Brain surgery in a cat with a meningioma

Surgical resection of twenty-three cases of brain meningiomaMeningioma is the most common primary brain tumor in cats. They are slow-growing, extra-axial, well-defined tumors typically arising from the cells of the arachnoid layer of the leptomeninges. Meningioma is commonly regarded as a benign tumor in cats because of its slow growth, low metastasis and low recurrence rate.

Clinical presentation: Meningiomas in cats tend to be very large at the time of diagnosis. The main reasons for this, is their common location within the brain makes them show mild neurological changes.

Feline meningiomas rarely present with generalized seizures. Behavior changes is the common complaint from cat parents. However, these behavior changes can be subtle and very different in every cat. Therefore, by the time they are investigated, the meningioma is commonly very large.

Treatment and prognosis: Because of the large size the clinical presentation is very often related to the mass effect and increased intracranial pressure rather the original brain tissue damage. Surgical resection is considered the best treatment to release such pressure and prevent recurrence. The median survival time for dogs treated with surgery alone is 6 to 7 months . But in feline meningiomas, surgical resection is associated with a significantly longer survival time after diagnosis. The cat on this video presented clinical signs for several months before it was referred for imaging and surgery and he still survive another 1.5 years after surgery alone.  In canine meningiomas radiation therapy after surgery, ultrasonic aspiration  (CUSA) during excision, navigation system and MRI scanning during surgery seem to prolong the life expectancy of the patients. There is not enough information regarding how much will feline meningiomas beneficiate from these techniques.

On this video we are removing a midline parietal lobe meningioma in a cat that was originally suspected to have ear problems. On this video you can see me peeling the temporal muscle from the parietal bone. The temporal muscle is attached to the midline, but as we will be removing all that bone we will need to reconstruct it back so we can suture temporal muscle to its original position.

I drill the bone away with a burr. I won’t replace that bone back, for 2 reasons, one the hyperostosis secondary to the tumor and that a titanium plate replacement is quicker and simpler.

The tumor comes in almost one piece. This is a typical characteristic of a feline meningioma when compared to a canine meningioma. Feline meningiomas are easier to resect and to recognize when doing brain surgery as they are more solid and very distinctive from brain parenchyma.

Once the tumor is removed and the bleeding is under controlled a custom made titanium plate is fixed to the parietal bone with titanium screws which are 2 mm. I now can suture the temporal muscle back to its original position thanks the titanium plate.

I always like to reconstruct the skull, I try not to ever leave the brain exposed as there’s a risk of the muscles collapsing and compressing the brain parenchyma. Moreover, suturing the temporal muscles to each other might be difficult due to the tension, particularly in brachycephalic breeds with a more globoid skull.

Post-op: During surgery these cases tend to receive dexamethasone and sometimes mannitol or hypertonic saline if signs of increased intracranial pressure are observed along with antibiotics and pain relief. The recovery is fantastic, a good surgery will lead to a cat being able to behave almost like a normal cat the following day. Although these surgeries are not very painful we always prepare a good pain relief/light sedation plan for the first night after surgery.