Since its birth over 50 years ago, the field of stereotactic surgery has evolved into two separate but intimately related fields. Although functional neurosurgery is still practiced by those few neurosurgeons with special training, stereotactic image guided neurosurgery is commonly used and should be familiar to all neurosurgeons.
Stereotactic Primer
Image guided stereotactic surgery involves the use of three-dimensional guidance systems to efficiently approach pathological structures within the brain to facilitate craniotomy or to treat masses with focused radiation, as with stereotactic radiosurgery or brachytherapy.
Functional neurosurgery involves the use of three-dimensional guidance systems and related neurophysiological techniques to do procedures that change the function of the nervous system, that is, to make lesions or to stimulate anatomical targets to treat movement disorders, pain, epilepsy or certain psychiatric illnesses. Functional neurosurgery remains a true subspecialty, practiced only by those neurosurgeons with specialized training in the neuroanatomical and neurophysiological background. It involves problems more often in the realm of neurologists than neurosurgeons.
Image guided stereotactic surgery, however, has evolved into a discipline that every neurosurgeon should know. The use of guidance techniques can make craniotomy more efficient, minimizing the size of the exposure and the invasiveness, allowing an approach through the least eloquent path, defining resection boundaries that may not be apparent to the surgeon’s eye, and minimizing manipulation of brain tissue outside the pathologic process. All this may add up to improved outcome, faster recuperation, fewer adverse neurological sequelae and, consequently, less cost in the long run.
Stereotactic radiotherapy with the Gamma Knife or linear accelerator will not be practiced by all neurosurgeons. A few neurosurgeons would practice conformal stereotactic radiotherapy that involves focussed fractionated radiation techniques that permit maximal radiation to a tumor while minimizing radiation to the rest of the brain. Yet, all neurosurgeons should know the indications, limitations, and potential complications of these techniques.
Knowledge is Power
As stereotactic radiosurgery becomes available to most potential patients, its use as a primary modality or adjunct treatment cannot be ignored. For instance, there is increasing statistical evidence that the outcome may be better in certain patients with acoustic neurinoma treated with stereotactic radiosurgery rather than conventional surgery. It is no longer necessary to leave a patient with a severe neurological deficit in an attempt to resect a tumor or a residual portion of tumor intimately involving cranial nerves or brain stem when it could be treated as well with stereotactic radiosurgery or conformal stereotactic radiotherapy.
The neurosurgeon only can apply the best clinical judgment during surgery if he or she knows whether that last bit of tumor could be treated better by stereotactic radiation or whether the risk of injury to a cranial nerve or venous sinus is justified.
Information about stereotactic and functional neurosurgery has become important for all neurosurgeons, especially those now using image guided techniques for craniotomy.
A Specialty on the Rise
The number of neurosurgeons practicing image guided stereotactic techniques is growing rapidly. The number of neurosurgeons who recognize the importance of knowing about stereotactic radiation techniques is increasing. This has resulted in a renewed interest in membership in the Joint Section for Stereotactic and Functional Neurosurgery, as well as membership in the American Society for Stereotactic and Functional Neurosurgery and the World Society for Stereotactic and Functional Neurosurgery. We invite all neurosurgeons to become members, since we believe that all neuroosurgeons should have an interest in the ever-expanding field of stereotactic surgery.
Further information about membership and application forms can be obtained through the AANS Membership Services Department at
(847) 378-0508.
Editor’s Note: The World Society for Stereotactic and Functional Neurosurgery Annual Meeting is September 11-14, 2001, in North Sydney, Australia. For information, go to www.wssfn.org.
class=”pulldown”>Philip L. Gildenberg, MD, PhD, is Past-Chairman, Joint Section on Stereotactic and Functional Neurosurgery.