Telemetric intraventricular pressure measurements after third ventriculocisternostomy in a patient with noncommunicating hydrocephalus

To examine and document intraventricular pressure (IVP) dynamics in an adult after endoscopic third ventriculocisternostomy performed as treatment for hydrocephalus associated with aqueductal stenosis.

A 30-year-old man who had undergone ventriculoperitoneal shunting at age 21 years for aqueductal stenosis caused by a tectal mass presented with symptoms and imaging studies consistent with shunt malfunction. He underwent urgent ventriculoscopic third ventricular ventriculocisternostomy, which resolved his symptomatology. The existing shunt was not revised. At the time of surgery, a catheter connected to an intracranial pressure TeleSensor device (Radionics, Burlington, MA) was inserted into the ventricular system. Postoperatively, the patient's recovery was assessed by IVP recordings. This system allowed us to record IVP in an awake patient with a functioning third ventriculocisternostomy.

We observed an initial postoperative IVP of 17 cm H2O in the supine position, which decreased to 0 cm H2O at 90 degrees of head elevation. The IVP decreased during the first 48 hours postoperatively to 0 to 2 cm H2O when supine. By 1 week postoperatively, the patient's IVP had returned to a baseline of 15 to 17 cm H2O when supine, with a gradual decrease to 0 cm H2O at 30 degrees of head elevation. Three months postoperatively, the patient's IVP in the supine position was 8 cm H2O, with IVP decreasing to 0 cm H2O at 45 degrees of head elevation. Magnetic resonance (MR) imaging performed at that time revealed evidence of flow through the third ventriculocisternostomy.

We conclude that after an initial period of adjustment, the IVP in this patient returned to an unremarkable baseline despite the novel fluid pathway into the prepontine cistern. This may represent maturation of the breach through the third ventricular floor or brain recovery from a period of high pressure. Also, the shape of the postural IVP curve closely resembled that observed in patients who are not hydrocephalic. These data represent the first documentation of the intraventricular pressure response to ventriculocisternostomy and suggest possible intracerebral responses to this alteration in cerebrospinal fluid flow.