Parasagittal Meningioma

Parasagittal Meningioma: Presentation, Diagnosis and Surgical Treatment

1. PARASAGITTAL MENINGIOMA Dr. FARRUKH JAVEED

2. MENINGIOMAS First describes by Harvey Cushing in 1922. Tumors that are believed to arise from the ARACHNOID CAP CELLS around the arachnoid granulation. 2

3. Radiological features of Meningioma extra-axial masses broad dural base h omogeneous well defined margins buckling dural tail hyperostosis 20-30 % have some calcification 3

4. TYPES OF MENINGIOMA 4

5. PARASAGITTAL MENINGIOMA Cushing and Eisenhardt defined a parasagittal meningioma as one that fills the parasagittal angle, with no brain tissue between the tumor and the superior sagittal sinus. 6

6. PATHOGENESIS Parasagittal meningiomas tend to occur where arachnoid granulations are denser, with about 15 % of tumors presenting with invasion of the SSS . H igher incidence of atypical and malignant meningiomas has been reported in the parasagittal region when compared with meningiomas in other locations, about 3.7% and 14.8%, respectively .

7. WHO GRADING

8. HITOPATHOLOGICAL TYPES 9

9. SUPERIOR SAGITTAL SINUS 10

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11. most parasagittal veins (70%) join the SSS in a segment of the sinus located between the coronal suture and 2 cm behind it. The anterior half of the SSS is narrower and has fewer associated venous lacunae and smaller numbers of adjoining cortical veins entering the sinus than the posterior half, which facilitates surgical exploration. 12

12. I n anterior third tumors 52.1% of cases had collateral blood flow through cortical veins, in middle or posterior third tumors, collateral drainage occurred through cortical veins in 67% of cases. Collateral blood flow through the extracerebral veins occurred in 56 % of patients regardless of the location along the sinus. 13

13. CLASSIFICATION (according to location) Anterior third (between the crista galli and the coronal suture ): ranged from 14.8 to 33.9 % Middle third (from the coronal to the lambdoid suture): ranged from 44.8 to 70.4 % Posterior third (from the lambdoid suture to the torcula ): ranged from 9.2 to 29.6%

14. CLASSIFICATION (according to SSS involvement) Bonnal and Brotchi first provided a surgical classification of parasagittal meningiomas in 1978 that included eight tumor subtypes. But later this classification was modified and it describes five tumor subtypes developed to facilitate resection strategies. Then S indou and associates presented another classification dividing these tumors into 6 types. 15

15. BROTCHI CLASSIFICATION (modified) 16

16. SINDOU & ALVERNIA CLASSIFICATION 17

17. CLINICAL PRESENTATION Presenting symptomatology is largely related to the proximity of the lesion to the Rolandic fissure . T hese patients typically present with sensory or motor seizures involving the contralateral lower extremity . After seizures, contralateral hemiparesis constitutes the second most common presenting symptom. Other features can be paresthesias , papilledema, and dementia.

18. Tumors arising from either the anterior or posterior third, however, can remain undetected for long periods of time until mass effect triggers noticeable symptoms. Lesions in the anterior third occasionally present with a long-standing history of headaches or a frontal lobe syndrome , whereas posterior third–based lesions may present with homonymous hemianopsia . 19

19. PRESENTING FEATURES 20

20. WORKUP 21

21. X RAY X Ray no longer have a role in the diagnosis or management of meningiomas. Historically a number of features were observed, including: enlarged meningeal A. grooves hyperostosis or lytic regions calcification

22. COMPUTERIZED TOMOGRAPHY CT is often the first modality employed to investigate neurological signs or symptoms, and often is the modality which detects an incidental lesion.  60% slightly hyper-dense to normal brain 20-30% have some calcification  8 72% brightly and homogenously contrast enhance 8 , less frequent in malignant or cystic variants Hyperostosis

23. COMPUTED TOMOGRAPHY ( CT) It is particularly beneficial in cases in which either hyperostotic or lytic calvarial changes are expected because it can aid in planning of the craniotomy flap . Also helpful in planning the prosthetic implants for cranioplasty. 24

24. MRI Brain with Contrast The imaging study of choice for evaluation of parasagittal meningiomas . specific information on the size and consistency of the lesion and on its relationship with the falx , the meninges, the surrounding cerebral cortex, and the vascular structures involved. 25

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27. MRA/MRV Magnetic resonance angiography (MRA) in combination with contrast-enhanced MRI is now considered the gold standard in most centers. MRA provides accurate, noninvasive visualization of the arterial and venous anatomy, which facilitates analysis of sinus patency and invasion, and visualization of collateral venous drainage patterns that develop following sinus occlusion . Magnetic resonance venography (MRV) can provide preoperative insight on venous infiltration and visualize collateral venous anastomoses. 28

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29. DIGITAL SUBTRACTION ANGIOGRAPHY Before surgery, visualization of venous anatomy is fundamental in operative planning. Details on patency of the sinus, arterial tributaries to the tumor and its relationship with cortical structures, and location of cortical draining veins and their point and angle of entry into the SSS are carefully considered. 30

30. For large meningiomas (> 5 cm), determination of arterial feeding branches to the tumor, which may arise from the anterior or middle cerebral arteries, can facilitate preemptive intraoperative devascularization by selective embolization. DSA is an invasive diagnostic procedure with variable morbidity risks. 31

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32. TREATMENT OPTIONS Observation: asymptomatic elderly, tumor <3cm Radical resection of the sinus with/without venous reconstruction: total or partial invasion of the sinus by tumor Resection of tumor up to the sinus and leaving the sinus intact with later radiosurgery: better long term effects, fewer complications Radiosurgery: tumors <3cm size 33

33. PRE-OPERATIVE CONSIDERATIONS ENDOVASCULAR INTERVENTIONS: EMBOLIZATION: Preoperative embolization has been used as an adjuvant therapy to reduce intraoperative blood loss and decrease surgical time in meningioma surgery 34

34. Embolization (A,B) Preoperative angiogram demonstrating arterial feeders and dural arteriovenous fistulas. ( C,D) Embolization of the fistula and neoplastic mass. 35

35. SHUNTING In most cases, venous collateralization typically prevents the onset of intracranial hypertension as a result of sinus occlusion from invading tumor . If intracranial hypertension presents, surgical decompression and tumor resection are attempted. An alternative palliative method for intracranial hypertension therapy is ventriculoperitoneal shunt (VPS) placement, which can decrease intracranial pressure until further venous collateralization develops or additional aggressive surgical treatment is performed. 36

36. OPERATIVE APPROACH PATIENTS’s POSITION: The location of the lesion along the SSS dictates the position . Anterior third tumors: supine with the head slightly flexed. Middle third tumors: supine or lateral with the area overlying the tumor positioned as the highest point in the vertical plane. Posterior third tumors: semisitting , lateral, three-quarter prone , or prone position with the tumor below the horizontal plane. 37

37. Intraoperative Neuronavigation and Neurophysiological Monitoring It allows for smaller incisions, tailored craniotomies, and anatomical localization of eloquent cortex, which translates into decreased morbidity, faster healing times, and improved cosmesis . 38

38. Surgical Incision Patients are secured in a three-point fixation head holder. A modified bi-coronal skin incision is made for tumors in the anterior third of the SSS . A trapdoor or horseshoe shaped incision is made for tumors on the middle or posterior third of the SSS. The incision extends at least 2 cm across the midline and is placed with careful dissection of the subjacent pericranium, which can later be used for dural reconstruction. 39

39. Craniotomy Most authors recommend multiple burr holes, but consensus regarding the specific placement of the parasagittal burr holes is lacking. Some surgeons prefer to place burr holes right over the SSS by using controlled drilling with small drill bits and conduct the dural release from the inner table in a medial to lateral direction. Others prefer to place burr holes on both sides of the sinus and perform the dural dissection and the release of the sinus wall from lateral to medial until both parasagittal burr holes are communicated epidurally. 40

40. It should expose an area 2 to 3 cm anterior and 2 to 3 cm posterior to the tumor margins . It must cross the midline and should expose the contralateral hemisphere at least 2 cm beyond the edge of the sinus or the lateral extent of the tumor, whichever is more lateral . Elevation of the bone flap can be complicated by engorged diploic anastomosis and by frequently encountered invasion of the dura and bone by the tumor. 41

41. Dural Opening A semilunar dural flap based along the SSS is elevated under direct microscopic visualization of the pial surface to avoid injury to cortical draining veins. The contralateral dura is opened in the same fashion but only when the tumor significantly involves the contralateral hemisphere . 42

42. Tumor Resection 43

43. Tumor Resection If the lesion is extrapial, a surgical plane can be obtained and the space between the pia and the capsule can be developed with cottonoid strips, which are placed circumferentially from the periphery to the midline and mobilized toward the deeper planes as dissection progresses. If the tumor has violated the pial surface, gentle dissection with selective bipolar coagulation is used to separate the capsule . For tumors greater than 3 cm in diameter, which constitute a large portion of the surgical lesions, internal debulking with ultrasonic aspiration or monopolar cautery must be performed to facilitate dissection of the tumor capsule . 44

44. All vascular structures must be identified and followed to determine their contribution to the tumor vasculature before coagulation because pericallosal and callosomarginal branches are frequently parasitized by these tumors and supply the infero-medial aspect of the lesions . 45

45. Dural Closure Dural closure can be performed with either: a pericranial graft harvested during the opening, fascia temporalis if accessible through the opening incision a dural substitute such as allogenic human skin, bovine pericardium or bovine dermis. Watertight closure is important. 46

46. Sinus Management Conservative Resection with Residual Intrasinusal Tumor Sinus Exploration Primary Repair and Grafting Bypass 47

47. GRADING OF SURGICAL RESECTION 48

48. GRADING OF SURGICAL RESECTION 49

49. COMPLICATIONS The mortality is about 10 %, most commonly with the middle third tumors. Morbidity rate is about 12%. Hemorrhage (intraoperative, postoperative) Cerebral edema Air embolism Post-op infections 50

50. Thank you 51