Pre-operative assessment of ventricular size and ventricle-to-hemisphere area ratio permits estimation of the need for ventriculo-peritoneal shunt insertion during the first three months of postnatal life in fetuses before fetoscopic surgery for spina bifida aperta

Purpose: Minimally-invasive fetoscopic surgery of spina bifida aperta (SBA) may improve postnatal neurological outcome as well as obviate the need for hydrocephalus treatment. The purpose of this analysis was to evaluate the potential of simple ultrasound measurements taken before fetal surgery in estimating the need for ventriculo-peritoneal shunt insertion during the first three months of postnatal life.

Patients and methods: 35 Patients were included. The ventricular atrium was measured in a standardized transverse plane of the fetal head. In addition, the lateral ventricle/hemisphere-area-ratio was measured in the same plane. The rate of ventricular peritoneal shunt insertion was assessed at three months of postnatal life. Cumulative frequencies for shunt insertion were calculated for both measurements.

Results: A pre operative ventricular atrial diameter of ≤12 mm was associated with a shunt rate of 37%, and a diameter of ≥14 mm with a shunt rate of 100%. A ventricle/hemisphere-area-ratio of ≤0.3 was associated with the need for shunting in approximately 30%, a ratio of ≥0.3 was associated with the need for shunting in approximately 60%.

Conclusion: The sonographic assessment of both ventricular size and ventricle/hemisphere-area-ratio in fetuses before minimally-invasive fetoscopic surgery for spina bifida aperta permits to estimate the need for ventriculo-peritoneal shunt insertion during the first three months of postnatal life. This observation may aid in parental counseling and decision-making.