Discussion
The nasal cavity and paranasal sinuses (frontal, ethmoid, sphenoid and
maxillary sinuses) form an anatomical and functional unit covered by the
same mucosa. The drainage of these sinuses is from small and narrow
openings into the nasal cavity. 3 While early on, the
aeration of these sinuses was detected by anatomical measurements,
cadaver studies and conventional radiography, today detection is
performed with CT imaging (Computerized tomography) with evaluation in
all sections and provides more accurate data. 7
Cavalieri method is an effective method used to calculate the volume of
anatomical structures. It is used to measure the volumes on 3D
radiographs of structures that cannot be isolated. In this method, the
object whose volume is to be calculated is divided into sections of the
same thickness on the radiograph. In these sections, the area of the
relevant object is calculated by using the planimetry or the point
counting methods. The total volume is calculated by multiplying the
calculated total area with the section thickness. 8Although the Cavalieri method has been used frequently for calculating
volumes of anatomic structures. Today, different workflows have been
determined with newly developed software and the volumes of anatomic
structures are now calculated with these software. In the present study
the method used by Tretiakow et al. has been employed for volume
calculation. 9 After image acquisition, axial,
coronal, and sagittal planes were generated by the software and the
segmentation process was navigated and inspected. The “threshold”,
“scissors”, “islands”, “level” and “smoothing” tools were used
respectively and paranasal sinus volumes were calculated.
The complex structure and pneumatization of the paranasal sinuses have
been evaluated in numerous studies in different populations and both
patient groups with underlying sinus diseases and non-diseased patients
have been reported to have considerable anatomic variations.7, 10-12 The same data were also widely investigated
before and after different non-surgical and surgical interventions for
various pathologic conditions. 4, 8, 13-18 Changes in
paranasal sinus morphologies are often varying degrees of hypoplasia,
and it has been observed that the formal configurations are commonly
preserved. This situation has been reported in genetic syndromes that
cause growth center arrests, interval pressure alterations and
osteonecrosis. 10 Shape asymmetries are frequently
reported among CLP (cleft lip and palate) human fetuses. Especially the
sphenoid sinuses can vary in shape and size. It has been also shown that
the maxillary sinuses of CLP fetuses are insufficient in size compared
to fetuses without CLP. 1
Le Fort I osteotomy is one of the techniques among subspecialties of
maxillofacial surgery and enables to treat dentofacial deformities of
the midface. In this technique, temporary disconnection of the complete
maxilla from the midface is required. While it enables to move the
maxilla in three dimensions superior repositioning of the maxilla is
typically necessary in the maxillofacial deformity treatment with a
vertical maxillary excess, such as cases of long face, open bite, or
mentum protrusion. 8 Studies investigating the anatomy
of paranasal sinuses before and after Le Fort I osteotomy are great in
number. It has been reported that the impact of Le Fort I osteotomy on
the upper airway spaces depends on the amount and direction of the
skeletal movements, age, gender, and individual variations, and that Le
Fort I osteotomy can have an important impact on sinus health.15,16 The volume of maxillary sinuses increases
compared to that of the pre-surgery and there are reports of possible
complications after Le Fort I osteotomy such as causing or aggravating
pre-existing maxillary sinus inflammatory processes such as acute
sinusitis, the incidence of rhinosinusitis symptoms and iatrogenic
damage. 13,16,18