Radiological anatomy of hypoplastic sphenoid sinuses

The degree of pneumatization of the sphenoid sinus varies in different individuals, including the absence of air cavities in the body of the bone or their hypoplasia. Such options are quite rare, they should be considered when planning and choosing a method of surgical treatment. Objective. To classify sphenoid sinuses of unusual size and shape. Patients and methods. The data of cone-beam computed tomography of 16 patients aged 22 to 70 years with dental and ENT pathology, who had an unusual size and shape of the sphenoid sinuses, were studied in order to classify them. On axial scans, the maximum transverse size (width, diameter) of the sinus was measured. On parasagittal scans, the position of the posterior wall of each sphenoid sinus relative to the sella turcica was assessed, and the distance to the plane drawn through the anterior wall of the sella turcica was also measured. Results. There were 13 cases of unilateral and 3 cases of bilateral hypoplasia of the sphenoid sinus. Bilateral hypoplasia is a rare variant of individual variability. With unilateral hypoplasia, the contralateral air cavity may not extend beyond the body of the sphenoid bone or extend into other parts of it or adjacent structures. Conclusion. When diagnosing unilateral hypoplasia of the sphenoid sinus, one should not only consider its distance from the anterior wall of the Turkish saddle but also correlate the absolute dimensions of the two air cavities.