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Computerized "Stealth System" for Brain Surgery
Imagine virtual brain surgery-using a computer to plan the surgical approach and tell the surgeon where to operate. Sound like futuristic "Star Wars" technology? This technology, known as Frameless Stereotaxy using the STEALTH System, is now available and in use at Theda Clark Medical Center in Neenah.

Frameless Stereotaxy, also known as Computer Interactive Surgery, or Image-Guided Surgery, has been developed to assist the surgeon with extensive visual information to optimize localization of anatomy and assist in surgical planning. The STEALTH System uses a patient's CT scans and MRI scans to maintain a continuous spatial relationship between the patient's anatomy and the patient's scan images during the surgical procedure using three-dimensional digitizers and powerful computer workstations. The systems are designed for use during surgery and can be employed for surgical planning as well as intraoperative localization and verification of surgeon location.

Frameless Stereotaxy was derived from older neurosurgical procedures which utilized a frame attached to the patient's head with pins inserted into the skull. After application of the frame, the patient would then undergo CT or MRI imaging, creating a basis for a highly accurate coordinate system of the patient's anatomy. The coordinate system allows for the position of any anatomic structure to be defined in relation to the Stereotactic head ring. In this fashion, precise localization (+/- 1 mm) can be achieved for localization of targets inside the head, such as a small brain tumor. While the Stereotactic frame is stable and accurate, it is unpleasant for the patient and restricts movement in and around the operative field.

The STEALTH System uses the same concept of the localization without the need for the head ring and has proven to be much more convenient, time-saving, and more comfortable than frame-based stereotactic neurosurgery. In a typical case, small surface markers referred to as fiducials are applied to the patient's forehead and scalp. The patient then undergoes a CT scan or MRI scan, and the information including the location of the fiducials is fed into a complex computer. The patient then undergoes induction of general anesthesia and positioning on the operating room table. The location of each fiducial is registered with the computer. The computer is then able to generate three-dimensional images of the patient's head, including surface fiducial markers and internal anatomy. Various instruments with light-emitting diodes can then be registered in three-dimensional space. By using the geometric principles of light reflected from the light-emitting diodes during the procedure, the computer is able to calculate the position of the tip of the instrument and display that location in a real-time fashion on the computer screen. Using this technology, the surgeon is able to determine the optimal trajectory to a tumor and plan the operative approach to avoid eloquent brain tissue. The surgeon is also able to obtain a real-time readout of his position during any portion of the surgical procedure, aiding in more complete removal of tumor while avoiding injury to sensitive structures. The system can also be used for directing needle biopsies as well as insertion of stimulating wire electrode leads for conditions like Parkinson's disease. Overall, the STEALTH System represents a tremendous advancement in computer-assisted interactive visualization of patient anatomy. The advantages of the system include:

1) Better pre-operative localization which allows the surgeon to make a smaller incision and smaller opening in the skull for many procedures.
2) Safer surgery with decreased incidence of post-operative neurological deficits.
3) More complete resection of tumors.
4) Shorter hospital stay.
5) Decreased length of surgical procedure time.

The STEALTH System has already been used on approximately 25 cases at Theda Clark Medical Center for various brain tumors, skull-base tumors, pituitary tumors, arteriovenous malformations, ventricular catheter placements, and spinal procedures. With appropriate software, Ear, Nose & Throat surgeons have also used the system for certain complex sinus surgeries. The STEALTH System and frameless stereotaxy have revolutionized the way complex brain surgery is performed. With the development of new software, frameless stereotaxy will soon be applied to all regions of the body.

For more information about the STEALTH System, contact neurosurgeons, Thomas M. Wascher, MD, FACS or Karl A. Greene, MD, PhD, NeuroSpine Center of Wisconsin, Appleton (920) 882-8200.


For more information call 920-882-8200 or 1-888-231-5236

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5320 West Michaels Drive   |   Appleton, WI 54913-8400   |   Phone: (920) 882-8200 or (888) 231-5236   |   Fax: (920) 882-8210