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

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.

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

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

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

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%

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

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 9-12 cranial neuropathies , brain stem and spinal cord compression syndrome Unclassified (entire clivus , other types )

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

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

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

Observation and results Extent of excision Gross total Subtotal/Partial

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 )

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%)

Lateral Petrous meningioma Pre-op Post-op

CP angle meningioma Pre-op Post-op

Tentorial meningioma Pre-op Pre-op Post-op

Tentorial Meningioma Pre-op Pre-op Post-op

Ventral foramen magnum meningioma Pre-op Post-op

Dorsal Foramen magnum meningioma Pre-op Post-op

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

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

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

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

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

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.

Thank you…..