Image guided sinus surgery utilizes computerized tomography CT scans of the sinus cavity and produces a three-dimensional reconstruction. This allows surgeons to pinpoint locations of specific sinuses or other significant structures during the endoscopic surgery. This also provides for viewing the position of surgical instruments during surgery. Avoiding the eye, nerves, major blood vessels, and the brain during the procedure is essential. When procedures requiring dissection in the vicinity of these structures is anticipated or the nasal anatomy is altered from injury or previous surgery, image guided surgery is utilized.
This technology provides for seamless function during surgery with real time navigation. Image guidance is also applied in other minimally invasive procedures that are executed outside the sinuses in other areas of the skull. This technology was developed for neurosurgery and was quickly accepted for use in endoscopic sinus surgery (ESS) due to risks of disrupting structures outside the sinus cavity.
Data sets consistent with commonly used guidance systems are provided by most computerized tomography (CT) scanners. The data required may also be provided by radiology on a CD-ROM or transferred through a network directly into the image guidance system. Surgeons must undergo training in use of the system and it must be reiterated that the technique continues to require knowledge and skill in surgery.
Preparing for Surgery
Before surgery, patients must have a computerized tomography scan with the use of a headset that is specially designed to incorporate metallic land marking. This allows registration of the imaging to the patient’s anatomy automatically in the operating room. Collected data is then transferred to the system before the surgery begins. A thick foam mattress is positioned under the patient during surgery to restrict interference with the metal table.
During the Surgery
New systems have made it possible for surgeons to operate under any anesthetic technique instead of requiring general anesthesia. Absolute fixation of the head was required by the tracking system in the earlier technology. More recent technology has provided for head movement and registration can be maintained during the procedure. The headset used during the CT scan is also worn during the surgery to correlate the tracking system with the head position.
Before the procedure begins, the accuracy of registration is verified by testing landmarks on the face of the patient with images on the computer monitor. Any variations in device accuracy are monitored with the use of the coordinates stored before surgery.
During surgery, the system allows the surgeon to navigate critical features and continue safely to each new step of the surgery. This is especially advantageous when removing nasal and sinus polyp disease.