Overview
This lecture reviews key endoscopic procedures for treating obstructive hydrocephalus and intraventricular pathology, focusing on operative steps, anatomical landmarks, and surgical considerations.
Endoscopic Third Ventriculostomy (ETV)
- ETV is a common procedure for obstructive hydrocephalus caused by cerebral aqueduct obstruction.
- The goal is to create a new drainage pathway by making a hole in the floor of the third ventricle.
- Important anatomical landmarks include the basilar artery, clivis, mammillary bodies, and the dorsum sellae.
- Avoid damaging the mammillary bodies, midbrain, or perforating vessels during the procedure.
- The hole is enlarged using balloon dilation, providing effective CSF flow restoration.
- ETV is a quick operation (~10 minutes with experience).
Endoscopic Fenestration of Intraventricular Cysts
- Used for arachnoid cysts obstructing CSF pathways within the third ventricle.
- The cyst wall is cauterized and opened to equalize pressures and restore flow.
- The goal is to prevent obstruction at the foramen of Monro.
Endoscopic Biopsy of Intraventricular Tumors
- Especially relevant for pineal region and anterior third ventricle tumors.
- Small specimens can be obtained for diagnosis, aiding in treatment planning.
- Superficial bleeding can occur but is usually managed with irrigation.
Surgical Pearls and Precautions
- Always keep visual focus on the endoscope screen to avoid unintended injury.
- Beware of injuries caused by the proximal (non-tip) portion of the scope.
- Proper trajectory planning increases safety and visibility during neuroendoscopic procedures.
- Longer CSF pathways allow for better maneuverability of instruments.
Key Terms & Definitions
- Obstructive hydrocephalus — Enlargement of ventricles due to CSF flow blockage.
- Endoscopic third ventriculostomy (ETV) — Surgical creation of a hole in the third ventricle floor to bypass obstruction.
- Arachnoid cyst — Fluid-filled sac within the ventricles that can obstruct CSF flow.
- Foramen of Monro — Channel connecting lateral ventricles to the third ventricle.
- Balloon dilation — Use of a balloon to enlarge a surgically created opening.
- Trajectory — The planned path of surgical instruments during endoscopy.
Action Items / Next Steps
- Review ventricular system anatomy in detail for better understanding of surgical landmarks.
- Prepare for breakout sessions on pineal tumors.
- Study surgical room setup and neuroendoscopic equipment handling.