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Neurosurgery
Surgical Approaches to Tumors of the Third Ventricle
Built from Feldman — Neurosurgical Operative Atlas: Neuro-Oncology
What’s inside
8 sections · 73 slides
The Problem
Operating at the geometric center of the brain
- Why the third ventricle is hard to reach
- Two kinds of tumor: primary vs secondary
- The room has six walls — use the safe ones
- Four directions you can come from
- Every operation has two stages
- Two-stage framework: approach, then entry
Surgical Anatomy
The landmarks that keep you out of trouble
- Looking down from the lateral ventricle
- Follow the choroid plexus like a trail of breadcrumbs
- The roof is built in four layers
- The internal cerebral veins — handle with care
- The anterior wall, from top to bottom
- The lamina terminalis — a safe window in the front wall
- The vessels guarding the lamina terminalis
- Seeing the floor from below (endonasal view)
- Classifying suprasellar tumors by the stalk
Choosing the Approach
Let the tumor tell you how to reach it
- Three questions decide the route
- The golden rule: keep the far end loose
- Roof and upper tumors — come from above
- Two ways into the lateral ventricle
- Aiming the craniotomy: anterior or posterior
- Entry: transforaminal vs transchoroidal
- Interforniceal route — usually a trap
- Tumor removed via transcallosal-transchoroidal route
- Front-floor tumors — come through the lamina terminalis
- Craniopharyngioma via subfrontal translaminar route
- When you do NOT need to enter the ventricle
- Tumor that displaces rather than fills the ventricle
- Subfrontal access: one side or both?
- Selecting the endonasal (EEA) route
Before the Operation
Preparing the patient and the physiology
- Managing hydrocephalus and CSF diversion
- Endocrine and eye work-up
- Anesthesia and set-up on the day
Transforaminal & Transchoroidal
The superior route, step by step
- Positioning and skin incision
- Craniotomy and opening the dura
- Working down the interhemispheric fissure
- Through the callosum into the ventricle
- Orient yourself before you enter
- Transforaminal route — try the natural door first
- Transchoroidal corridor — opening the fissure
- Why medial, not lateral, keeps you safe
- A safe trick at the foramen
- Removing the tumor: hollow it out first
- Vessels inside vs on the capsule
- Closing the superior approach
Translamina Terminalis
The anterior route through the front wall
- Positioning and the subfrontal approach
- Craniotomy and orbital rim removal
- Draining cisterns down to the lamina
- Finding the lamina
- Opening the lamina terminalis
- Prefixed vs postfixed chiasm decides your room
- Removing the tumor through a small door
- Closing the anterior approach
Endoscopic Endonasal
Reaching the floor from below, through the nose
- Positioning and access to the sphenoid sinus
- Septectomy and sphenoidotomy
- Opening the sella and suprasellar space
- Removing the tumor from below
- Craniopharyngioma removed by endoscopic endonasal route
- Watertight reconstruction — the make-or-break step
After the Operation
Monitoring, drainage, and complications
- Immediate postoperative care
- Drains and the decision to shunt
- Complications from the corridor itself
- Diabetes insipidus and the triple-phase response
- Take-home messages
- Neurosurgical Operative Atlas: Neuro-Oncology