Nasal Dorsum Anatomy of Major Different Ethnicities-Surgical Implications: A Multicenter Radiologic Study.

[BACKGROUND] The heterogeneity of nasal features across different racial and ethnic groups is evident. This large-scale multicenter study was performed to evaluate the dorsal keystone area and its relation to superficial nasal anatomy through computed tomography (CT) scans.

[METHODS] Six populations were included: South Caucasian, Middle Eastern, Black South African, Eastern Asian, Mestizo, and Eastern European. Each center obtained CT scans performed between January of 2020 and December of 2022 from patients presenting a nasal hump and from an age- and sex-matched control group. Osteocartilaginous measurements in relation to ethmoidal point and to rhinion, as well as their relation to superficial nasal anatomy, were collected from nasal CT scans in midsagittal view. These were compared between populations and, in each center, between patient groups (nasal hump versus no nasal hump).

[RESULTS] The study population included 600 patients (254 with nasal hump) with a mean age of 33.98 years (range, 18 to 59 years); 55.6% were women. Average distances from the ethmoidal point were 10.1 ± 3.5 mm to the rhinion and 1.68 ± 0.23 mm to the beginning point of the nasal hump. In 96% of cases, the ethmoidal point was cranial or no more than 5 mm caudal to the beginning of the nasal hump. S-shaped nasal bones were associated with nasal hump, but angulation (kyphion angle) did not correlate with nasal hump height.

[CONCLUSIONS] In most patients, the nasal hump has no ethmoid bone underneath it, and the apex is located over the septal cartilage. The ethmoidal point is a reliable landmark and should be considered when evaluating established and new preservation and structural rhinoplasty approaches.