In the OR: Image-guided Surgery Soups Up Need for Networks

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The proliferation of image-guided surgery (IGS) systems has been driven by advances in the technology of image manipulation, development of innovative minimally invasive surgical (MIS) procedures as well as the establishment of IT networks capable of linking areas of image acquisition, such as radiology or orthopedics, to the operating suite. While neurosurgeons were the first clinicians to recognize the benefits of implementation of this sophisticated equipment, other specialists have come to rely upon the exquisite anatomic and increasingly physiologic roadmaps these systems provide.

Naissan Vahman, research analyst of the orthopedics division of Millennium Research Group in Toronto, describes driving forces that have enhanced market penetration for the companies that produce the equipment.

The introduction of non-spinal orthopedic applications for such MIS procedures as knee arthroplasty or hip replacement has begun to propel IGS adoption. Some manufacturers have begun to produce specific software tailored to improve MIS procedures. The benefits of MIS have been well-documented in scientific literature as offering lower cost, shorter hospital stays, and less recuperative time compared to those experienced with traditional procedures.

Although IGS presents a huge benefit to the surgeons who recognize its value, there are limiting forces at work, not the least of which are the financial aspects. In this climate of constant cost containment, hospitals have been relatively slow to adopt these new systems that range from $100,000 for a basic set up to $400,000 for a fully functional system. In many institutions, significant modifications to the IT network infrastructure are required for efficient implementation of the technology.

Many hospitals are housed in older buildings, and laying or modifying a network with sufficient bandwidth to accommodate moving the huge image data files to the OR, is not always an easy task. Most operating suites were considered low on the priority list for inclusion in the IT network up to this point, largely because images were hand-carried on a variety of media (film, CDs, optical disks, or Zip disks) via "sneaker-net" to the OR.

Richard Buscholz, M.D., F.A.C.S., the K.R. Smith endowed professor of neurosurgery for Saint Louis University School of Medicine, is one of the developers and patent holders of the system known as StealthStation (currently produced by Medtronic). With a current installed base of 1,400 units worldwide, the technology is available in a wide array of institutions.

In the original incarnation of the system, StealthStation employed a large series of drive bays specifically programmed to permit receipt of images from each particular scanner in that healthcare setting. This circumstance required significant effort to retrofit all existing StealthStations in the hospital as the institution replaced CT or MRI scanners.

"Now that IT has begun to take off in hospitals, we have found that we can rely on a standardized format [DICOM] to do image retrieval and archiving," says Bucholz. "Having said that, there appear to be certain dialects of DICOM which are still somewhat problematic for our system, but, in general, I would say that an increasing number of scanners now are at least speaking in the same language."

Because image data sets are quite large (for example, a typical CT scan includes 50 to 100 images, each are 512 x 512 pixels in size where each pixel is made up of 16 bits of grey tone) the network must be configured to support image data file transfers. Without sufficient bandwidth in the network, the images would consume a large proportion of the network's capability, and render it useless for other functions such as managing electronic medical records, or other IS activity.

Additionally, without some level of PACS (picture archiving and communications system) connectivity, the scanners do not function as servers, and they are just another presence on the network. Buscholz explains that unless there is a PACS, they cannot patch into the scanners and transmit the images over the network.

Kamal Thapar, M.D., Ph.D., FRCSC, director of the department of neurosurgery at Sacred Heart Hospital, Eau Claire, Wis., explains that their PACS functions quite well to transfer images to their BrainLAB planning station.

"The goal is to fully and faithfully merge virtual space with real space and that's what image guidance allows you to do," says Thapar. "There are relatively few