Clinically Significant Variation of Paranasal Sinuses on CT-Scan

Abstract

Anatomical variations are not diseases and can be found in every individual. Due to the anatomical variations, the structural changes occur in nearby anatomical relations. By keeping in mind, the vast range of anatomical variations in nasal cavity and paranasal sinuses (PNS), every case of sinusitis must be planned carefully to avoid dreadful complications of surgical procedures. Sinus anatomical variations have been associated with the etiology of sinusitis. In this regard computed tomography (CT) imaging has become an important diagnostic tool. CT Scan imaging of nose and para nasal sinuses is mandatory in patients with history of sinusitis in order to evaluate the detailed anatomy which includes normal anatomy, anatomical variations, bony details and the extent of the disease pathology. Certain anatomical variants are supposed to be a causative factor for development of sinus pathology and hence it becomes compulsory for the radiologist to be aware of the anatomical variants of nasal cavity and PNS especially if the subject is considered for surgical intervention.

Sinonasal Anatomical Variations in Patients With Chronic Rhinosinusitis

“…According to Stammberger and Hawke [4], CT scan of the paranasal sinuses will offer a surgical road map of the nose and paranasal sinuses to determine the existence of substantial anatomic anomalies -which may predispose the patient to chronic or recurring acute rhinosinusitis attacks. Some anatomical variations are surgically risky and can predispose neurovascular structures associated with the paranasal sinuses, such as the optic nerve and the internal carotid artery, to a fatal injury during endoscopic sinus surgery [5]. Understanding these anatomical variances is therefore critical in designing endoscopic sinus and endoscopic skull base procedures.…”

Relationship between sinonasal anatomical variations and symptom severity in patients with chronic rhinosinusitis

“…The common anatomical variants identified in humans include Agger nasi, concha bullosa, Haller cell, Onodi cell, septal deviation, pneumatized uncinate process, and paradoxical middle turbinate. [ 7 8 ] Definition of some anatomical variants is described below: Agger nasi cells are variant of ethmoidal cells located in the anterior superior portion of the middle turbinate and can obstruct the frontal recess. Concha bullosa is the pneumatization of the middle turbinate and can obstruct drainage of osteomeatal complex.…”

“…The role of these anatomical variants in the etiopathogenesis and exacerbation of chronic rhinosinusitis is still debated. [ 9 10 ] Some studies have implicated anatomical variants in the etiopathogenesis of chronic rhinosinusitis,[ 8 11 ] whereas others have identified no statistically significant link between anatomical variants and the development of chronic rhinosinusitis. [ 12 13 ] Furthermore, studies have shown that the prevalence of these anatomical variants is not significantly higher in patients with chronic rhinosinusitis than the general population.…”

“…Some anatomical variants are surgically dangerous and can predispose the neurovascular structures related to the paranasal sinuses such as optic nerve and the internal carotid artery to a fatal injury during endoscopic sinus surgery. [ 8 ] Therefore, understanding these anatomical variations is vital in planning for endoscopic sinus and endoscopic skull base surgeries. To understand the details of the anatomical variations and to determine the extent of disease within the paranasal sinuses, computed tomography (CT) scan is required.…”