Prenatal screening revealed a marked cerebral abnormality and absent occipital cranium, indicating cranial dysraphism. The patient was delivered via Caesarean section at 39 weeks of gestation. At birth, an extraordinarily large amount of the occipital cranium and skin was absent, and the parieto-occipital lobe and cerebellum were covered only by the subarachnoid membrane, leading to the diagnosis of encephalocele and aplasia cutis congenita (Fig. 1A, B). She also had hypoplasia of the corpus callosum, ectopic grey matter, enlarged massa intermedia, and aqueduct obstruction (Fig. 1C). Cerebrospinal fluid (CSF) leakage was closed with polyglycolic acid felt and fibrin glue, and an artificial dermis was used to cover the skin defect. Under meticulous sterile management in the neonatal care unit, the affected area was epithelialized without any sign of infection by 8 months of age, and the patient was discharged with the use of a custom-made headgear apparatus, while having mild motor deficit and severe mental retardation (Fig. 1D). Starting at 5 years of age, she experienced intractable epileptic spasms requiring treatment with multiple anti-seizure medications (phenobarbital, levetiracetam, lamotrigine, and vigabatrin), while she grew without the sign of infection and hydrocephalus in follow-up magnetic resonance imaging (MRI) until the age of 7 years and 4 months (Fig. 1E). Since then her unstable gait gradually became obvious. She was subsequently referred to our neurosurgical department at 8 years of age.
Neurological examination on admission revealed that the patient was alert, and there was no noticeable paresis in the extremities. However, her gait disturbance was significant; therefore, she was unable to walk without support. MRI revealed markedly enlarged lateral ventricles. The third ventricle was also dilated, the floor of which projected downwards. In contrast, the fourth ventricle was not dilated (Fig. 2).
The patient underwent ETV under general anesthesia. A burr hole was placed in the right frontal region near the cranial edge (Fig. 3A). A plastic sheath was inserted into the anterior horn of the right lateral ventricle through which a flexible neuroendoscopic system (EVIS LUCERA SPECTRUM video imaging system; Olympus, Tokyo, Japan) was introduced. The third ventricle was reached via the abnormally dilated foramen of Monro. Anatomical structures, such as bilateral mammillary bodies and infundibular recess, were easily identified, and the ETV was completed using endoscopic forceps and a balloon catheter without complication (Fig. 3B, C). The postoperative course was uneventful, and her gait improved after surgery. Postoperative head MRI revealed that the lateral and third ventricles were markedly reduced in size (Fig. 4). In addition, the images showed an improvement in the downward extension of the third ventricular floor. The patient’s clinical status remained stable over the subsequent 5-month period.