Staged neurosurgical approach for giant and progressive neonatal arachnoid cysts: a case series and review of the literature.

OBJECTIVES: Prenatally diagnosed complex arachnoid cysts are very rare. While the true prenatal incidence is still unknown, they account for approximately 1% of intracranial masses in newborns. They rarely exhibit rapid growth or cause obstructive hydrocephalus, but if they increase to such a dimension during pregnancy, the ideal management is not well established. We present our detailed perinatal experience, covering prenatal diagnosis, a compassionate delivery process, and neonatal stabilization. Finally, a thorough postnatal neurosurgical intervention was performed. Initially, our focus was on the gradual reduction of cyst size as a primary effort, followed by subsequent definitive surgical treatment.

METHODS: This case series shows the treatment course of three fetuses with antenatally diagnosed large arachnoid cysts. We present pre- and postnatal management and imaging, as well as the surgical treatment plan and the available clinical course during follow-up.

RESULTS: Two girls and one boy were included in the current review. All three cases presented with prenatally diagnosed complex arachnoid cysts that increased in size during pregnancy. The mean gestational age at delivery was 35 weeks (range 32 to 37 weeks), and all patients were delivered by a caesarian section. Increasing head circumference and compression of brain structures were indications for delivery, as they are associated with a high risk of excess intracranial pressures and CSF diapedesis, as well as traumatic delivery and maternal complications. All cysts were supratentorial in location; one expanded into the posterior fossa, and one was a multicompartment cyst. All children underwent an initial surgical procedure within the first days of life. To relieve cyst pressure and achieve a reduction in head circumference, an ultrasound-guided or endoscopic-assisted internal shunt with drainage of the cyst to the ventricles or subdural/subarachnoid space was inserted. Definite surgical therapy consisted of cyst marsupialization and/or cysto-peritoneal shunt implantation. All children survived without severe neurodevelopmental impairments.

CONCLUSION: With the cases presented, we demonstrate that the slow reduction of immense cyst size as an initial procedure until optimal requirements for final surgical treatment were achieved has proven to be optimal for neurological outcome. Special emphasis has to be taken on the delicate nature of premature newborn babies, and surgical steps have to be thoroughly considered within the interdisciplinary team.