The Intersinus Septal Cell: Anatomic, Radiologic, and Clinical Correlation

Abstract

Functional endoscopic frontal sinus surgery requires detailed knowledge of intranasal anatomy. Occasionally frontal sinusitis involves the intersinus septal cell (ISSC), which has not been described in the modern era of nasal endoscopy and computed tomography (CT). To study the ISSC, we reviewed 300 CT scans: 200 clinical and 100 cadaveric. We found ISSC in 70 (35%) of clinical scans, with six subjects having multiple ISSC. The cadaveric prevalence was slightly less at 31%. We further classified the ISSC according to the following criteria: type I, enclosed completely within the thin intersinus septum or bridging its entire inferior-superior extent; type II, bordered partially by this thin septum and partially by the thick septal base formed by the nasofrontal bone; type III, enclosed completely within the nasofrontal bone, often extending between frontal recesses rather than the actual sinuses. This report supplements our radiologic ISSC analysis with our experiences in five clinical cases.