Image-guided surgery (IGS) lets a surgeon track the position of implants and instruments in a virtual-reality display relative to the patient's anatomy. The aim is to guide the device safely and precisely to its target in three dimensions - and to reduce the invasiveness of procedures to a minimum. For example, navigated otolaryngologic surgery makes it easier to perform complicated sinus and temporal bone surgeries. Navigated orthopedic surgery ensures that an implant is precisely positioned. Its use in other surgical specialties is being evaluated. Here's what you need to consider when deciding whether to invest in IGS equipment. Assess the clinical benefits.

Assess the clinical benefits
By adding an IGS system to your facility, you can shift cases to your freestanding outpatient ORs that you may have been hesitant to host. Moving cases to a surgical facility you've invested in should not only increase profitability and efficiency, but also help you comply with "safe harbor" guidelines.

Studies to quantify the long-term clinical benefits of using image-guided navigation technology are under way. Presently, no one would state that IGS is the "standard of care" for all specialties or cases that can employ a navigation system. Rather, the reason to use this equipment is as an adjunctive tool when performing specific surgical cases. It is not a substitute nor is it a replacement for good surgical judgment.

I do not use IGS on every sinus case I perform. But the technology facilitates transnasal surgical techniques which, previously, external facial approaches may have been required. The learning curve for sinus surgeons to incorporate this "tool" is relatively short. Using IGS technology for functional endoscopic sinus surgery does not change the basic surgical technique or the endoscopes and forceps you'll use.

Where does IGS fit?
To assess how well IGS might fit in to your facility, review historical utilization, both in terms of specific surgeons and surgical specialties, then project for future growth. Be alert for specialties that you can add to your facility. Some questions to consider:

• Are you a single-specialty or multi-specialty center? Some IGS systems can accommodate several surgical specialties (some are designed for single-specialty use). IGS systems designed to be used by several specialties present an opportunity for a facility to purchase additional software packages as growth occurs, resulting in a significant cost savings when compared to buying a second system. Increased volume is the key to recouping your investment in this equipment. Depending on your local reimbursement environment and correct coding, potentially an additional fee via an "add-on" CPT code may be charged by the surgeon when using an IGS system either in a hospital OPD or ASC setting. Because this code hasn't been approved for use in the Medicare ASC procedure list, it's less likely that the ASC would receive an additional facility fee when a navigation system is used during a surgical case.
• How widely used is IGS at competing hospitals and ASCs in your community? Perhaps you can lure surgeons and their cases away from other local institutions. Potentially, the purchase of an IGS system may stimulate new physicians within the community to become utilizers of or even investors in your facility.
• How will IGS affect OR efficiency? It takes longer to set up image-guided navigation equipment for each procedure. Ultimately, even if additional "front end" time is required, the goal should be to maintain or improve the present OR daily caseload.
• Does IGS present marketing opportunities for the facility? IGS may offer PR opportunities to enhance the prestige of your center.

Evaluate each IGS system
Form a committee of administrators and surgeons to decide which specialties and procedures to evaluate. Set up your priority list and create a criteria scale for each item of evaluation (set-up time, intraoperative precision, ease of use and price).

When viewing system demonstrations or performing hands-on trials, decide which features you absolutely need and which are less important. To me, the make-or-break factors are a system's ability to maintain navigation accuracy throughout the case and ease of use.

Reproducibility of results in terms of registration, accuracy and navigation will affect surgical efficiency and facility profitability. Consider that the patient resides in the "real world" while the radiographic image displayed on the IGS system exists in a "virtual world." Part of the initialization and set-up program involves linking the two together so that when you introduce an instrument into the surgical field, a representation of that instrument will be seen in its correct spatial orientation on the IGS video display. The methods used to "register" the patient and "calibrate" the instruments vary by manufacturer. Depending on the method employed, this can be the most time-consuming part of the pre-surgical set-up process. More importantly, it is probably the most critical step in terms of navigation accuracy, which correlates to surgical precision.

Secondly, look at how many times you have to repeat certain steps of this process. Intraoperatively, if the "reference device" on the patient or on the navigation instrument moves, you may have to "re-register" the patient and "re-calibrate" the instruments. For sinus surgery, it has been stated that as little as 2 millimeters of "slippage" can alter surgical outcome. A system that requires you to repeat certain critical steps may be a detriment rather than an asset to the OR's profitability.

Avoid the temptation of letting price alone dictate your purchase decision. IGS systems can vary significantly in price according to their features, software packages and options. If you've planned well, the equipment will be utilized for (and the cost will be amortized over) five to seven years. Keep in mind the case mix and the specialties you plan to incorporate under the IGS umbrella. Remember, the loss of one case per week over the course of a single year potentially results in a revenue loss that can virtually equal the entire cost of a new navigation system. Finally, do not forget corporate reliability when considering the purchase of this or any other significant piece of capital equipment.