Relationship Between Maxillary Sinus Hypoplasia and Maxillary Occlusal Cant: A Cone Beam CT Study

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Prevalence of Maxillary Sinus Hypoplasia and Silent Sinus Syndrome: A Radiological Cross-Sectional Retrospective Cohort Study

Background Maxillary sinus hypoplasia (MSH), associated with enophthalmos and hypoglobus in the silent sinus syndrome (SSS), is a poorly studied condition. The real incidence of MSH and SSS in the adult population is not known. Our study aims at estimating the radiological prevalence of MSH and identifying undiagnosed cases of SSS in a retrospective cohort. Methods A cross-sectional retrospective cohort study was performed in adults, without a history of maxillofacial surgery or trauma, undergoing head CT scans. A radiological database of 1012 consecutive scans was reviewed independently by two authors to identify patients with signs of MSH and SSS and associated findings (septal deviation, uncinate deviation, concha bullosa, sinus opacification, bony rarefaction, and pterygopalatine fossa enlargement). The findings of MSH and SSS were compared with radiological reports. Results 891 eligible CT scans were analyzed. MSH and SSS prevalences were 6.17% (n = 55) and 0,56% (n = 5), respectively. The maxillary sinus was normally or partially ventilated in 96.36% of MSH patients. Lateralization of the uncinate process was detected in about 50% of MSH patients, while a septal deviation towards the affected sinus was detected in 21.82%. In 20% of MSH scans, a concha bullosa was identified. Radiological reports identified a single MSH case. Conclusions Our study confirmed the literature data on MSH prevalence, while it determined a precedently unknown prevalence for SSS, underestimated in the radiology reports. This prevalence needs further confirmation but suggests a routine accurate comparison of both maxillary sinuses in CT scans.

Relationship Between Maxillary Sinus Hypoplasia and Maxillary Occlusal Cant: A Cone Beam CT Study

Background: maxillary sinus hypoplasia (MSH) has been reported to cause a cant in the orbital plane. No similar reports exist about the possible impact on the maxilla. The aim of this study was to assess if MSH is associated with maxillary occlusal plane (MOP) cant, and if dental or mandibular factors influenced the existence of the MOP cant. Methods: 80 cone beam CT images of subjects with MSH were analyzed for type of MSH, degree of MOP cant, open or cross bite, mandibular asymmetry, and degenerative joint disease of the temporomandibular joints. The subjects were compared with a control group matched by age and gender. Results: The degree of MOP cant (range 0-5.1°) was not statistically significantly different in unilateral vs bilateral MSH, or between the different types of MSH. The frequency of open bite, crossbite, mandibular asymmetry, or degenerative joint disease in unilateral vs bilateral MSH, or between the different types of MSH was not statistically significantly different. Between the case and control, there was no statistically significant difference in the degree of MOP cant (1.3±1.1° vs 1.1±0.9°, respectively), or frequency of dental and mandibular factors. There was low positive linear correlation between MOP cant and mandibular symmetry in MSH subjects (Spearman’s rho= 0.23) and controls (Spearman’s rho= 0.187). Conclusions: The data suggests a view of the alveolar bone as the adaptable skeletal unit to ensure and bridge the functionality between the nasomaxillary complex and TMJ system – two systems with very different function, and therefore largely independent “matrix units”.

Assesment of Prelacrimal Recess in Patients With Maxillary Sinus Hypoplasia Using Cone Beam Computed Tomography

Background The prelacrimal recess approach, is frequently preferred in creating a minimally invasive surgical corridors. Objective The aim of this study was to evaluate the Prelacrimal recess (PLR) anatomy using Cone Beam Computed Tomography in patients with Maxillary Sinus Hypoplasia. Methods The paranasal Cone Beam Computed Tomography series of 84 adults were analyzed retrospectively. The antero-posterior and mesio-distal widths of the PLR and the antero-posterior width of the naso-lacrimal duct were measured. The patients were divided into three groups according to the antero-posterior width of PLR to evaluate the feasibility of prelacrimal recess approach as Type 1 (0-3 mm), Type 2 (>3–7 mm) and Type 3 (>7 mm). Results The mean antero-posterior width of PLR was 3.11 ± 1.49mm in the patients and 4.77 ± 1.76 mm in the controls. The mean mesio-distal width of PLR was 7.64 ± 1.49 mm in the patients and 3.17 ± 2.05 mm in the controls. The mean antero-posterior width of naso-lacrimal duct was 9.58 ± 2.80 mm in the patients and 9.46 ± 2.42 mm in the controls. Conclusions The width of the antero-posterior PLR in patients with Maxillary Sinus Hypoplasia was found to be significantly lower in comparison to individuals with normal maxillary sinuses in the measurements performed on paranasal Cone Beam Computed Tomography scans. Hence, while planning a Functional Endoscopic Sinus Surgery with prelacrimal recess approach for maxillary sinus, the anatomical structure of the naso-sinusoidal region should be carefully analyzed, and individual anatomical variations such as Maxillary Sinus Hypoplasia should not be ignored.