Anatomic Variations of the Frontal Recess and Frontal Sinusitis: Computed Tomographic Analysis

ABSTRACT

BACKGROUND AND OBJECTIVES: The frontal recess (FR) cells, including the frontal cell (FC), agger nasi cell (ANC), supraorbital ethmoid cell (SOC) and inter-frontal sinus septal cell (IFSSC), can interfere with the drainage system of the frontal sinus. We evaluated the relationship between the FR cells and the frontal sinusitis. SUBJECTS AND METHODS: All paranasal sinus CT scans performed from July 2004 through June 2005 were reviewed. Of the 675 scans reviewed, 317 patients (634 sides) were selected for data collection. Exclusion criteria included a clinical history of neoplasms, bony deformities, and extensive disease responsible for obscuring the bony anatomy. Similarly, CT scans with severe artifacts were also excluded. RESULT: FCs were present in 21.9% of the patients. According to the Bent's classification, the prevalence of each FC type was as follows; type 1 FC (13.6%), type 2 FC (3.2%), type 3 FC (1.9%) and type 4 FC (3.1%). Of the four types of FR cells, type 4 had a significant association with frontal sinusitis. The incidence of hyperpneumatized frontal sinus, ANC, SOC, IFSSC were significantly higher among patients with the FC than those without the FC (p<0.05). Patients without the ANC or with type 1 uncinate process, according to Stammberger's classification, displayed a higher frequency of frontal sinusitis (p<0.05). There was a statistically significant decrease in the frequency of frontal sinusitis among patients with hypopneumatized frontal sinus (p<0.05). CONCLUSION: In our series, the frontal sinusitis was influenced by each types of FC, attachment sites of uncinate process and the degree of frontal sinus pneumatization. Therefore, these anatomic variations in the frontal recess should be appropriately addressed during the surgical management of the frontal sinusitis.