A brain tumor is a mass of abnormal cells in the brain that can develop in people of all ages. A tumor can be cancerous (malignant) or non-cancerous (benign). The American Brain Tumor Association estimates more than 700,000 people are living with a brain tumor.1 

Surgery is the primary treatment for some brain tumors, but not every tumor requires an incision. Advances in technology and surgical instruments mean some tumors are accessible through the body’s natural corridors, such as the nostrils or the mouth. Some tumors are also accessible through small incisions in a natural crease of the eyelid or behind the ear. These are called keyhole approaches because the opening is approximately the size of a keyhole. 

Dr. Nathan Zwagerman

“Our ability to work in much smaller spaces has greatly improved in recent years,” said Nathan Zwagerman, MD, a neurosurgeon at Froedtert & the Medical College of Wisconsin Froedtert Hospital who specializes in minimally invasive techniques to remove brain tumors. “By using natural pathways everyone has, we can offer an alternative in some cases to the traditional craniotomy procedure, which involves removing a substantial portion of bone.”

A faster, less painful recovery

Brain surgery is a major procedure, but people who undergo keyhole procedures are able to leave the hospital within one to two days. If people need additional treatment, such as chemotherapy or radiation therapy, they may be able to start it sooner. With a traditional craniotomy, people usually spend five to seven days recovering in the hospital.

A keyhole approach allows for minimal disruption of important structures in the brain, such as nerves that control vision and hearing, making it less likely that a person will experience changes in function.

While incisions with a keyhole procedure are minuscule, the surgeon has a wide-angle view of the tumor and its margins, as well as the structures around it because these procedures are performed using an endoscope instead of a microscope. An endoscope is a slender tube with a camera and light attached to it.

“The endoscope provides a much greater visualization of every sub-region,” Dr. Zwagerman said. “While a surgical microscope’s zoom gives you an increasingly narrow field of vision, the endoscope’s camera view is precise and much broader.”

Since the incisions (if there are any) are small, there is also a cosmetic advantage.

The tumor determines the approach

There are more than 120 different types of brain tumors. The tumor’s characteristics dictate the type of surgery a person should get. People with skull base tumors are ideal candidates for a keyhole approach. Skull base tumors are deep-seated lesions located in a band around the bottom of the head, behind the eyes, the ears and the nose. This includes people with tumors near the optic nerves and pituitary gland and tumors in the frontal and temporal lobes of the brain.

However, not all people who need brain surgery are good candidates for a minimally invasive approach. Dr. Zwagerman estimates about half of the patients in his practice can be treated with a minimally invasive approach. For the other half, he performs traditional craniotomies, which involves an opening in part of the skull bone.

Tumors located in or on the upper area of the head are best treated with traditional craniotomies. Secondary brain tumors, also called metastatic tumors, are cancerous tumors that begin elsewhere in the body and spread to the brain. These may also require a traditional craniotomy.

There are cases where treatment calls for only a partial removal of the tumor in order to relieve symptoms. In this case, a keyhole approach may be effective.

“The patient’s symptoms, the location of the tumor and the type of tumor are the determining factors,” Dr. Zwagerman said.

Minimally invasive brain surgery requires a specific set of surgical skills, training and experience. For more information on surgical options for brain tumors, visit: froedtert.com/brain-spine-tumor/treatment/surgery.


1https://www.abta.org/about-brain-tumors/brain-tumor-education/

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