PARASAGITTAL MENINGIOMA

Parasagittal Meningioma

Parasagittal or Paramedian Meningiomas are superficial tumors located next to the midline in the skull convexity. These tumors are closely related to the superior sagittal sinus. This sinus is a large venous channel located in the midline between both brain hemispheres. It collects most of the blood from the veins draining the brain. Parasagittal Meningiomas may partially invade or fully obstruct the superior sagittal sinus.

Parasagittal Meningiomas can grow to a formidable size and create ongoing pressure on the underlying causing brain swelling or edema. Occasionally the overlying cranial bone is invaded by a tumor and a lump can be felt under the scalp. Parasagittal Meningiomas can be located in the frontal, parietal or occipital region next to the midline and along the superior sagittal sinus.

Symptoms

The location of the parasagittal Meningioma along the midline determines the possible symptoms and deficits associated with it.

• Headache – New onset of headache which can be localized to the location of the tumor or generalized when related to increased intracranial pressure.
• Seizures – Frontal tumors tend to cause focal motor or sensory seizures on the contralateral side of the tumor. It can be associated with speech arrest when the tumor is on the dominant brain hemisphere. A seizure can be the first Symptoms of Meningiomas before diagnosis
• loss of peripheral vision
• contralateral leg and foot weakness and loss of sensation

Treatment

Symptomatic parasagittal Meningiomas are generally treated with surgery. Small to medium size incidental tumors without associated brain edema can be treated with observation and surveillance by MRIs. Elderly patients with small to medium size tumors associated with mild symptoms and without significant mass effect can be treated primarily with CyberKnife or Proton Bean radiation therapy.

Surgical Treatment at the Meningioma Center

Parasagittal Meningiomas are superficial and easily accessed by surgery. In the Meningioma Center, the Surgery of these tumors is treated with the smallest possible incision and bone opening in the skull (craniotomy) next to the midline. The craniotomy is tailored to the location and size of the tumor. The size of the craniotomy and localization of the tumor is guided by a computer-assisted device that can pinpoint the site and identify the anatomy of the tumor (Stealth Station or BrainLab Station).

Tumor resection is carried out with magnification with the surgical microscope to allow elevation of the tumor away from the underlying brain following natural anatomical planes of dissection. This strategy avoids unnecessary trauma or damage to the brain tissue. The tumor is removed and dissected in a piecemeal fashion after breaking the tumor with an ultrasonic device which decreases the tumor pressure and facilitates its dissection.

Opening of the superior sagittal sinus is necessary for the removal of tumors invading the sinus. This is followed by repairing the sinus. Resection of the whole sinus is carried out when the sinus is completely obstructed pre-operatively. When there is an invasion of the overlying cranial bone the involved bone is removed and the cranial defect is repaired with a cranioplasty. Resection of the meningeal origin of the tumor is necessary to allow complete removal of the tumor.

Prognosis

Treatment of parasagittal Meningiomas Meningioma through focused small craniotomies and microsurgical technique improves chances of completely removing the tumor with total function preservation or recovery of function that includes pre-operative motor deficits, and visual difficulties, speech difficulties, and cognitive dysfunction. Pre-operative seizures are often well controlled with or without medication after atraumatic tumor resection. Small surgical openings or craniotomies decrease the duration of surgery, soft tissue trauma and swelling, post-operative pain, and hospital stay.

Adequate Treatment of parasagittal Meningiomas enhances the potential for patients to return to their lifestyle and job occupation. Maximal removal of the tumor including the superior sagittal invasion, bone invasion, and meningeal origin of the tumor maximizes the chances of the patient progressing without tumor recurrence.