Convexital meningioma describes those tumors whose attachment is not to the dura of the skull base and does not involve a dural venous sinus or the falx. Such tumors may arise from any area of the dura over the convexity but are more common along the coronal suture and near the parasagittal region. Various classifications regarding location have been proposed. Patients usually present with seizures, headaches, or a focal neurological deficit, depending on the tumor location. Inmost situations MRIgives all the information the surgeon needs. It is no longer needed to request angiography in most patients with convexity meningiomas because the blood supply is known and the procedure does not add any crucial information in planning the operation. Embolization is not needed in these patients. The feeding meningeal arteries can be occluded early in the course of the operation.
Most of these meningiomas can be removed completely and the patient cured. Inpositioning the patient for the operation, the scalp overlying the central portion of the tumor is placed at the highest level, if this is possible. Usually a U-shaped incision is used. The incision for a tumor centered along the matrix of the tumor. A free bone flap is elevated. with care to preserve the pericranial tissue that will be needed for a graft to replace the dural defect. Hyperostosis or involvement of bone by the tumor is handled as usual. After dural pericranial sutures are placed. the dura is opened circumferentially around the tumor, with occlusion of the meningeal arteries as these are encountered. The dura is left attached to the tumor and is used to apply gentle traction. The removal of tumor from the brain and the closure are the same as described for parasagittal meningiomas. A special circumstance occurs when the tumor arises over the frontotemporal junction. Two points should be emphasized. First, the middle cerebral artery branches may be adherent to the medial capsule, and great care must be exercised in removing this tumor. Second, some of the dural attachment may extend over the floor of the anterior fossa, sphenoid wing, and floor and anterior wall of the middle fossa. This dura must be removed, sometimes even into the lateral edge of the superior orbital fissure. The dural defect can usually be repaired by sewing a graft directly to the edge of the remaining dura, using a small needle. After the intracranial dura is sewn, the graft can be tented along the bone edge and then the convexity margin of dura closed.
Most of the patients are cured with low recurrence rate, in the case that a remnant is left behind. Postoperative complications include a temporary increase in hemiparesis and sensory loss, difficulty controlling seizures, and deep venous thrombosis; wound infection. All patients had a good result. The recurrence rate is low.
A young 49 years gentleman started to complain of headache with weakness of the right side of the body for one year with numbness of his right side of the body. MRI of the brain performed 6 months ago showed convexital meningioma of the left fronto-parietal region inside the sensorimotor strip with wide matrix.
The patient was advised by some doctors to wait, until he deteriorated and progressed convulsions with deepening of the paresis. Repeat MRI done 3 days ago showed the mass to be doubled in size, for what he came to the clinic 10-March-2005. The patient is known diabetic with arterial hypertension. The patient was operated as seen in the video and all the stages during surgery were smooth with lyodura replaced the tumorous dural resected part, with radical resection of the tumor. It was noticed that the patient upon recovery showed elevated BP and demonstrated dense paresis of his right side of the body with total aphasia. CT-scan done 2 hours after surgery showed hematoma the same size as the tumor. Repeat CT-scan done 4 hours later done showed slight increase in the hematoma. Despite the fact that the patient showed slight improvement, but he was urgently taken to the operating room and evacuation of the hematoma was performed and the active bleeding site identified and controlled. Immediate postsurgical CT-scan done, which showed complete removal of the hematoma.