sch.36 surgical management of sphenoid wing meningioma
TRANSCRIPT
Surgical Management of Sphenoid Wing Meningiomas
Schmidek Chapter 36GERARDO GUINTO
Outline
• Anatomy• Classification• Clinical course• Diagnosis• Treatment• Complication and result
Anatomy
Classification
En-plaque meningiomas• Spheno-orbital meningiomas or hyperostotic
meningiomas of the sphenoid wing• Carpet-like dural growth tumor• It frequently extends posteriorly toward the cavernous
sinus and anteriorly toward the orbital apex, where it causes proptosis and oculomotor deficits growth tumor
Globoid meningiomas• Deep, inner, or clinoidal
– Most common– Subtype : tumors without extradural growth and tumors
with extradural growth into the cavernous sinus• Middle • Lateral, outer, or pterional
Clinical course• Most common : Protosis which usually is slowly
evolving, unilateral, nonpulsatile, and irreducible• Protosis Ddx
– Hyperostosis of the orbital walls– Periorbital tumor invasion– Intraorbital tumor– Venous stasis caused by compression of the
ophthalmic veins
Clinical course• Related symptoms : headache, orbital pain, visual
deficit, ptosis, diplopia, ectropion, conjunctivitis, corneal ulceration, and scleral hemorrhages
• Clinoidal meningioma– Visual field problems– When tumor invade cavernous sinus, the most common
symptoms are oculomotor deficit (especially on cranial nerve VI) and facial hypoesthesia
Clinical course• Middle or alar meningiomas
– Late symptoms– Headache and signs or symptoms suggesting increased
intracranial pressure, such as nausea, vomiting, and papilledema
• Not common– Memory impairment– Olfactory hallucinations– Personality changes – Seizures– Hemiparesis
Diagnosis• CT• MRI• Angiography
Computed tomography• The extent of bone invasion• The dural component of these tumors is typically found
as an isodense image with contrast enhancement• The most common locations of hyperostosis of en-
plaque meningiomas– the lesser wing of the sphenoid bone– the greater wing of the sphenoid– the roof of the orbit– the inferior orbital fissure– the infratemporal fossa– the orbital rim.
Computed tomography• Globoid tumors : well-defined isodense lesions that
present an intense and homogeneous contrast enhancement• Clinoidal meningiomas : hyperostosis of the anterior
clinoid process (ACP), causing narrowing of the optic canal and the superior orbital fissure
MRI• Globoid meningiomas show different appearances on
MRI– When their vascularity is not so marked, they usually
present as a homogeneous isointense lesion in both T1- and T2-weighted images
– When they are highly vascularized (angioblastic meningiomas), multiple hypointense images (“empty signals”) can be seen in the interior of the tumor
MRI• Gadolinium enhancement is usually intense and uniform• T2-weighted image is particularly useful in demonstrating
perilesional edema• Functional MRI• MRA
Angiography• Selective catheterization provides specific information
about the blood supply of the tumorand allows the possibility of preoperative embolization
Treatment• Indication
– all patients who are in good health and have a tumor size greater than 2.5 cm
– presence of signs or symptoms– changes in the adjacent cerebral(edema)
• Objective– radical excision of the tumor, which means resection of the
lesion, along with the dural implant (1-cm margin) and all hyperostotic bone
Treatment• Preparation : general anesthesia, antiepileptic drugs, broad-
spectrum antibiotics, neurophysiologic monitoring• Positioning and Incision• Preserve : superficial temporal artery, frontotemporal branch
of facial nerve •
Pterional• Pterional craniotomy• Hyperostosis is usually seen immediately in the
pterion once the temporal muscle is detached : craniotomy about 5 cms from lesion
• Resection of hyperostosis : 1 cm from margin• The meningeal portion of the tumor : 1 cm from margin• In some cases of predominantly osseous tumors :
craniectomy
Pterional
Alar or middle• Frontotemporal craniotomy• Extradural resection of the lesser wing of the sphenoid
bone• Bone removal is continued until complete exposure of the
superior orbital fissure and base of the ACP• Dura open in curvilinear frontotemporal incision• Splitting of the sylvian fissure is done• “En bloc” resection is only possible in small tumors• Debulking is preferred in the majority of these cases• Leaving deeper portions and dural implant for the end of the
procedure.
Clinoidal• Frontotemporal craniotomy• Bone resection of the sphenoid ridge from the pterion to
the base of the ACP• If there is an orbital component of the tumor, the
posterolateral wall of the orbit is also removed• Anterior clinoidectomy : holding the ACP with a rongeur
and applying a gentle “wiggle and jiggle” movement of the surgeon’s wrist
• The curvilinear dural incision is done• Splitting of the sylvian fissure is done
Clinoidal• Initially, the dural implants in the frontal and temporal
regions are coagulated, which reduces vascular supply of the tumor and facilitates its resection
• Dissection of the tumor• The optic nerve is next referred intradurally and released
from the tumor• Extirpation of the dural implant is done
En Plaque• Pterional craniotomy is combined with an OZ osteotomy
when the lesion extends into the inferior orbital fissure, infratemporal fossa or orbit
• It is easy to observe the totality of the hyperostosis from a lateral perspective and the drilling begins
• All infiltrated dura are resected, attempting to extend this resection beyond the area of dural enhancement seen on imaging studies.
En Plaque
Reconstruction and closure• Closure of the dura
– Local tissue : aponeurotic galea, pericranium, or temporal fascia
– Distant tissue : fascia lata or abdominal fascia
• Reconstruction of the pterional defect– Autologous materials : split calvarial bone graft or ribs – Synthetic materials : methylmethacrylate and titanium
Reconstruction and closure• The floor, the orbital rim or both are removed, all
authors agree that reconstruction is required due to the high risk of orbital ptosis, postoperative diplopia, or cosmetic defect
• Reconstruction of the orbital walls is controversial : the superior and lateral walls of the orbit
Complication• Postoperative hematoma, especially epidural, due to the
wide dural detachment done in some cases and the spaces created by resection of large bone formations
• CSF leakage due to wide resection of the dural implant• Seizure• Cosmetic• Infection : when prosthetic materials are used for
reconstruction or when frontal ethmoid or sphenoid sinuses are inadvertently opened
Result• The short and midterm follow-up results after SWM
resection are excellent• In the majority of cases,gross total resection is
accomplished with minimal morbidity• However, the critical point is in long-term follow-up
because of the high risk of recurrence, which is inversely proportional to the degree of tumor resection
• Factors : incomplete resection of these tumors are extent of bone invasion, underevaluation of the dural component, and invasion of adjacent neurovascular structures, anaplasia