Trigeminal Schwannoma Flashcards
(24 cards)
CN stretched and caudally displaced
Trigeminal Schwannoma
VII-VIII COmplex
ICA
Abducens
Oculomotor
Displaced by TS?
Medially
CN IV displaced
TS
Cranially
Goal of surgery TS?
Preserve non-involved facicles
TS that arise from Gasserian Ganglion > grow in interdural space in Meckel cave
Localized at middle cranial fossa
TYPE A
Approach that provides direct access to tumor and minimize brain retraction
Inter-dural skull base approach
Approach
Involves frontotemporal craniotomy, unroofing of the orbit, drilling of the anterior clinoid and anterior wall of the middle fossa then exposure of SOF
Dolenc approach
TS originate from cisternal portion of CN V
Located within CP angle cistern
Type B TS
Artery preserved, impinged by Type B TS?
Superior cerebellar artery
TS with middle and posterior fossa involvement?
Type C
TS Extend into the orbit, pterygopalatine fossa, maxilla, and infratemporal fossa?
Type D Tumors
Approach to Type D TS?
Extradural, periauricular, infratemporal
Radiosurgery goal in TS?
“Tumor growth control”
Volumetric regression in radiosurgery
50%
Mean margin dose TS
13.1-18.5 Gy
Morbidity Rates?
- 7-8.7% facial hypoesthesia
- 9% - 8.7 facial pain
- 9% trigeminal and motor weakness
Response of schwannomas to stereotactic surgery?
Central loss of contast enhancement
Slight tumor expansion
Used for large, recurrent, inoperable TSs?
FEBRT
Resection rate
Jefferson A?
88%
Resection rate
Jefferson B?
71%
Resection rate
Jefferson C?
81%
Recurrence rate TS?
60%
TS WHO grade?
I
Where Schwannomas arise?
Distal to oligodendroglia-Schwann cell juncion
