Chiari malformation appears to be an acquired and progressive condition that develops in the first months of life, because of a disproportion between hindbrain growth and an abnormally small posterior fossa, a consequence of the premature fusion of lambdoid and cranial base sutures. Venous hypertension caused by stenosis of the jugular foramen can also be present in these patients, resulting in intracranial hypertension and/or hydrocephalus. Careful MRI evaluation is recommended for the forms of craniosynostosis at a high risk of developing hindbrain herniation. The selection of posterior cranial vault expansion as the first surgical procedure is advocated. In selected cases, treatment of the posterior cranial deformity by occipital vault remodelling and treatment of the Chiari-like deformity by suboccipital decompression can be carried out using the same surgical procedure.

Central nervous system (CNS) complications during treatment of childhood acute lymphoblastic leukemia (ALL) remain a challenging clinical problem. Outcome improvement with more intensive chemotherapy has significantly increased the incidence and severity of adverse events. This study analyzed the incidence of neurological complications during ALL treatment in a single pediatric institution, focusing on clinical, radiological, and electrophysiological findings. Exclusion criteria included CNS leukemic infiltration at diagnosis, therapy-related peripheral neuropathy, late-onset encephalopathy, or long-term neurocognitive defects. During a 9-year period, we retrospectively collected 27 neurological events (11%) in as many patients, from 253 children enrolled in the ALL front-line protocol. CNS complications included posterior reversible leukoencephalopathy syndrome (n = 10), stroke (n = 5), temporal lobe epilepsy (n = 2), high-dose methotrexate toxicity (n = 2), syndrome of inappropriate antidiuretic hormone secretion (n = 1), and other unclassified events (n = 7). In conclusion, CNS complications are frequent events during ALL therapy, and require rapid detection and prompt treatment to limit permanent damage.

Endoscopic third ventriculostomy should be considered as an alternative procedure to ventriculo-peritoneal shunting and external ventricular draining for the emergency control of severe hydrocephalus caused by posterior fossa tumors, since it can quickly eliminate symptoms, and hence, can delay surgery scheduling if required. Even though ETV does not prevent postoperative hydrocephalus in all cases, it does protect against acute postoperative hydrocephalus due to cerebellar swelling. In addition, it eliminates the risks of cerebrospinal fluid (CSF) infection related to external drainage and minimizes the risk of overdrainage because it provides more physiological CSF drainage than the other procedures. Since postoperative hydrocephalus is very often physically obstructive, ETV should always be considered a possible treatment procedure.

The correct interpretation of the modern neuroradiologic techniques may help in selecting adequate treatment between the two main options (third ventriculostomy or shunting). In the last decades, endoscopic third ventriculostomy has become the first-line treatment of aqueductal stenosis; however, some issues, such as the cause of failures in well selected patients, long-term outcome in infant treated with ETV, and effect of persistent ventriculomegaly on neuropsychological developmental, remain unanswered.

Endoscopic placement of a stent in the aqueduct is more effective in preventing the repeated occlusion of the aqueduct than aqueductoplasty alone and should be indicated as the initial treatment in each case of compatible anatomy.