Excerpt from Sinusitis, Sphenoid, Acute, Surgical Treatment

Synonyms, Key Words, and Related Terms: acute sphenoiditis, acute sphenoid sinusitis

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Acute sphenoid sinusitis is relatively uncommon; comparatively, chronic sphenoid sinusitis is more common. Signs and symptoms are often subtle; therefore, the diagnosis can be difficult to make. However, early diagnosis and treatment are essential because the disease can be rapidly progressive and complications can be devastating. Complications arise from the relationship of the sphenoid sinus to vital vascular, neurologic, and optic structures. Treatment is initially medical; surgery is reserved for unresponsive disease and impending complications. Surgical treatment involves opening the sphenoid sinus, establishing drainage, and obtaining material for culture. Endoscopic methods of sphenoidotomy are now accepted, and several approaches have been described. Open approaches, including an external ethmoidectomy or transseptal approach, can also be used. The outcome of sphenoid sinusitis is highly dependent on the speed of diagnosis.

History of the Procedure: The sphenoid sinus has been described as the forgotten sinus or neglected sinus because of its anatomical location and the difficulty in diagnosing disease there. Diseases of the sphenoid often were determined only when complications arose. With the advent of modern imaging techniques and a higher index of suspicion, diseases of the sphenoid are much more easily found and treated. Modern imaging, antibiotic, and surgical options have changed the presentation and, often, the treatment of acute sphenoid sinusitis.

Problem: According to the American Academy of Otolaryngology—Head and Neck Surgery (AAO-HNS) task force on rhinosinusitis, sinusitis is defined as an inflammatory response involving mucous membranes of the nasal cavity and paranasal sinuses, fluids within these cavities, and/or bone. The condition is classified as acute if it persists for 4 weeks or fewer. In contrast, a subacute infection is defined as lasting 4-12 weeks, and a chronic infection persists for more than 12 weeks.

When this inflammatory response occurs in the sphenoid sinus, the result is sphenoid sinusitis or sphenoiditis. The disease may be limited to the sphenoid sinus or, more commonly, may involve multiple sinuses or pansinusitis.

Frequency: Sphenoid sinusitis often occurs in the context of pansinusitis. In the preantibiotic era, Teed reported an incidence of sphenoid involvement of 33% in patients with pansinusitis. A 1977 study by Wisberger and Dedo suggested that in the antibiotic era, incidence decreased to 8%. Isolated sphenoid sinusitis is much less common. Lew reported a 2.7% incidence in patients hospitalized for sinusitis in a 12-year period. Of these incidences, only one half had acute disease. Hnatuk et al suggest that the incidence is actually much lower, and that sphenoid sinusitis represents fewer than 1% of all cases of sinusitis.

Etiology: The microbiology of acute sphenoid sinusitis differs from that of uncomplicated maxillary sinusitis. Whereas maxillary sinusitis is caused predominantly by Streptococcus pneumoniae, Haemophilus influenzae, and Moraxella catarrhalis, sphenoid sinusitis has a different profile. Gram-positive organisms predominate, with Staphylococcus aureus most common, followed by Streptococcus pneumoniae. Chronic sphenoid sinusitis can be caused by both gram-negative and gram-positive organisms, anaerobes, and mixed flora, which are more common. Fungal disease also must be considered, especially in the context of a patient who is immunocompromised.

Pathophysiology: The pathophysiology of sphenoid sinusitis involves blockage of sinus ostia and impaired mucociliary clearance leading to stasis and secondary bacterial infection. Several predisposing factors have been implicated. Anatomic differences include variations in the position of the intersinus septum and small or abnormally placed ostia. .....