- Surgeon preference: The patient is positioned (supine, prone, lateral, etc.) in accordance with surgeon preference. The authors prefer to place shunts using the supine position with the head turned to the contralateral side. When fenestrations are performed, the authors prefer to place the patient in the lateral or prone position.
- +/- Head holder
- Routine scalp incision
Most cases are treated with shunting.
- Shunt lateral ventricle if aqueduct open: If the cerebral aqueduct is patent, a lateral ventricle shunt usually provides the best result.
- Controversy if aqueduct closed: CSF flow across the aqueduct may be obstructed in 40–75% of patients. In these cases, a lateral ventricle shunt alone can result in a pressure gradient between the supratentorial and infratentorial compartments, with concomitant upward transtentorial herniation. In such cases, a cyst shunt should be placed. An additional lateral ventricle shunt may be indicated if the hydrocephalus persists. If two shunts are placed, controversy exists as to whether they should be joined together by a y-connector or should be separate systems. Neither system has been shown to be universally advantageous.
- Overdrainage by shunt: Programmable valves may be useful to help prevent overdrainage.
Endoscopic third ventriculostomy
- Occasionally fenestration more effective: Craniotomy for cyst fenestration into the infra- or supratentorial ventricular or subarachnoid space may be an effective treatment in some cases (6).
- Various sites for fenestration: The site of fenestration depends on the patient’s particular anatomy. Cysts can be fenestrated into the cerebellopontine angle, fourth ventricle, lateral ventricle, or basal cisterns. Fenestration is performed via craniotomy, with microscopic visualization.
- Fenestration large: In cases of cyst fenestration, the cyst is widely opened. No stent is uniformly useful, but surgical cellulose may maintain patency. The cyst wall should not be stripped, as it may cause unnecessary bleeding and injury to the brain.
- Frameless stereotaxy: Frameless stereotaxy and ultrasound may be useful surgical adjuvants.