Surgical approach to Falcine MeningiomaEric C.Chang, Frederick G.Barker II, William T.Curry

Schmidek Chapter 33

Outline

• Intro

• Symptom and Presentation

• Radiographic findings

• Operative technique

• Postoperative care

• Summary

Intro

• 5-9 % of all intracranial meningioma

• Falcine meningioma often conceal by cerebral cortex

• Large falcine meningioma can grow superiorly to secondarily invade SSS

• Classified based on their relationship to SSS

Symptom and Presentation

• Anterior third of SSS• Frontal lobe syndrome

• Slow progressive symptom : short attention span, poor short-term memory, personality change, apathy and emotional instability

• Sign of increase ICP : headache, papilledema, or optic atrophy

• Ddx : age-related dementia

• Frequently larger in size at the time of presentation than tumors in other regions

Symptom and Presentation

• Middle third of SSS• Spastic weakness and focal seizures that involve the contralateral foot and leg

• Patients to seek earlier medical intervention

• Posterior third of SSS• Persistent headache and hemianopsia

• Visual hallucination

• Calcarine fissure : anopia to the inferior quadrant

• Tentorium cerebelli : anopia in the upper quadrants

• Large tumors : homonymous hemianopsia with macular sparing

Radiographic findings

• MRI : gold standard• Extend bilaterally, acquiring a dumbbell or bi-lobed shape

• T1 : iso-hypo intensity

• T2 : hypo- to iso-intense firm

malignant meningiomas greater edema

• T1 c Gd : defining the tumor’s anatomic location, size, and cortical involvement

• T2 and FLAIR : pial inversion of brain tumor

Radiographic findings

• Cerebral angiography• Gold standard : digital subtraction angiography (DSA)

• tumor’s arterial feeding

• course, displacement, encasement

• patency of the superior sagittal sinus• draining cortical veins

Radiographic findings

• MR angiography/venography• limitation : flow-related artifacts, sensitivity to patient movement

• CT-angiography/venography (CTA/CTV)

Operative technique

• Anesthesia and preparation• Reduced ICP : furosemide, mannitol,hyperventilation• Preoperative plan involves resection or manipulation of the sagittal sinus :

precordial Doppler, intra-atrial venous catheter• Somatosensory evoked potentials or direct cortical stimulation

• Positioning• Anterior third of SS : supine position with the head slightly elevated• Middle third of SS : supine with the head elevated and flexed, semiprone or

lateral approach• Posterior third of SS : lateral position

Operative technique

• Neuro-navigation• helpful in planning out the skin incision and the borders of the craniotomy

• Skin incision• Anterior third of SS : bi-coronal incision

• Middle third of SS : horseshoe/U-shaped incision that has its base laterally

• Posterior third of SS : horseshoe/U-shaped incision that has its base toward the occiput

Operative technique

• Craniotomy• Encompass tumor margin 1-2 cm

• Tumors that extend across the midline : single piece or in two section

• Tumors that extend to the surface : avoid injury to underlying cortex and veins

• Dural opening• U-shaped dura incision

• Elevating the dural flap medially to avoid tearing potentially important bridging veins

• For bilateral tumors : the dura on the contralateral side is also incised

Operative technique

• Tumor resection• Veins along the anterior third of the sinus can usually be ligated without

neurologic consequences

• Establish the anterior and posterior limits of the tumors

• The cortex should not be retracted more than 2 cm away from the falx and the sinus

• The blood supply to the tumor from the falcine arteries is sectioned by cauterizing

• The falx in the inferior-to-superior direction approximately 1 cm anterior and 1 cm posterior to the margins of the tumor

Operative technique

• Tumor resection• Intracapsular enucleation is used to debulk the tumor

• The capsule is peeled away from the cortex

• In cases where there is pial invasion in areas involving eloquent brain, it is advisable to leave a thin rim of tumor attached to the cortex rather than risk debilitating neurologic compromise

• Mindful of the branches of the ACA, including the pericallosal and callosomarginal arteries

Operative technique

• Management of sinus invasion• Can grow and extend to involve the superior sagittal sinus

• Leaving a fragment of invasive tumor : higher rate of recurrence

• Attempting to achieve a Simpson I : the venous circulation at greater risk

• Based on their age, symptoms, tumor location, degree of sinus involvement, and the robustness of the cortical venous collaterals

Operative technique

• Three main surgical strategies• 1.Simple resection of the outer dural layer with the tumor and coagulation of

the inner layer at the sites of tumor attachment

• 2.For disease involving the superior sagittal sinus involves resecting the invaded sinus wall(s) and repairing the sinus

• 3. Simple coagulation of residual tumor or resection of the involved sinus without venous reconstruction

Operative technique

• Sindou and Alvernia, six-stage classification scheme for progressively tumor invasion into the sinuses• Type I lesions involve just the outer surface of the sinus wall

• Type II lesions have the tumor extending into the lateral recess of the superior sagittal sinus

• Type III tumors infiltrate into the lateral sinus wall

• Type IV lesions tumor invaded into the roof of the sinus

• Types V and VI tumors completely occlude the sinus, with and without wall invasion

Operative technique

• Closure• Closed primary

• Dura plasty• Bone flap or bone reconstruction

Postoperative care

• kept well hydrated to prevent delayed venous thrombosis

• Continue steroid to 72 hr then tape

• Anti-epileptic drug• No history of seizure : continue 12 wk

• History of seizure : EEG no sign of seizure

• CT/MRI

• CTA

• Venous graft : anticoagulant