Abstract
Objective: To develop a surgical navigation map made of silicone rubber sheet for use in the nasal cavity.
Method: A print-out of a life-sized sagittal CT sectional image showing the outline of the nasal septum of one side of the nasal cavity was produced. Then, an outline (L1) was drawn of the nasal septum (lower nostril-bottom of the nasal cavity-anterior wall of the sphenoid sinus-skull base-upper nostril). Important targets were marked, such as a line (L2) between the entry point on the anterior wall of the sphenoid sinus (P1) and the upper nostril. A piece of a silicone rubber sheet (KOKEN CO. Ltd., Japan, 0.5 mm thick) was cut out following L1, and the marked targets were copied on by punching small holes of different shapes through the silicone sheet.
After septoplasty, the sterilized piece of silicone sheet was placed into the nasal cavity and fitted to the curves of the bottom of nasal cavity to the nostril along the reconstructed nasal septum. The punched holes provided the positions or the directions of landmarks when performing endoscopy.
Results: More than 200 cases requiring endoscopic sinus surgery (ESS) have been operated on without any complications. Pre-operative preparation took about 20 minutes, and several minutes were required to insert and position the silicone sheet during the operation. Once the silicone sheet was fitted, the punched holoes showing landmarks were easily located by endoscopy. Positional errors were small enough to perform ESS and were no more than 2 mm.
Discussion: Because it is a projection map onto the nasal septum, accuracy is good in the sagittal plane. The silicone sheet works as a navigation aid for such targets that can be well located in the sagittal plane.
Conclusions: The surgical navigation map is easy to use without expensive equipment or an extra monitor.
