Expertise in skull base surgery

Skull base tumors pose significant challenges, due to their close proximity to important neurovascular structures and potential extension into neural canals or the cavernous sinus. Surgical resection can be associated with significant morbidity, including damage to the optic nerve and leakage of cerebral spinal fluid. Mayo Clinic in Rochester, Minn., has specialists with experience in a range of innovative surgical techniques for treatment of these complex cases.

"Everything we do centers around maximal safe resection of tumors, limiting comorbidity to patients and trying to get them back to the normal work or family life they previously had," says Jamie J. Van Gompel, M.D., a neurosurgeon at Mayo Clinic in Minnesota.

Mayo's experience with skull base lesions ranges from rare types — esthesioneuroblastomas, chordomas and chondrosarcomas — to the more common meningiomas, pituitary tumors, craniopharyngiomas and sinonasal malignancies. Mayo's expertise extends across several specialties. In addition to neurosurgeons, the skull base surgery team at Mayo comprises radiologists, otorhinolaryngologists, otologists, oncologists, radiation oncologists and plastic surgeons. "There are a lot of advantages to having a facility with expertise in all fields," Dr. Van Gompel says. "We have developed a team with deep experience."

Neuroradiologists play a key role in diagnostic work and preoperative planning, as well as interpreting postoperative CT scans and MRI. During surgery Mayo neuroradiologists can use intraoperative MRI, which is particularly helpful in cases of more-complex lesions based in the central skull. The surgery is usually performed by both a neurosurgeon and an otorhinolaryngologist. "There are two expert sets of eyes, and often intraoperative discussion about what's best for the patient," Dr. Van Gompel says.

Mayo's practice focuses on using minimally invasive procedures whenever possible. In addition to an endoscopic endonasal approach, in which the tumor or lesion is removed through the nose, Mayo is also expanding its practice of endoscopic-assisted cranial surgery. That procedure requires a smaller craniotomy than cranial surgery performed with a microscope because while the microscope focuses light narrowly on a tumor, the endoscope emanates light outward. Endoscopic-assisted craniotomy can be used to reach very deep lesions with less morbidity.

"With the microscope, craniotomies often are large because the opening determines the light at the resection," Dr. Van Gompel explains. "The endoscope brings visualization to the field where you're working, restricting the opening that you need. Therefore, patients should have less approach-related morbidity but the same tumor-related outcomes."

Proton beam therapy

To enhance treatment options for skull base tumors, Mayo is constructing a proton beam therapy facility in Rochester. When it opens, Mayo will be one of the few centers in the Midwest capable of offering both minimally invasive skull base surgery and proton beam therapy in a single center. That treatment regime is particularly appropriate for patients with chondrosarcoma or chordoma — tumors that tend to occur in older adolescents and young adults, for whom complex resection and large doses of radiation pose risks of long-term complications.

Approaches tailored to the patient

The range of experience and expertise at Mayo Clinic allows patients to receive care appropriate to their individual needs. "Endoscopic techniques are absolutely critical for treating chondrosarcomas and chordomas, in order to reach the portion of the skull base that can't be reached in any other way," Dr. Van Gompel says.

Yet open procedures remain necessary. Dr. Van Gompel is currently conducting research that indicates that in remotely located lesions, a traditional open approach can address one portion of the petrous apex. "But there is a smaller subsegment that you cannot see in the open approach," he notes. "So there actually are places and particular pathologies that need both open and endoscopic approaches."