The present study aims to compare ethmoid, sphenoid and maxillary sinus volumes of patients with maxillary deficiency requiring Le Fort osteotomy with healthy patients, by employing computed tomography imaging. No accessible information could be found on this subject during literature search. The authors believe anatomical knowledge of these structures in patients with maxillary deficiency will influence all branches performing surgeries in these areas.

The anatomy of the paranasal sinuses is important for many surgeon groups. The precise knowledge of such structures with variable anatomy will be important for the preservation of these structures and the management of complications in surgeries such as endoscopic sinus surgery and osteotomies involving the maxilla such as Le Fort osteotomies. The maxillomandibular complex is often affected by developmental problems and growth problems, and unilateral, bilateral, horizontal, vertical and / or transverse deficiencies are observed. Treatment of this complex is often performed by surgical intervention involving one or both jaws. In surgeries involving the maxilla, maxillary sinuses are affected by the surgery and affect the course of surgery. Paranasal sinuses are also very important structures for closely related endoscopic sinus surgeries. Detailed preoperative investigation is crucial for patient selection and hence desired outcome. Study was conducted in Ankara University Faculty of Dentistry with Ethical approval number:08/03. Computed tomography scans of 120 patients (59 maxillary deficiency patients and 61 healthy controls) were included in the study. CT scan indications for the group with maxillary deficiency was surgical preparation for Le Fort I osteotomy. The control group had no maxillary deficiency and CT images were obtained for several reasons such as temporomandibular disease, preparation for orthodontic treatment, obstructive sleep apnea and also paranasal sinus imaging Patients with a history of trauma in the midline skull base were excluded. Statistically significant results were obtained between groups for ethmoid and maxillary sinus volumes (left and right). Ethmoid and maxillary sinus volumes (left and right) were smaller in the Le Fort group. No statistically significant differences were present for sphenoid sinus volume of two groups and for the left and right maxillary sinus volumes in both groups.

Inclusion Criteria for the study group:

- Maxillary deficiency (CT scans involving the head and paranasal sinuses, obtained for Le Fort I osteotomy).

Inclusion Criteria for the control group:

-Healthy patients. (CT scans involving the head and paranasal sinuses, obtained for several reasons such as temporomandibular disease, preparation for orthodontic treatment, obstructive sleep apnea and also paranasal sinus imaging, no maxillary deficiency).

Exclusion Criteria: Patients with a history of trauma in the midline skull base were excluded.

Study population consisted of 58 male and 62 female participants, aged between 18-69.