Orientation of the premaxilla in the origin of septal deviation

While most people believe the nasal septum to have intrinsic deviation and overgrowth in patients seeking rhinoplasty, an alternative concept is that a mal-oriented premaxilla causes extrinsic septal buckling and external extrusion of the septal cartilage. In this sense, the premaxillary bone plays a significant role in the pathogenesis of septal deviation. This study was performed to determine if non-traumatically acquired septal/nasal functional and aesthetic pathology or septal deviation may be related to the orientation of the premaxilla relative to the skullbase.

A retrospective, single-center study of patients in the general population who underwent maxillofacial CT scans and presented for the evaluation of nasal obstruction. CT scans were used to measure features of both pathologic and non-pathologic nasal septums.

A total of 68 subjects were evaluated. When comparing patients with a premaxillary-skullbase angle of greater than 81° (the mean of the study group) to those of less than 81°, and a more obtuse nasolabial angle was observed (p = 0.0269). When comparing the extremes of premaxillary rotation, specifically, greater than 87° (mean 91.7°, SD 5.1) and less than 77° (mean 70.7°, SD 3.6), the differences were more pronounced with regard to caudal septal excess (p = 0.0451) and septal deviation in the axial plane (p = 0.0150).

Septal developmental changes may involve an overly rotated or more vertically oriented premaxillary bone relative to the skull base. An understanding of the cause of septal deformity may provide insight into the design of improved treatments.