Skull Base & Skull Base Surgery

Skull base surgery may be performed to remove noncancerous or cancerous growths and abnormalities on the underside of the brain, the skull base, or the top few vertebrae of the spinal column.

The skull is composed of bones and cartilage that form the face and the cranium surrounding the brain. You can feel the bones of the cranium on top of the skull. The 5 bones that form the bottom, or base, of the cranium, also form the roof of the nasal cavity, the eye socket, some of the sinuses, and the bones surrounding the inner ear.

The skull base is a crowded and complicated area with different openings passing through the spinal cord, blood vessels, and nerves. This area is such a difficult area to see, so skull base surgery may be done by a minimally invasive endoscopic procedure. In this procedure, the surgeon inserts instruments through the natural openings in the skull—the nose or mouth—or by making a small hole just above the eyebrow. This type of surgery may require a team of specialists, including a neurosurgeon supported by an ENT (ear, nose, and throat) surgeon, maxillofacial surgeon, and radiologist.

Prior to the development of endoscopic skull base surgery, the only way to remove growths in this area of the body was by making an opening in the skull. In some cases, this type of surgery may still be needed.

What is skull base surgery used for?

These are some of the growths and conditions that may be treated by skull base surgery:

Types of skull base surgery

Skull base surgery can be done in two main ways. Although the preferred and more advanced method is endoscopic, open surgery is also an option, depending on the type of growth that needs to be removed and its location:

• Endoscopic or minimally-invasive skull base surgery. This type of advanced surgery usually means a smaller incision is made under general anaesthetic. A surgeon may make a small opening inside the nose to allow a neurosurgeon to remove a growth through a thin tube called an endoscope. An MRI is a type of picture taken of the skull base using magnets and a computer. It may be performed by a radiology specialist while the neurosurgeon is operating to help them make sure all of the growth has been removed.

• Open skull base surgery. This type of surgery may require incisions in the facial area and in the skull under general anaesthetic. Parts of bone may need to be removed so that the growth can be reached and removed.

Common Symptoms 

You may have many possible symptoms from a growth or abnormality in the skull base area. Symptoms will depend on the size, type, and location of the growth or abnormality and may include:

• Headache
• Dizziness
• Facial Pain
• Weakness of the Face
• Visual problems
• Numbness
• Ringing in the ears or loss of hearing
• Frequent sinus infections or nasal congestion

Diagnosis of Skull Base Conditions

The diagnosis of conditions that may require skull base surgery is based on your symptoms and a physical exam. Because this area can’t be seen directly, these exams and imaging studies are essential parts of the diagnosis:

• Biopsy. A small piece of the growth in the skull base may be taken out and looked at under a microscope. An endoscope could be used to take a biopsy through the nose and sinuses. Biopsies may also be done by fine need aspiration or excisional biopsy.
• Brain imaging studies. Scans such as MRI (magnetic resonance imaging), MRA (magnetic resonance angiogram), PET (positron emission tomography), and CT (computed tomography) scans create detailed images of the skull to help your medical team see a growth or abnormality.
• Other tests. Your cranial nerves, balance, muscle activity, hearing and vision may all be checked. Investigation or scans of other areas and systems of the body may also be checked.

Treatment of Skull Base Conditions

In addition to endoscopic and open skull base surgery, these treatments may be needed, depending on the type of growth or abnormality of the skull base:

• Chemotherapy. These are drugs used to treat growths caused by cancer.
• Radiation therapy. X-ray treatment may be used to control a growth in the skull base that can’t be entirely removed by surgery.
• Gamma knife. This particular type of radiation therapy uses precise X-ray beams to target growth in the skull base.
• Proton beam therapy. This is another type of radiation therapy designed to have greater accuracy and dosing for tumors.
• Particle therapy. This is the newest form of radiotherapy. It uses high-energy particles with fewer side effects. Carbon-ion radiotherapy is a form of particle therapy.