A minimally invasive endoscopic procedure holds promise for safely removing large brain tumors from an area at the bottom of the skull, near the sinus cavities, clinical researchers at the Brain Tumor Center at the University of Cincinnati Neuroscience Institute (UCNI) at University Hospital have found.
The findings, to be published in the April 2010 issue of the Journal of Neurosurgery and previously published online in October 2009, have important implications for patients with large pituitary tumors (pituitary macroadenomas).
"This is the first time that a quantitative advantage has been shown for the use of endoscopy in cranial surgery," says Philip Theodosopoulos, MD, principal investigator of the study, director of skull base surgery at UC and a neurosurgeon with the Mayfield Clinic.
"This signals the dawn of a new era in minimally invasive cranial surgery. We have moved from the realm of assessing whether it is feasible to studying its clinical effectiveness. In this way, it is slowly starting to change from a novelty to standard treatment, setting the bar for the quality of surgical outcomes higher than ever before."
Although tumors of the pituitary gland, located near the base of the skull, are benign, pituitary macroadenomas can wreak havoc, causing acromegaly (an overproduction of growth hormone), Cushing disease (an overproduction of the hormone cortisol) and hyperthyroidism, as well as visual problems, headaches and dizziness.
When removing pituitary macroadenomas (tumors that are larger than 10 millimeters), surgeons have employed three distinct routes to the tumor:
- Through the skull, in a procedure called a craniotomy.
- Through an incision under the upper lip and then through the septum, which must be split apart.
- Through the nostrils -- a transnasal approach -- without an incision.
The endoscopic transsphenoidal approach, Theodosopoulos says, follows natural anatomical corridors and causes less disruption of nasal tissues. This approach, as the new study reveals, also holds benefits related to complete tumor removal, which is important for the patient's quality of life.
Removing an entire pituitary macroadenoma can be difficult because the tumor's growth pattern can cause it to extend through the sinus corridor, which is out of the surgeon's view.
Surgeons can ensure that the entire tumor has been removed if their hospital operating room is equipped with a technology known as intraoperative MRI, or ioMRI. The surgery-prolonging technology enables surgeons to take MRI scans while the patient is still under anesthesia and on the operating table. The UC Neuroscience Institute at University Hospital has had ioMRI since 1999, but the expensive technology is not available at most hospitals.