[Anatomic variations of the sinuses; multiplanar CT-analysis in 641 patients].

INTRODUCTION

The diagnostic workup proceeding paranasal sinus surgery routinely includes coronal CT views to get an exact representation of the microanatomy in the region of the lateral nasal wall and the anterior skull base. Axial and sagittal views are often not available, yet they can provide important additional information.

STUDY DESIGN AND METHODS

It was the aim of the current study to analyse multislice CT data sets in order to determine the incidence of anatomical variants. The investigation was performed as a retrospective, monocentrical study on n = 641 patients. Prior paranasal sinus surgery was defined as the sole exclusion criterion.

RESULTS

The analysis of the data showed the following anatomical variants of frontoethmoidal cells: Kuhn Typ I: 17.0 %, Typ II6.8 %, Typ III: 12.5 %, Typ IV: 0.1%. The prevalence for Agger nasicells was 80.0 %, that for supraorbital cells was 10.2 %, that for suprabullar cells was 28.2%, that for frontal bullae was 16.0% and the one for cells of the interfrontal septum was 11.9 %. The incidence of other anatomical variants was as follows: Concha Bullosain 22.2 %, Haller cells in 16.0 %, pneumatised Uncinate Process in 8.8% and Onodi Cells in 8.4 %.

CONCLUSIONS

A multiplanar reconstruction of the frontoethmoidal complex with its numerous variants is essential in the preoperative workup of patients with conditions of the frontal sinus. This advantage can even be enhanced by using navigation systems, even though they are not available for every rhinosurgeon yet. However, navigation systems should not be considered as a surrogate for lacking anatomical knowledge.