Ventricular puncture refers to the removal of cerebrospinal fluid directly from the intracranial ventricular system by way of an open fontanel or suture. The procedure is appropriate for young patients with signs of impending brain herniation from acute untreated hydrocephalus. Once excess fluid is removed, definitive treatment with a ventriculoperitoneal (VP) shunt follows. A ventricular puncture requires a thorough knowledge of anatomy and an understanding of the risks and benefits of the procedure. Ideally, a neurosurgeon should perform a ventricular puncture. When a neurosurgeon is unavailable, only the most experienced physician should attempt this procedure. The need for a ventricular puncture implies that the patient is unstable from untreated intracranial hypertension. For this reason, the physician should perform the procedure in an area where acute decompensation can be quickly managed, such as an emergency department (ED), intensive care unit, or operating room.

The anterior horn of the lateral ventricle lies directly beneath the lateral border of the anterior fontanel, an area of nonossified tissue in the skull that allows for brain growth (Fig. 44.1). The anterior fontanelle remains “open” until it is gradually replaced by bony skull at around 12 to 18 months of age. This area corresponds to the coronal suture in an older child, which is approximately 2 cm from the midline. In a patient with hydrocephalus, dilation of the ventricles creates a large potential site for puncture. Most importantly, the physician must not puncture too close to the sagittal midline, where the venous sagittal sinus is located (Fig. 44.1).

Hydrocephalus occurs under two conditions: obstructive hydrocephalus, in which a physical blockage of the ventricular system is present, and communicating hydrocephalus, in which the capacity to absorb cerebrospinal fluid is exceeded by the production of cerebrospinal fluid. Common causes of chronic obstructive hydrocephalus include congenital aqueductal stenosis, posterior fossa tumors, and other congenital anomalies (e.g., Dandy-Walker malformation). Meningitis is the most common cause of communicating hydrocephalus. Acute decompensation with cerebral herniation is more likely to occur in a patient with acute obstructive hydrocephalus, which may complicate head trauma, intracranial hemorrhage, or space-occupying lesions (e.g., abscess, tumor) that impinge on the ventricular system (1).

The primary indication for ventricular puncture is cerebral herniation due to hydrocephalus that is unresponsive to hyperventilation and diuretics in a patient with an open fontanel or coronal suture. Physical findings suggestive of this condition include unilateral or bilateral pupillary dilation, ocular cranial nerve abnormalities, focal neurologic findings, and decorticate or decerebrate posturing (see also Chapters 42 and 43). Before performing ventricular puncture, the physician must consider other potential causes of these findings for which this procedure would not be indicated, such as brain tumor without hydrocephalus, head trauma with cerebral edema, subdural hematoma, and epidural hematoma. Consultation and concurrent management with a neurosurgeon, as well an imaging study such as computed tomography (CT) or magnetic resonance imaging (MRI) of the head or cerebral ultrasound, should precede the procedure whenever possible. Ventricular puncture is not indicated for the patient with hydrocephalus who is asymptomatic. Furthermore, a patient with a closed fontanel and sutures requires a surgical approach to the ventricular system.