7 Sphenoid Wing Meningioma

Remi Nader

Fig. 7.1 T1-weighted magnetic resonance imaging sequences with contrast illustrating sphenoid wing meningioma. (A) Axial, (B) sagittal, and (C,D) coronal sections of interest are shown.

Clinical Presentation

A 53-year-old woman presents with a history of chronic headaches on the right side for several years with more recent exacerbation.

She reports a history of partial seizures for the past 9 months.

The patient has a long history of left-sided decreased sensation along her face, arm, and lower extremity, as well as some subjective weakness along her left side. She claims that these symptoms have been present since she sustained a stroke about a year ago.

She also complains of some right-sided blurred vision and decreased visual acuity along the right eye.

She has some gait disturbances.

She is referred with magnetic resonance imaging (MRI) (Fig. 7.1). You are told that the lesion observed was present 5 years ago but was about half its current size.

Questions

Interpret the MRI scan.
Give a differential diagnosis and the most likely diagnosis.
Give a classification of the most likely diagnosis.
What is your initial management?
How would you approach the lesion surgically?
You decide to resect the lesion via a pterional approach. After the lesion is completely removed, you have a large dural defect. How do you address this defect?
You are able to remove the lesion in its entirety and a surrounding rim of dura up to the level of the sphenoid wing, where you can only cauterize the adherent dural edge, but are unable to resect it. How would you grade your resection and based on what classification?
What are the clinical implications to this grading?
How do you manage her seizures postoperatively?

Answers

Interpret the MRI scan.

A 4 × 4 × 2-cm right frontotemporal dural-based tumor is seen.
The mass is abutting the sylvian fissure.
There also appeared to be an attachment along the lateral aspect of the right sphenoid wing.
There is some mild mass effect; however, there is no midline shift and no hydrocephalus.

Give a differential diagnosis and the most likely diagnosis.

Most likely diagnosis is meningioma.
Differential diagnosis
- Tumor
  - Primary: hemangiopericytoma, primary bony lesion
  - Metastatic lesion
Less likely diagnoses include
- Infection: brain abscess, subdural empyema, meningitis
- Vascular lesion: arteriovenous malformation
- Inflammatory condition: sarcoidosis
- Traumatic: subdural or epidural hematoma

Give a classification based on this location of the most likely diagnosis.

Sphenoid wing meningioma 1

Lateral

Intermediate

Medial
What is your initial management?
- Admit the patient to the hospital.
- Obtain preoperative laboratory studies: complete blood count, electrolytes, prothrombin time/partial thromboplastin time, type and cross match 2 to 4 units.
- Start dexamethasone (6 mg every 6 hours recommended) if vasogenic edema is suspected.
- Seizure prophylaxis: continue her home regimen or if uncontrolled, change regimen (phenytoin, phenobarbital, or valproate are the recommended options; levetiracetam [Keppra, U.C.B. S.A., Brussels, Belgium] may be used as an adjunct)
- Obtain preoperative angiogram with possibility of embolization.
- Obtain medical clearance because of her history of stroke.
- May also get other imaging studies such as a computed tomography (CT) scan to assess hyperostosis, and magnetic resonance angiography (MRA) if an angiogram is unobtainable.^1,2
How would you approach the lesion surgically?
- Preoperative steps in surgical management
  - Priority is to preserve and improve function.
  - Steroids preoperatively for 48 hours
  - Control blood pressure during anesthesia.
  - Furosemide, mannitol, intravenous antibiotics
  - Head positioning (Mayfield 3-point fixation)
    - Elevate the head above heart level.
    - Head rotation: 30 to 40 degrees
    - Supine, elevated shoulder ipsilateral to tumor
  - Preoperative frameless navigation scan to mark incision and location of the tumor
- Intraoperative considerations
  - Minimize brain retraction.
  - Plan skin incision to allow full exposure of the tumor.
  - Preserve pericranial tissue attachment to scalp for dural repair.
  - Right pterional or cranio-orbito-zygomatic craniotomy
  - Exposure of lateral sphenoid wing extradurally via bone drilling of the sphenoid
  - Intraoperative ultrasound may be used as an adjunct.
  - Expose as little normal brain as possible.
  - Extensive internal decompression prior to capsule resection
  - Use Cavitron ultrasonic surgical aspirator or cautery loop.
  - Use intraoperative microscope for magnification.
  - Have a self-retaining retractor such as the Budde halo (Integra, Plainsboro, NJ) or Greenberg halo (Codman, Raynham, MA) available.
  - Debulk tumor internally prior to resecting the outer capsule.
  - Remove en block if possible with rim of dura surrounding the tumor.
  - Spare vessels “en passage” especially at the sylvian fissure.
  - Drill hyperostotic bone.
- Postoperative considerations
  - Taper steroid schedule over 1 to 2 weeks.1–4
You decide to resect the lesion via a pterional approach. After the lesion is completely removed, you have a large dural defect. How do you address this defect?
- The defect needs to be closed; several options are available.
  - Bovine pericardium
  - Fascia lata (requires preparing a harvesting site)
  - Pericranium (also requires harvesting and potentially expanding the incision)
  - Synthetic dural substitute
- Closure of the defect may be further optimized by using fibrin glue around the suture line to prevent cerebrospinal fluid seepage.^1,2
You are able to remove the lesion in its entirety and a surrounding rim of dura up to the level of the sphenoid wing, where you can only cauterize the adherent dural edge but are unable to resect it. How would you grade your resection and based on what classification?
- Simpson grade 2 resection
- Note the Simpson grading scale for meningioma resection^5,6:
  - Grade 1 – Resection complete with the dural attachment
  - Grade 2 – Coagulation of dural attachment
  - Grade 3 – Resection of tumor only with dural attachment left behind
  - Grade 4 – Subtotal resection
  - Grade 5 – Decompression
What are the clinical implications to this grading?
- There is a 20% rate of recurrence at 5 years with Simpson grade 2 resections.^5,6
How do you manage her seizures postoperatively?
- Keep her on her preoperative antiepileptic regimen if this was controlling seizures before the surgery.
- Do not discontinue for at least 6 months to 1 year until you are sure she is seizure free.
- Frequent follow-ups (monthly) to check antiepileptic levels
- May elect to get the neurology service involved
- Seizure control can be achieved in up to 88% of patients undergoing complete resection of meningioma.⁷