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The Horizons of Intraoperative Imaging
How in-OR fluoroscopy is advancing beyond the C-arm.
David Bernard
Publish Date: October 10, 2007   |  Tags:   Surgical Video and Imaging

The O-arm promises to make surgery so precise that it could let your physicians think that they're flirting with ' dare we say it ' perfection.

"The idea [of intraoperative imaging] doesn't necessarily start with efficiency, it starts with safety," says neurosurgeon Evan Packer, MD, of the Delray Medical Center in Delray Beach, Fla. "You can almost be perfect every time at the outset."

Think of the O-arm as a C-arm with 360-degree X-ray vision that captures a series of exposures around the patient to deliver three-dimensional, CAT-style images for diagnosis, navigation and confirmation - all without a trip to the radiology department. The O-arm's $750,000 price tag is steep, but the advantages that fluoroscopic imaging devices bring to interventional procedures - accuracy, efficiency, speed, better outcomes - have earned them a regular place at the OR table while also influencing the basics of surgery.

A surgical marketing executive says intraoperative imaging is fueling the shift from inpatient facilities to surgery centers and even to office-based procedures. He considers pain management to be the highest-growth segment of the imaging business. Experts expect the minimally invasive orthopedic, spine, neurosurgery, ENT, urology and pain procedures both spurred and guided by fluoroscopic imaging to remain in high demand. Here, some imaging observers discuss the latest advances in fluoroscopic intraoperative imaging and offer their views on its future.

Advantages of intraoperative imaging
The modern OR is a nexus of visual information, with vital signs monitors, PACS, overhead and endoscopic cameras and ultrasound devices delivering input to video screens mounted around the table. Perhaps the most revolutionary of this information has been that which is captured and displayed by fluoroscopic imaging devices.

C-arms and other on-site, in-OR, fluoroscopic imaging equipment provide high-quality diagnostic views of a patient's anatomy in the operative position. The immediate feedback assists surgeons in navigating small-incision surgical procedures or difficult-to-reach areas.

Before the advent of such technology, "the most efficacious way of telling where we were was a CAT scan," says Lloyd Zucker, MD, a neurosurgeon on staff at Delray Medical Center. "That meant you'd have to close the patient, take him from the OR to the CAT, make sure you'd accomplished what you'd set out to do and take the patient to ICU. If he needed more done, there'd be a later surgery." Even then, the resulting image was a variable in any following surgeries, since the CAT scan, like pre-operative X-rays, wouldn't show an exact congruence of image to anatomy due to changes in patient positioning.

Because intraoperative imaging doesn't require the patient to be moved from the OR, or the table, it overcomes the limitations of computerized axial tomography in more than just speeding the surgical workflow and announcing outcomes sooner. It also lets surgical staff monitor the progress of the surgery, from verifying instrument or implant placement to confirming that a procedure's aims have been met, and offering opportunities for immediate adjustment if they haven't or instant response if potential complications are detected.

"It's not disruptive technology, but transformative technology," says Henry Soch, vice president of imaging intelligence products for Sg2, a healthcare consulting firm in Skokie, Ill. "You can determine, to the surgeon's satisfaction, the result in live information before completing the procedure, for better results, as opposed to completing the procedure and scheduling a follow-up visit, and perhaps a second surgery." Besides offering advantages to the surgeon, this literal "X-ray vision" also benefits the patient by attaining the best possible outcome.

The O-arm in the OR
At Delray Medical Center, Drs. Packer and Zucker have been using the O-arm in their neuro and spine procedures. Dr. Packer admits that he and his colleagues were initially skeptical about the machine, which combines OR fluoroscopy with a stereotactic guidance system for on-site visualization.

"We had a lot of doubts based on what we'd seen, since manufacturers make a lot of claims," he recalls. "We went out and saw it in operation on-site. We were blown away by how efficient, and how easy, it is to use, how it's improved surgery. It's changed our confidence levels. It's probably in use every day."

While its 360-degree, 3-D vision is a big step beyond the images produced by C-arms, its mobility is limited as compared to its imaging predecessor. As opposed to mobile C-arms, which can bring imaging to whichever OR demands it, the O-arm is confined to the center's larger ORs, says Dr. Zucker. "It's a big thing in the OR. It's not a fixed thing, so it can be moved, but it won't fit cleanly into a small room."

Delray Medical Center's O-arm system is one of about 26 in use in facilities nationwide and the first to be installed in Florida. It's found uses in spine, neurosurgery, orthopedics and ENT procedures. Even the center's urologists have inquired as to its potential use in prostate seed implantation, say the doctors.

"The reality is becoming that anything that uses a C-arm - anything that may benefit from the ability to guide externally - may benefit from the accuracy of this," says Dr. Zucker. "The process of development is certainly there."

Noting the trend toward multidisciplinary teams gathering around procedures, Dr. Packer agrees. "Any facility that is versed in spine surgery will realize the system's applications for ENT, vascular or ortho procedures." While those applications may require different software and skill sets, he says, "they just require interested people to do them."

Chief among those "interested people" should be your radiological staff. "Our radiology staff took the reins, learned everything there was to know about it, taught us what it could do," says Dr. Packer. At its foundation, he says, the operation and safe use of O-arm technology follow from those of existing technology. "It starts out with being a good X-ray tech." (See "5 Steps to Improved C-arm Safety" on page 88.)

As with any emerging technology, corporate support is essential, namely solid backing from the manufacturer's representatives to train and service the capital investment. "Any time you deal with complex equipment, there are going to be challenges," says Dr. Packer. "It's a matter of gaining experience to understand and troubleshoot those quirks. That's why one thing we negotiated in the deal was excellent support."

C-arm upgrades
At about three-quarters of a million dollars - nearly as much as MRI or CAT scan equipment - and hardly compact, there's not a great likelihood that the O-arm imaging system will soon permeate the surgical center market the way that the C-arm did. Imaging observers note, however, that recently available

C-arm advances make a move toward approximating the O-arm's abilities.

Three-dimensional volumetric imaging from a C-arm can be attained through hardware and software upgrades, says Mr. Soch. The rapid rotation of the arm around the patient can generate 50 to 100 exposures spanning 120 to 160 degrees in the space of about 10 or 15 seconds, he says. The images can be reconstructed as a 3-D image set similar to that of a CAT scan, but at a lower radiation dose.

"As the computer got faster and more powerful on fixed platform [C-arm] models, clinicians said it would be helpful for use in ensuring accuracy in surgery," says Mr. Soch. He says that C-arm 3-D volumetric imaging is regularly used in orthopedic procedures such as vertebroplasty, to determine whether the appropriate amount of cement has been used, or kyphoplasty, to monitor the inflation of the balloon.

"This is the main technology on the horizon that we think it going to change the way that ambulatory surgery is done," he says. "CAT and MRI are just too cost-prohibitive to have on an outpatient surgery basis."

Several manufacturers have introduced the upgrades - which include a faster computer, a disk drive with more storage space, software enabling data set reconstruction and the mechanism to drive the C-arm's rotation - for their high-end systems, and Mr. Soch anticipates an eventual migration of the technology to more basic systems as well.

The estimated cost of the upgrades is about $70,000 to $80,000 for mobile C-arm models and about $100,000 to $150,000 for fixed-platform models.

The future of imaging
Early generations of intraoperative imaging devices were large and immobile, but as Mr. Soch points out, as surgery moved to surgical centers, the development of smaller, more mobile and less expensive equipment became commercially feasible. Future advances, he says, will follow a similar path of clinical demand.

One influence is the providers who are taking surgery out of hospitals and into ambulatory ORs. "Hospital-based practitioners who are looking to expand what they're doing, to carve out a piece of independence, they may be inclined to use the same type of equipment they're familiar with from the hospital," says the marketing exec. "But they're not necessarily experts in the imaging field, and they may demand more specialized functions as they build experience. There are a whole set of needs here."

Perhaps the weightiest need for physician-owners and facility managers involves the economics of capital equipment. While a future of falling prices for imaging equipment is desirable, but not entirely predictable, the hard line will remain balancing cost versus return.

"Do you have an efficient enough procedure volume to make [an imaging purchase] financially worthwhile?" asks Mr. Soch. "Look at the types of procedures that are done at your facility. Will it be a standard part of those interventional procedures?"

Even as intraoperative imaging devices find more and more uses, will your staff be skilled enough to efficiently integrate them into your workflow? As a trend, facilities want their ORs to adopt higher technologies, says the marketing exec, "but they also want to be able to clear out that room in 20 minutes and bring in a new case." As a result, staff cross-training may involve greater use of imaging equipment.

The demand for "interoperability" - the principle behind such catch phrases as "integrated surgical suite," "wall of knowledge" and other depictions of the OR of the future - also offers a view into the role that imaging systems will increasingly play in the future. The harnessing together of surgical imaging and information systems to input into a single, multi-faceted guidance system - one that allows, for instance, the ability to easily switch back and forth between fluoroscopic and endoscopic imaging - could provide additional perspectives on anatomical visualization and navigation. "There are great opportunities in interoperability, but it hasn't really exploded yet," says the marketing exec.

"This is the first generation," says Dr. Packer about his facility's O-arm technology. "In the future, we'll be seeing potentially smaller equipment that emits less radiation."

At present, he says, the results of fluoroscopic intraoperative imaging are very close to live pictures, but the future may bring constantly updated, true real-time images. "The software for navigation and the overall image guidance should be much better, more accurate," he says. "But this [current O-arm] is a big step."