Surgery for Pituitary Tumors

More and more, this surgery is done by a team of surgeons that includes a neurosurgeon and an otolaryngologist (ENT surgeon).

To reach the pituitary, the surgeon first makes a small cut inside the nose, and then opens the bony walls of the sphenoid sinus with small surgical instruments. Other small tools are then passed through the opening to remove the tumor.

The surgeon can look at the tumor and nearby structures with an endoscope, a thin fiber-optic tube with a tiny video camera at the tip.

No part of the brain is touched during transsphenoidal surgery, so the chance of damaging the brain is very low. There are fewer side effects with this approach than with craniotomy (see below), and there's also no visible scar. But it’s sometimes harder to take out large tumors this way.

When this surgery is done by an experienced neurosurgeon and the tumor is small (a microadenoma), the chances that it can be removed completely are high. If the tumor is large or has grown into the nearby structures (such as nerves, brain tissue, or the tissues covering the brain) the chances of removing the tumor completely are lower, and the chance of damaging nearby brain tissue, nerves, and blood vessels is higher.

Craniotomy

If the pituitary tumor is larger or more complicated, a craniotomy may be needed. This surgery is done through an opening in the front of the skull, off to one side. The surgeon has to work carefully beneath and between the lobes of the brain to reach the tumor.

A craniotomy has a higher chance of brain injury and other side effects than transsphenoidal surgery for small tumors, but it’s safer for large and complex tumors because the surgeon is better able to see and reach the tumor as well as nearby nerves and blood vessels.

Planning surgery

For both transsphenoidal surgery and craniotomy, the surgeon may use image guidance with MRI or CT scans before surgery to learn as much as they can about the tumor and nearby structures. It's important to know how big the tumor is, exactly where it is in the pituitary, whether it has spread beyond the pituitary gland, and where important nearby structures are. This helps plan the best way to do the surgery and gives an idea of how likely it is that the tumor can be removed completely.

Rarely, for very large tumors that have spread to nearby tissues, both types of surgery are used at the same time to try to remove all of the tumor.

In general, smaller pituitary tumors are easier to treat with surgery. The larger and more invasive the tumor, the less likely it is that the tumor can be removed completely. Side effects also tend to be more likely after surgery to remove large, invasive tumors.

Possible side effects of surgery

Some complications, such as bleeding, infections, or reactions to anesthesia (the drugs used to make you sleep during surgery), can occur during or after any type of surgery. These are rare, but they can happen.

Surgery for pituitary tumors is done in a very small space that is surrounded by important structures. Surgeons are extremely careful to limit any problems both during and after surgery. Still, very rarely, pituitary surgery might result in damage to the large arteries, brain tissue, or nerves near the pituitary. This could result in complications such as brain damage, a stroke, or long-term vision problems.

Most people who have transsphenoidal surgery will have a sinus headache and congestion for up to a week or 2 after surgery.

When surgeons use the transsphenoidal approach to reach the pituitary gland, they create a temporary pathway between the nasal sinuses and airways and the brain. Until this heals, a person can get meningitis, which is inflammation of the meninges (the thin protective layers covering the brain). Damage to the meninges can also lead to leakage of cerebrospinal fluid (CSF, the fluid that bathes and cushions the brain) out of the nose. The chance of this happening depends to some extent on the size and type of tumor.

Diabetes insipidus (see Signs and Symptoms of Pituitary Tumors), which happens when not enough vasopressin is released by the posterior pituitary, may occur right after surgery, but it usually improves on its own within a few weeks after surgery.

Damage to other parts of the pituitary can lead to symptoms from a lack of pituitary hormones. This is rare after surgery for small tumors, but it may be unavoidable when treating some larger tumors. Low hormone levels after surgery can be treated with medicines to replace certain hormones normally made by the pituitary and other glands.

You will be watched closely after surgery, and your blood levels of hormones and other important substances will be checked often.

Some side effects might need to be treated. For example:

• If diabetes insipidus doesn't get better on its own, it may need to be treated with a desmopressin nasal spray.
• If vitamin and/or mineral levels change, you may need supplements for a while. For instance, potassium levels often drop, so you may need to get it intravenously (IV, or in a vein) right after surgery.

Talk to your doctor about what you should watch for and what you should do if you have any problems.