Question: Tell me about computer-assisted or image-guided endoscopic sinus surgery.
Answer: Computer-assisted surgery was initially developed for accurate localization during neurosurgical procedures. The application of this technique in endoscopic sinus surgery is available in many major centers. This system allows the surgeon to localize the tip of the surgical instrument in the paranasal sinuses, generally within 1-2 mm of accuracy on coronal, axial, and sagittal CT images. Computer-assisted endoscopic sinus surgery can potentially aid the surgeon, especially when working in or near difficult areas such as the frontal sinuses, sphenoid sinus, skull base and orbit.

These systems are not universally available. While they are helpful in specific cases, they are not always necessary for an experienced, skillful surgeon to perform difficult procedures. While they do provide potential advantage in specific situations. They are NOT, at this stage, associated with decreased surgical risk.

Question: Is image guidance surgery an important advance?
Answer: The first revolutionary change in the surgical treatment of the sinuses was the introduction and refinement of endoscopic techniques. The second important development in the modern history of rhinology was the introduction of powered instrumentation. Now we are seeing a third turning point, which is the use of intraoperative image guidance in endoscopic sinus surgery.

Question: What devices are used?
Answer: There are a number of companies making image-guidance systems, and the basic elements are the same in all of them. All of these devices have a tracking system, a head set, and a computer with hardware and software that interprets the information it receives from an instrument that is used inside the nose that has been registered with the system.

There are two types of image guidance surgery devices: optical and electomagnetic.

• In optical devices, a direct and uninterrupted line-of-sight between the patient and the image guidance system is necessary. The headset does not need to be present when the patient has a CT scan. Registration of fiducials, or positioning points, is required when the patient is in the operating room before the image guidance system may be used.
• The electromagnetic devices require that the patient wear a headset during the CT scan, and then this headset must be used at the time of surgery. The problems with line-of-site that are present in the optical systems is not an issue in the electromagnetic systems. Also the fiducials are on the headset, so markers or registration of fiducials is not required.

Question: Any summary thoughts about new technology in sinus surgery?
Answer: There have been a number of advances in rhinology in the 21st century. As we celebrate these advances and use them to the benefit of our patients, we must always remember the basic principles that always take priority over technology: anatomic knowledge, surgical ability, and clinical judgement.