SMALLER SITE A mini C-arm is more maneuverable and takes up less space than a full-sized C-arm, making it ideal for foot and ankle cases.

High-quality intraoperative imaging lets surgeons navigate confidently around joints and confirm exact hardware placement during increasingly complex procedures. If you're looking to enhance the imaging capabilities in your ortho ORs, here are some factors and recent advances in C-arm technology you'll want to consider.

1. Size
One of the first decisions you'll face is whether to choose a full-sized mobile C-arm, which is capable of imaging practically any part of a patient, head to toe, or a mini C-arm, a more compact unit that's ideal for scanning just the extremities or smaller operative sites. To choose between the two, assess the variety and volume of procedures that require fluoroscopic imaging at your facility.

A full-sized mobile C-arm is built big enough to fit around your largest patients, making them ideal for spine surgery and procedures performed on hips and large fractures. But it's not the only reason. Larger units also deliver more imaging power for a greater ability to see through soft tissue and higher quality images, and often offer magnification functions.

If your facility doesn't host a high volume of large orthopedic cases, you might be hesitant to spend your capital budget on equipment that can cost as much as $100,000 to $140,000. The latest C-arms are capable of more than just musculoskeletal imaging, though. If your facility is ready to expand its services, and can make the C-arm available to pain management, urology or even vascular specialists, you can keep scheduling larger ortho cases, while also growing your business by filling slots on the schedule.

If, on the other hand, it's your hand surgery business that's really thriving — or your foot and ankle service line is making great strides — you'll need a high-functioning mini C-arm. The compact unit is more conveniently maneuvered in and around the OR and its reduced footprint leaves more space for other technologies.

SHOW TIME Newer C-arms offer improved image quality along with the safer use of radiation.

Plus, a mini C-arm saves you the expense of acquiring additional imaging equipment. In order to fluoroscopically image a patient on a table with a full-sized C-arm, that table has to be constructed from radiolucent materials. With a mini C-arm, your OR team can use the surgical table you already have. By inverting the arm (which is draped for use in the sterile field), they can use the image intensifier as the operating surface for the hand, foot or ankle. Incidentally, this inverted-position use has also been found to reduce radiation exposure to the patient and the surgeon (osmag.net/joR7EM).

If you see your surgeons doing a lot of mini-C-arm-suitable cases, then by all means go with the compact unit. At $50,000 or under, a mini C-arm is less expensive and does an equally good job to a full-sized unit. But obtaining a larger unit that's able to serve multiple purposes can attract surgeons in other disciplines.

2. Imaging and control
Newer C-arm models incorporate special imaging functions that not only improve the surgical view, but provide a measure of safety for the surgical team and patient. "As Low As Reasonably Achievable" (ALARA) is the guiding principle for the safe use of C-arms and other imaging equipment (see "How Safe Are Your Imaging Practices?" on p. 22). Your surgeons want high-quality images, but you need to limit the amount of radiation exposure in the process. "Coning down" is an automated function available on newer machines that reduces the radiation dose without adversely affecting the resulting image. It focuses the beam to minimize the area exposed to radiation (to protect the patient) and decrease the amount of radiation scattered (to protect the staff).

It's called "coning down" because traditionally it has worked as a shrinking circle, like a camera lens or the eye's iris. Some newer C-arms, however, can "cone in" by cropping the image vertically from the left and right sides toward the midline of the view, creating a narrow rectangular image. This can improve visualization in difficult-to-view areas and in obese patients. For example, if you're in the spine, the radiation beamed in to image the ribs and shoulder blades is unnecessary for ALARA purposes and unhelpful for viewing the area of immediate importance. Adjusting the C-arm to focus its energy just on the spinal elements delivers the optimal image.

The ability to selectively enhance fluoroscopic images is another advance that's available in some newer C-arms. This feature is achieved through how the system reads the imaging data and presents it to the user, not through how it is captured. Being able to program the system's settings to increase the contrast between items of different densities in the imaging field creates a sharper view of the bony elements in the primary area of focus and reduces the prominence of soft tissue. A clearer, easier-to-interpret image decreases the need to take more pictures and expose the patient and team to more radiation. Image enhancement features can often be operated via a C-arm's touchscreen interface.

READY FOR ACTION A full-sized mobile C-arm provides the power necessary to image spines, hips and large fractures.

Getting the right shot during C-arm imaging can be tricky. Truth be told, many surgeons would rather control the imaging exposures themselves. In smaller centers, in fact, they may not have any surgical staffers who can be assigned solely to handle C-arm operations for them. For those reasons, a pedal system that allows the surgeon to control when an image is shot at the tap of a foot is a feature worth looking for in a C-arm.

3. Connectivity
Once your C-arm has captured images, what can you do with them? It's another important factor to consider. Traditionally, image output has involved display screens and peripheral printers. The displays have seen some advances, including articulation and detachability that allow you to clear a space at the surgical field while still seeing their images.

While the printing of images to paper or X-ray film is still in use, digital connectivity is an exciting new development. The ability of C-arms to integrate directly with electronic medical records or picture archiving and communication systems (PACS) enables the transfer and saving of image files to a central location. Then, whether surgeons are in the OR, the office or at the patient's bedside, they have immediate access to all the pictures they've taken during the procedure.