Radiological assessment of the lateral osteotomy line-lacrimal system distance on three-dimensional models.

[AIMS] One of the most commonly performed operations in aesthetic, plastic, and reconstructive surgery is rhinoplasty, the aim of which is to construct an altered nasal shape, either for aesthetic or functional reasons. The lateral osteotomy is the most traumatic step of rhinoplasty, and is generally difficult to perform. The lacrimal system can be damaged during the lateral osteotomy procedure. In this study, we aimed to measure the distance between the lacrimal system and the lateral osteotomy line, and to determine the safe and ideal osteotomy level, which is very important in rhinoplasty procedures. We also evaluated the safe relationship of this osteotomy level with the lacrimal system by constructing a three-dimensional model.

[MATERIALS AND METHODS] The three-dimensional models were constructed on axial planes using paranasal computed tomographic (CT) images of 40 male and 40 female patients. The 'lateral osteotomy model' was designed in three dimensions. The axial CT images were obtained from the model. On the CT images, the distance between the lateral osteotomy line and the lacrimal system was assessed by measuring three distances. The first was the distance between the anterior lacrimal crest and the lateral osteotomy line. The second was the distance from the midpoint between the anterior lacrimal crest and the inferior meatus to the lateral osteotomy line. The third was the distance between the opening of the lacrimal canal to the inferior meatus and the lateral osteotomy line.

[RESULTS] No lacrimal system injury was seen on any of the models. The shortest distance was found between the anterior lacrimal crest and the lateral osteotomy line, measured at 4.5 mm and 5.0 mm in the female and male patients, respectively.

[CONCLUSION] Performing the lateral osteotomy meticulously while paying attention to remaining anterior to the medial canthal ligament will not lead to any lacrimal system injury.