Preliminary Deformational Studies on a Finite Element Model of the Nasal Septum Reveals Key Areas for Septal Realignment and Reconstruction

Background. With the current lack of clinically relevant classification methods of septal deviation, computer-generated models are important, as septal cartilage is indistinguishable on current imaging methods, making preoperative planning difficult. Methods. Three-dimensional models of the septum were created from a CT scan, and incremental forces were applied. Results. Regardless of the force direction, with increasing force, the septum first tilts (type I) and then crumples into a C shape (type II) and finally into an S shape (type III). In type I, it is important to address the dislocation in the vomer-ethmoid cartilage junction and vomerine groove, where stress is concentrated. In types II and III, there is intrinsic fracture and shortening of the nasal septum, which may be dislocated off the anterior nasal spine. Surgery aims to relieve the posterior buckling and dislocation, with realignment of the septum to the ANS and possible spreader grafts to buttress the fracture sites. Conclusion. By identifying clinically observable septal deviations and the areas of stress concentration and dislocation, a straighter, more stable septum may be achieved. 1. Introduction Nasal septal deviation is a common nasal deformity. It can be a congenital disorder or a consequence of nasal trauma. Deviation of the bony or cartilaginous component of the nasal septum from the midline leads to its deviation. This results in external nasal deformity, internal nasal obstruction due to nasal airway constriction, or a combination [1–3]. Presently, septal deviation classification has largely been descriptive, based on nasal septal geometry and relationships between the bony and cartilaginous septa [4–7]. Jang et al. [6] presented a simplified classification of nasal deviation and the associated treatment outcome into five types based on the orientation of the bony pyramid and the cartilaginous vault. Jin et al. [7] presented a four-category classification of septal deviation based on the morphology, site, severity, and its influence on the external nose. Buyukertan et al. [4] reported a morphometric study of nasal septal deviation by separating the nasal septum into 10 segments. They concluded that the system would constitute a new, objective, simple, and practical classification system. I. Baumann and H. Baumann [8] argued that the existing nomenclatures of septal deviation only dealt with nasal septum deformation exclusively and were rarely used in routine clinical work. They instead presented a method for the classification of septal deviations based upon the anatomical