Paranasal sinus development in children: A magnetic resonance imaging analysis

Morphometric analysis of the maxillary sinus in patients with nasal septum deviation

The aim of this study was to evaluate the relationship between nasal septum deviation, which is common in the general population, and maxillary sinus volume. A retrospective assessment was made for 96 patients with nasal septum deviation without coexisting sinonasal morbidity and compared to 60 healthy individuals. A three-dimensional reconstruction of computed tomography images was used to assess a total of 312 maxillary sinus volumes. Septal deviation angles and volumes were also measured to standardize and determine the severity of the septal deviations. Septal deviations were right-sided in 36.5% of the cases (n = 35) and left-sided in 63.5% (n = 61). Deviation angles varied between 5° and 24.4°, with a mean value of 12.9 ± 5.0. The mean value for the deviation volume was 4.6 ± 1.5 cm(3) (range 1.7-9.4). The right and left maxillary sinus volumes were 11.8 ± 4.7 cm(3) and 11.5 ± 4.4 cm(3), respectively, in control group. Statistically significant discrepancy was observed between the ipsilateral and contralateral maxillary sinus volumes, in regard to the side of the septal deviation in study group. Maxillary sinus volumes were found to be significantly smaller on the ipsilateral side of septal deviation compared with the contralateral side.

Searching for the cheese: does ethmoid pneumatization affect the location of the anterior ethmoid artery?

Endoscopic sinus surgery is a widely used technique in otolaryngologic practice. To avoid complications, the locations of important anatomical structures, such as the anterior ethmoid artery (AEA), should be determined preoperatively. We want to evaluate the effect of ethmoid cavity pneumatization on the location of the AEA and to determine consistent landmark(s) for locating the AEA. 524 consecutive patients undergoing sinus CT scans between February and October 2012 were reviewed retrospectively. After the exclusion criteria were applied, 150 CT scans (300 sides) were selected for the study. A statistically significant positive correlation was found between ethmoid pneumatization and the distance of the AEA to the attachment of the inferior turbinate to the lateral nasal wall (Spearman's rho = 0.305; p < 0.001). Likewise, a statistically significant positive correlation was found between ethmoid pneumatization and the distance between the AEA and the frontonasal junction (Spearman's rho = 0.219; p < 0.001). We found that the artery was located mostly between the second and third lamellae [n 211 (71 %) cases]. There was no statistically significant correlation between ethmoid pneumatization and AEA location in terms of the lamellae. Increased ethmoid volume increases the distance of the AEA from the frontonasal junction and the lateral attachment of the inferior turbinate. However, increased pneumatization of the ethmoid cavity did not affect AEA localization in terms of the lamellae. Based on our findings, we suggest that using the lamellae to locate the AEA is reliable.

Sinus imaging for diagnosis of chronic rhinosinusitis in children

Chronic rhinosinusitis (CRS) is a relatively common disease in children but is often overlooked because at times the clinical symptoms are subtle and nonspecific. This makes imaging very important in the diagnosis. Among the different techniques, plain radiography has limited utility,whereas CT scan and MRI have a major role in evaluating the modifications caused by the disease. In particular, a CT scan provides higher resolution of bone and soft tissue and removes the overlapping structures that are present in conventional radiography. CT is recommended in isolated sphenoid sinusitis, is essential in diagnosing fungal sinusitis, and is the technique of choice when orbital complications are suspected. MRI allows investigation of not only the morphology of structures, but their intrinsic biophysical and biochemical properties, such as water content, cellular density, lipid or blood product deposits, and fibrosis. MRI allows better soft tissue differentiation and high spatial resolution images depicting fine details. When indicated, MRI with contrast gadolinium-based agents may better characterize the local disease extension or its diffusion beyond paranasal and nasal cavities and has excellent contrast resolution. A combination of CT and MRI is useful in cases of diagnostic difficulties,especially when complications are involved.

Three-dimensional morphometric analysis of paranasal sinuses and mastoid air cell system using computed tomography in pediatric population

OBJECTIVES

To evaluate the volumetric relationship between the mastoid air cell (MAC) and paranasal sinus (PNS) in the pediatric population using three-dimensional reconstruction and the analysis technique of CT.

STUDY DESIGN

Retrospective cross-sectional study was conducted at a university-based, secondary referral hospital.

METHODS

PNS CT imaging data of 62 children (40 boys and 22 girls; mean age=13.4 ± 4.0 years) was reconstructed to the three-dimensional model with the surface-rendering algorithm (lower threshold of -1024 HU and upper threshold of -318 HU), and subsequently measuring the volume of the three PNSs (frontal, maxillary and sphenoid) and MAC. Hierarchical linear regression analysis was used to control the effect of age.

RESULTS

Controlling the effect of age, no significant linear regression relationship was found between the volume of MAC and PNSs. It was observed that PNSs and MAC showed a significant linear relationship with age. The regression slopes of PNSs were larger than that of MAC, especially the growth of maxillary and sphenoid sinuses was faster and larger than that of the frontal sinus and MAC. As the coefficient of determination was extremely small, the aging process itself could not effectively explain the volume variation of PNSs and MAC.

CONCLUSION

No interaction was observed in the pneumatization of the three PNSs (frontal, maxillary, and sphenoid) and MAC. It was found that the growths of PNSs and MAC are influenced by age. Further, maxillary and sphenoid sinuses tend to grow faster and become larger than the frontal sinus and mastoid air cell system. Thus, it is verified that environmental factors could be involved in the postnatal pneumatization process of the PNSs and MAC, which might influence MAC to a greater extent than the PNSs.

Palatonasal recess on medial wall of the maxillary sinus and clinical implications for sinus augmentation via lateral window approach

BACKGROUND

Anatomic variations of the maxillary sinus determine the degree of difficulty in performing sinus augmentation. Whereas some variations, e.g., the septum and morphology of the sinus, have been extensively studied, the structure of the medial wall has never been investigated. The aims of this study are to measure the location and angulation of the palatonasal recess (PNR) on the medial wall and identify risk sites that are related to the shape of the PNR.

METHODS

Cone-beam computed tomography (CBCT) scans were screened from the University of Michigan School of Dentistry database. Edentulous sites with <10 mm between the floor of the maxillary sinus and the alveolar crest were selected. The residual ridge height (RH), the distance between the PNR and the alveolar crest, and the angulation of the PNR were measured on the selected sagittal planes. The percentage of sites (risk sites) with recesses that were <90° and <15 mm from the alveolar crest was calculated. The PNR location and angulation were compared among premolar and molar edentulous sites.

RESULTS

Two hundred seventy-four sites were studied. The mean ± SE PNR location was 14.2 ± 2.8 mm, 13.1 ± 2.2 mm, and 12.5 ± 2.5 mm for the second premolar, first molar, and second molar sites, respectively, with significant differences between the second premolar and second molar sites. The mean PNR angulation was 109.8° ± 25.3°, 121.6° ± 22.1°, and 144.9° ± 23.1° in the corresponding sites, with significant differences among the site groups. The respective percentages of risk sites were 15%, 8.2%, and 2.4% in the second premolar, first molar, and second molar sites.

CONCLUSIONS

Maxillary sinuses with acute-angled PNRs might present a challenge for performing sinus augmentation. Therefore, this anatomic structure should be carefully evaluated.