1. Posterior Fossa Meningiomas
Dr Hrushikesh Kharosekar
Dr V Velho
Grant Medical College and Sir J J Group of Hospitals, Mumbai

3. Introduction
10% of all intracranial meningioma arise in Posterior fossa .
Generally slow growing and can become large before causing symptoms
Most of these tumors are histologically benign and potentially curable.
Microsurgical resection is treatment of choice for the majority of these lesions.
Their site ,location, and proximity to important structures makes excision challenging.

4. Posterior fossa meningioma ( Sekhar et.al.)
Type1 Cerebellar convexity – lateral tentorial
Type2 Cerebellopontine angle- upto petrous ridge
Type 3 Jugular foramen
Type4 Petroclival
Type5 Foramen magnum
Type 6 Unclassified

5. Aims & Objectives
To highlight the technical difficulties encountered during excision of these tumors and discuss their modes of management

6. Material and methods Total no. of cases – 124 cases (April 2004-2014)
Study design – retrospective
C P angle , petroclival , Cerebellar convexity ,tentorial , Jugular foramen , foramen magnum meningioma were included
Investigations – Contrast enhanced CT scan , MRI scan with MRA and MRV
All patients underwent surgical excision
Complications and outcomes were analysed

7. Observation and Results
Sex
No. of cases
(n=124) %
Male 31
25%
Female 93
75%
Age group(Yrs.)
No. of cases
(n=124) %
10- 30 31
25%
30-50 65
53.1%
50-70 28
21.8%

8. Observation and results
Tumor location
No. of cases
( n=124) %
C P angle meningioma 44
35.4
Petroclival 15
12.5
lateral Tentorial
Cerebellar convexity 29
23.3
Jugular foramen 03
2.4
foramen magnum 10 8
Unclassified (entire clivus , other types ) 08
6.4

9. Presentation Tumor location Clinical presentation C P angle meningioma
5,7,8 cranial neruopathies , brain stem and cererbellar compression syndrome
Petroclival
3-12 cranial neuropathies , brain stem and cererbellar compression syndrome
Lateral Tentorial
3,5,6,7,8 cranial neruopathies , headache ,brain stem and cererbellar compression syndrome
Cerebellar convexity
Headache , Cerebellar syndrome , increase ICP
Jugular foramen
9-11 cranial neuropathies , brain stem compression syndrome
Foramen magnum
Increase ICP cranial neuropathies , brain stem and spinal cord compression syndrome
Unclassified (entire clivus ,
other types )

10. Surgical Approach Tumor location Surgical Approach
C P angle meningioma
Retromastoid craniectomy/craniotomy
Petroclival
Transpetrous approach
Lateral Tentorial
Cerebellar convexity
Suboccipital Craniectomy /craniotomy
Jugular foramen
Foramen magnum
Suboccipital craniectomy/craniotomy+ C1 laminectomy
Far lateral approach
Unclassified (entire clivus ,
other types )
Extended far lateral approach

11. CSF Diversion CSF Diversion procedure : required in 44 cases
No. of cases
Ventriculo-peritoneal shunt 36
External Ventricular drainage 8

12. Extent of resection Tumor location GTR STR PR 42 1 10 4 12 3 - 29 2 8
C P angle meningioma (n=44) 42 1
Petroclival (n=15) 10 4
Lateral Tentorial (n=15) 12 3 -
Cerebellar convexity (n=29) 29
Jugular foramen (n=3) 2
Foramen magnum (n=10) 8
Unclassified (entire clivus , other types ) (n=8) 5
Total (n=124)
108 13

13. Observation and results Extent of excision
Gross total
Subtotal/Partial

14. Complications Cranial nerve dysfunction Long tract deficit CSF leakage
Tumor location
Cranial nerve dysfunction
Long tract deficit
CSF leakage
Stupor and coma
Sinus thrombosis
C P angle meningioma 5 1 4 -
Petroclival 6
Lateral Tentorial 3
Cerebellar convexity
Jugular foramen 2
Foramen magnum
Unclassified (entire clivus , other types )

15. Recurrence ( on follow up of average 2-5yrs )
Tumor location
Recurrnece
C P angle meningioma 1
Petroclival 2
Lateral Tentorial
Cerebellar convexity -
Jugular foramen
Foramen magnum
Unclassified (entire clivus , other types )
Total No of recurrences= 7 (i.e 5.6%)

16. Lateral Petrous meningioma
Pre-op
Post-op

17. CP angle meningioma
Pre-op
Post-op

18. Tentorial meningioma
Pre-op
Pre-op
Post-op

19. Tentorial Meningioma
Pre-op
Pre-op
Post-op

20. Ventral foramen magnum meningioma
Pre-op
Post-op

21. Dorsal Foramen magnum meningioma
Pre-op
Post-op

22. Pre operative CT and MRI with contrast Images
INCISURAL MENINGIOMA
Pre operative CT and MRI with contrast Images
NSICON’2013
Post operative CT and MRI Images

23. Operative technique
Position : Lateral Semisitting for retromastoid craniectomy Incision : S-shaped retromastoid

25. Retromastoid Suboccipital Craniotomy
Surgical Approaches
Retromastoid Suboccipital Craniotomy
preferred approach for
CP angle Meningioma
Petroclival meningioma
Lateral tentorial Meningioma

26. Disussion Other approches are –
Petrous Craniotomy variants – Petroclival tumors
Transjugular Variants – Jugular foramen meningioma
Suboccipital craniotomy + C1 laminectomy – formen magnum meningioma
Far lateral approach- ventral foramen magnum meningioma

27. Technical difficulties
Sinus infiltration – Radiotherapy /follow up
Large and vascular tumor – approach to the attachment site first ( possibly),Embolization
Trajectory through cranial nerves and vessels-internal debulking followed by capsular dissection
Adhesion and engulfment to cranial nerves- Intraoperative facial nerve monitor
Adhesion to brain stem - intraoperative neurophysiological monitoring , avoid traction and coagulation
Loss of tumor –brain interface

28. Conclusion
Posterior fossa meningioma are difficult to excise due to close relation to cranial nerves and vessels
The use of microscope , CUSA , intraopeartive nerve monitor help in removal and preserving surrounding important anatomical structures
Although neurological deterioration is common postoperatively, recovery does occur completely after total removal thus increasing the recurrence free period & improving the outcome.

29. Thank you…..