[Intraoperative navigation in paranasal sinus surgery with the Philips "Neuroguide" system].

OBJECTIVE

To investigate the feasibility, precision and usefulness of computer aided surgery in ENT-sinus surgery.

MATERIAL AND METHODS

5 Patients with chronic sinus pathology and an indication for sinus surgery were elected. For intraoperative navigation we used a Philips "NEUROGUIDE" system and surgical instruments with LED's. Navigation procedures are described in detail in the paper, the system's precision was measured by pointing at anatomical landmarks. The accuracy was measured as the distance in millimeter between the bony structures of the CT scan on screen and the haircross of the pointer's tip on the screen. Another parameter of the systems accuracy was calculated by the system itself as the root mean square error in millimeter (RMSE) between the registered markers position and the marker position in the CT data set.

RESULTS

Axial 3/3/1 mm spiral CT provided sufficient resolution, data transfer via optical disk was practicable. Positioning of the navigation equipment required some experience and the registration of the patients head position needed attention, as the markers have to be pointed at precisely. During operation, the head tracking system must not change its position on the patients head to ensure a correct navigation display. The main advantage of the computed navigation system was the constant orientation during the sinus surgical procedure. Frontiers and critical anatomical structures could be identified in the corresponding CT data set, thus enabling the surgeon to decide on the further procedure. At present stage, the operation time was increased through the handling of the navigation system for at about 15 min, resulting in additional time of narcosis.

CONCLUSION

We found the computed navigation system Philips "NEUROGUIDE" system to be an established technical aid, ready to use for ENT sinus surgery, in our cases with a precision between 1 and 3 mm. These results were similar to results obtained with a SPOCS Navigation System from Aesculap, as previously published by us [17].