Biomedical Engineering Reference
In-Depth Information
Thus, soon after the introduction of CT scanning, existing stereotactic sys-
tems (e.g., Leksell, Reichert-Mundinger, and Todd-Wells) were modified so that
CT images could be used for co-registration (19). However, these older, pre-CT
systems were constrained by their initial design purpose, i.e., to access deep
midline brain structures, and the first modifications did not take advantage of the
potential for navigation throughout the cranial vault as imaged by CT.
In the late 1970s, the Brown-Roberts-Wells stereotactic system was in-
vented based on a whole new concept for both co-registering image and physical
space and accessing that space, particularly the surface and periphery of the
brain (6,7). During this period, Kelly demonstrated that these stereotactic sys-
tems could be combined with computer graphic techniques to define and target
not only single points, but also multiple points representing the three-
dimensional volume and position of lesions within the brain. That is, stereotactic
techniques could be used for volumetric craniotomies to navigate to specific
lesions within the brain for biopsy and ablation (16,17). These advances led to
more precise and smaller cranial skull openings to approach lesions, which de-
creased the morbidity of many brain operations.
At the same time, operating microscopes, which provide exquisite lighting
and magnification, as well as endoscopic visual techniques using both monocu-
lar and binocular video images directed either to both eyes or formatted stereo-
scopically on a computer console, became routine tools to enhance the surgeon's
operating precision. Additionally, the development of approaches through and
below the skull and in all quadrants around the spine to lesions in the brain and
the spinal cord decreased potential operative damage (11).
In the mid to late 1980s, several neurosurgeons—including Roberts, Wata-
nabe, and Bucholz—introduced the concept of frameless stereotactic localiza-
tion by mating three-dimensional digitizers designed to be used in the industrial
workplace with advanced computer graphics (8,12,22,25,27). These devices
were introduced into neurosurgical practice in the early 1990s, tested, and com-
mercialized, and have become an accepted standard of care for surgical ap-
proaches to most intracranial lesions and many spinal lesions.
Neurosurgeons practicing at the end of the twentieth century could rely on
highly defined CT, MRI, functional MRI, and PET images of actual brain le-
sions and structures to plan a surgical procedure, and they had established opera-
tive magnification and unique frameless approaches from all quadrants of the
cranial vault and spine to manage ablation and resection of those lesions while
protecting surrounding normal structures.
2.4. Robots
The next frontier involved mating these technologies with robots (see pre-
ceding chapter 7 by Kirchner and Spenneberg). During the mid-1980s, several
neurosurgical investigators, including Kwoh, Young, Drake, Benebid, and
