Having brain surgery today doesn't necessarily mean an open-skull surgery (crainiotomy) like it used to. With surgical navigation devices such as endoscopes and high-definition cameras in their tool belts, brain surgeons are often able to remove tumors via a minimally invasive procedure through the patient's nose. It's like having "GPS for the brain," neurological surgeon Daniel Kelly, MD, told Medical Device Daily.

Kelly, director of the brain tumor center at Saint John's Health Center (Santa Monica, California) and a faculty member at the John Wayne Cancer Institute at Saint John's, is the senior author of new study designed to assess the safety and effectiveness of this endonasal approach to removing particularly large tumors known as giant pituitary adenomas.

The endonasal approach to removing brain tumors is far from new – it's been a treatment option for a couple of decades, Kelly says – but until this study there had not been a modern-era assessment to find out how safe and effective the procedure is for these large and difficult brain tumors.

"I treat a lot of patients with pituitary tumors and many types of brain tumors through this endonasal approach and periodically we like to look at how we're doing," Kelly said. He noted that this is a multimodality approach and that many of these patients require additional treatments such as hormone replacement therapy or radiation.

According to St. John's, giant pituitary adenomas – which can grow to the size of an egg and invade nearby structures – are not cancerous, however they can cause visual loss and impair many of the body's most basic functions.

Pituitary adenomas are noncancerous tumors of the pituitary, the master gland that rules the endocrine system. Located in the skull base below the brain and behind the nasal cavity, the pituitary secretes powerful hormones that coordinate other glands, controlling such basic functions as growth and development, metabolism, the stress response, sexual function and water balance. Pituitary adenomas arise in about 1 in 1,000 individuals; about 10% of surgically treated adenomas are giant, 4 cm in diameter or larger, according to St. John's.

As adenomas enlarge, they can cause pituitary gland failure by cutting off the flow of hormones. Headaches, visual loss and other symptoms may develop slowly over months or years, but can also happen over hours or days if there is bleeding into the tumor, called pituitary apoplexy. Giant adenomas often grow around the pituitary gland and skull base into areas where critical blood vessels and nerves travel, making complete surgical removal impossible, St. John's noted.

Endonasal surgery allows doctors to remove many kinds of brain tumors through a nostril. Reaching the tumor through a natural opening eliminates the need for a craniotomy and in experienced hands, creates less trauma, fewer complications and a shorter recovery time. "Patients prefer the idea of a minimally invasive procedure through a natural opening," Kelly said.

The procedure is performed using an operating microscope and an endoscope (a surgical telescope) for highly magnified, high-definition panoramic views of the surgical site. Specialized instruments are passed through the nasal cavity into the skull base to remove the tumor. A computerized guidance system for surgical navigation completes the high-tech arsenal of modern endonasal skull base surgery.

The new study reviewed 10 years worth of cases involving 51 giant adenoma patients operated on by Kelly. Their symptoms included progressive visual loss, hormonal problems, tumor bleeding and/or headaches. Using a multimodality approach combining surgery with focused radiation therapy and/or medical therapy, tumors were effectively controlled in 96% of patients, according to the study. About 60% required only endonasal surgery, while about 40% received surgery plus one or more additional treatments to control residual tumor.

According to the study, 82% of 38 patients who had pre-operative visual loss regained some or all of their vision; no patients experienced new visual loss. Also, prior to surgery, 80% of the study group had suffered hormonal loss such as low sex hormones (hypogonadism), low thyroid (hypothyroidism) or growth hormone deficiency. Of these patients, nearly half had improved hormonal function after surgery, however 15% showed a deterioration in hormonal function. Ultimately, 75% of the 51 patients still required hormone replacement therapy to compensate for the loss of normal pituitary function due to damage caused by the tumor.

"This study shows that endonasal surgery has evolved into a safe and effective treatment of these large and difficult tumors," Kelly said. "The vast majority of such tumors can now be removed or effectively debulked through this minimally invasive approach."

Kelly noted that there are still some giant adenomas that require a craniotomy because they may be too massive to be removed through the nostril, or because they may be too far off the midline. However, this study shows that the endonasal approach is a safe and effective option for the great majority of these patients, he said.

"This is particularly welcome because our patients are typically in the prime of life," Kelly said. "To be struck with a deteriorating quality of life related to hormonal loss, headaches or severe visual impairment can be devastating. Fortunately, treating these tumors through a nostril and avoiding a craniotomy is the first step in getting these patients back to health."

Even though many patients may need radiation or medical therapy, and long-term hormonal replacement therapy, Kelly said that, "with properly coordinated care, most can look forward to an excellent quality of life."

Kelly told MDD that this minimally invasive approach to treating brain tumors would not be possible without the advances that the neurosurgical field has seen in devices, such as endoscopes and other surgical navigation tools. Thanks to better instrumentation, "this is just the way we do it now," he said.

Amanda Pedersen, 229-471-4212; amanda.pedersen@ahcmedia.com