BrainLAB develops new wrinkle on image-guided surgery computers

When surgeons first gained new vision in the operating room through the use of image-guided surgery systems, they paid a price in the reduced mobility of their hands. Following the path of the telecommunications industry, however, wireless surgical technology is now resulting in enhanced freedom of movement in the OR.

At first, image-guided surgery workstations used arm-based surgical navigation systems, which presented a relatively fixed obstacle that the surgeon had to work around. Then, second-generation active-marker guidance systems were developed that use light-emitting surgical instruments tracked by video. While eliminating the rigid arm, these active-marker systems came with wires attached to power the light-emitting diodes on the surgical instruments.

BrainLAB, a Munich, Germany, medical technology firm specializing in equipment for neurosurgery and radiation oncology applications, has brought the wireless revolution to surgery with the introduction of its passive-marker-based VectorVision image-guided surgery system.

VectorVision received 510(k) clearance from the Food and Drug Administration in April. Ten systems are installed in the U.S., according to Eric Lindquist, vice president of sales for BrainLAB (USA), the firm's Palo Alto, CA-based U.S. subsidiary.

The passive markers central to VectorVision are essentially little reflective balls, Lindquist said. These balls can be attached to most types of surgical instruments, which is different from active-marker systems that require the use of specialized instruments supplied by the image-guided surgery vendor. VectorVision can also track multiple instruments, up to four at one time, which is an advance over previous technology.

The guidance system uses two infrared-emitting cameras. Each camera has a ring of emitters that surrounds the lens. The infrared light is reflected off the passive markers back into the video camera. Because two cameras are used, the system can triangulate data, presenting instrument location in real-time on three-dimensionally processed medical images of the patient.

"Surgeons rely on their eyes to assimilate information and to understand the environment they are operating in," Lindquist said. "In the past, CT images up on a light box have given additional information to aid their intuition. What our image-guided surgery system does is to take it one step further. It provides patient-specific information internally in real- time. As the instruments move, the surgeon can see the direct result in patient-specific data."

VectorVision is typically sold to neurosurgeons for use in cranial and spinal surgery, he said. The system is based on a Microsoft Windows NT operating system, in contrast to Unix-based competing products. This allows for greater ease of use and portability between hardware systems. VectorVision runs on a Digital Equipment (DEC) Alpha RISC microprocessor.

"Right now, DEC makes the fastest NT workstation out there," Lindquist said. "But, as other processors get faster, it (VectorVision) is completely portable. We can run it on any system that supports Windows NT."

BrainLAB has also worked with the German microscope company Möller-Wedel to integrate operating microscope technology into VectorVision, he said. This allows for microprecision guidance in some surgical applications.

While VectorVision's initial justification is seen in its improved clinical outcomes, the company hopes to present an economic rationale as well, by showing that surgery times can be reduced and complete surgical resection made more likely through use of the guidance system, Lindquist said. With improved surgical outcomes, recurrences of the condition treated would be less likely. This would benefit both the patient and cost-conscious managed-care administrators.