Operative Planning

• Review imaging to confirm size of the ventricles and relation of lesion to ventricle
  
• Magnetic resonance images to illustrate the proper trajectory
  
• Consider stereotaxy for normal size ventricles or assistance in trajectory

Equipment

• Mayfield head holder
  
• Rigid endoscope
  
• Video monitor
  
• Endoscopic instruments
  
• Frameless stereotaxy if indicated
  
• High-speed drill
  
• Mastoid retractor

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 all endoscopic equipment, including monitor, are functioning properly prior to induction of anesthesia

Anesthetic Issues

• Preoperative antibiotics 30 minutes prior to incision

Positioning

• Patient is placed in supine or lateral position (depending on the indication) and with head fixed in Mayfield head holder if stereotaxy is to be used
  
• Head of the bed is elevated
  
• Plan most appropriate approach; it is easier to work in a dilated ventricle rather than the small ventricle
  
• Wires for bipolar cautery, endoscope, and monitors run from the foot to the head of the bed

Planning of Incision

• Minimal shave is performed and a 1-inch cranial incision is planned

Endoscopic Equipment Set-up

• During the prep, the assistant ensures that the following occur:
  
  
  
  • Image from the endoscope is oriented properly. It is easiest to use written text such as the labeling on the outside of a sterile suture box or marking pen.
    
  • Flow rate on endoscope is set to 10 to 20 mL/min; prefer warm lactated ringer’s solution.
    
  • Sheath on introducer is “cracked” or undone slightly to facilitate opening of the sheath once it is placed into the brain. A mark at 5 cm is placed to avoid deeper penetration.
    
  • If using the endoscope holder, this is functioning properly and secured to the table.
    
  • Fogarty balloon inflates and deflates properly.
    
  • Ensure that all instruments are functional and slide down endoscope channels.

Introduction of Endoscope

• The dura is opened and the dural leaflets are coagulated with bipolar cautery.
  
• The blunt introducer with sheath is passed through the brain, not more than 5 cm, or until cerebrospinal fluid (CSF) is encountered.
  
• The endoscope is introduced and the choroid plexus and the foramen of Monro are identified. It is important to insert the endoscope into the introducer expeditiously to prevent the rapid egress of CSF that may result in postoperative subdural hematomas.

Intraventricular Anatomy

Techniques

• If the image is blurred look for technical problems: check the video camera attachment. Other causes include turbid CSF, or brain tissue sticking on the lens.
  
• Bleeding: this is minor and typically stops with irrigation; includes bleeding from injury to the veins or choroid plexus; consider leaving an external ventricular drain in this situation.
  
• Loss of orientation: if uncertain where the endoscope is in the ventricular system, reorient with known landmarks or use stereotaxy.

Management

• The routine use of an intraventricular catheter is not necessary. If significant bleeding occurs, or if the surgeon wishes to perform intracranial pressure monitoring in the postoperative period, an intraventricular catheter can be placed. Aggressive ventricular drainage, however, is discouraged as this may promote failure of the ventriculostomy.
  
• A noncontrast head CT is performed on the first postoperative day to assess for bleeding and pneumocephalus.