| The Surgical Technologist | OCTOBER 2015 450 type is an electromagnetic system that employs a magnetic field to register reference points on the patient. Although the electromagnetic system does not need to be seen by the computer to track the surgery, it requires wires and a large amount of metal in the magnetic field that can cause a skewed reading. The purpose of image-guided technology in Function- al Endoscopic Sinus Surgery (FESS) is to clarify complex anatomy in select cases. Although this technology is at the discretion of the surgeon and facility, it is typically used for sphenoid, frontal and posterior ethmoid surgeries. Candidates for FESS using image-guided systems generally are patients with previous surgeries that may need revi- sion, or those with any distorted anatomy due to abnormal anatomical landmarks, polyps, benign or malignant neo- plasms or CSF leaking. D I AGNOS I S Diagnosis of a patient for potential sinus surgery begins with an examination of the ear, nose and throat to deter- mine what is causing the pathology. Depending on the relationship to allergy, infection or obstruction, X-rays, blood or allergy tests may be required as well as a CT scan. Sinus surgery, although safe, generally is the last resort and performed when maximal medical therapy has failed, typically when the patient has chronic sinusitis. After the diagnosis but before surgery, CT images are taken and downloaded into the IGS where the patient’s CT scan is displayed onto a monitor in axial, sagittal and coronal positions. These views give the surgeon the capabilities to create a surgical trajectory in the same way an astronaut or pilot would create a flight plan. Today’s state-of-the-art technology allows precision within 2mm and is intended as an aid during surgical procedures to locate anatomical structures that may otherwise be skewed. Furthermore, the system tracks the placement of instruments in real-time pro- jecting the image on the monitor, thus showing the surgeon exactly where the instruments are located in the sinus cavity. P R EOP ER A T I V E F I E L D A ND SE T UP The equipment used is dependent on a surgeon’s and facili- ties’ preference. In this case preparation of such a surgery requires the following equipment, supplies and instru- ments needed to facilitate a thorough and inclusive sur- gery. SURG I C A L P R EPA R A T I ON Following a routine timeout initiated by the circulating nurse, the patient is placed under anesthesia. A tracker is strapped to the forehead of the patient where the IGS regis- ters the instruments. A mobile emitter is attached to the OR bed pointing directly at the patient’s nose at 15 to 25cm in distance to insure trackers are inside the electromagnetic field to record placement and display viewing on the monitor. No skin prep is necessary as the nasal area is considered clean contaminated. Per the preference of the surgeon, the patient will be injected with 1% lidocaine epinephrine injection into the septum, turbinates and any polyps. The nasal cavity will be packed with pledgets soaked in 0.25% bupivacaine hydrochloride and epinephrine 1:1000 mixed 50/50. Ten minutes will need to pass to ensure the epinephrine will be effective in vasoconstriction. During this time, the surgical tech will drape three towels in tri- angulation across the patient’s mouth and alongside each ear exposing the nose, eyes and forehead area. A split sheet drape will be placed on the patient and all suction, the cam- era, straight shot cords and IGS equipment will be put in place. SURG I C A L I N T ERV EN T I ON To begin the procedure, the surgeon will use the IGS tracing instrument to register the patient tracker with the instru- Today’s computer image-guided surgery system works by correlating a map of the patient’s anatomy using a CT or MRI scan of the patient with a steri-static performing head registry and subsequently integrating the instru- ments used in the surgery. The instruments then oper- ate like a GPS reflecting their placement as images seen on the computer monitor showing exactly where the sur- geon is working.