Article
Controlled trepanation of the frontal sinus by using intraoperative navigation
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Published: | September 22, 2005 |
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Introduction: Most of the surgical interventions of the anterior skull base can be performed via endonasal approach due to the development of endoscopic and microscopic techniques. But extensive pathologies require extranasal approaches, e.g. the bicoronal incision with good functional and cosmetic results, first published by Unterberger in 1953. The high complication rate of 18 to 33% is caused by the variable anatomy of the frontal sinuses.
Material and methods: We report on eight surgical procedures via bicoronal incision which were performed by using an intraoperative electrooptic navigation system (VectorVision², BrainLAB, Germany). Patients were seven men and one woman (mean age 54,6 ys.) with the half of them suffering from a chronic sinusitis with mucocele. Two had osteomas and two patients inverted papillomas.
The frontal sinuses were manually segmented in the preoperative dataset. An invasive skull-mounted adapter (Laterostern) attached behind the intended line of incision was used for referencing. Registration was done with the laserscanner z-touch. Intraoperatively, the borders of the frontal sinus were identified via straight pointer an marked onto the calotte with a safety margin of 2 mm. Afterwards the cap was prepared with an oscillating saw starting from a previously drilled hole of 2mm diametre. After resection of the underlying pathology the cap was reinstalled an fixed by sutures in 6 cases of osteosynthesis material in two cases.
Results: We noted no complications during these procedures, the average navigation precision was 1.4 mm as estimated by anatomical landmarks. The surgeons classified the use of the navigation system as "helpful" in three cases and "necessary" in five cases. Except for one patient all are free of relapse with a postoperative period of 9 to 23 months.
Dicussion: None of the patients showed exposition or damage of the dura or orbital structures. Sindwani et al. reported on a similar study with 15 patients and they also did not see any complications. Therefore we conclude that the use of an intraoperative navigation system is an indispensible tool in extranasal frontal sinus surgery via bicoronal incision and increases the clinical benefit for the patient.