Stereotactic Endoscopic Third Ventriculostomy

Operative Planning

Review imaging to confirm obstructive hydrocephalus and third ventricular dilatation
Using sagittal magnetic resonance (MR) images, determine site of burr hole relative to coronal suture for optimal trajectory through foramen of Monro to site of ventriculostomy
Using axial MR images, determine the location of the dorsum sellae and its relationship to the basilar artery

Equipment

Operating Room Set-up

Bipolar cautery
Video monitors placed at foot of bed
Ventriculostomy and ventriculoperitoneal shunt equipment should be in room and available for use
Ensure that endoscopic equipment including monitor is functioning properly prior to induction of anesthesia

Anesthetic Issues

Positioning

Patient is placed supine with head fixed in Mayfield head holder if frameless stereotaxy is to be used. If ventricles are significantly dilated, one may opt to proceed without stereotaxy, in which case the head can be placed in a foam donut or horseshoe head holder.
Neck is kept in midline and flexed slightly. Head of the bed is elevated.
Unless contraindicated, plan for an approach from the right side. The patient is positioned such that the anesthesiologist is on the patient’s left and the scrub technician is on the right.
Monitors for stereotaxy and endoscopy are placed at the foot of the bed with the surgeon and assistant at the head of the bed.
Wires for bipolar cautery, endoscope, and monitors run from the foot of the bed to the head.

Stereotaxy is utilized to determine site of incision for optimal trajectory.
If stereotaxy is not used, the parasagittal incision is placed on, or just anterior to, the coronal suture, ~3.5 cm lateral to the midline.
Minimal shave is performed and a 1-inch cranial incision is planned.
A wide prep is performed as if for a ventriculoperitoneal shunt, only if uncertain about the ability to perform the endoscopic procedure.

Incision and Burr Hole

A small 1-inch incision is made down to the periosteal layer, and a mastoid retractor is used to retract the skin. Hemostasis is achieved with bipolar cautery.
The periosteal layer is dissected from the underlying bone, and the coronal suture is identified.
Frameless stereotaxy is used to confirm the site of burr hole placement and trajectory.
A power drill with pediatric-sized perforator bit is used to create burr hole.
Bone wax is applied for hemostasis.
Dura is coagulated with bipolar cautery.

Set-up of Endoscopic Equipment