Management of Hydrocephalus in Patients with Craniosynostosis

Hydrocephalus and craniostenosis are the two main conditions faced by pediatric neurosurgeons. In a small part of the cases, the two entities are associated with the same patient. This imposes specific difficulties and entails the need to know the peculiar aspects of the interaction between these two diseases. Most cases of hydrocephalus in the context of craniostenosis involve syndromic cases, with about 12% of patients with syndromic craniostenosis having progressive dilatation of the ventricles. In cases of nonsyndromic craniostenosis involving one or more sutures, the occurrence of hydrocephalus is anecdotal, affecting less than 0.5% of patients. Pathophysiology: The pathophysiological mechanism underlying hydrocephalus in cases of craniostenosis has not yet been fully elucidated. In cases of nonsyndromic craniostenosis, the association appears to be fortuitous. In syndromic cases, hydrocephalus is attributed to mechanical difficulties in cerebrospinal fluid drainage linked to herniation of the cerebellar tonsils through the foramen magnum, compression of the Sylvius aqueduct due to a narrow posterior fossa or problems with venous hypertension. In addition, subdural fluid collections may be present and raise doubts in some cases, especially scaphocephaly. In the opposite direction, secondary craniostenosis can arise in cases of hydrocephalus treated with a ventriculoperitoneal shunt. In some cases, this condition can cause cranial deformity and restriction of brain expansion, and the therapeutic decision is difficult. Assessment: As in other cases of hydrocephalus, the main objective should be to identify the occurrence of intracranial hypertension. This can be done based on the typical clinical picture and also on the disproportionate growth of the head circumference. Imaging exams are essential at this stage, and magnetic resonance imaging (MRI) can show, in addition to ventricular dilation, typical signs such as transependymal transudation. Although there have already been initiatives to directly measure intracranial pressure, this approach can be costly and invasive. In this context, noninvasive means of measuring intracranial pressure may be useful. Treatment: The management of cases of hydrocephalus associated with craniostenosis is performed, in most cases, by means of ventriculoperitoneal shunt. However, it is necessary to evaluate the particularities of performing the procedure in a scenario in which other surgeries will be necessary for the treatment of craniostenosis. In cases selected according to a favorable neuroimaging evaluation, it is possible to try the use of endoscopic third ventriculostomy, although the failure rate is considerable.