The main treatment of many pituitary tumors is surgery. How well the surgery works depends on the type of tumor, its exact location, its size, and whether it has spread into nearby tissues.
Transsphenoidal surgery is the most common way to remove pituitary tumors. Transsphenoidal means that the surgery is done through the sphenoid sinus, a hollow space in the skull behind the nasal passages and below the brain. The back wall of the sinus covers the pituitary gland.
For this approach, the neurosurgeon makes a small incision under the upper lip (above the upper teeth) or along the nasal septum (the cartilage between the 2 sides of the nose). Then the surgeon cuts along the septum back toward the sphenoid sinus. To reach the pituitary, the surgeon opens the boney walls of the sphenoid sinus with small surgical chisels, drills, or other instruments depending on the thickness of the bone and sinus.
This approach has many advantages. First, no other part of the brain is touched. Second, the chance of damage to the rest of the brain is very low. And last, there is no visible scar. But it is hard to remove large tumors this way. When the surgery is done by an experienced neurosurgeon and the tumor is a microadenoma, the cure rates are high (greater than 80%). 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 for a cure by surgery are lower.
A newer approach is to use an endoscope to perform transsphenoidal surgery. The endoscope is a thin fiber-optic tube with a tiny camera lens at the tip. In this approach, the incision under the upper lip or the front part of the nasal septum is not needed, because the endoscope allows the surgeon to see well through a small incision that is made in the back of the nasal septum. The surgeon passes instruments through normal nasal passages and opens the sphenoid sinus to reach the pituitary gland and remove the tumor. The use of this technique is limited by the tumor's position and the characteristics of the sphenoid sinus.
For larger or more complicated pituitary tumors, a craniotomy (an operation in which the surgeon makes an opening through the skull bones) may be needed. The surgeon has to carefully work around some of the brain tissue to reach some portions of the tumor with this approach, so it has a much higher chance of having neurologic complications than transsphenoidal surgery.
As a general rule for pituitary tumors, the larger and more invasive the tumor, the less likely the tumor can be cured by surgery. Smaller tumors are more easily treated with surgery.
Possible side effects of surgery
Surgery on the pituitary gland is a serious operation, and surgeons are very careful to try to limit any problems either during or after surgery. Complications during or after surgery such as bleeding, infections, or reactions to anesthesia are rare, but they can happen.
Damage to large arteries, to nearby brain tissue, or to nerves near the pituitary rarely can result in brain damage, a stroke, or blindness. Damage to the membranes surrounding the brain (called the meninges), occurs rarely but can result in meningitis (infection and inflammation of the meninges). Damage to the meninges can also lead to leakage of cerebral spinal fluid (the fluid that bathes and cushions the brain).
Diabetes insipidus (discussed in "How are pituitary tumors diagnosed?") occurs commonly right after surgery but it usually gets better with time. This condition usually improves on its own within 1 to 2 weeks after surgery. If it is permanent, it can be treated with a desmopressin nasal spray.
Damage to the rest of the pituitary can lead to symptoms from a lack of pituitary hormones. This is rare after surgery for small tumors, but may be unavoidable when treating some larger macroadenomas. If levels of pituitary hormones are low after surgery, this can be treated with medicine to replace certain hormones normally made by the pituitary and other glands.
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