What is Skull Base Surgery?
Skull base surgery is performed to remove or repair an abnormality on the bony surface beneath the brain—the skull base. At the Columbia Skull Base Tumor Center, our neurosurgeons offer particular expertise in the procedures available to treat these tumors.
Many vital structures, such as large blood vessels and important nerves, exit and enter the skull at its base. The skull base separates the brain from the eyes, nose, ears and other facial structures. It starts above the eyebrows and slopes downward, ending at the back of the neck, where the foramen magnum is located.
The floor of the skull is divided into three regions from front to back: the anterior cranial fossa, the middle cranial fossa (centered around the pituitary) and the posterior cranial fossa, which contains the brainstem and the cerebellum.
The brainstem is the connection between the brain and spinal cord, containing nerves involved in the control of breathing, blood pressure, eye movements and swallowing. The brainstem connects to the spinal cord through the foramen magnum. The cerebellum, lying behind the foramen magnum, is involved with coordination and balance.
Adding to the complexity of the skull base is the fact that each of its regions is at a different level. When a person is standing and looking forward, the anterior cranial fossa is highest, and the posterior cranial fossa is lowest.
The skull base has historically been difficult to access, which has made brain abnormalities occurring in this area correspondingly difficult to treat, but surgical advances and improvements in neuroimaging have made skull base abnormalities accessible and surgically treatable.
Advances continue to be made that render this procedure less invasive, and our world-class neurosurgeons use the latest techniques and technology. Skull base surgery can be performed to the highest standards of safety and effectiveness by either of two available approaches. Physicians choose an approach in each case depending on where abnormalities are and what is best, overall, for each patient.
- Craniotomy—This is a traditional, open surgery technique in which portions of the skull are temporarily removed to provide the neurosurgeon access to the brain. For certain brain abnormalities, this approach can now be performed using minimally invasive techniques, minimizing the size both of incisions and of the opening in the skull.
- Transsphenoidal surgery—This is a minimally invasive procedure in which the operation is performed through the nostrils or inside of the mouth and is done with the aid of an endoscope. Only very small incisions are made, and usually they are not visible.
When is this procedure performed?
Skull base surgery is performed when a brain abnormality is found near the skull base. At the Skull Base Tumor Center, our neurosurgeons always first consider conservative options such as medication, but often surgery is the primary treatment to address the abnormality.
Brain abnormalities that are treated with skull base surgery include, but are not limited to, skull base tumor, aneurysm, trigeminal neuralgia, brain abscess, hematoma, arteriovenous malformation and hydrocephalus.
How is this procedure performed?
At Columbia, our neurosurgeons assemble a multidisciplinary team when performing skull base surgery to provide the best possible outcome. Any combination of the following doctors, in addition to the neurosurgeon, may be part of the surgical team:
- Head and neck surgeon
- Plastic surgeon
- Oral and maxillofacial surgeon
Whether a patient’s operation will proceed by craniotomy or by transsphenoidal methods, skull base surgery starts with general anesthesia, so the patient does not feel pain during the operation.
The neurosurgeon begins by making an incision on the scalp, usually near the location of the skull base abnormality, and then delicately reflects the skin and muscle to reveal the skull. With the skin and muscle reflected, the neurosurgeon can create an opening in the skull by temporarily removing a bone flap. The bone flap will be replaced toward the end of surgery. The removal of bone is a very delicate procedure requiring sophisticated technical skills to avoid damaging structures along the skull base. The removal of bone is designed to provide access to the tumor in a way that avoids manipulation of the brain.The opening is as small as possible; its size depends on what is needed to treat the particular abnormality.
Through the opening, the dura mater is visible. The neurosurgeon uses surgical scissors to make an incision in the dura mater, exposing the brain.
With the brain exposed, the neurosurgeon can begin expertly navigating to the abnormality. The skull is occupied by fragile structures, such as brain tissue, nerves and blood vessels, and has little room to accommodate instruments. The neurosurgeon uses an operating microscope and other specialized technology to provide a clear view of the many structures and precisely navigate to the brain abnormality. Also, to help plan the best route to the abnormality, the neurosurgeon uses stereotactic techniques, employing tools such as magnetic resonance imaging (MRI) scan and computed tomography (CT) scan along with computer technology to produce three-dimensional images of the brain.
Next, depending on the brain abnormality, additional procedures are performed to treat the condition.
With the condition treated, the neurosurgeon sutures closed the incision in the dura mater and secures the bone flap back in place with titanium plates and screws. Lastly, the neurosurgeon stitches up the incision on the scalp. The procedure is finished.
Unlike craniotomy, transsphenoidal surgery usually does not require visible incisions, and if any are visible, they are very small. Also, the surgeon performs the procedure by going through the nose or mouth.
The operation begins with inserting the tip of an endoscope through one of the nostrils, and then opening up the sphenoid sinus at the back of the nasal cavity. An endoscope or microscope provides light and magnification so the surgeon has a clear view of the surgical field deep inside the nose. Instruments are passed through the nose to repair or remove the brain abnormality, and the neurosurgeon achieves the highest precision by using stereotactic techniques to produce a three-dimensional map of nerves, blood vessels and other structures in a patient’s brain.
After the brain abnormality is removed or repaired, any incisions made are stitched. The operation is complete.
How should I prepare for this procedure?
Be sure to tell your doctor about any medications or supplements, including herbs or vitamins, you take. It is essential for your doctor to be made aware of these because certain medications or supplements, such as warfarin and aspirin, can increase bleeding during the operation, and your doctor will need to determine whether your medication schedule should be adjusted.
Also, let your doctor know of any allergies you may have to food or medications.
Because general anesthesia is used during surgery, you will be asked to stop eating and drinking at midnight the night before the operation. If your doctor has advised you to continue taking certain medications on the day of surgery, do so with a small sip of water.
On the day of surgery, be sure to wear loose, comfortable clothing. You will be instructed to not wear makeup, jewelry or nail polish. Do not wear contact lenses; instead, wear your glasses.
For your hospital stay, do your best to pack lightly. A few items that patients like to bring include toiletries, dentures and additional clothing for when they are discharged from the hospital.
Make sure to arrange transportation home from the hospital because you will not be permitted to drive yourself home after surgery.
What can I expect after the procedure?
How long will I stay in the hospital?
Typically, patients who undergo transsphenoidal surgery stay in the hospital for one or two days and then are discharged. Those who undergo craniotomy usually stay longer, around one week.
Will I need to take any special medications?
Patients who undergo transsphenoidal surgery are prescribed medication for pain and sometimes nausea, and those who undergo craniotomy may take additional medications, such as those to prevent brain swelling and seizure.
When can I resume exercise?
Patients who receive transsphenoidal surgery can expect to resume light exercise, such as swimming or jogging, about two weeks after surgery and any other exercise after about four weeks. Patients are often walking the day after surgery but may notice that they tire easily and need to rest often. This is normal.
Patients who undergo craniotomy are encouraged to get up and walk every day if they have the energy, but should not resume exercise until the neurosurgeon approves such activity. Craniotomy is a more invasive operation than transsphenoidal surgery, so recovery will be longer. Once the neurosurgeon approves, patients can start with light exercise and eventually build to more strenuous exercise. However, any form of exercise should be done with a partner or under supervision until the patient has fully recovered.
What follow-up will I receive?
After surgery, a patient will be scheduled for several follow-up appointments with the neurosurgeon and possibly other specialists, such as an endocrinologist, neurologist, otolaryngologist or ophthalmologist, depending on the treated brain abnormality and whether any new symptoms arose after skull base surgery, such as a problem with vision.
During these appointments, the neurosurgeon will evaluate the patient’s progressing recovery in detail. Depending on the treated brain abnormality, the neurosurgeon may order imaging studies to visualize the brain or conduct other tests.
Patients are strongly encouraged to attend all follow-up appointments in order to have the best possible recovery and long-term outcome. While recovering, patients should always inform their doctors of any new or worsening symptoms, even if the changes seem minor.
Will I need rehabilitation or physical therapy?
The need for rehabilitation or physical therapy largely depends on the brain abnormality treated. Skull base surgery itself usually does not lead to a need for rehabilitation or physical therapy.
Will I have any long-term limitations due to skull base surgery?
Any potential long-term limitations depend primarily on the brain abnormality treated. Skull base surgery itself usually does not result in long-term limitations.
Dr. Richard Anderson (Pediatric), Dr. Jeffrey Bruce, Dr. Neil Feldstein (Pediatric), Dr. Grace Mandigo, Dr. Guy McKhann, Dr. Marc Otten, Dr. Sameer Sheth and Dr. Michael Sisti are experts in skull base surgery. Each can also offer you a second opinion.