Evaluation of the bone resistance of the sphenoid and ethmoid sinuses.

Functional endoscopic sinus surgery can be associated with iatrogenic complications. Some anatomical structures have been identified this clinically as specific danger sites. The aim of this study was to confirm and to compare these clinical data with measurements of the bone resistance of the sphenoid and ethmoid walls and to point out regions that have increased bony fragility. Critical dynamometric evaluation of the resistance to breakage of these bony structures was made on 21 anatomic specimens. This study allowed the authors to localization of surgical complications, to demonstrate that other regions renowned for their fragility can be relatively robust, and to point out that robust sites can be dangerously fragile as a result of individual morphological variations. Results from this study provide a supplement to the guidelines for novice surgeons to use in identifying dangerous areas.