[Development of the spheno-ethmoid paranasal sinus system using axial computerized tomography imaging].

BACKGROUND

Exact knowledge of age- and sex-related development of the paranasal sinuses is essential to assess their role in infantile diseases in the midface region. Moreover it helps to minimize the risk in case of therapeutic intervention.

METHODS/PATIENTS: On the basis of more than 5600 axial computed tomographic images (CT images) we evaluated the sex-related size (width and length) and evidence of the different sinuses from birth to age 25 focussing on the central part of the paranasal sinuses, the ethmoidal cells, and the sphenoidal sinuses.

RESULTS/CONCLUSIONS: The sphenoethmoidal complex is of special interest in early ages since it is already completely developed in newborns (ethmoidal cells: 94% for both sexes) or at least shows a rapid development during the first decade. After age 8, both sinuses are almost regularly represented on CT with identical percentages as an indication of common origin. This is confirmed by only slight differences in size between the two sexes (ethmoidal cells: 5,7 - 10,1%: sphenoid sinuses: 5,4-9,7%) after termination of expansion and by similar periods of expansion (ethmoid cells: until age 10, female, to 14, male and female in length; sphenoidal sinuses: until age 14, female, to 15, male and female) which partly differ from the other sinuses. However, the difference between male and female sinuses is statistically significant primarily at later ages (age 25: length of sphenoidal sinuses: p < 0.0001/width of ethmoidal cells: p = 0.0117/length of ethmoidal cells: p = 0.0072). The definitive size of the ethmoidal cells (male: width 16.4 mm x length 40.7 mm: female: 14.9 mm x 38.5 mm) agrees with the results obtained from anatomic and radiologic studies. In contrast, we found substantial variability in both directions (up to 214%) for the sphenoidal sinuses. Since on almost 60-70% of the CT images the intersphenoidal septum was not represented, we can provide more detailed data about the whole sphenoidal complex (male: width 31.0 mm x length 24.5 mm; female: 29.4 mm x 26.9 mm). In conclusion, our findings agree with the data from other studies using different methods. Moreover we can determine size of the different sinuses at any time between birth and age 25 for both sexes. The ethmoidal cells and the sphenoidal sinuses are highly significant in early infantile paranasal sinus diseases.