The pituitary is a small gland located in the brain that regulates all other hormones. It is the size and shape of a pea. When abnormal cells begin to grow forming tumors, regulatory hormones may fluctuate. Any one of the endocrine glands can be affected. Large tumors or those unable to be medically managed must be removed in a procedure called transsphenoidal surgery. While complications related to surgery are not common, patients must be informed of the possible outcomes.
Normal Pituitary Tissue Damage
The normally pea-sized gland, the pituitary, can increase in size to more than 5cm under the influence of cancer cells. Endocrinologists refer to them as macroadenomas when they are more than 1cm in size. A macroadenoma causes patients to experience symptoms directly related to hypersecretion, hyposecretion or dysregulation of hormones. Surgery is required to reduce the size of the aberrant gland which can cause compression of surrounding structures. Due to the small size of the pituitary, the most common complication of surgery is damage to normal tissue. Damage to normal tissue may require a lifetime regimen of replacement hormones termed hormone replacement therapy (HRT). Depending on the extent of the damage, HRT may include one or more of the following: thyroid hormone, cortisol, growth hormone, estrogen, or testosterone. Expert surgeons have a complication rate of approximately 5 to 10 percent, according to the Neuroendocrine Clinical Center and Pituitary Tumor Center.
Diabetes Insipidus
Surgical related damage to the back of the pituitary gland or posterior pituitary, causes a condition known as diabetes insipidus. Damage to this portion of the pituitary interferes with the production of antiduretic hormone (ADH) that is produced by pituitary cells. Antidiuretic hormone helps to maintain the bodies water volume by opening pores in the kidney that allow water to enter the blood stream. If ADH is absent, the water in the kidney leaves the body. This initiates the thirst mechanism. Diabetes insipidus patients have large amounts of urine and water intake. Diabetes insipidus occurs in approximately 1 to 2 percent of cases as a permanent condition as reported by the Neuroendocrine Clinical Center & Pituitary Tumor Center, a joint operation of Massachusetts General Hospital and Harvard Medical School.
Carotid Artery Damage
In close proximity to the pituitary gland are major arteries called the carotids. They are located on both sides of the pituitary. Harm to these arteries can be catastrophic. Although a rare occurrence, stroke and death are risks that accompany the surgery. Less than one person per thousand surgeries performed experience this type of complication, says the Neuroendocrine Clinical Center & Pituitary Tumor Center.
Bleeding
Removal of the pituitary tumor is not always complete. This is a decision made by the surgeon. Blood vessels associated with the remaining tumor can continue bleeding. Tumor tissue tends to be easily disrupted and may leak after being surgically manipulated. This can be a problem as their is little room in the brain for extra fluid. If this complication occurs, surgeons may decide to reoperate.
Spinal Fluid Leak
The fluid that coats the brain is called spinal fluid. The cavity that houses the pituitary gland is called the sella turcica. Normally, this area of the brain is separated from spinal fluid by a thin membrane. When a tumor is removed this connection can be incidentally broken allowing spinal fluid to enter the space. In order to prevent this, surgeons place a piece of fat obtained from the abdomen. This does not always prevent the problem and spinal fluid may leak regardless into sella turcica causing increased risk of infection and inflammation. The Neuroendocrine Clinical Center & Pituitary Tumor Center reports that patients typically need a second surgery to correct.
