The importance of anatomic abnormalities as a cause of sinusitis remains an area of significant controversy, especially in the pediatric population. It is best to think of these anatomic structures as variants of normal, and not as abnormalities. This issue is of some importance because if anatomic variations are not associated with increased sinusitis, the cause of sinusitis is more likely to be systemic, and possibly more amenable to medical management. If the problem is more systemic, conservative surgical procedures may be adequate. The anatomy is most effectively assessed by computed tomography (CT) scans.

Most anatomic variations are found equally in control and sinusitis patients.22'23 There is convincing evidence that the incidence of anatomic variations increases with age.20 In general, anatomic variations are not associated with increased sinusitis24 and the incidence of anomalies is similar in diseased and control patients.22 The variations thought to be most likely associated with increased sinusitis are septal deviation, infraorbital cells, choncha bullosa, and a narrowed middle meatus or infundibu-lum. Jones et al.24 found no association between sinusitis and these anatomic variations in adults and children. Because the incidence of variations is low, their 100 cases may not be high enough to demonstrate an association.

Septal deviation increases with age. Septal deviation could cause narrowing of the middle meatus on the side of the deviation and be associated with an increased incidence of sinusitis. Elahi et al.25 found an association between a higher incidence of ostiomeatal complex (OMC) obstruction and sinusitis and increasing nasoseptal deviations. In children, the deviation is rarely significant enough to cause disease or warrant surgical intervention.

Infraorbital cells could easily close the natural maxillary ostium with increasing size. The incidence ranges form 5.2% in pediatric patients26 to 45.1% in adults.23 Stackpole and Edel-stein27 graded the size of infraorbital cells and correlated it with radiologic evidence of sinusitis. As the size of the infraorbital cell increased there was a higher incidence of maxillary sinusitis. In children, the bulk of the infraorbital cells are small and our data do not show a correlation.

A choncha bullosa could be associated with significant narrowing of the middle meatus and infundibulum. Once again the evidence is mixed. The incidence varies from 5.5%20 to 53%28 and the incidence increases with age.6 Calhoun et al.,29 Jorissen et al.,22 and Scribano et al.30 found the concha bullosa was associated with an increased risk of sinusitis. Lam et al.,31 Zinreich et al.,32 Tonai and Baba,33 Jones et al.,24 and Bolger et al.23 found no evidence of increased sinus disease with concha bullosa. Nadas et al.28 sized and defined the location of concha bullosa and correlated it with the incidence of sinusitis. These investigators found that the usually accepted hypothesis that the concha bullosa may contribute to the pathogenesis of inflammatory sinus disease seems doubtful.

The uncinate bulla is more common than is generally appreciated at about 12%.34 In children, it is not readily diagnosed. Studies looking at this variation and sinusitis have not been performed. Narrowing of the middle meatus on CT scan did not show a higher incidence of sinusitis.24 The exception to this is narrowing secondary to scarring of the middle meatus after surgery. In the pediatric patient the middle meatus is likely more prone to scarring because of the dimensions.

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