The ‘ridge’—A safer entry to the sphenoid sinus during functional endoscopic sinus surgery in children

Abstract

Otolaryngologists may be required to enter the sphenoid sinus for a variety of reasons. Infections are certainly the most common cause for such invasive procedures and include pansinusitis, isolated sphenoid mucopyoceles or mycetomas, or suspected neoplasms. A variety of techniques are described for sphenoid entry, but none are recognized as completely safe or without risk l-5 We have identified two anatomic landmarks not previously described that direct the surgeon towards a safer approach to the sphenoid sinus using functional endoscopic sinus (FES) surgery techniques. This approach preserves the functional concepts of identifying and enlarging the natural ostium without destroying normal mucociliary flow patterns. FES surgery has proven to be an effective method for treating patients afflicted with medically recalcitrant chronic sinusitis. Even though surgical visibility is substantially improved with the use of sinus endoscopes, entry into the sphenoid sinus remains a very precarious portion of the procedure. The location of the vital anatomic structures behind the anterior sphenoid wall is variable. The internal carotid artery may be located immediately behind the wall, or may be essentially dehiscent, with a very thin bony wall offering only minimal protection from the surgeon’s encroachment. The optic nerve is often visualized in the anterior portion of the superiolateral quadrant with varying degrees of protrusion into the sphenoid sinus. The optic nerve also may be minimally protected by a very thin bony covering. Although the pituitary gland and maxillary division of the trigeminal nerve are seldom injured, both must be given proper attention to avoid injury. Precise identification of the anterior sphenoid wall also can be a challenge. There is often confusion as to whether or not a visualized bony structure is a septation of the posterior ethmoid cells, the anterior wall of the sphenoid, or the posterior wall of the sphenoid. The potential for injury to vital surrounding structures is increased when performing sphenoidotomies in children. We have identified two previously undescribed endoscopic anatomic landmarks, and have developed a new technique that has consistently permitted a safer entry