Intraoperative computer aided navigation in ENT sinus surgery using Philips "NEUROGUIDE" system

Objective: To investigate the feasibility, precision and usefulness of comp uter aided surgery in ENT-sinus surgery. Material and Methods: 5 Patients with chronic sinus pathology and an indica tion for sinus surgery were elected. For intraoperative navigation we used a Philips "NEUROGUIDE" system and surgical instruments with LED's. Navigati on 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 o n screen and the haircross of the pointer's tip on the screen. Another para meter of the systems accuracy was calculated by the system itself as the ro ot mean square error in millimeter (RMSE) between the registered markers po sition and the marker position in the CT data set. Results: Axial 3/3/1 mm spiral CT provided sufficient resolution, data tran sfer via optical disk was practicable. Positioning of the navigation equipm ent required some experience and the registration of the patients head posi tion needed attention,as the markers have to be pointed at precisely. Durin g operation, the head tracking system must not change its position on the p atients head to ensure a correct navigation display. The main advantage of the computed navigation system was the constant orientation during the sinu s surgical procedure,frontiers and critical anatomical structures could be identified in the corresponding CT data set,thus enabling the surgeon to de cide on the further procedure. At present stage,the operation time was incr eased through the handling of the navigation system for at about 15 min, re sulting in additional time of narcosis. Conclusion: We found the computed navigation system Philips "NEUROGUIDE" sy stem to be an established technical aid, ready to use far ENT sinus surgery , in our cases with a precision between 1 and 3 mm. These results were simi lar to results obtained with a SPOCS Navigation System from Aesculap, as pr eviously published by us [17].