbrain Herniation Seen Before and after Prenatal Neural Tube Defect Repair Associated with a Worse Functional Level Than Anatomical Level at Birth?

Objective To determine if the evaluation of the fetal ventricular system and hindbrain herniation (HBH) is associated with motor outcome at birth in prenatally repaired open neural tube defect (NTD). Methods Retrospective cohort study of 47 patients with NTD who underwent prenatal repair (17 fetoscopic; 30 open-hysterotomy). At referral and 6 weeks postoperatively, the degree of HBH, ventricular atrial widths and ventricular volume were evaluated by MRI. Head circumference and ventricular atrial widths were measured on ultrasound at referral and during the last ultrasound before delivery. Anatomic level of the lesion (LL) was determined based on the upper bony spinal defect detected by ultrasound. We considered the functional level as worse than anatomical level at birth when the motor level was equal or worse than the anatomical LL. Results 26% (12/47) of the cases showed worse functional level than anatomical level at birth. Having a HBH below C1 at the time of referral was associated with a worse functional level than anatomical level at birth (OR = 9.7, CI95 [2.2-42.8], p < 0.01). None of the other brain parameters showed a significant association with motor outcomes at birth. Conclusions HBH below C1 before surgery was associated with a worse functional level than anatomical level at birth.